SpringBoot中Mybatis + Druid 数据访问的详细过程

目录

• 1、简介
• 2、JDBC
• 3、CRUD操作
• 4、自定义数据源 DruidDataSource

• 1、配置 Druid 数据源监控
• 2、配置 Druid web 监控 filter

• 1. 导入mybatis所需要的依赖
• 2.配置数据库连接信息
• 3，创建实体类
• 4.配置Mapper接口类
•  5.编写controller
• 6.SpringBoot 整合

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <scope>runtime</scope>
</dependency>

spring:
  datasource:
    username: root
    password: 123456
    #?serverTimezone=UTC解决时区的报错
    url: jdbc:mysql://localhost:3306/mybatis?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8

package com.kk;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.SQLException;
@SpringBootTest
class Springboot04DataApplicationTests {
    @Autowired
    DataSource dataSource;
    @Test
    void contextLoads() throws SQLException {
        //查看默认的数据源 class com.zaxxer.hikari.HikariDataSource   dbcp
        System.out.println(dataSource.getClass());
        //获得数据库连接
        Connection connection = dataSource.getConnection();
        System.out.println(connection);
        connection.close();
    }
}

@Bean
public ConfigurableServletWebServerFactory webServerFactory() {
    TomcatServletWebServerFactory factory = new TomcatServletWebServerFactory();
    factory.addConnectorCustomizers(new TomcatConnectorCustomizer() {
        @Override
        public void customize(Connector connector) {
            connector.setProperty("relaxedQueryChars", "|{}[]");
        }
    });
    return factory;
}

package com.kk.controller;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;
import java.util.Map;
@RestController
public class JDBCController {
    //JdbcTemplate 是 core 包的核心类，用于简化 JDBC操作，还能避免一些常见的错误，如忘记关闭数据库连接
    //Spring Boot 默认提供了数据源，默认提供了 org.springframework.jdbc.core.JdbcTemplate
    //JdbcTemplate 中会自己注入数据源，使用起来也不用再自己来关闭数据库连接
    @Autowired
    JdbcTemplate jdbcTemplate;
   	//查询数据库的所有信息
    //没有实体类，数据库中的东西怎么获取? Map
   	//List 中的1个 Map 对应数据库的 1行数据
    //Map 中的 key 对应数据库的字段名，value 对应数据库的字段值
    @GetMapping("/userList")
    public List<Map<String ,Object>> userList(){
        String sql="select * from user";
        List<Map<String, Object>> list_maps = jdbcTemplate.queryForList(sql);
        return list_maps;
    }
    @GetMapping("/addUser")
    public String addUser(){
        String sql="insert into mybatis.user(id,name,pwd) values(2,'dabai','123456')";
       jdbcTemplate.update(sql);
        return "update-ok";
    }
    @GetMapping("/updateUser/{id}")
    public String updateUser(@PathVariable("id") int id){
        String sql="update mybatis.user set name=?,pwd=? where id="+id;
        //封装
        Object[] objects = new Object[2];
        objects[0]="xiaobai";
        objects[1]="9999999";
        jdbcTemplate.update(sql,objects);
        return "updateUser-ok";
    }
    @GetMapping("/deleteUser/{id}")
    public String deleteUser(@PathVariable("id") int id){
        String sql="delete from mybatis.user where id=?";
        jdbcTemplate.update(sql,id);
        return "deleteUser-ok";
    }
}

	 @Configuration
    @ConditionalOnMissingBean({DataSource.class})
    @ConditionalOnProperty(
        name = {"spring.datasource.type"}
    )
    static class Generic {
        Generic() {
        }
        @Bean
        public DataSource dataSource(DataSourceProperties properties) {
            return properties.initializeDataSourceBuilder().build();
        }
    }

