mybatis-plus拦截器、字段填充器、类型处理器、表名替换、SqlInjector(联合主键处理)

最近有个练手的小例子,大概就是配置两个数据源,从一个数据源读取数据写到另一个数据源,虽然最后做了出来,但是不支持事务。。。就当是对mybatis-plus/mybatis组件使用方式的记录吧,本次例子使用的仍是mybatis-plus

回忆一下mybatis核心对象:

  • Configuration 初始化基础配置,比如MyBatis的别名等,一些重要的类型对象,如,插件,映射器,ObjectFactory和typeHandler对象,MyBatis所有的配置信息都维持在Configuration对象之中
  • SqlSessionFactory SqlSession工厂
  • SqlSession 作为MyBatis工作的主要顶层API,表示和数据库交互的会话,完成必要数据库增删改查功能
  • Executor MyBatis执行器,是MyBatis 调度的核心,负责SQL语句的生成和查询缓存的维护
  • StatementHandler 封装了JDBC Statement操作,负责对JDBC statement 的操作,如设置参数、将Statement结果集转换成List集合。
  • ParameterHandler 负责对用户传递的参数转换成JDBC Statement 所需要的参数,
  • ResultSetHandler 负责将JDBC返回的ResultSet结果集对象转换成List类型的集合;
  • TypeHandler 负责java数据类型和jdbc数据类型之间的映射和转换
  • MappedStatement MappedStatement维护了一条<select|update|delete|insert>节点的封装,
  • SqlSource 负责根据用户传递的parameterObject,动态地生成SQL语句,将信息封装到BoundSql对象中,并返回
  • BoundSql 表示动态生成的SQL语句以及相应的参数信息

组件介绍

拦截器

mybatis可以在执行语句的过程中对特定对象进行拦截调用,主要有四个

  • Executor (update, query, flushStatements, commit, rollback, getTransaction, close, isClosed) 处理增删改查
  • ParameterHandler (getParameterObject, setParameters) 设置预编译参数
  • ResultSetHandler (handleResultSets, handleOutputParameters) 处理结果
  • StatementHandler (prepare, parameterize, batch, update, query) 处理sql预编译,设置参数

这四个是可以拦截的对象,大概的做法是实现mybatis拦截器的接口并在上面添加注解来确定拦截那些方法

下面是接口Interceptor所要实现的方法,setPropertites可以用来初始化,而plugin则包装目标对象供拦截器处理,基于动态代理实现,Plugin类是动态代理类,对实现Interceptor的接口的类进行处理,而实现的拦截器会被加入到拦截器链进行处理

Object intercept(Invocation var1) throws Throwable;

default Object plugin(Object target) {

return Plugin.wrap(target, this);

}

default void setProperties(Properties properties) {

}

plugin.warp方法

拦截器链:

public class InterceptorChain {

private final List<Interceptor> interceptors = new ArrayList();

public InterceptorChain() {

}

public Object pluginAll(Object target) {

Interceptor interceptor;

for(Iterator var2 = this.interceptors.iterator(); var2.hasNext(); target = interceptor.plugin(target)) {

interceptor = (Interceptor)var2.next();

}

return target;

}

public void addInterceptor(Interceptor interceptor) {

this.interceptors.add(interceptor);

}

public List<Interceptor> getInterceptors() {

return Collections.unmodifiableList(this.interceptors);

}

}

并在handler里面添加这些拦截器类,执行pluginAll方法,返回一个经过代理链处理的对象

实现该接口以后,要添加注解来表明拦截哪些方法,方法则是上面四个对象的拥有的方法。下面这个注解则是指定了拦截哪些对象的哪个方法,args则是被拦截方法的参数

public @interface Signature {

Class<?> type();

String method();

Class<?>[] args();

}

比如这个例子

@Signature(type = Executor.class, method = "update", args = {MappedStatement.class, Object.class})

Signature注解就对应上面的接口、方法及其参数,然后在拦截器添加一个@Intercepts,这个注解的内容是Signature注解数组

有了拦截器,初步想法是根据方法拦截,如果select则使用读数据源,增删改则使用写数据源,这个其实原理和之前写的一篇代码级别读写分离很相似,也是通过ThreadLocal存放当前线程的数据源,然后通过拦截器来判断用哪个数据源,交由AbstarctRoutingDataSource来根据ThreadLoacl里面的值来处理。

但是有个问题,两个数据源转换,表名、字段名不一定相等,比如从pgsql的一个叫user_info表里的数据转到mysql叫user表的数据,字段名都不相同

我的处理方法是查询对象的目标的字段名为准,然后给每个字段一个注解指向修改对象的数据源表字段名,如果查询目标表没有插入目标表的字段,便在select的时候默认select null或者用代码限定查询的字段。这里首先先定义了三个注解,分别对应查、改相应的数据源、表名、字段

@Target(ElementType.TYPE)

@Retention(RetentionPolicy.RUNTIME)

public @interface TranDB {

DBType from();

DBType to();

Class object();

}

public @interface TranField {

String from() default "";

String to();

String empty = "null";

}

public @interface TranTable {

String from();

String to();

}

User类

@TranTable(from = "user_info", to = "user")

public class User {

@TranField(to = "id")

@TableId

private Integer userId;

@TranField(to = "wx_nickname")

private String userAccount;

@TranField(to = "roles")

private String mobile;

@TranField(from=TranField.empty,to="create_time")

private Date createTime;

@TranField(from=TranField.empty,to="update_time")

private Date updateTime;

@TranField(from=TranField.empty,to="bonus")

private Integer bonus;

@TranField(to="wx_id")

private String[] test;

}

UserMapper

@TranDB(from = DBType.PGSQL,to=DBType.MYSQL,object=User.class)

public interface UserMapper extends BaseMapper<User> {

}

这里添加一个缓存mapper信息类,方便在拦截器中调用,其中有个成员变量是用来存储mapperName对应的TranDB注解信息,拦截器通过拦截的方法获取mapper名称,再通过这个mapper信息类获取他的TranDB注解,这个注解里面有对应的实体class,可以用来获取字段信息注解及表名信息注解,而另一个成员变量则是用来存放待会说到的表名替换,这里面实现了两个接口,一个通过spring容器加载资源的接口,另一个则是用来初始化bean的。

package com.trendy.task.transport.config;

import com.baomidou.mybatisplus.extension.parsers.ITableNameHandler;

import com.trendy.task.transport.annotations.TranDB;

import com.trendy.task.transport.handler.SelfTableNameHandler;

import com.trendy.task.transport.util.CamelHumpUtils;

import org.springframework.beans.factory.InitializingBean;

import org.springframework.beans.factory.annotation.Value;

import org.springframework.context.ResourceLoaderAware;

import org.springframework.core.io.Resource;

import org.springframework.core.io.ResourceLoader;

import org.springframework.core.io.support.ResourcePatternResolver;

import org.springframework.core.io.support.ResourcePatternUtils;

import org.springframework.core.type.classreading.CachingMetadataReaderFactory;

import org.springframework.core.type.classreading.MetadataReader;

import org.springframework.core.type.classreading.MetadataReaderFactory;

import java.util.*;

