Java基础-SSM之mybatis多对多关联

　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　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teas，stus，links表

use yinzhengjie;create table teas(id int primary key auto_increment , tname varchar(20)) ;create table stus(id int primary key auto_increment , sname varchar(20)) ;        create table links(tid int , sid int) ;alter table links add constraint fk_tid foreign key (tid) references teas(id) ;    alter table links add constraint fk_sid foreign key (sid) references stus(id) ;

2>.添加Maven依赖

1 
      2 
     
       5     
      
       4.0.0
       6     
      
       cn.org.yinzhengjie
       7     
      
       Mybatis
       8     
      
       1.0-SNAPSHOT
       9     
      
       10         
       
        11             
        
         junit
        12             
        
         junit
        13             
        
         4.11
        14         
       15         
       
        16             
        
         mysql
        17             
        
         mysql-connector-java
        18             
        
         5.1.17
        19         
       20         
       
        21             
        
         org.mybatis
        22             
        
         mybatis
        23             
        
         3.2.1
        24         
       25     
      26 
     

3>.目录结构如下：

 

二.编写自定义类

1>.Stu.java 文件内容

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.one2many; 7  8 import java.util.ArrayList; 9 import java.util.List;10 11 /**12  *    客户13  */14 public class Customer {15     private Integer id ;16     private String name ;17     private int age ;18 19     //建立从Customer到Order之间一对多关系,因为一个客户可能会有多个订单。我们将多个订单放在一个list中。20     private List
     
       orders = new ArrayList
      
       () ;21 22     public List
       
         getOrders() {23         return orders;24     }25 26     public void setOrders(List
        
          orders) {27         this.orders = orders;28     }29 30     public Integer getId() {31         return id;32     }33 34     public void setId(Integer id) {35         this.id = id;36     }37 38     public String getName() {39         return name;40     }41 42     public void setName(String name) {43         this.name = name;44     }45 46     public int getAge() {47         return age;48     }49 50     public void setAge(int age) {51         this.age = age;52     }53 }
        
       
      
     

2>.Tea.java 文件内容

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.many2many; 7  8 import java.util.ArrayList; 9 import java.util.List;10 11 public class Tea {12     private Integer id ;13     private String tname ;14 15     public Tea(String tname){16         this.tname = tname ;17     }18     public Tea(){19     }20     private List
     
       stus = new ArrayList
      
       () ;21 22     public Integer getId() {23         return id;24     }25 26     public void setId(Integer id) {27         this.id = id;28     }29 30     public String getTname() {31         return tname;32     }33 34     public void setTname(String tname) {35         this.tname = tname;36     }37 38     public List
       
         getStus() {39         return stus;40     }41 42     public void setStus(List
        
          stus) {43         this.stus = stus;44     }45 46     public void addStus(Stu...stus){47         for(Stu ss : stus){48             this.getStus().add(ss) ;49             ss.getTeas().add(this) ;50         }51     }52 }
        
       
      
     

 

三.编写配置文件

1>.mybatis-config.xml 文件内容（需要开启批处理模式）

1 
      2  3  6 
     
       7     
      
        8         
        9         
       10         
       11         
       12         
       13     
      14 15     
      16     
      
       17         
       18         
       19     
      20 21     
      
       22         
       
        23             
        24             
        
         25                 
         26                 
         27                 
         28                 
         29             
        30         
       31     
      32     
      
       33         
       34         
       35         
       36     
      37 
     

2>.StuMapper.xml 文件内容

1 
     2 4 
     5 
     
      6     
      
       7         insert into stus(sname) values(#{sname}) ;8     
      9 
     

3>.TeaMapper.xml 文件内容

1 
      2  4 
      5 
     
       6     
      
        7         insert into teas(tname) values(#{tname}) ; 8     
       9     10     
      
       11       
       
        12         insert into links(tid,sid) values(#{id}, #{s.id}) ;13       
       14     
      15 16     
      
       17       delete from links where tid = #{id} ;18       delete from teas where id = #{id}19     
      20 21 22 23     
      
       24         
       25       delete from links where tid = #{id} ;26         
       27       update teas set tname = #{tname} where id = #{id} ;28         
       29         
       
        30             insert into links(tid,sid) values(#{id} , #{s.id}) ;31         
       32     
      33 34     
      35         select36           t.id tid,37           t.tname ttname ,38           s.id sid ,39           s.sname ssname40         from41           teas t42           left outer join links l on l.tid = t.id43           left outer join stus s on s.id = l.sid44         where45           t.id = #{id}46     47     48     
      
