Java进阶知识35 mybatis+Oracle 单向一对多关联之CRUD操作【xml 版】

本文知识点（目录）：

      1、导读
          1.1、技术概述
          1.2、本文使用的jar包、项目结构图
      2、本文所有代码（xml版）
          2.1、数据库脚本（oracle.sql）
          2.2、mybatis.xml 核心配置文件
          2.3、MyBatisUtils 工具类（用于连接数据库）
          2.4、实体类（Team、Member ）以及对应的xxxxxMapper.xml 配置文件
          2.5、DAO层（Team类对应的接口及接口实现类、Member类对应的接口及接口实现类）
          2.6、测试类（TestMemberDao）及测试结果

1、导读

1.1、技术概述

a.本文使用的是Oracle+mybatis框架，单向一对多关联，以Member为主；（数据表之间的关系：team是主表，member是从表）

b.实现了CURD等操作：新增、修改、删除、批量删除、查询全部、多条件查询、根据id查询、查询某个团队下的所有成员。

c.本文只测试/演示DAO层与数据库之间的连接以及数据的CRUD操作

d.本项目的使用环境：MyEclipse10.7 + JDK1.8 + Oracle11g + mybatis3.1.1

1.2、本文使用的jar包、项目结构图

2、本文所有代码（xml版）

2.1、数据库脚本（oracle.sql）

 1 -- 一对多
 2 -- 1、创建表
 3 create table team(-- 团队表
 4     id number(5) primary key,
 5     name varchar2(20),
 6     description varchar2(50)
 7 );
 8 
 9 create table member(-- 成员表
10     id number(5) primary key,
11     name varchar2(20),
12     sex smallint, -- 用number(1)也行，0代表男，1代表女
13     team_id number(5),
14     constraint member_team_fk foreign key(team_id) references team(id)
15 );
16 
17 -- 2、创建序列
18 create sequence team_seq
19 minvalue 1    --最小值
20 maxvalue 99999    -- 最大值
21 increment by 1    --从1开始计数
22 start with 1    --每次加1
23 nocycle        --一直累加，不循环
24 nocache;    --不建缓冲区。
25 
26 create sequence member_seq
27 minvalue 1    
28 maxvalue 99999    
29 increment by 1 
30 start with 1    
31 nocycle        
32 nocache;    
33 
34 -- 3、创建触发器
35 create or replace trigger team_tg
36   before insert on team for each row 
37     begin
38       select team_seq.Nextval into:new.id from dual;
39   end;
40 
41 create or replace trigger member_tg
42   before insert on member for each row 
43     begin
44       select member_seq.Nextval into:new.id from dual;
45   end;
46 
47

2.2、mybatis.xml 核心配置文件

 1 <?xml version="1.0" encoding="UTF-8" ?>
 2 <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
 3 "http://mybatis.org/dtd/mybatis-3-config.dtd">
 4 <configuration>
 5     <environments default="development">
 6         <environment id="development">
 7             <transactionManager type="JDBC" />
 8             <dataSource type="POOLED">
 9                 <property name="driver" value="oracle.jdbc.driver.OracleDriver" />
10                 <property name="url" value="jdbc:oracle:thin:@localhost:1521:shoreid" />
11                 <property name="username" value="zhangsan" />
12                 <property name="password" value="123456" />
13             </dataSource>
14         </environment>
15     </environments>
16 
17     <mappers><!-- 5、通过SqlSession对象读取XXXXXMapper.xml映射文件中的对应操作id，从而获取sql语句； -->
18         <mapper resource="com/shore/o2m/entity/MemberMapper.xml"/>
19         <mapper resource="com/shore/o2m/entity/TeamMapper.xml"/>
20     </mappers>
21 </configuration>