/**

* Mapper信息缓存类

*/

public class MapperAuxFeatureMap implements ResourceLoaderAware, InitializingBean {

private static ResourceLoader resourceLoader;

@Value("${tran.mapperlocation}")

public String MAPPER_LOCATION ;

public static final String TABLEPREFIX="t_";

//表名处理

public Map<String, ITableNameHandler> tableNameHandlerMap;

//mapper文件的注解

public Map<String, TranDB> mapperTranDbMap;

//通过方法获取mapper名称

public static String getMapperNameFromMethodName(String source){

int end = source.lastIndexOf(".") + 1;

String mapper = source.substring(0, end - 1);

mapper = mapper.substring(mapper.lastIndexOf(".") + 1);

return mapper;

}

@Override

public void setResourceLoader(ResourceLoader resourceLoader) {

MapperAuxFeatureMap.resourceLoader=resourceLoader;

}

@Override

public void afterPropertiesSet() throws Exception {

ResourcePatternResolver resolver = ResourcePatternUtils.getResourcePatternResolver(resourceLoader);

MetadataReaderFactory metaReader = new CachingMetadataReaderFactory(resourceLoader);

Resource[] resources = resolver.getResources("classpath*:"+MAPPER_LOCATION.replace(".","/")+"/**/*.class");

mapperTranDbMap = new HashMap<>();

tableNameHandlerMap = new HashMap<>();

for (Resource r : resources) {

MetadataReader reader = metaReader.getMetadataReader(r);

String className = reader.getClassMetadata().getClassName();

Class<?> c = Class.forName(className);

if (c.isAnnotationPresent(TranDB.class)) {

String name = c.getSimpleName();

TranDB tranDB = c.getAnnotation(TranDB.class);

mapperTranDbMap.put(name, tranDB);

String value = tranDB.object().getSimpleName();

tableNameHandlerMap.put(TABLEPREFIX+ CamelHumpUtils.humpToLine(value),new SelfTableNameHandler(tranDB.object()));

}

}

}

}

替换数据源的部分代码,对query和update(即增删改)方法进行拦截,改方法使用mysql数据源,查方法使用pgsql数据源

package com.trendy.task.transport.dyma;

import com.trendy.task.transport.annotations.TranDB;

import com.trendy.task.transport.config.MapperAuxFeatureMap;

import org.apache.ibatis.executor.Executor;

import org.apache.ibatis.mapping.MappedStatement;

import org.apache.ibatis.mapping.SqlCommandType;

import org.apache.ibatis.plugin.*;

import org.apache.ibatis.session.ResultHandler;

import org.apache.ibatis.session.RowBounds;

import java.util.Properties;

/**

* @author: lele

* @date: 2019/10/23 下午4:24

*/

@Intercepts({

@Signature(type = Executor.class, method = "update", args = {MappedStatement.class, Object.class}),

@Signature(type = Executor.class, method = "query", args = {MappedStatement.class, Object.class,

RowBounds.class, ResultHandler.class})

})

public class DynamicDataSourceInterceptor implements Interceptor {

private MapperAuxFeatureMap mapperAuxFeatureMap;

public DynamicDataSourceInterceptor(MapperAuxFeatureMap mapperAuxFeatureMap) {

this.mapperAuxFeatureMap = mapperAuxFeatureMap;

}

@Override

public Object intercept(Invocation invocation) throws Throwable {

//如果读取数据,使用From的库,否则使用To库

DBType db =null;

Object[] objects = invocation.getArgs();

MappedStatement statement = (MappedStatement) objects[0];

String mapper = MapperAuxFeatureMap.getMapperNameFromMethodName(statement.getId());

TranDB tranDB = mapperAuxFeatureMap.mapperTranDbMap.get(mapper);

if (statement.getSqlCommandType().equals(SqlCommandType.SELECT)) {

db = tranDB.from();

} else {

db = tranDB.to();

}

DynamicDataSourceHolder.setDbType(db);

return invocation.proceed();

}

@Override

public Object plugin(Object o) {

if (o instanceof Executor) {

return Plugin.wrap(o, this);

} else {

return o;

}

}

@Override

public void setProperties(Properties properties) {

}

}

然后对字段进行修改的拦截器,这里为什么要继承AbstactSqlPaserHandler呢,因为可以复用他的方法,以及为后来加入表名替换的类做准备,这里的流程是获取原来字段的名字,并改为TranField的to所存储的内容

package com.trendy.task.transport.handler;

import com.baomidou.mybatisplus.core.toolkit.PluginUtils;

import com.baomidou.mybatisplus.extension.handlers.AbstractSqlParserHandler;

import com.trendy.task.transport.annotations.TranDB;

import com.trendy.task.transport.annotations.TranField;

import com.trendy.task.transport.config.MapperAuxFeatureMap;

import com.trendy.task.transport.util.CamelHumpUtils;

import org.apache.ibatis.executor.statement.StatementHandler;

import org.apache.ibatis.mapping.BoundSql;

import org.apache.ibatis.mapping.MappedStatement;

import org.apache.ibatis.mapping.SqlCommandType;

import org.apache.ibatis.plugin.*;

import org.apache.ibatis.reflection.MetaObject;

import org.apache.ibatis.reflection.SystemMetaObject;

import java.lang.reflect.Field;

import java.sql.Connection;

import java.sql.Statement;

import java.util.HashMap;

import java.util.Map;

/**

* @author: lele

* @date: 2019/10/23 下午5:12

*/

@Intercepts({

@Signature(

type = StatementHandler.class,

method = "prepare",

args = {Connection.class, Integer.class}

),

@Signature(

type = StatementHandler.class,

method = "update",

args = {Statement.class}

),

@Signature(

type = StatementHandler.class,

method = "batch",

args = {Statement.class}

)

})

public class FieldHandler extends AbstractSqlParserHandler implements Interceptor {

private MapperAuxFeatureMap mapperAuxFeatureMap;

public FieldHandler(MapperAuxFeatureMap mapperAuxFeatureMap) {

this.mapperAuxFeatureMap = mapperAuxFeatureMap;