       49         
       50         
       51         
       
        52             
        53             
        54         
       55     
      56 
     

 

四.编写测试代码

1>.测试多对多代码如下：

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.many2many.Stu; 9 import cn.org.yinzhengjie.mybatis.domain.many2many.Tea;10 import org.apache.ibatis.io.Resources;11 import org.apache.ibatis.session.SqlSession;12 import org.apache.ibatis.session.SqlSessionFactory;13 import org.apache.ibatis.session.SqlSessionFactoryBuilder;14 import org.junit.Test;15 16 import java.io.InputStream;17 18 /**19  * 测试多对多20  */21 public class TestMany2Many {22     @Test23     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         Tea t1 = new Tea("t1");28         Tea t2 = new Tea("t2");29 30         Stu s1 = new Stu("s1");31         Stu s2 = new Stu("s2");32         Stu s3 = new Stu("s3");33         Stu s4 = new Stu("s4");34 35         t1.addStus(s1 , s2 , s3);36         t2.addStus(s2 , s3 , s4);37 38         sess.insert("teas.insert" , t1);39         sess.insert("teas.insert" , t2);40 41         sess.insert("stus.insert" , s1);42         sess.insert("stus.insert" , s2);43         sess.insert("stus.insert" , s3);44         sess.insert("stus.insert" , s4);45 46         sess.update("teas.updateLinks" , t1);47         sess.update("teas.updateLinks" , t2);48 49         sess.commit();50         sess.close();51     }52 53     @Test54     public void testDeleteTea() throws Exception {55         InputStream in = Resources.getResourceAsStream("mybatis-config.xml");56         SqlSessionFactory sf = new SqlSessionFactoryBuilder().build(in);57         SqlSession sess = sf.openSession();58         sess.delete("teas.deleteOne" , 7) ;59         sess.commit();60         sess.close();61     }62 63     /**64      * 更新65      */66     @Test67     public void testUpdate() throws Exception {68         InputStream in = Resources.getResourceAsStream("mybatis-config.xml");69         SqlSessionFactory sf = new SqlSessionFactoryBuilder().build(in);70         SqlSession sess = sf.openSession();71         Tea t1 = new Tea("tttt") ;72         t1.setId(8);73 74         Stu s1 = new Stu();75         s1.setId(13);76 77         Stu s2 = new Stu();78         s2.setId(14);79 80         t1.addStus(s1,s2);81 82         sess.update("teas.update" , t1) ;83         sess.commit();84         sess.close();85     }86 87     @Test88     public void testSelectOne() throws Exception {89         InputStream in = Resources.getResourceAsStream("mybatis-config.xml");90         SqlSessionFactory sf = new SqlSessionFactoryBuilder().build(in);91         SqlSession sess = sf.openSession();92         Tea obj = (Tea)sess.selectOne("teas.selectOne", 7);93 94         System.out.println(obj.getTname());95         sess.commit();96         sess.close();97     }98 }

 2>.统计函数和分页查询

1 
       2  3  6 
      
        7     
       
         8         
         9         
        10         
        11         
        12         
        13     
       14 15     
       16     
       
        17         
        18         
        19     
       20 21     
       
        22         
        
         23             
         24             
         
          25                 
          26                 
          27                 
          28                 
          29             
         30         
        31     
       32     
       
        33         
        34         
        35     
       36 
      

1 
       2  4 
       5 
      
        6     
        7         select count(*) from stus 8      9 10 11     
       12       select13         t.id tid ,14         t.tname ttname ,15         s.id sid ,16         s.sname ssname17       from18         teas t19           left outer join links l on l.tid = t.id20           left outer join stus s on s.id = l.sid21     22 23     
       24         select * from stus where id > #{id} limit #{offset} , #{limit}25     26 
      

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 org.apache.ibatis.io.Resources; 9 import org.apache.ibatis.session.SqlSession;10 import org.apache.ibatis.session.SqlSessionFactory;11 import org.apache.ibatis.session.SqlSessionFactoryBuilder;12 import org.junit.Test;13 14 import java.io.InputStream;15 import java.util.HashMap;16 import java.util.List;17 import java.util.Map;18 19 /**20  * 测试统计21  */22 public class TestStat {23     @Test24     public void testInsert() throws Exception {25         InputStream in = Resources.getResourceAsStream("mybatis-config.xml");26         SqlSessionFactory sf = new SqlSessionFactoryBuilder().build(in);27         SqlSession sess = sf.openSession();28         int count = sess.selectOne("stats.countStus");29         List

　　测试的目录结构如下：