2.3、MyBatisUtils 工具类（用于连接数据库）

 1 package com.shore.common.utils;
 2 
 3 import java.io.Reader;
 4 
 5 import org.apache.ibatis.io.Resources;
 6 import org.apache.ibatis.session.SqlSession;
 7 import org.apache.ibatis.session.SqlSessionFactory;
 8 import org.apache.ibatis.session.SqlSessionFactoryBuilder;
 9 
10 /**
11  * @author DSHORE/2020-3-12
12  *
13  */
14 public class MyBatisUtils {
15     private static ThreadLocal<SqlSession> threadLocal = new ThreadLocal<SqlSession>();
16     private static SqlSessionFactory sqlSessionFactory;
17     
18     static{
19         try {
20             //1、读取配置
21             Reader reader = Resources.getResourceAsReader("mybatis.xml");
22             //2、创建SqlSessionFactory
23             sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
24         } catch (Exception e) {
25             e.fillInStackTrace();
26             throw new RuntimeException(e);
27         }
28     }
29     
30     private MyBatisUtils() { }
31     
32     //3、获取SqlSession
33     public static SqlSession getSqlSession(){
34         SqlSession sqlSession = threadLocal.get();
35         if (sqlSession == null) {//如果上面获取不到SQLSession，将通过下面的方式来获取
36             sqlSession = sqlSessionFactory.openSession();
37         }
38         return sqlSession;
39     }
40     
41     //7、关闭SqlSession
42     public static void closeSqlSession() {
43         SqlSession sqlSession = threadLocal.get();
44         if (sqlSession != null) {
45             sqlSession.close();
46             threadLocal.remove();
47         }
48     }
49 }

2.4、实体类（Team、Member）以及对应的xxxxxMapper.xml 配置文件

Team.java

 1 package com.shore.o2m.entity;
 2 
 3 import java.util.Set;
 4 
 5 /**
 6  * @author DSHORE/2020-3-17 
 7  * mybatis：单向一对多，以Member为主
 8  * team表与member表之间的关系：team是主表，member是从表
 9  */
10 public class Team {// 一的一方
11     private Integer id;
12     private String name;
13     private String description;
14     private Set<Member> members;
15 
16     //省略Setters和Getters方法
17 }

TeamMapper.xml 配置文件

 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 
 5 <mapper namespace="teamNameSpace">
 6     <resultMap id="teamResultMap" type="com.shore.o2m.entity.Team">
 7         <id property="id" column="id" /> <!-- property和 column不能省略 -->
 8         <result property="name" column="name" />
 9         <result property="description" column="description" />
10         <!-- 单向一对多关联，以Member为主，一的一方 -->
11         <collection property="members" resultMap="memberNameSpace.memberResultMap"></collection>
12     </resultMap>
13 
14     <!--======================= 新增 ============================= -->
15     <insert id="addTeam" parameterType="com.shore.o2m.entity.Team">
16         <!-- 返回当前，刚刚插入的数据的id，用于member表的外键team_id -->
17         <selectKey order="AFTER" keyProperty="id" resultType="int">
18             <!-- 这里的id是自增长的（序列+触发器），具体请看oracle.sql中的数据表脚本 -->
19             select max(id) as id from team
20             <!-- select team_seq.Nextval as id from dual -->
21         </selectKey>
22         insert into team(name,description)
23         values(#{name,jdbcType=VARCHAR},#{description,jdbcType=VARCHAR})
24     </insert>
25 
26     <!--===================== 根据id查询 ========================== -->
27     <select id="findById" parameterType="int" resultMap="teamResultMap">
28         select * from team where id = #{id,jdbcType=NUMERIC}
29     </select>
30     
31     <!--====================== 查询所有 =========================== -->
32     <select id="selectAll" resultMap="teamResultMap">
33         select * from team  
34     </select>
35 </mapper>

Member.java

 1 package com.shore.o2m.entity;
 2 
 3 /**
 4  * @author DSHORE/2020-3-17 
 5  * mybatis：单向一对多，以Member为主
 6  * team表与member表之间的关系：team是主表，member是从表
 7  */
 8 public class Member {
 9     private Integer id;
10     private String name;
11     private Integer sex;
12     private Team team;
13 
14     //省略Setters和Getters方法
15 
16     @Override
17     public String toString() {
18         return "Member [id=" + id + ", name=" + name + ", sex=" + sex
19                 + ", team=" + team + "]";
20     }
21 }