}

@Override

public Object plugin(Object target) {

return target instanceof StatementHandler ? Plugin.wrap(target, this) : target;

}

@Override

public Object intercept(Invocation invocation) throws Throwable {

StatementHandler statementHandler = PluginUtils.realTarget(invocation.getTarget());

MetaObject metaObject = SystemMetaObject.forObject(statementHandler);

super.sqlParser(metaObject);

MappedStatement mappedStatement = (MappedStatement) metaObject.getValue("delegate.mappedStatement");

BoundSql boundSql = (BoundSql) metaObject.getValue("delegate.boundSql");

Boolean select = mappedStatement.getSqlCommandType().equals(SqlCommandType.SELECT);

if (!select) {

//通过获取mapper名称从缓存类中获取对应的注解

String mapperName = MapperAuxFeatureMap.getMapperNameFromMethodName(mappedStatement.getId());

TranDB tranDB = mapperAuxFeatureMap.mapperTranDbMap.get(mapperName);

//获取类的所有属性

Class clazz = tranDB.object();

Map<String, Field> mapField = new HashMap<>(clazz.getFields().length);

while (!clazz.equals(Object.class)) {

Field[] fields = clazz.getDeclaredFields();

for (Field field : fields) {

field.setAccessible(true);

mapField.put(field.getName(), field);

}

clazz = clazz.getSuperclass();

}

//替换sql

String sql = boundSql.getSql();

for (Map.Entry<String, Field> entry : mapField.entrySet()) {

String sqlFieldName = CamelHumpUtils.humpToLine(entry.getKey());

if (sql.contains(sqlFieldName)) {

String from = entry.getValue().getAnnotation(TranField.class).to();

sql = sql.replaceAll(sqlFieldName, from);

}

}

metaObject.setValue("delegate.boundSql.sql", sql);

}

return invocation.proceed();

}

}

现在还有一个问题要处理,就是表名替换,但是这个有个小坑,这个功能也相当于上面替换sql的功能比如insert into user(user_info,user_id) values ...,比如把user这个表名替换为user_info这个表来执行,此时的插入语句会把所有user的替换成user_info,这时候官方的建议是用@TableName这个注解更改表名避免出现这个情况

表名处理器

使用:实现ITableNameHandler,并实现接口方法返回一个表名字

package com.trendy.task.transport.handler;

import com.baomidou.mybatisplus.extension.parsers.ITableNameHandler;

import com.trendy.task.transport.annotations.TranTable;

import org.apache.ibatis.reflection.MetaObject;

/**

* @author: lele

* @date: 2019/10/24 下午2:39

* 表名替换的handler

*/

public class SelfTableNameHandler implements ITableNameHandler {

private final Class clazz;

public SelfTableNameHandler(Class clazz) {

this.clazz = clazz;

}

@Override

public String dynamicTableName(MetaObject metaObject, String sql, String tableName) {

TranTable t = (TranTable) clazz.getAnnotation(TranTable.class);

if (sql.toLowerCase().startsWith("select")) {

return t.from();

} else {

return t.to();

}

}

}

也可以注入到mp自带的分页那个拦截器中

@Bean

public FieldHandler fieldHandler() {

FieldHandler f = new FieldHandler(mapperAuxFeatureMap());

DynamicTableNameParser t = new DynamicTableNameParser();

t.setTableNameHandlerMap(mapperAuxFeatureMap().tableNameHandlerMap);

f.setSqlParserList(Collections.singletonList(t));

return f;

}

字段填充器

mysql的表里有创建时间、修改时间、积分,对于这些字段,而pgsql表里面没有,这时候想在插入时使用一个默认的值,这时候可以使用字段填充器

做法:实现MetaObjectHandler接口,并重写里面的方法,然后在字段的@TableField的fill类型里面说明需要填充时情况

例子,对createTime,updateTime,bouns进行默认填充,使用getFieldValueByName和setFieldValByName方法进行赋值

package com.trendy.task.transport.handler;

import com.baomidou.mybatisplus.core.handlers.MetaObjectHandler;

import org.apache.ibatis.reflection.MetaObject;

import java.util.Date;

/**

* @author lulu

* @Date 2019/10/24 23:15

* 自动填充的handler

*/

public class DefaultFieldValueHandler implements MetaObjectHandler {

public static final String CREATETIME = "createTime";

public static final String UPDATETIME = "updateTime";

public static final String BOUNS = "bonus";

private void handle(String name, MetaObject metaObject, Object target) {

Object o = getFieldValByName(name, metaObject);

if (o == null) {

setFieldValByName(name, target, metaObject);

}

}

@Override

public void insertFill(MetaObject metaObject) {

handle(CREATETIME, metaObject, new Date());

handle(UPDATETIME, metaObject, new Date());

handle(BOUNS, metaObject, 500);

}

@Override

public void updateFill(MetaObject metaObject) {

handle(UPDATETIME, metaObject, new Date());

}

}

然后为user添加注解@TableField的注解

@TranField(from=TranField.empty,to="create_time")

@TableField(fill = FieldFill.INSERT)

private Date createTime;

@TranField(from=TranField.empty,to="update_time")

@TableField(fill = FieldFill.INSERT_UPDATE)

private Date updateTime;

@TranField(from=TranField.empty,to="bonus")

@TableField(fill= FieldFill.INSERT)

private Integer bonus;

然后在全局配置中加入这个字段填充器类

@Bean

public GlobalConfig globalConfig() {

GlobalConfig globalConfig = new GlobalConfig();

globalConfig.setBanner(false);

globalConfig.setMetaObjectHandler(defaultFieldValueHandler());

return globalConfig;

}

工厂类配置上全局配置 sqlSessionFactory.setGlobalConfig(globalConfig());

类型处理器

类型处理器,用于 JavaType 与 JdbcType 之间的转换,用于 PreparedStatement 设置参数值和从 ResultSet 或 CallableStatement 中取出一个值,比如把String、Integer、Long、Double放到数据库里面用逗号分隔形式存储,此时可以

自定义类型处理器,这里针对上面四个对象数组实现类型转换处理,setxxx方法主要是对参数进行处理,然后把处理后的结果放入数据库中,而get方法则处理从数据库取出来的数据该如何处理,这里接受一个lambda函数作为方法转换,即字符串-》目标类型,这里定义一个抽象类统一处理方法,然后具体转换方法由子类实现

package com.trendy.task.transport.handler;

import org.apache.ibatis.type.BaseTypeHandler;

import org.apache.ibatis.type.JdbcType;

import org.apache.ibatis.type.MappedJdbcTypes;

import org.apache.ibatis.type.MappedTypes;

import java.sql.CallableStatement;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.util.function.Function;

