使用MyBatis对表执行CRUD操作

1、定义sql映射xml文件

　　userMapper.xml文件的内容如下：

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      17         select * from users where id=#{id}18     19     20     
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       22         insert into users(name,age) values(#{name},#{age})23     
      24     25     
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       27         delete from users where id=#{id}28     
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       32         update users set name=#{name},age=#{age} where id=#{id}33     
      34     35     
      36     
      37         select * from users38     39     40 
     

　　单元测试类代码如下：

1 package me.gacl.test; 2  3 import java.util.List; 4 import me.gacl.domain.User; 5 import me.gacl.util.MyBatisUtil; 6 import org.apache.ibatis.session.SqlSession; 7 import org.junit.Test; 8  9 public class TestCRUDByXmlMapper {10 11     @Test12     public void testAdd(){13         //SqlSession sqlSession = MyBatisUtil.getSqlSession(false);14         SqlSession sqlSession = MyBatisUtil.getSqlSession(true);15         /**16          * 映射sql的标识字符串，17          * me.gacl.mapping.userMapper是userMapper.xml文件中mapper标签的namespace属性的值，18          * addUser是insert标签的id属性值，通过insert标签的id属性值就可以找到要执行的SQL19          */20         String statement = "me.gacl.mapping.userMapper.addUser";//映射sql的标识字符串21         User user = new User();22         user.setName("用户孤傲苍狼");23         user.setAge(20);24         //执行插入操作25         int retResult = sqlSession.insert(statement,user);26         //手动提交事务27         //sqlSession.commit();28         //使用SqlSession执行完SQL之后需要关闭SqlSession29         sqlSession.close();30         System.out.println(retResult);31     }32     33     @Test34     public void testUpdate(){35         SqlSession sqlSession = MyBatisUtil.getSqlSession(true);36         /**37          * 映射sql的标识字符串，38          * me.gacl.mapping.userMapper是userMapper.xml文件中mapper标签的namespace属性的值，39          * updateUser是update标签的id属性值，通过update标签的id属性值就可以找到要执行的SQL40          */41         String statement = "me.gacl.mapping.userMapper.updateUser";//映射sql的标识字符串42         User user = new User();43         user.setId(3);44         user.setName("孤傲苍狼");45         user.setAge(25);46         //执行修改操作47         int retResult = sqlSession.update(statement,user);48         //使用SqlSession执行完SQL之后需要关闭SqlSession49         sqlSession.close();50         System.out.println(retResult);51     }52     53     @Test54     public void testDelete(){55         SqlSession sqlSession = MyBatisUtil.getSqlSession(true);56         /**57          * 映射sql的标识字符串，58          * me.gacl.mapping.userMapper是userMapper.xml文件中mapper标签的namespace属性的值，59          * deleteUser是delete标签的id属性值，通过delete标签的id属性值就可以找到要执行的SQL60          */61         String statement = "me.gacl.mapping.userMapper.deleteUser";//映射sql的标识字符串62         //执行删除操作63         int retResult = sqlSession.delete(statement,5);64         //使用SqlSession执行完SQL之后需要关闭SqlSession65         sqlSession.close();66         System.out.println(retResult);67     }68     69     @Test70     public void testGetAll(){71         SqlSession sqlSession = MyBatisUtil.getSqlSession();72         /**73          * 映射sql的标识字符串，74          * me.gacl.mapping.userMapper是userMapper.xml文件中mapper标签的namespace属性的值，75          * getAllUsers是select标签的id属性值，通过select标签的id属性值就可以找到要执行的SQL76          */77         String statement = "me.gacl.mapping.userMapper.getAllUsers";//映射sql的标识字符串78         //执行查询操作，将查询结果自动封装成List
     
      返回79         List
      
        lstUsers = sqlSession.selectList(statement);80         //使用SqlSession执行完SQL之后需要关闭SqlSession81         sqlSession.close();82         System.out.println(lstUsers);83     }84 }
      
     

二、使用MyBatis对表执行CRUD操作——基于注解的实现

　　1、定义sql映射的接口

　　UserMapperI接口的代码如下：

1 package me.gacl.mapping; 2  3 import java.util.List; 4 import me.gacl.domain.User; 5 import org.apache.ibatis.annotations.Delete; 6 import org.apache.ibatis.annotations.Insert; 7 import org.apache.ibatis.annotations.Select; 8 import org.apache.ibatis.annotations.Update; 9 10 /**11  * @author gacl12  * 定义sql映射的接口，使用注解指明方法要执行的SQL13  */14 public interface UserMapperI {15 16     //使用@Insert注解指明add方法要执行的SQL17     @Insert("insert into users(name, age) values(#{name}, #{age})")18     public int add(User user);19     20     //使用@Delete注解指明deleteById方法要执行的SQL21     @Delete("delete from users where id=#{id}")22     public int deleteById(int id);23     24     //使用@Update注解指明update方法要执行的SQL25     @Update("update users set name=#{name},age=#{age} where id=#{id}")26     public int update(User user);27     28     //使用@Select注解指明getById方法要执行的SQL29     @Select("select * from users where id=#{id}")30     public User getById(int id);31     32     //使用@Select注解指明getAll方法要执行的SQL33     @Select("select * from users")34     public List
     