<!-- https://mvnrepository.com/artifact/com.alibaba/druid -->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid</artifactId>
    <version>1.2.6</version>
</dependency>

type: com.alibaba.druid.pool.DruidDataSource

#Spring Boot 默认是不注入这些属性值的，需要自己绑定
#druid 数据源专有配置
initialSize: 5
minIdle: 5
maxActive: 20
maxWait: 60000
timeBetweenEvictionRunsMillis: 60000
minEvictableIdleTimeMillis: 300000
validationQuery: SELECT 1 FROM DUAL
testWhileIdle: true
testOnBorrow: false
testOnReturn: false
poolPreparedStatements: true
#配置监控统计拦截的filters，stat:监控统计、log4j：日志记录、wall：防御sql注入
#如果允许时报错  java.lang.ClassNotFoundException: org.apache.log4j.Priority
#则导入 log4j 依赖即可，Maven 地址： https://mvnrepository.com/artifact/log4j/log4j
filters: stat,wall,log4j
maxPoolPreparedStatementPerConnectionSize: 20
useGlobalDataSourceStat: true
connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=500

<!-- https://mvnrepository.com/artifact/log4j/log4j -->
<dependency>
    <groupId>log4j</groupId>
    <artifactId>log4j</artifactId>
    <version>1.2.17</version>
</dependency>

public class SpringbootDemoDataApplicationTests {
    //注入数据源
    @Autowired
    DataSource dataSource;
    @Test
    public void contextLoads() throws SQLException {
        //看一下默认数据源
        System.out.println(dataSource.getClass());
        //获得连接
        Connection connection =   dataSource.getConnection();
        System.out.println(connection);
        DruidDataSource druidDataSource = (DruidDataSource) dataSource;
        System.out.println("druidDataSource 数据源最大连接数：" + druidDataSource.getMaxActive());
        System.out.println("druidDataSource 数据源初始化连接数：" + druidDataSource.getInitialSize());
        //关闭连接
        connection.close();
    }
}

package com.kk.config;
import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.support.http.StatViewServlet;
import com.alibaba.druid.support.http.WebStatFilter;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import javax.servlet.Filter;
import javax.sql.DataSource;
import java.util.HashMap;
import java.util.Map;
@Configuration
public class DruidConfig {
    @ConfigurationProperties(prefix = "spring.datasource")  //关联application.yaml中的spring.datasource
    @Bean
    public DataSource druidDataSource(){
        return new DruidDataSource();
    }
    //配置 Druid 监控管理后台的Servlet；
    //内置 Servler 容器时没有web.xml文件，所以使用 Spring Boot 的注册 Servlet 方式
    @Bean
    public ServletRegistrationBean statViewServlet() {
        ServletRegistrationBean bean = new ServletRegistrationBean(new StatViewServlet(), "/druid/*");
        Map<String, String> initParams = new HashMap<>();
        initParams.put("loginUsername", "admin"); //后台管理界面的登录账号
        initParams.put("loginPassword", "123456"); //后台管理界面的登录密码
        //后台允许谁可以访问
        //initParams.put("allow", "localhost")：表示只有本机可以访问
        //initParams.put("allow", "")：为空或者为null时，表示允许所有访问
        initParams.put("allow", "");
        //deny：Druid 后台拒绝谁访问
        //initParams.put("kuangshen", "192.168.1.20");表示禁止此ip访问
        //设置初始化参数
        bean.setInitParameters(initParams);
        return bean;
        //这些参数可以在 com.alibaba.druid.support.http.StatViewServlet 的父类 com.alibaba.druid.support.http.ResourceServlet 中找到
    }
    //filter
    @Bean
    public FilterRegistrationBean webStatFilter(){
        FilterRegistrationBean<Filter> bean = new FilterRegistrationBean<>();
        bean.setFilter(new WebStatFilter());
        //可以过滤哪些请求？
        HashMap<String, String> initParameters = new HashMap<>();
        //这些东西不进行统计
        initParameters.put("exclusions","*.js,*.css,/druid/*");
        bean.setInitParameters(initParameters);
        return bean;
    }
}