/**

* @author lulu

* @Date 2019/10/25 21:46

*/

//@MappedJdbcTypes({})表明处理哪种jdbc类型

@MappedTypes(Object[].class)//表明处理哪种javatype

public abstract class AbstractArrayTypeHandler<T> extends BaseTypeHandler<Object[]> {

//这里接受一个lambdah函数做转换处理

private final Function<String,T> method;

public AbstractArrayTypeHandler(Function<String,T> method){

this.method=method;

}

@Override

public void setNonNullParameter(PreparedStatement preparedStatement, int i, Object[] objects, JdbcType jdbcType) throws SQLException {

StringBuilder sb=new StringBuilder();

for(Object o:objects){

sb.append(o.toString()+",");

}

sb.deleteCharAt(sb.length()-1);

preparedStatement.setString(i,sb.toString());

}

@Override

public T[] getNullableResult(ResultSet resultSet, String s) throws SQLException {

return getArray(resultSet.getString(s));

}

@Override

public T[] getNullableResult(ResultSet resultSet, int i) throws SQLException {

return getArray(resultSet.getString(i));

}

@Override

public Object[] getNullableResult(CallableStatement callableStatement, int i) throws SQLException {

return getArray(callableStatement.getString(i));

}

protected T[] getArray(String source){

if(source==null){

return null;

}

String[] resString=source.split(",");

if(this.method==null){

return (T[])resString;

}

T[] resArray= (T[]) new Object[resString.length];

for (int i = 0; i < resString.length; i++) {

resArray[i]=method.apply(resString[i]);

}

return resArray;

}

}

然后定义一个工厂存放子类

package com.trendy.task.transport.handler;

import java.util.function.Function;

/**

* @author lulu

* @Date 2019/10/25 22:33

*/

public interface ArrayTypeHandlerFactory {

class IntegerArrayTypeHandler extends AbstractArrayTypeHandler<Integer>{

public IntegerArrayTypeHandler() {

super(Integer::parseInt);

}

}

class DoubleArrayTypeHandler extends AbstractArrayTypeHandler<Double>{

public DoubleArrayTypeHandler(){

super(Double::parseDouble);

}

}

class LongArrayTypeHandler extends AbstractArrayTypeHandler<Long>{

public LongArrayTypeHandler(){

super(Long::parseLong);

}

}

class StringArrayTypeHandler extends AbstractArrayTypeHandler<String>{

public StringArrayTypeHandler(){

super(null);

}

}

}

指定处理类型

@TableField(typeHandler = ArrayTypeHandlerFactory.StringArrayTypeHandler.class)

好了,现在来测试下,

@Test

public void selectById() {

List<User> userList = userService.list(new LambdaQueryWrapper<User>().select(User::getUserId,User::getMobile,User::getUserAccount,User::getTest));

userService.saveBatch(userList);

}

大概就到这里,代码完整版的github地址:GitHub - 97lele/transport

但是这个有个缺陷,就是不支持事务,还有saveOrUpdate方法也不支持,因为两个数据源都不一样,他是先查,看是否有再做更新或者插入操作,这些问题仍需解决,且当作一个使用方法记录的小例子吧

补充

mybatis-plus默认的baseMapper不支持批量的插入和更新,有时候会为了这个批量的方法去继承serviceImpl类,而这个类有没有其他的业务代码在里面,继承仅仅是为了获取批量操作的方法,会显得这个类有点”贫血“

对于这种情况,偶然看到一个开源的项目onemall对BaseMapper做了扩展,使它支持了批量插入的做法,在此基础下,我也做了一定的扩展

根据自己的见解,简单描述下流程:

核心就是自定义一个sql自动注入器,mybatis-plus会扫描mapper类 ,为每个mapper类构造一个MappedStatement(相当于mapper里的一个sql)

添加到配置类里面(具体在下面(2)),只会在初始化时候执行一次,而我们要做的,就是把某个特定mapper,注入我们想要的模板方法

具体注入在MybatisMapperAnnotationBuilder,注入动态sql,getSqlInjector获取sql注入器,并为当前的MapperBuilderAssistant对象(类似于mapper)注入mappedStatement(sql)

(1)注入开始,里面的inspectInject就是

inspectInject就会把abstractMethod一一注入进去

public void inspectInject(MapperBuilderAssistant builderAssistant, Class<?> mapperClass) {

Class<?> modelClass = extractModelClass(mapperClass);

if (modelClass != null) {

String className = mapperClass.toString();

Set<String> mapperRegistryCache = GlobalConfigUtils.getMapperRegistryCache(builderAssistant.getConfiguration());

if (!mapperRegistryCache.contains(className)) {

List<AbstractMethod> methodList = this.getMethodList(mapperClass);

if (CollectionUtils.isNotEmpty(methodList)) {

TableInfo tableInfo = TableInfoHelper.initTableInfo(builderAssistant, modelClass);

// 循环注入自定义方法

methodList.forEach(m -> m.inject(builderAssistant, mapperClass, modelClass, tableInfo));

} else {

logger.debug(mapperClass.toString() + ", No effective injection method was found.");

}

mapperRegistryCache.add(className);

}

}

}

((2)抽象方法注入类,最终放到configuration类缓存,形成一个sql

具体看看AbstractMethod的实现类,而默认的DefaultSqlInject类就有我们baseMapper所包含的默认方法,我们要添加多两个方法,批量更新和批量插入

下面开始编码

首先继承AbstarctMethod类,实现我们想注入的sql模板

对于批量插入,使用 insert into table columns values (values),(values),(values)

对于批量更新,使用 update table set xx=xx,xx=xx where xx=xx;update table set xx=xx,xx=xx where xx=xx;update table set xx=xx,xx=xx where xx=xx;进行分号分割

因为要用到标签解析的功能,需要用script包裹起来。

具体初始化模板如下, 对其进行填充

public enum CustomSqlMethodEnum {

/**

* 批量插入

*/

INSERT_BATCH("insertBatch",

"批量插入",

"<script>\n"

+ "INSERT INTO %s %s VALUES \n"

+ "<foreach collection=\"collection\" item=\"item\" separator=\",\"> %s\n </foreach>\n"

+ "</script>"),

/**

* 批量更新

*/

UPDATE_BATCH("updateBatchByIds",

"批量更新",

"<script>\n" +

"<foreach collection=\"collection\" item=\"item\" separator=\";\"> update %s set %s where %s </foreach>\n"

+ "</script>"

),

/**

* 根据联合键查询

*/

SELECT_BY_COMPOSEKEYS("selectByComposeKeys",

"联合主键查询",

"<script>" +

" select <choose> <when test=\"ew!=null and ew.sqlSelect != null and ew.sqlSelect != ''\"> ${ew.sqlSelect} </when> <otherwise> * </otherwise> </choose> from %s "

