mybatis-注解开发（1个表的增删改查）-（1）

不使用 mapper.xml文件

mybatis的常用注解

@Insert：实现新增
@Update：实现更新
@Delete：实现删除
@Select：实现查询
@Result：实现结果集封装
@Results：可以与@Result 一起使用，封装多个结果集
@One：实现一对一结果集封装
@Many：实现一对多结果集封装

1)创建user类

@data
public class User {

    private int id;
    private String username;
    private String password;
    private Date birthday;

    //当前用户具备哪些角色
    private List roleList;
}

2)编写UserMapper接口

import org.apache.ibatis.annotations.*;
import java.util.List;
public interface UserMapper {

    @Insert("insert into user values(#{id},#{username},#{password},#{birthday})")
    public void save(User user);

    @Update("update user set username=#{username},password=#{password} where id=#{id}")
    public void update(User user);

    @Delete("delete from user where id=#{id}")
    public void delete(int id);

    @Select("select * from user where id=#{id}")
    public User findById(int id);

    @Select("select * from user")
    public List findAll();
}

3）配置mybatis核心配置文件 加载指定接口所在的包

<?xml version="1.0" encoding="UTF-8" ?>



    
    

    
    
        
    


    
    
        
            
            
                
                
                
                
            
        
    
    

    
    
        
        
    

jdbc.properties配置

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/test
jdbc.username=root
jdbc.password=root

log4j配置

### direct log messages to stdout ###
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.err
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{ABSOLUTE} %5p %c{1}:%L - %m%n

### direct messages to file mylog.log ###
log4j.appender.file=org.apache.log4j.FileAppender
log4j.appender.file.File=c:/mylog.log
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%d{ABSOLUTE} %5p %c{1}:%L - %m%n

### set log levels - for more verbose logging change 'info' to 'debug' ###
log4j.rootLogger=debug, stdout

4) 编写测试类 测试数据是否能增删查改

public class MyBatisTest {

    private UserMapper mapper;

    @Before
    public void before() throws IOException {
        InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);
        SqlSession sqlSession = sqlSessionFactory.openSession(true);
        mapper = sqlSession.getMapper(UserMapper.class);
    }


    @Test
    public void testSave(){
        User user = new User();
        user.setUsername("tom");
        user.setPassword("abc");
        mapper.save(user);
    }

    @Test
    public void testUpdate(){
        User user = new User();
        user.setId(18);
        user.setUsername("lucy");
        user.setPassword("123");
        mapper.update(user);
    }

    @Test
    public void testDelete(){
        mapper.delete(18);
    }

    @Test
    public void testFindById(){
        User user = mapper.findById(2);
        System.out.println(user);
    }

    @Test
    public void testFindAll(){
        List all = mapper.findAll();
        for (User user : all) {
            System.out.println(user);
        }
    }

}