//filter
@Bean
public FilterRegistrationBean webStatFilter(){
    FilterRegistrationBean<Filter> bean = new FilterRegistrationBean<>();
    bean.setFilter(new WebStatFilter());
    //可以过滤哪些请求？
    HashMap<String, String> initParameters = new HashMap<>();
    //这些东西不进行统计
    initParameters.put("exclusions","*.js,*.css,/druid/*");
    bean.setInitParameters(initParameters);
    return bean;
}

<!-- https://mvnrepository.com/artifact/org.mybatis.spring.boot/mybatis-spring-boot-starter -->
<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>2.2.0</version>
</dependency>

# 数据库驱动：
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
# 数据源名称
spring.datasource.name=defaultDataSource
# 数据库连接地址
spring.datasource.url=jdbc:mysql://localhost:3306/mybatis?useUnicode=true&characterEncoding=utf-8&serverTimezone=UTC
# 数据库用户名&密码：
spring.datasource.username=root
spring.datasource.password=123456

package com.kk;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import javax.sql.DataSource;
import java.sql.SQLException;
@SpringBootTest
class Springboot05MybatisApplicationTests {
    @Autowired
    DataSource dataSource;
    @Test
    void contextLoads() throws SQLException {
        System.out.println(dataSource.getClass());
        System.out.println(dataSource.getConnection());
    }
}

package com.kk;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import javax.sql.DataSource;
import java.sql.SQLException;
@SpringBootTest
class Springboot05MybatisApplicationTests {
    @Autowired
    DataSource dataSource;
    @Test
    void contextLoads() throws SQLException {
        System.out.println(dataSource.getClass());
        System.out.println(dataSource.getConnection());
    }
}

package com.kk.mapper;
import com.kk.pojo.User;
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;
import java.util.List;
//这个注解表示 这是一个mybatis 的mapper类
@Mapper  //controller层
@Repository  //spring
public interface UserMapper {
    List<User> queryUserList();
    User queryUserById(int id);
    int addUser(User user);
    int updateUser(User user);
    int deleteUser(int id);
}

package com.kk.controller;
import com.kk.mapper.UserMapper;
import com.kk.pojo.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;
@RestController
public class UserController {
    @Autowired
    private UserMapper userMapper;
    @GetMapping("/queryUserList")
    public List<User> queryUserList(){
        List<User> userList = userMapper.queryUserList();
        for (User user : userList) {
            System.out.println(user);
        }
        return userList;
    }
    //根据id选择用户
    @GetMapping("/queryUserById")
    public String selectUserById(){
        User user = userMapper.queryUserById(1);
        System.out.println(user);
        return "ok";
    }
    //添加一个用户
    @GetMapping("/addUser")
    public String addUser(){
        userMapper.addUser(new User(1,"大黄","9999999"));
        userMapper.addUser(new User(3,"大黄","9999999"));
        userMapper.addUser(new User(4,"大黄","9999999"));
        return "ok";
    }
    //修改一个用户
    @GetMapping("/updateUser")
    public String updateUser(){
        userMapper.updateUser(new User(5,"黄毛","999999"));
        return "ok";
    }
    //根据id删除用户
    @GetMapping("/deleteUser")
    public String deleteUser(){
        userMapper.deleteUser(5);
        return "ok";
    }
}

# 整合mybatis
# 设置别名以及设置能让spring识别
#指定myBatis的核心配置文件与Mapper映射文件
# 注意：对应实体类的路径
mybatis.type-aliases-package=com.kk.pojo
mybatis.mapper-locations=classpath:mybatis/mapper/*.xml

@ConfigurationProperties(
    prefix = "mybatis"
)
public class MybatisProperties {
    public static final String MYBATIS_PREFIX = "mybatis";
    private static final ResourcePatternResolver resourceResolver = new PathMatchingResourcePatternResolver();
    private String configLocation;
    private String[] mapperLocations;
    private String typeAliasesPackage;
    private Class<?> typeAliasesSuperType;
    private String typeHandlersPackage;
    private boolean checkConfigLocation = false;
    private ExecutorType executorType;
    private Class<? extends LanguageDriver> defaultScriptingLanguageDriver;
    private Properties configurationProperties;
    @NestedConfigurationProperty
    private Configuration configuration;