+ "<where> <foreach collection=\"collection\" item=\"item\" open=\"(\" close=\")\" separator=\"or\"> ( %s ) </foreach> <if test=\"ew!=null and ew.sqlSegment != null and ew.sqlSegment != ''\">\n" +

"AND ${ew.sqlSegment}\n" +

"</if> </where> </script>"

),

/**

* 根据联合键查询

*/

SELECT_IDS_BY_COMPOSEKEYS("selectIdsByComposeKeys",

"联合主键查询id",

"<script>" +

" select %s from %s "

+ "<where> <foreach collection=\"collection\" item=\"item\" open=\"(\" close=\")\" separator=\"or\"> ( %s ) </foreach> </where> </script>"

),

/**

* 根据联合主键删除

*/

DELETE_BY_COMPOSEKEYS("deleteByComposeKeys",

"联合主键删除",

"<script>" +

" delete from %s "

+ "<where> <foreach collection=\"collection\" item=\"item\" open=\"(\" close=\")\" separator=\"or\"> ( %s ) </foreach> </where> </script>"

),

/**

* 根据联合主键更新

*/

UPDATE_BY_COMPOSEKEYS("updateByComposeKeys"

, "联合主键批量修改",

"<script>\n" +

"<foreach collection=\"collection\" item=\"item\" separator=\";\"> update %s set %s where %s </foreach>\n"

+ "</script>"

);

private final String method;

private final String desc;

private final String sql;

CustomSqlMethodEnum(String method, String desc, String sql) {

this.method = method;

this.desc = desc;

this.sql = sql;

}

public String getMethod() {

return method;

}

public String getDesc() {

return desc;

}

public String getSql() {

return sql;

}

}

下面是构造批量插入和更新的代码逻辑

批量插入:主要是构造——表名、插入列、插入值,这里为了防止覆盖数据库默认值,也可以做if test 的那种判空,来取消插入,不过比较麻烦,这里就不做了

public class InsertBatch extends AbstractMethod {

@Override

public MappedStatement injectMappedStatement(Class<?> mapperClass, Class<?> modelClass, TableInfo tableInfo) {

KeyGenerator keyGenerator = new NoKeyGenerator();

CustomSqlMethodEnum sqlMethod = CustomSqlMethodEnum.INSERT_BATCH;

// ==== 拼接 sql 模板 ==============

StringBuilder columnScriptBuilder = new StringBuilder(LEFT_BRACKET);

StringBuilder valuesScriptBuilder = new StringBuilder(LEFT_BRACKET);

// 主键拼接

if (StringUtils.isNotBlank(tableInfo.getKeyColumn())) {

//(x1,x2,x3

columnScriptBuilder.append(tableInfo.getKeyColumn()).append(COMMA);

//(item.xx,item.xx

valuesScriptBuilder.append(SqlScriptUtils.safeParam(SQLConditionWrapper.ITEM + DOT + tableInfo.getKeyProperty())).append(COMMA);

}

// 普通字段拼接

List<TableFieldInfo> fieldList = tableInfo.getFieldList();

for (TableFieldInfo fieldInfo : fieldList) {

//有更新默认填充器的不参与赋值

if (!fieldInfo.isWithInsertFill() && fieldInfo.isWithUpdateFill()) {

continue;

}

columnScriptBuilder.append(fieldInfo.getColumn()).append(COMMA);

valuesScriptBuilder.append(SqlScriptUtils.safeParam(SQLConditionWrapper.getCondition(fieldInfo.getProperty()).toString())).append(COMMA);

}

// 替换多余的逗号为括号

//(x1,x2)

columnScriptBuilder.setCharAt(columnScriptBuilder.length() - 1, ')');

//(item.xx,item.xx2)

valuesScriptBuilder.setCharAt(valuesScriptBuilder.length() - 1, ')');

// sql 模板占位符替换

String columnScript = columnScriptBuilder.toString();

String valuesScript = valuesScriptBuilder.toString();

String sql = String.format(sqlMethod.getSql(), tableInfo.getTableName(), columnScript, valuesScript);

// === mybatis 主键逻辑处理:主键生成策略,以及主键回填=======

String keyColumn = null;

String keyProperty = null;

// 表包含主键处理逻辑,如果不包含主键当普通字段处理

if (StringUtils.isNotBlank(tableInfo.getKeyProperty())) {

if (tableInfo.getIdType() == IdType.AUTO) {

/** 自增主键 */

keyGenerator = new Jdbc3KeyGenerator();

keyProperty = tableInfo.getKeyProperty();

keyColumn = tableInfo.getKeyColumn();

} else {

if (null != tableInfo.getKeySequence()) {

keyGenerator = TableInfoHelper.genKeyGenerator(sqlMethod.getMethod(), tableInfo, builderAssistant);

keyProperty = tableInfo.getKeyProperty();

keyColumn = tableInfo.getKeyColumn();

}

}

}

// 模板写入

SqlSource sqlSource = languageDriver.createSqlSource(configuration, sql, modelClass);

return this.addInsertMappedStatement(mapperClass, modelClass, sqlMethod.getMethod(), sqlSource, keyGenerator, keyProperty, keyColumn);

}

}

更新sql构造,这里要注意字段上的字段策略(FieldStrategy),附上处理类

public class UpdateBatchByIds extends AbstractMethod {

@Override

public MappedStatement injectMappedStatement(Class<?> mapperClass, Class<?> modelClass, TableInfo tableInfo) {

CustomSqlMethodEnum sqlMethod = CustomSqlMethodEnum.UPDATE_BATCH;

/**

* update table set <if test ="item.pro!=null">key1=#{item.pro}</if>, key2=#{item.pro2} where keycolom = %s

* */

StringBuilder withChevScript = new StringBuilder();

StringBuilder lastFiledScriptBuilder=new StringBuilder();

StringBuilder keyScriptBuilder = new StringBuilder();

if (StringUtils.isNotBlank(tableInfo.getKeyColumn())) {

keyScriptBuilder.append(tableInfo.getKeyColumn()).append(EQUALS).append(SqlScriptUtils.safeParam(SQLConditionWrapper.ITEM + DOT + tableInfo.getKeyProperty()));

}

List<TableFieldInfo> fieldList = tableInfo.getFieldList();

for (int i = 0; i < fieldList.size(); i++) {

TableFieldInfo fieldInfo = fieldList.get(i);

Boolean isLast=(i==(fieldList.size()-1));

