Java基础-SSM之mybatis的树形控件（自关联）
Java基础-SSM之mybatis的树形控件（自关联）
作者：尹正杰
版权声明：原创作品，谢绝转载！否则将追究法律责任。
一.准备测试环境（创建数据库表）
1>.创建areas表；
use yinzhengjie;create table areas(id int primary key auto_increment , areaname varchar(30) , pid int) ;
2>.添加Maven依赖
1 <?xml version="1.0" encoding="UTF-8"?>2 <project xmlns="http://maven.apache.org/POM/4.0.0"
3 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
4 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
5 <modelVersion>4.0.0</modelVersion>
6 <groupId>cn.org.yinzhengjie</groupId>
7 <artifactId>Mybatis</artifactId>
8 <version>1.0-SNAPSHOT</version>
9 <dependencies>
10 <dependency>
11 <groupId>junit</groupId>
12 <artifactId>junit</artifactId>
13 <version>4.11</version>
14 </dependency>
15 <dependency>
16 <groupId>mysql</groupId>
17 <artifactId>mysql-connector-java</artifactId>
18 <version>5.1.17</version>
19 </dependency>
20 <dependency>
21 <groupId>org.mybatis</groupId>
22 <artifactId>mybatis</artifactId>
23 <version>3.2.1</version>
24 </dependency>
25 </dependencies>
26 </project>
二.编写自定义类（area.java）
1 /*2 @author :yinzhengjie
3 Blog:http://www.cnblogs.com/yinzhengjie/tag/Java%E5%9F%BA%E7%A1%80/
4 EMAIL:y1053419035@qq.com
5 */
6 package cn.org.yinzhengjie.mybatis.domain.self;
7
8 import java.util.ArrayList;
9 import java.util.List;
10
11
12 /**
13 * 自关联
14 */
15 public class Area {
16 private Integer id ;
17
18 private String areaName ;
19 //上级区域
20 private Area parentArea ;
21
22 public Area(){
23 }
24
25 public Area(String name){
26 this.areaName = name;
27 }
28
29 private List<Area> children = new ArrayList<Area>();
30
31 public Integer getId() {
32 return id;
33 }
34
35 public void setId(Integer id) {
36 this.id = id;
37 }
38
39 public String getAreaName() {
40 return areaName;
41 }
42
43 public void setAreaName(String areaName) {
44 this.areaName = areaName;
45 }
46
47 public Area getParentArea() {
48 return parentArea;
49 }
50
51 public void setParentArea(Area parentArea) {
52 this.parentArea = parentArea;
53 }
54
55 public List<Area> getChildren() {
56 return children;
57 }
58
59 public void setChildren(List<Area> children) {
60 this.children = children;
61 }
62
63 //定义用于绑定关系的方法
64 public void addChildren(Area...areas){
65 for(Area a : areas){
66 this.getChildren().add(a) ;
67 a.setParentArea(this);
68 }
69 }
70 }
三.编写配置文件
1>.mybatis-config.xml 文件内容
1 <?xml version="1.0" encoding="UTF-8" ?>2 <!DOCTYPE configuration
3 PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
4 "http://mybatis.org/dtd/mybatis-3-config.dtd">
5 <configuration>
6 <properties>
7 <property name="driver" value="com.mysql.jdbc.Driver"/>
8 <property name="url" value="jdbc:mysql://localhost:5200/yinzhengjie"/>
9 <property name="username" value="root"/>
10 <property name="password" value="yinzhengjie"/>
11 </properties>
12
13 <!-- 我们使用typeAliases标签给我们自定义类起个别名。-->
14 <typeAliases>
15 <typeAlias type="cn.org.yinzhengjie.mybatis.domain.self.Area" alias="_Area" />
16 </typeAliases>
17
18 <environments default="development">
19 <environment id="development">
20 <transactionManager type="JDBC"/>
21 <dataSource type="POOLED">
22 <property name="driver" value="${driver}"/>
23 <property name="url" value="${url}"/>
24 <property name="username" value="${username}"/>
25 <property name="password" value="${password}"/>
26 </dataSource>
27 </environment>
28 </environments>
29 <mappers>
30 <!-- 我们使用mapper标签指定映射文件，使用resource指定具体的路径，如果没有写绝对路径，默认的根路径就在resources目录中-->
31 <mapper resource="AreaMapper.xml"/>
32 </mappers>
33 </configuration>
2>.AreaMapper.xml 文件内容
1 <?xml version="1.0" encoding="UTF-8" ?>2 <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