MemberMapper.xml 配置文件

 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 
 5 <mapper namespace="memberNameSpace">
 6     <resultMap id="memberResultMap" type="com.shore.o2m.entity.Member">
 7         <id property="id" column="id"/> <!-- property和 column不能省略-->
 8         <result property="name" column="name"/>
 9         <result property="sex" column="sex"/>
10         <!-- 单向一对多关联，以Member为主，多的一方 -->
11         <association property="team" column="team_id" resultMap="teamNameSpace.teamResultMap"/>
12     </resultMap>
13     
14     <!--======================= 新增 ============================= -->
15     <insert id="addMember" parameterType="com.shore.o2m.entity.Member">
16         insert into member(name,sex,team_id)
17          values(#{name,jdbcType=VARCHAR},#{sex,jdbcType=NUMERIC},#{team.id,jdbcType=NUMERIC})
18     </insert>
19     
20     <!--======================= 修改 ============================= -->
21     <update id="updateMember" parameterType="com.shore.o2m.entity.Member">
22         update member 
23         set 
24             <if test="name != null">
25                 name=#{name,jdbcType=VARCHAR},
26             </if>
27             <if test="sex != null">
28                 sex=#{sex,jdbcType=NUMERIC},
29             </if>
30             <if test="team.id != null">
31                 team_id=#{team.id,jdbcType=NUMERIC} 
32             </if>
33         where id=#{id,jdbcType=NUMERIC}
34     </update>
35     
36     <!--===================== 根据id查询 =========================== -->
37     <select id="findById" parameterType="int" resultMap="memberResultMap">
38         select m.*,t.* 
39          from member m,team t
40         where m.team_id = t.id and m.id = #{id}
41     </select>
42     
43     <!--===================== 多条件查询=========================== -->
44     <!-- resultMap和 parameterType的区别：
45         如果用resultMap="memberResultMap"；则，member表以及关联表team中的数据都查询出来。
46         如果用parameterType="com.shore.o2m.entity.Member"；则，查询结果只有member表的数据，team表为null。
47     -->
48     <select id="multiconditionalQuery" parameterType="map" resultMap="memberResultMap">
49         select m.*,t.* from member m,team t
50         <where>
51             and m.team_id = t.id
52             <if test="memberName != null">
53                 and m.name = #{memberName}
54             </if>
55             <if test="teamName != null">
56                 and t.name = #{teamName}
57             </if>
58         </where>
59     </select>
60     
61     <!--================== 查询指定战队下，所有队员 ==================== -->
62     <select id="selectAll" parameterType="String" resultMap="memberResultMap">
63         select m.*,t.*
64         from member m,team t
65         where m.team_id = t.id and t.name = #{teamName}
66     </select>
67     
68     <!--======================== 删除 ============================== -->
69     <delete id="deleteByMemberId" parameterType="int">
70         delete from member where id=#{id}
71     </delete>
72     
73     <!--======================= 批量删除 ============================ -->
74     <delete id="batchDeleteById">
75         delete from member where id in 
76         <foreach item="ids" collection="list" open="(" separator="," close=")">
77             #{ids}
78         </foreach>
79     </delete>
80 </mapper>

2.5、DAO层（Team类对应的接口及接口实现类、Member类对应的接口及接口实现类）

ITeamDao.java（接口类）

 1 package com.shore.o2m.dao;
 2 
 3 import java.util.List;
 4 
 5 import com.shore.o2m.entity.Team;
 6 
 7 /**
 8  * @author DSHORE/2020-3-17
 9  *
10  */
11 public interface ITeamDao {
12     public int addTeam(Team team);//新增
13     
14     public Team findByTeamId(int id);//根据id查询
15     
16     public List<Team> listAll();//查询所有团队/战队
17 }