//有插入默认填充器的不参与赋值

if (fieldInfo.isWithInsertFill() && !fieldInfo.isWithUpdateFill()) {

continue;

}

boolean change = false;

if (Objects.equals(fieldInfo.getUpdateStrategy(), FieldStrategy.NOT_NULL) && !fieldInfo.isWithUpdateFill()) {

SQLConditionWrapper.appendNotNull(withChevScript, fieldInfo.getProperty());

change = true;

}

if (Objects.equals(fieldInfo.getUpdateStrategy(), FieldStrategy.NOT_EMPTY) && !fieldInfo.isWithUpdateFill()) {

SQLConditionWrapper.appendNotEmpty(withChevScript, fieldInfo.getProperty());

change = true;

}

if (change) {

withChevScript.append(fieldInfo.getColumn()).append(EQUALS).append(SqlScriptUtils.safeParam(SQLConditionWrapper.getCondition(fieldInfo.getProperty()).toString()));

withChevScript.append(COMMA).append("</if>");

if(isLast&&lastFiledScriptBuilder.length()==0){

//如果没有其他字段替补,弄个占位的,不然会出现语法错误的情况

withChevScript.append(tableInfo.getKeyColumn()).append(EQUALS).append(tableInfo.getKeyColumn());

}

}else{

lastFiledScriptBuilder.append(fieldInfo.getColumn()).append(EQUALS).append(SqlScriptUtils.safeParam(SQLConditionWrapper.getCondition(fieldInfo.getProperty()).toString())).append(COMMA);

}

}

//处理多余的逗号

if(!StringUtils.isBlank(lastFiledScriptBuilder)&&!StringUtils.isBlank(withChevScript)){

int leftChevIndex= withChevScript.lastIndexOf(LEFT_CHEV);

if(withChevScript.charAt(leftChevIndex-1)!=','){

withChevScript.replace(leftChevIndex,leftChevIndex+1,",<");

}

if(lastFiledScriptBuilder.lastIndexOf(COMMA)==lastFiledScriptBuilder.length()-1){

lastFiledScriptBuilder.deleteCharAt(lastFiledScriptBuilder.length()-1);

}

}

withChevScript.append(lastFiledScriptBuilder);

// sql 模板占位符替换

String sql = String.format(sqlMethod.getSql(), tableInfo.getTableName(), withChevScript, keyScriptBuilder);

// 模板写入

SqlSource sqlSource = languageDriver.createSqlSource(configuration, sql, modelClass);

return this.addUpdateMappedStatement(mapperClass, modelClass, sqlMethod.getMethod(), sqlSource);

}

}

public class SQLConditionWrapper {

public final static String ITEM = "item";

public static StringBuilder appendNotNull(StringBuilder builder, String property) {

return appendEnd(appendStart(builder, getCondition(property)));

}

public static StringBuilder appendNotEmpty(StringBuilder builder, String property) {

StringBuilder condition = getCondition(property);

StringBuilder append = appendStart(builder, condition)

.append(" ").append(AND).append(" ").append(condition).append(EXCLAMATION_MARK).append(EQUALS).append(" ").append("''");

return appendEnd(append);

}

private static StringBuilder appendEnd(StringBuilder builder) {

builder.append("\"")

.append(RIGHT_CHEV);

return builder;

}

private static StringBuilder appendStart(StringBuilder builder, StringBuilder item) {

builder.append(LEFT_CHEV)

.append("if test=\"")

.append(item).append(EXCLAMATION_MARK).append(EQUALS).append(NULL);

return builder;

}

public static StringBuilder getCondition(String property) {

return new StringBuilder()

.append(ITEM).append(DOT).append(property);

}

}

然后就自定义mapper及sql注入器

public interface CustomMapper<T> extends BaseMapper<T> {

/**

* 批量插入

* @param collection 批量插入数据

* @return ignore

*/

int insertBatch(@Param("collection") Collection<T> collection);

/**

* 批量更新

* @param collection

* @return

*/

int updateBatchByIds(@Param("collection") Collection<T> collection);

}

这里sql注入器要判断下是继承了该类,才进行方法扩展

@ConditionalOnExpression("${mybatis-plus.custom-mapper.enabled:true}")

@Component

public class CustomSqlInject extends DefaultSqlInjector {

//初始化时候会加载

@Override

public List<AbstractMethod> getMethodList(Class<?> mapperClass) {

List<AbstractMethod> methodList = super.getMethodList(mapperClass);

//属于自己定义的mapper才添加方法

if (((ParameterizedTypeImpl) mapperClass.getGenericInterfaces()[0]).getRawType().equals(CustomMapper.class)) {

methodList.add(new InsertBatch());

methodList.add(new UpdateBatchByIds());

}

if (((ParameterizedTypeImpl) mapperClass.getGenericInterfaces()[0]).getRawType().equals(ComposeKeyMapper.class)) {

methodList.add(new SelectByComposeKeys());

methodList.add(new SelectIdsByComposeKeys());

methodList.add(new UpdateByComposeKeys());

methodList.add(new InsertBatch());

}

return methodList;

}

}

可以直接注入到spring里面,或者通过进行设置

GlobalConfigUtils.getGlobalConfig(sqlSessionFactory.getConfiguration()).setSqlInjector(xx)

测试一下,定义实体,下面的typeHandler可以去掉,

@TableName(

value = "demo"

)

@Data

@Accessors(chain = true)

public class Demo extends BaseEntity {

private static final long serialVersionUID = 1L;

@TableId("id")

private Long id;

@TableField("name")

private String name;

@TableField(

value = "age",

typeHandler = LongFormatAESEncryptHandler.class

)

private Long age;

@TableField(

value = "secret",

typeHandler = StringFormatAESEncryptHandler.class

)

private String secret;

@TableField(

value = "CREATED_ID",

fill = FieldFill.INSERT

)

private Long createdId;

@TableField(

value = "CREATED_BY",

fill = FieldFill.INSERT

)

private String createdBy;

@TableField(

value = "CREATION_DATE",

fill = FieldFill.INSERT

)

private Date creationDate;

@TableField(

value = "CREATED_BY_IP",

fill = FieldFill.INSERT

)

private String createdByIp;

@TableField(

value = "LAST_UPDATED_ID",

fill = FieldFill.UPDATE

)

private Long lastUpdatedId;

@TableField(

value = "LAST_UPDATED_BY",

fill = FieldFill.UPDATE

)

private String lastUpdatedBy;

@TableField(

value = "LAST_UPDATE_DATE",

fill = FieldFill.INSERT_UPDATE

)

private Date lastUpdateDate;

@TableField(

value = "LAST_UPDATED_BY_IP",

fill = FieldFill.UPDATE

)

private String lastUpdatedByIp;