3 "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
4 <!-- 定义名字空间 -->
5 <mapper namespace="areas">
6 <!-- useGeneratedKeys的值为true时，表示需要使用数据库深层的keys，同时我们需要指定使用哪个深层的key。而指定具体使用哪个key我们使用keyProperty来定义！ -->
7 <insert id="insert" useGeneratedKeys="true" keyProperty="id">
8 insert into areas(areaname,pid) values(#{areaName}, #{parentArea.id}) ;
9 </insert>
10
11 <select id="selectOne" resultMap="rm_Area">
12 select
13 s.id sid ,
14 s.areaname sname ,
15 p.id pid ,
16 p.areaname pname,
17 c.id cid ,
18 c.areaname cname
19 from
20 areas s
21 left outer join areas p on p.id = s.pid
22 left outer join areas c on s.id = c.pid
23 where
24 s.id = #{id} ;
25 </select>
26
27 <resultMap id="rm_Area" type="_Area">
28 <id column="sid" property="id" />
29 <result column="sname" property="areaName" />
30 <association column="pid" property="parentArea" javaType="_Area">
31 <id column="pid" property="id"/>
32 <result column="pname" property="areaName"/>
33 </association>
34 <collection property="children" ofType="_Area" column="sid">
35 <id column="cid" property="id"/>
36 <result column="cname" property="areaName"/>
37 </collection>
38 </resultMap>
39 </mapper>
四.编写测试代码
1>.编写测试代码如下：
1 /*2 @author :yinzhengjie
3 Blog:http://www.cnblogs.com/yinzhengjie/tag/Java%E5%9F%BA%E7%A1%80/
4 EMAIL:y1053419035@qq.com
5 */
6 package cn.org.yinzhengjie.mybatis.test;
7
8 import cn.org.yinzhengjie.mybatis.domain.self.Area;
9 import org.apache.ibatis.io.Resources;
10 import org.apache.ibatis.session.SqlSession;
11 import org.apache.ibatis.session.SqlSessionFactory;
12 import org.apache.ibatis.session.SqlSessionFactoryBuilder;
13 import org.junit.Test;
14
15 import java.io.InputStream;
16 import java.util.List;
17
18 /**
19 * 测试自关联
20 */
21 public class TestSelf {
22 @Test
23 public void testInsertCustomer() throws Exception {
24 InputStream in = Resources.getResourceAsStream("mybatis-config.xml");
25 SqlSessionFactory sf = new SqlSessionFactoryBuilder().build(in);
26 SqlSession sess = sf.openSession();
27 Area china = new Area("zhongguo") ;
28 Area bj = new Area("beijing") ;
29 Area hb = new Area("hebeisheng") ;
30 Area haidian = new Area("haidian") ;
31 Area chaoyang = new Area("chaoyang") ;
32 Area shijiangzhuang = new Area("shijiangzhuang") ;
33 Area handan = new Area("handan") ;
34 Area guangfugucheng = new Area("guangfugucheng-1") ;
35 Area wahuanggong = new Area("wahuanggong-2") ;
36
37 //绑定关联关系
38 china.addChildren(bj,hb);
39 bj.addChildren(haidian,chaoyang);
40 hb.addChildren(shijiangzhuang,handan);
41 handan.addChildren(guangfugucheng,wahuanggong);
42
43
44 //往数据库中插入数据
45 sess.insert("areas.insert" , china);
46 sess.insert("areas.insert" , bj);
47 sess.insert("areas.insert" , hb);
48 sess.insert("areas.insert" , haidian);
49 sess.insert("areas.insert" , chaoyang);
50 sess.insert("areas.insert" , shijiangzhuang);
51 sess.insert("areas.insert" , handan);
52 sess.insert("areas.insert" , guangfugucheng);
53 sess.insert("areas.insert" , wahuanggong);
54
55 //提交事物
56 sess.commit();
57 sess.close();
58
59 System.out.println("数据插入成功！");
60 }
61
62 @Test
63 public void testSelectOne() throws Exception {
64 InputStream in = Resources.getResourceAsStream("mybatis-config.xml");
65 SqlSessionFactory sf = new SqlSessionFactoryBuilder().build(in);
66 SqlSession sess = sf.openSession();
67 Area obj = sess.selectOne("areas.selectOne" , 2) ;
68 List<Area> children = obj.getChildren();
69 for (Area child : children) {
70 System.out.println(child.getAreaName());
71 }
72 sess.commit();
73 sess.close();
74 }
75 }
2>.查询数据库执行结果如下：
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