TeamDao.java （接口类ITeamDao的实现类）

 1 package com.shore.o2m.dao.impl;
 2 
 3 import java.util.ArrayList;
 4 import java.util.List;
 5 
 6 import org.apache.ibatis.session.SqlSession;
 7 
 8 import com.shore.common.utils.MyBatisUtils;
 9 import com.shore.o2m.dao.ITeamDao;
10 import com.shore.o2m.entity.Team;
11 
12 /**
13  * @author DSHORE/2020-3-17
14  *
15  */
16 public class TeamDao implements ITeamDao {
17     SqlSession sqlSession = null;
18 
19     @Override //新增
20     public int addTeam(Team team) {
21         sqlSession = MyBatisUtils.getSqlSession();
22         try {
23             return sqlSession.insert("teamNameSpace.addTeam", team);
24         } catch (Exception e) {
25             sqlSession.rollback();//如果出现异常,则,事务回滚
26             System.out.println(e.getMessage());//打印异常信息
27         } finally {
28             sqlSession.commit();//提交事务
29             MyBatisUtils.closeSqlSession();//关闭SqlSession
30         }
31         return 0;
32     }
33 
34     @Override //根据id查询
35     public Team findByTeamId(int id) {
36         List<Team> teams = new ArrayList<Team>();
37         Team team = null;
38         sqlSession = MyBatisUtils.getSqlSession();
39         try {
40             teams = sqlSession.selectList("teamNameSpace.findById",id);
41             if (teams != null && teams.size() > 0) {
42                 team = teams.get(0);
43             }
44         } catch (Exception e) {
45             System.out.println(e.getMessage());
46         } finally {
47             MyBatisUtils.closeSqlSession();
48         }    
49         return team;
50     }
51 
52     @Override //查询所有团队/战队
53     public List<Team> listAll() {
54         List<Team> teams = new ArrayList<Team>();
55         sqlSession = MyBatisUtils.getSqlSession();
56         try {
57             teams = sqlSession.selectList("teamNameSpace.selectAll");
58         } catch (Exception e) {
59             System.out.println("error:" + e.getMessage());
60         } finally {
61             MyBatisUtils.closeSqlSession();
62         }
63         return teams;
64     }
65 }

IMemberDao.java（接口类）

 1 package com.shore.o2m.dao;
 2 
 3 import java.util.List;
 4 
 5 import com.shore.o2m.entity.Member;
 6 
 7 
 8 /**
 9  * @author DSHORE/2020-3-17
10  *
11  */
12 public interface IMemberDao {
13     public int addMember(Member member);//新增
14     
15     public int updateMember(Member member);//修改
16     
17     public Member findByMemberId(int id);//根据id查询
18     
19     public List<Member> multiconditionalQuery(String teamName, String memberName);//多条件查询
20     
21     public List<Member> listAllByTeam(String teamName);//查询指定战队下，所有队员
22     
23     public int deleteMember(int id);//删除
24     
25     public int batchDeleteById(List<Integer> ids);//批量删除
26 }