}

继承自定义mapper

public interface TempMapper extends CustomMapper<Demo> {

}

controller了的两个方法,可以支持事务

@GetMapping("/testBatch")

@Transactional(rollbackFor = Exception.class)

public void testBatch() {

List<Demo> demos = new LinkedList<>();

for (int i = 0; i < 10; i++) {

Demo de = new Demo().setAge(Long.valueOf(i))

.setId(Long.valueOf(i + 1))

.setName("test" + i)

.setSecret(UUID.randomUUID().toString());

demos.add(de);

}

tempMapper.insertBatch(demos);

}

@GetMapping("/testBatch2")

@Transactional(rollbackFor = Exception.class)

public void testBatch2() {

List<Demo> demos = new LinkedList<>();

for (int i = 0; i < 5; i++) {

Demo de = new Demo().setAge(Long.valueOf(i))

.setId(Long.valueOf(i + 1))

.setName("test-change" + i)

.setSecret(UUID.randomUUID().toString());

demos.add(de);

}

tempMapper.updateBatchByIds(demos);

//int i=1/0;

}

对于自定sql注入,还可以抽取一些公用的方法进行添加,比如逻辑删除,版本号更新,进行联合主键的批量修改和查询,下面给出联合主键的处理方案

下面是构造根据wrapper和联合主键进行查询的,核心也是定义好sql,然后进行注入,但这里需要自定义一个注解来标识哪个是联合主键

@Retention(RetentionPolicy.RUNTIME)

@Target(ElementType.FIELD)

public @interface ComposeKey {

}

public class SelectByComposeKeys extends AbstractMethod {

@Override

public MappedStatement injectMappedStatement(Class<?> mapperClass, Class<?> modelClass, TableInfo tableInfo) {

CustomSqlMethodEnum sqlMethod = CustomSqlMethodEnum.SELECT_BY_COMPOSEKEYS;

//select #{ew.sqlSelect} from table_name where (composekey1=xx and composekey2=xx) or (composekey1=xx1 and composekey2=xx1)

String sqlTemplate = sqlMethod.getSql();

String tableName = tableInfo.getTableName();

List<TableFieldInfo> composeKeys = tableInfo.getFieldList().stream().filter(e -> e.getField().isAnnotationPresent(ComposeKey.class))

.collect(Collectors.toList());

if(CollectionUtils.isEmpty(composeKeys)){

throw new ApiException("not composeKey found in class:"+modelClass.getName());

}

StringBuilder builder=new StringBuilder();

for (int i = 0; i < composeKeys.size(); i++) {

TableFieldInfo composeKey = composeKeys.get(i);

builder.append(composeKey.getColumn()).append(EQUALS).append(SqlScriptUtils.safeParam(SQLConditionWrapper.ITEM + DOT + composeKey.getProperty()));

if(i!=composeKeys.size()-1){

builder.append(" ").append(AND).append(" ");

}

}

String finalSql = String.format(sqlTemplate, tableName, builder);

SqlSource sqlSource = languageDriver.createSqlSource(configuration, finalSql, modelClass);

return this.addSelectMappedStatementForTable(mapperClass,sqlMethod.getMethod(),sqlSource,tableInfo);

}

}

更新操作

public class UpdateByComposeKeys extends AbstractMethod {

@Override

public MappedStatement injectMappedStatement(Class<?> mapperClass, Class<?> modelClass, TableInfo tableInfo) {

CustomSqlMethodEnum sqlMethod = CustomSqlMethodEnum.UPDATE_BY_COMPOSEKEYS;

/**

* update table set <if test ="item.pro!=null">key1=#{item.pro}</if>, key2=#{item.pro2} where keycolom = %s

*/

StringBuilder withChevScript = new StringBuilder();

StringBuilder lastFiledScriptBuilder = new StringBuilder();

StringBuilder keyScriptBuilder = new StringBuilder();

StringBuilder placeHolder = new StringBuilder();

List<TableFieldInfo> fieldList = tableInfo.getFieldList();

for (int i = 0; i < fieldList.size(); i++) {

TableFieldInfo fieldInfo = fieldList.get(i);

Boolean isLast = (i == (fieldList.size() - 1));

if (fieldInfo.getField().isAnnotationPresent(ComposeKey.class)) {

keyScriptBuilder.append(" ").append(fieldInfo.getColumn()).append(EQUALS).append(SqlScriptUtils.safeParam(SQLConditionWrapper.ITEM + DOT + fieldInfo.getProperty()))

.append(" ").append(AND);

placeHolder.append(fieldInfo.getColumn()).append(EQUALS).append(fieldInfo.getColumn()).append(COMMA);

continue;

}

//有插入默认填充器或者主键的不参与赋值

if (fieldInfo.isWithInsertFill() && !fieldInfo.isWithUpdateFill()) {

continue;

}

boolean change = false;

if (Objects.equals(fieldInfo.getUpdateStrategy(), FieldStrategy.NOT_NULL) && !fieldInfo.isWithUpdateFill()) {

SQLConditionWrapper.appendNotNull(withChevScript, fieldInfo.getProperty());

change = true;

}

if (Objects.equals(fieldInfo.getUpdateStrategy(), FieldStrategy.NOT_EMPTY) && !fieldInfo.isWithUpdateFill()) {

SQLConditionWrapper.appendNotEmpty(withChevScript, fieldInfo.getProperty());

change = true;

}

if (change) {

withChevScript.append(fieldInfo.getColumn()).append(EQUALS).append(SqlScriptUtils.safeParam(SQLConditionWrapper.getCondition(fieldInfo.getProperty()).toString()));

withChevScript.append(COMMA).append("</if>");

if (isLast && lastFiledScriptBuilder.length() == 0) {

//如果没有其他字段替补,弄个占位的,不然会出现语法错误的情况

if (placeHolder.length() > 0) {

//删除多余的逗号

placeHolder.deleteCharAt(placeHolder.length() - 1);

withChevScript.append(placeHolder);

}

}

} else {

lastFiledScriptBuilder.append(fieldInfo.getColumn()).append(EQUALS).append(SqlScriptUtils.safeParam(SQLConditionWrapper.getCondition(fieldInfo.getProperty()).toString())).append(COMMA);

}

}

if (placeHolder.length() == 0) {

throw new ApiException("not composeKey found in class:" + modelClass.getName());

}

//处理多余的逗号

if (!StringUtils.isBlank(lastFiledScriptBuilder) && !StringUtils.isBlank(withChevScript)) {

int leftChevIndex = withChevScript.lastIndexOf(LEFT_CHEV);

if (withChevScript.charAt(leftChevIndex - 1) != ',') {

withChevScript.replace(leftChevIndex, leftChevIndex + 1, ",<");

