@TableId(type = IdType.AUTO) //通过添加注解改变MP的id策略

AUTO(0),  //id自增
NONE(1),  //未设置主键类型
INPUT(2), //用户输入id，可通过自己注册自动填充插件进行填充
//以下类型只有当插入id为空时才会自动填充
ID_WORKER(3),  //全局唯一id（idWorker）
UUID(4),  //全局唯一id（UUID）
ID_WORKER_STR(5); //字符串全局唯一id（idWorker的字符串表示）

@TableField(value = "email") //指定数据表中字段名  
private String mail;  
  
@TableField(exist = false)  
private String address; //在数据库表中是不存在的

@TableField(select = false) //查询时不返回该字段的值  
private String password;

public void testUpdateById() {  
    User user = new User();  
    user.setId(1L); //条件，根据id更新  
    user.setAge(19); //更新的字段  
    user.setPassword("666666");  
  
    int result = this.userMapper.updateById(user);  
}

public void testUpdate() {  
    User user = new User();  
    user.setAge(20); //更新的字段  
    user.setPassword("8888888");  
  
    QueryWrapper<User> wrapper = new QueryWrapper<>();  
    wrapper.eq("user_name", "zhangsan"); //匹配user_name = zhangsan 的用户数据  
  
    //根据条件做更新  
    int result = this.userMapper.update(user, wrapper);  
}

public void testUpdate2() {  
  
    UpdateWrapper<User> wrapper = new UpdateWrapper<>();  
    wrapper.set("age", 21).set("password", "999999") //更新的字段  
    .eq("user_name", "zhangsan"); //更新的条件  
  
    //根据条件做更新  
    int result = this.userMapper.update(null, wrapper);   
}

public void testDeleteById(){  
    // 根据id删除数据  
    int result = this.userMapper.deleteById(2L);  
}

public void testDeleteByMap(){  
  
    Map<String,Object> map = new HashMap<>();  
    map.put("user_name", "zhangsan");  
    map.put("password", "999999");  
  
    // 根据map删除数据，多条件之间是and关系  
    int result = this.userMapper.deleteByMap(map); 
}

public void testDelete(){  
  
    //用法一：  
    QueryWrapper<User> wrapper = new QueryWrapper<>();  
    wrapper.eq("user_name", "caocao1")  
	        .eq("password", "123456");  
  
    //用法二：  
    User user = new User();  
    user.setPassword("123456");  
    user.setUserName("caocao");  
  
    QueryWrapper<User> wrapper = new QueryWrapper<>(user);  
  
    // 根据包装条件做删除  
    int result = this.userMapper.delete(wrapper);   
}

public void  testDeleteBatchIds(){  
    // 根据id批量删除数据  
    int result = this.userMapper.deleteBatchIds(Arrays.asList(10L, 11L));   
}

public void testSelectById() {  
    User user = this.userMapper.selectById(2L);  
    System.out.println(user);  
}

public void testSelectBatchIds(){  
    // 根据id批量查询数据  
    List<User> users = this.userMapper.selectBatchIds(Arrays.asList(2L, 3L, 4L, 100L));  
    for (User user : users) {  
        System.out.println(user);  
    }  
}

public void testSelectOne(){  
    QueryWrapper<User> wrapper = new QueryWrapper<>();  
    //查询条件  
    wrapper.eq("password", "123456");  
    
    // 查询的数据超过一条时，会抛出异常  
    User user = this.userMapper.selectOne(wrapper);  
}

public void testSelectCount(){  
  
    QueryWrapper<User> wrapper = new QueryWrapper<>();  
    wrapper.gt("age", 20); // 条件：年龄大于20岁的用户  
  
    // 根据条件查询数据条数  
    Integer count = this.userMapper.selectCount(wrapper);  
    System.out.println("count => " + count);  
}

public void testSelectList(){  
    QueryWrapper<User> wrapper = new QueryWrapper<>();  
    //设置查询条件  
    wrapper.like("email", "itcast");  
  
    List<User> users = this.userMapper.selectList(wrapper);  
    for (User user : users) {  
        System.out.println(user);  
    }  
}

@Configuration  
@MapperScan("cn.itcast.mp.mapper") //设置mapper接口的扫描包  
public class MybatisPlusConfig {  
  
  
    @Bean //配置分页插件  
    public PaginationInterceptor paginationInterceptor(){  
        return new PaginationInterceptor();  
    }  
  
}

public void testSelectPage(){  
  
    Page<User> page = new Page<>(3,1); //查询第3页，查询1条数据  
  
    QueryWrapper<User> wrapper = new QueryWrapper<>();  
    //设置查询条件  
    wrapper.like("email", "itcast");  
  
    IPage<User> iPage = this.userMapper.selectPage(page, wrapper);  
    System.out.println("数据总条数： " + iPage.getTotal());  
    System.out.println("数据总页数： " + iPage.getPages());  
    System.out.println("当前页数： " + iPage.getCurrent());  
  
    List<User> records = iPage.getRecords();  
    for (User record : records) {  
        System.out.println(record);  
    }  
  
}