MemberDao.java（接口类IMemberDao的实现类）

  1 package com.shore.o2m.dao.impl;
  2 
  3 import java.util.ArrayList;
  4 import java.util.HashMap;
  5 import java.util.List;
  6 import java.util.Map;
  7 
  8 import org.apache.ibatis.session.SqlSession;
  9 
 10 import com.shore.common.utils.MyBatisUtils;
 11 import com.shore.o2m.dao.IMemberDao;
 12 import com.shore.o2m.entity.Member;
 13 
 14 /**
 15  * @author DSHORE/2020-3-17
 16  *
 17  */
 18 public class MemberDao implements IMemberDao {
 19 
 20     @Override //新增
 21     public int addMember(Member member) {
 22         SqlSession sqlSession = MyBatisUtils.getSqlSession();
 23         try {
 24             return sqlSession.insert("memberNameSpace.addMember", member);
 25         } catch (Exception e) {
 26             sqlSession.rollback();//如果出现异常,则,事务回滚
 27             System.out.println(e.getMessage());//打印异常信息
 28         } finally {
 29             sqlSession.commit();//提交事务
 30             MyBatisUtils.closeSqlSession();//关闭SqlSession
 31         }
 32         return 0;
 33     }
 34 
 35     @Override //修改
 36     public int updateMember(Member member) {
 37         SqlSession sqlSession = MyBatisUtils.getSqlSession();
 38         try {
 39             return sqlSession.insert("memberNameSpace.updateMember", member);
 40         } catch (Exception e) {
 41             sqlSession.rollback();
 42             System.out.println(e.getMessage());
 43         } finally {
 44             sqlSession.commit();
 45             MyBatisUtils.closeSqlSession();
 46         }
 47         return 0;
 48     }
 49 
 50     @Override //根据id查询
 51     public Member findByMemberId(int id) {
 52         List<Member> members = new ArrayList<Member>();
 53         Member member = null;
 54         SqlSession sqlSession = MyBatisUtils.getSqlSession();
 55         try {
 56             members = sqlSession.selectList("memberNameSpace.findById",id);
 57             if (members != null && members.size() > 0) {
 58                 member = members.get(0);
 59             }
 60         } catch (Exception e) {
 61             System.out.println(e.getMessage());//打印错误/异常信息
 62         } finally {
 63             MyBatisUtils.closeSqlSession();//关闭SqlSession
 64         }    
 65         return member;
 66     }
 67 
 68     @Override //多条件查询
 69     public List<Member> multiconditionalQuery(String teamName, String memberName) {
 70         List<Member> members = new ArrayList<Member>();
 71         SqlSession sqlSession = MyBatisUtils.getSqlSession();
 72         try {
 73             Map<String, String> map = new HashMap<String, String>();
 74             map.put("teamName", teamName);
 75             map.put("memberName", memberName);
 76             members = sqlSession.selectList("memberNameSpace.multiconditionalQuery", map);
 77         } catch (Exception e) {
 78             System.out.println("error:" + e.getMessage());
 79         } finally {
 80             MyBatisUtils.closeSqlSession();
 81         }
 82         return members;
 83     }
 84 
 85     @Override //查询指定战队下，所有队员
 86     public List<Member> listAllByTeam(String teamName) {
 87         List<Member> members = new ArrayList<Member>();
 88         SqlSession sqlSession = MyBatisUtils.getSqlSession();
 89         try {
 90             members = sqlSession.selectList("memberNameSpace.selectAll",teamName);
 91         } catch (Exception e) {
 92             System.out.println(e.getMessage());//打印错误/异常信息
 93         } finally {
 94             MyBatisUtils.closeSqlSession();//关闭SqlSession
 95         }    
 96         return members;
 97     }
 98 
 99     @Override //删除（只删除member表的消息，不删除关联表team的消息）
100     public int deleteMember(int id) {
101         SqlSession sqlSession = MyBatisUtils.getSqlSession();
102         try {
103             return sqlSession.delete("memberNameSpace.deleteByMemberId", id);
104         } catch (Exception e) {
105             sqlSession.rollback();
106             System.out.println(e.getMessage());
107         } finally {
108             sqlSession.commit();
109             MyBatisUtils.closeSqlSession();
110         }
111         return 0;
112     }
113 
114     @Override //批量删除（只删除member表的消息，不删除关联表team的消息）
115     public int batchDeleteById(List<Integer> ids) {
116         SqlSession sqlSession = MyBatisUtils.getSqlSession();
117         try {
118             return sqlSession.delete("memberNameSpace.batchDeleteById", ids);
119         } catch (Exception e) {
120             sqlSession.rollback();
121             System.out.println("error:"+e.getMessage());
122         } finally {
123             sqlSession.commit();
124             MyBatisUtils.closeSqlSession();
125         }
126         return 0;
127     }
128 
129 }