       getAll();35 }
     

　　需要说明的是，我们不需要针对UserMapperI接口去编写具体的实现类代码，这个具体的实现类由MyBatis帮我们动态构建出来，我们只需要直接拿来使用即可。

　　2、在conf.xml文件中注册这个映射接口

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　　单元测试类的代码如下：

1 package me.gacl.test; 2  3 import java.util.List; 4 import me.gacl.domain.User; 5 import me.gacl.mapping.UserMapperI; 6 import me.gacl.util.MyBatisUtil; 7 import org.apache.ibatis.session.SqlSession; 8 import org.junit.Test; 9 10 public class TestCRUDByAnnotationMapper {11 12     @Test13     public void testAdd(){14         SqlSession sqlSession = MyBatisUtil.getSqlSession(true);15         //得到UserMapperI接口的实现类对象，UserMapperI接口的实现类对象由sqlSession.getMapper(UserMapperI.class)动态构建出来16         UserMapperI mapper = sqlSession.getMapper(UserMapperI.class);17         User user = new User();18         user.setName("用户xdp");19         user.setAge(20);20         int add = mapper.add(user);21         //使用SqlSession执行完SQL之后需要关闭SqlSession22         sqlSession.close();23         System.out.println(add);24     }25     26     @Test27     public void testUpdate(){28         SqlSession sqlSession = MyBatisUtil.getSqlSession(true);29         //得到UserMapperI接口的实现类对象，UserMapperI接口的实现类对象由sqlSession.getMapper(UserMapperI.class)动态构建出来30         UserMapperI mapper = sqlSession.getMapper(UserMapperI.class);31         User user = new User();32         user.setId(3);33         user.setName("孤傲苍狼_xdp");34         user.setAge(26);35         //执行修改操作36         int retResult = mapper.update(user);37         //使用SqlSession执行完SQL之后需要关闭SqlSession38         sqlSession.close();39         System.out.println(retResult);40     }41     42     @Test43     public void testDelete(){44         SqlSession sqlSession = MyBatisUtil.getSqlSession(true);45         //得到UserMapperI接口的实现类对象，UserMapperI接口的实现类对象由sqlSession.getMapper(UserMapperI.class)动态构建出来46         UserMapperI mapper = sqlSession.getMapper(UserMapperI.class);47         //执行删除操作48         int retResult = mapper.deleteById(7);49         //使用SqlSession执行完SQL之后需要关闭SqlSession50         sqlSession.close();51         System.out.println(retResult);52     }53     54     @Test55     public void testGetUser(){56         SqlSession sqlSession = MyBatisUtil.getSqlSession();57         //得到UserMapperI接口的实现类对象，UserMapperI接口的实现类对象由sqlSession.getMapper(UserMapperI.class)动态构建出来58         UserMapperI mapper = sqlSession.getMapper(UserMapperI.class);59         //执行查询操作，将查询结果自动封装成User返回60         User user = mapper.getById(8);61         //使用SqlSession执行完SQL之后需要关闭SqlSession62         sqlSession.close();63         System.out.println(user);64     }65     66     @Test67     public void testGetAll(){68         SqlSession sqlSession = MyBatisUtil.getSqlSession();69         //得到UserMapperI接口的实现类对象，UserMapperI接口的实现类对象由sqlSession.getMapper(UserMapperI.class)动态构建出来70         UserMapperI mapper = sqlSession.getMapper(UserMapperI.class);71         //执行查询操作，将查询结果自动封装成List
     
      返回72         List
      
        lstUsers = mapper.getAll();73         //使用SqlSession执行完SQL之后需要关闭SqlSession74         sqlSession.close();75         System.out.println(lstUsers);76     }77 }
      
     

　　用到的MyBatisUtil工具类代码如下：

1 package me.gacl.util; 2  3 import java.io.InputStream; 4  5 import org.apache.ibatis.session.SqlSession; 6 import org.apache.ibatis.session.SqlSessionFactory; 7 import org.apache.ibatis.session.SqlSessionFactoryBuilder; 8  9 public class MyBatisUtil {10 11     /**12      * 获取SqlSessionFactory13      * @return SqlSessionFactory14      */15     public static SqlSessionFactory getSqlSessionFactory() {16         String resource = "conf.xml";17         InputStream is = MyBatisUtil.class.getClassLoader().getResourceAsStream(resource);18         SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(is);19         return factory;20     }21     22     /**23      * 获取SqlSession24      * @return SqlSession25      */26     public static SqlSession getSqlSession() {27         return getSqlSessionFactory().openSession();28     }29     30     /**31      * 获取SqlSession32      * @param isAutoCommit 33      *         true 表示创建的SqlSession对象在执行完SQL之后会自动提交事务34      *         false 表示创建的SqlSession对象在执行完SQL之后不会自动提交事务，这时就需要我们手动调用sqlSession.commit()提交事务35      * @return SqlSession36      */37     public static SqlSession getSqlSession(boolean isAutoCommit) {38         return getSqlSessionFactory().openSession(isAutoCommit);39     }40 }