}

if (lastFiledScriptBuilder.lastIndexOf(COMMA) == lastFiledScriptBuilder.length() - 1) {

lastFiledScriptBuilder.deleteCharAt(lastFiledScriptBuilder.length() - 1);

}

}

if(!StringUtils.isBlank(keyScriptBuilder)){

int i = keyScriptBuilder.lastIndexOf(AND);

keyScriptBuilder.delete(i,i+AND.length());

}

withChevScript.append(lastFiledScriptBuilder);

// sql 模板占位符替换

String sql = String.format(sqlMethod.getSql(), tableInfo.getTableName(), withChevScript, keyScriptBuilder);

// 模板写入

SqlSource sqlSource = languageDriver.createSqlSource(configuration, sql, modelClass);

return this.addUpdateMappedStatement(mapperClass, modelClass, sqlMethod.getMethod(), sqlSource);

}

}

public class SelectIdsByComposeKeys extends AbstractMethod {

@Override

public MappedStatement injectMappedStatement(Class<?> mapperClass, Class<?> modelClass, TableInfo tableInfo) {

CustomSqlMethodEnum sqlMethod = CustomSqlMethodEnum.SELECT_IDS_BY_COMPOSEKEYS;

//select composekeys from table_name where (composekey1=xx and composekey2=xx) or (composekey1=xx1 and composekey2=xx1)

String sqlTemplate = sqlMethod.getSql();

String tableName = tableInfo.getTableName();

List<TableFieldInfo> composeKeys = tableInfo.getFieldList().stream().filter(e -> e.getField().isAnnotationPresent(ComposeKey.class))

.collect(Collectors.toList());

if(CollectionUtils.isEmpty(composeKeys)){

throw new ApiException("not composeKey found in class:"+modelClass.getName());

}

StringBuilder builder=new StringBuilder();

StringBuilder select=new StringBuilder();

for (int i = 0; i < composeKeys.size(); i++) {

TableFieldInfo composeKey = composeKeys.get(i);

select.append(composeKey.getColumn());

builder.append(composeKey.getColumn()).append(EQUALS).append(SqlScriptUtils.safeParam(SQLConditionWrapper.ITEM + DOT + composeKey.getProperty()));

if(i!=composeKeys.size()-1){

builder.append(" ").append(AND).append(" ");

select.append(COMMA);

}

}

String finalSql = String.format(sqlTemplate,select, tableName, builder);

SqlSource sqlSource = languageDriver.createSqlSource(configuration, finalSql, modelClass);

return this.addSelectMappedStatementForTable(mapperClass,sqlMethod.getMethod(),sqlSource,tableInfo);

}

}

public class DeleteByComposeKeys extends AbstractMethod {

@Override

public MappedStatement injectMappedStatement(Class<?> mapperClass, Class<?> modelClass, TableInfo tableInfo) {

CustomSqlMethodEnum sqlMethod = CustomSqlMethodEnum.DELETE_BY_COMPOSEKEYS;

//delete from table_name where (composekey1=xx and composekey2=xx) or (composekey1=xx1 and composekey2=xx1)

String sqlTemplate = sqlMethod.getSql();

String tableName = tableInfo.getTableName();

List<TableFieldInfo> composeKeys = tableInfo.getFieldList().stream().filter(e -> e.getField().isAnnotationPresent(ComposeKey.class))

.collect(Collectors.toList());

if(CollectionUtils.isEmpty(composeKeys)){

throw new ApiException("not composeKey found in class:"+modelClass.getName());

}

StringBuilder builder=new StringBuilder();

for (int i = 0; i < composeKeys.size(); i++) {

TableFieldInfo composeKey = composeKeys.get(i);

builder.append(composeKey.getColumn()).append(EQUALS).append(SqlScriptUtils.safeParam(SQLConditionWrapper.ITEM + DOT + composeKey.getProperty()));

if(i!=composeKeys.size()-1){

builder.append(" ").append(AND).append(" ");

}

}

String finalSql = String.format(sqlTemplate, tableName, builder);

SqlSource sqlSource = languageDriver.createSqlSource(configuration, finalSql, modelClass);

return this.addDeleteMappedStatement(mapperClass, sqlMethod.getMethod(), sqlSource);

}

}

定义mappe类,这里对于原生的方法就不进行支持了

public interface ComposeKeyMapper<T> extends CustomMapper<T> {

/**

* @param params 查询的主键入参

* @param wrapper 查询的列会用到 ew.sqlSelect

* @return

*/

List<T> selectByComposeKeys(@Param("collection") Collection<T> params, @Param(Constants.WRAPPER) Wrapper<T> wrapper);

/**

* 批量更新

*

* @param params

*/

void updateByComposeKeys(@Param("collection") Collection<T> params);

/**

* 只查询主键

*

* @param params

* @return

*/

List<T> selectIdsByComposeKeys(@Param("collection") Collection<T> params);

/**

* 联合主键删除

* @param params

* @return

*/

int deleteByComposeKeys(@Param("collection")Collection<T> params);

/**

* 下面的方法不支持

* @param entity

* @return

*/

@Override

default int updateById(T entity) {

throw new UnsupportedOperationException();

}

@Override

default int updateBatchByIds(Collection<T> collection) {

throw new UnsupportedOperationException();

}

@Override

default T selectById(Serializable id) {

throw new UnsupportedOperationException();

}

@Override

default List<T> selectBatchIds(Collection<? extends Serializable> idList) {

throw new UnsupportedOperationException();

}

@Override

default int deleteBatchIds(Collection<? extends Serializable> idList){

throw new UnsupportedOperationException();

}

@Override

default int deleteById(Serializable id){

throw new UnsupportedOperationException();

}

}

可以看到查询是按照预期给出的,也支持wrapper形式的查询

要注意,xml文件里的优先级是比自定义注入的优先级高的,这里没给出单个update,单个查询,单个删除的方法,这些都可以根据自己业务需求弄一下,项目上没用到就不写了

对于sqlSession也可以自己做一些小优化

类型有reuse,编译一次可以继续服用,使用场景:执行同一个sql,参数值不同

默认的simple是每次都会编译一下

batch相当于一个会话里面执行多条sql

reuse示例

public static void executeReuse(Consumer<SqlSession> consumer) {

SqlSessionFactory factory = SpringContextHolder.getBean(SqlSessionFactory.class);

SqlSession sqlSession = factory.openSession(ExecutorType.REUSE, true);

try {

consumer.accept(sqlSession);

} finally {

sqlSession.close();

}

}

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