2.6、测试类（TestMemberDao）及测试结果

  1 package test.member;
  2 
  3 import java.util.ArrayList;
  4 import java.util.HashSet;
  5 import java.util.List;
  6 import java.util.Set;
  7 
  8 import org.junit.Test;
  9 
 10 import com.shore.o2m.dao.IMemberDao;
 11 import com.shore.o2m.dao.ITeamDao;
 12 import com.shore.o2m.dao.impl.MemberDao;
 13 import com.shore.o2m.dao.impl.TeamDao;
 14 import com.shore.o2m.entity.Member;
 15 import com.shore.o2m.entity.Team;
 16 
 17 /**
 18  * @author DSHORE/2020-3-17
 19  *
 20  */
 21 public class TestMemberDao {
 22     IMemberDao memberDao = new MemberDao();
 23     ITeamDao teamDao = new TeamDao();
 24     
 25     @Test //新增
 26     public void testAdd() {
 27         Member member = new Member();
 28         member.setName("王五");
 29         member.setSex(1);
 30         
 31         Member member2 = new Member();
 32         member2.setName("赵六");
 33         member2.setSex(0);
 34         
 35         //1、新建的方式
 36         Team team = new Team();
 37         team.setName("峡谷抓河蟹");
 38         team.setDescription("王者荣耀战队名称");
 39         
 40         Set<Member> members = new HashSet<Member>();
 41         team.setMembers(members);
 42         
 43         //2、使用数据中已有的数据  的方式
 44         /*Team team = teamDao.findByTeamId(2);
 45         member.setTeam(team);*/
 46         
 47         member.setTeam(team);
 48         member2.setTeam(team);
 49         
 50         System.out.println(teamDao.addTeam(team));//返回值：1     说明插入数据成功
 51         System.out.println(memberDao.addMember(member));//返回值：1
 52         System.out.println(memberDao.addMember(member2));//返回值：1
 53     }
 54     
 55     @Test //更新（修改）
 56     public void testUpdate() {
 57         Member member = new Member();
 58         member.setId(1);
 59         member.setName("张三");
 60         member.setSex(1);
 61         
 62         //把张三的所在战队id是1的，改为战队id是2。
 63         Team team = teamDao.findByTeamId(2);
 64         member.setTeam(team);
 65         
 66         System.out.println(memberDao.updateMember(member));//返回值：1
 67     }
 68     
 69     @Test //根据id查询
 70     public void testFindById() {
 71         System.out.println(teamDao.findByTeamId(1));//返回值：com.shore.o2m.entity.Team@722d95b3
 72         System.out.println(memberDao.findByMemberId(3));//返回值：Member [id=3, name=王五, sex=1, team=com.shore.o2m.entity.Team@6273305c]
 73     }
 74     
 75     @Test //多条件查询
 76     public void testMulticonditionalQuery() {
 77         //返回值：[Member [id=2, name=李四, sex=0, team=com.shore.o2m.entity.Team@5dd2b9b7]]
 78         System.out.println(memberDao.multiconditionalQuery("飞虎队", null));
 79         
 80         //返回值：[Member [id=1, name=张三, sex=1, team=com.shore.o2m.entity.Team@451c0d60]]
 81         System.out.println(memberDao.multiconditionalQuery(null, "张三"));
 82         
 83         //返回值：[Member [id=1, name=张三, sex=1, team=com.shore.o2m.entity.Team@5a0029ac]]
 84         System.out.println(memberDao.multiconditionalQuery("峡谷抓河蟹", "张三"));
 85     }
 86     
 87     @Test //查询指定战队下，所有队员
 88     public void testListAllByTeam() {
 89         List<Member> members = memberDao.listAllByTeam("峡谷抓河蟹");
 90         if (members == null) {
 91             System.out.println("members is null。");
 92         } else {
 93             //System.out.println(members.get(0));
 94             for (Member me : members) {
 95                 System.out.println(me);
 96                 /*返回值:
 97                  * Member [id=4, name=赵六, sex=0, team=com.shore.o2m.entity.Team@337b4703]
 98                  * Member [id=1, name=张三, sex=1, team=com.shore.o2m.entity.Team@6273305c]
 99                  * Member [id=3, name=王五, sex=1, team=com.shore.o2m.entity.Team@786c1a82]
100                  * */
101             }
102         }
103     }
104     
105     @Test //查询所有战队
106     public void testListAll() {
107         List<Team> teams = teamDao.listAll();
108         if (teams == null) {
109             System.out.println("teams is null。");
110         } else {
111             //System.out.println(teams.get(0));
112             for (Team te : teams) {
113                 System.out.println(te);
114                 /*返回值：
115                  * com.shore.o2m.entity.Team@4a57ea52
116                  * com.shore.o2m.entity.Team@51d8d39f
117                  * */
118             }
119         }
120     }
121     
122     @Test //删除 （只删除member表的消息，不删除关联表team的消息）
123     public void testDelete() {
124         System.out.println(memberDao.deleteMember(7));//返回值：1     说明删除数据成功
125     }
126     
127     @Test // 批量删除 （只删除member表的消息，不删除关联表team的消息）
128     public void testBatchDelete() {
129         List<Integer> ids = new ArrayList<Integer>();
130         ids.add(4);
131         ids.add(5);
132         ids.add(6);
133         System.out.println(memberDao.batchDeleteById(ids));//返回值：3     说明批量删除数据成功
134     }
135 }

到此已完结！有任何问题，可留言。

mybatis单向一对一关联映射：https://www.cnblogs.com/dshore123/p/12489304.html
mybatis单向一对多关联映射：https://www.cnblogs.com/dshore123/p/12493450.html
mybatis单向多对多关联映射：https://www.cnblogs.com/dshore123/p/12526016.html

原创作者：DSHORE

作者主页：http://www.cnblogs.com/dshore123/

原文出自：https://www.cnblogs.com/dshore123/p/12493450.html

posted @ 2020-03-14 18:25 DSHORE 阅读(782) 评论(0) 编辑收藏举报

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