mybatis的增删改查返回值小析（六）

本文验证了通过mybatis访问数据库时的，增删改查的返回值情况。

直接看代码。

1、service层

/**
     *@Author: Administrator on 2020/3/12 15:15
     *@param:
     *@return:
     *@Description:查询同步情况
     */
    @Override
    public PageInfo getSyncstatusPages(Syncstatus vo, int pageNo, int pageSize) {
        PageHelper.startPage(pageNo, pageSize);


       /* //查看增删改查的返回值
        //1新增：返回值自己定义，可以是void，int
        //1-1新增一条数据:插入成功,返回值为1
        int insert_success1 = yylfHttpServletMapper.insert("8", "2", "1");
        //1-2新增多条数据:插入成功，返回值为插入的数据条数，当有一条数据错误时，所有数据都会插入失败
        int insert_success2 = yylfHttpServletMapper.insert_duotiao("7");
        String insert_success3 = yylfHttpServletMapper.insert_duotiao_String("7");//不支持返回值为String类型
        //1-3新增一条数据:插入失败：主键冲突，会直接报异常
        int insert_failed = yylfHttpServletMapper.insert("1", "2", "1");
        //1-4插入null：属性为null，如果表中所有字段允许为null，插入一条所有值均为null的数据
        Syncstatus syncstatus1 = null;
        yylfHttpServletMapper.insertSyncstatus(syncstatus1);
        //1-5插入一个没有赋值的对象：属性为null，如果表中所有字段允许为null，插入一条所有值均为null的数据
        Syncstatus syncstatus2 = new Syncstatus();
        yylfHttpServletMapper.insertSyncstatus(syncstatus2);*/


        /*//2删除:返回值自己定义，可以是void，int
        //2-1删除成功：没有数据:返回值为0
        int delete_success1 = yylfHttpServletMapper.delete("0");
        //2-2删除成功：有多条数据：返回值为删除的数据条数
        int delete_success2 = yylfHttpServletMapper.delete_systemcode("2");
        //2-3删除失败：例如有外键:报异常
        int delete_fail = yylfHttpServletMapper.delete("1");*/

        //3更新:返回值自己定义，可以是void，int
        //3-1更新成功：没有数据，返回值为0
        int update_no = yylfHttpServletMapper.update_no("0");
        //3-2更新成功：有多条数据，返回更新的数据条数
        int update_duotiao = yylfHttpServletMapper.update_duotiao_systemcode("2");
        //3-3更新失败：例如有外键，报异常
        //int update_fail = yylfHttpServletMapper.update_fail("1");

        //4查询
        //4-1 没数:String 类型返回null
        Object object = yylfHttpServletMapper.select("0");
        //4-1 没数:集合 类型返回[]空集合
        Syncstatus syncstatus3 = new Syncstatus();
        syncstatus3.setStatus("7");
        List<Syncstatus> page0 = yylfHttpServletMapper.getSyncstatusList(syncstatus3);
        //4-1 没数:int 类型返回null,如果定义为int会报错。因为没数时返回null，可以将返回类型改为String
        String i = yylfHttpServletMapper.select_int(0);
        //4-1：当返回值为对象时，若返回值为空，则返回null
        //4-2 有数
        List<Syncstatus> pages = yylfHttpServletMapper.getSyncstatusList(vo);
        return new PageInfo<Syncstatus>(pages);
    }

2、mapper

/**
 * @author zs
 * @date 2019/10/18 16:03
 */
@Repository
public interface YylfHttpServletMapper {

    //删除预约临分未到期数据
    void deleteZrjunearnedfac(Date startdate);
    //保存预约临分未到期数据
    void addZrjunearnedfac(List<Zrjunearnedfac> zrjunearnedfacList);
    //删除据提取信息
    void deleteSyncstatus(String uuid);
    //保存数据提取信息
    void insertSyncstatus(Syncstatus syncstatus);
    //查询数据同步信息
    List<Syncstatus> getSyncstatusList(@Param("vo")Syncstatus vo);
    //获取日志信息
    List<InterfaceLog> getYylfNewLog(@Param("uuid")String uuid, @Param("sendsystemcode")String sendsystemcode);

    //新增
    int insert(@Param("uuid")String uuid, @Param("systemcode")String systemcode, @Param("status")String status);
    int insert_duotiao(@Param("uuid")String uuid);
    String insert_duotiao_String(@Param("uuid")String uuid);
    //删除
    int delete(@Param("uuid")String uuid);
    int delete_systemcode(@Param("systemcode")String systemcode);
    //修改
    int update_no(@Param("uuid")String uuid);
    int update_duotiao_systemcode(@Param("systemcode")String systemcode);
    int update_fail(@Param("uuid")String uuid);

    //查询
    Object select(@Param("uuid")String uuid);

    String select_int(@Param("uuid")int uuid);


}

3、mapper.xml

<insert id="insert" parameterType="java.util.Map">
    insert into aaa
      (uuid,systemcode,status)
    value
      (#{uuid,jdbcType=VARCHAR},#{systemcode,jdbcType=VARCHAR},#{status,jdbcType=VARCHAR})
  </insert>

  <insert id="insert_duotiao" parameterType="java.util.Map">
    insert into aaa
    (uuid,systemcode,status)
    value
    ('1','2','2'),('6','2','2')
  </insert>

  <insert id="insert_duotiao_String" parameterType="java.util.Map">
    insert into aaa
    (uuid,systemcode,status)
    value
    ('5','2','2'),('6','2','2')
  </insert>

  <delete id="delete">
    delete from aaa where uuid = #{uuid,jdbcType=VARCHAR}
  </delete>

  <delete id="delete_systemcode">
    delete from aaa where systemcode = #{systemcode,jdbcType=VARCHAR}
  </delete>

  <update id="update_no">
    UPDATE aaa SET status = '0' WHERE uuid = #{uuid,jdbcType=VARCHAR}
  </update>
  <update id="update_duotiao_systemcode">
    UPDATE aaa SET systemcode = '3' WHERE systemcode = #{systemcode,jdbcType=VARCHAR}
  </update>
  <update id="update_fail">
    UPDATE aaa SET uuid = '0' WHERE uuid = #{uuid,jdbcType=VARCHAR}
  </update>

  <select id="select">
    select uuid from aaa where uuid = '0'
  </select>

  <select id="select_int" resultType="String">
    select uuid from aaa where uuid = 0
  </select>

<select id="getSyncstatusList" resultMap="syncstatusToRow">
    select  uuid,startdate as paydate ,date(createtimefordw) as syndate ,status,
    sum(case when tablename='zrjunearnedfac'   then zrjcount end) as zrjunearnedfacNum,
    sum(case when tablename='zrjoutstandingfac'   then zrjcount end) as zrjoutstandingfacNum
    from syncstatus where 1=1
    AND systemcode = 'YYLF'
    <if test="  vo.startdate != null and vo.enddate !=null "  >
      AND startdate between  #{vo.startdate} and #{vo.enddate}
    </if>
    <if test="vo.status != '' and vo.status != null "  >
      AND status =  #{vo.status}
    </if>
    group by uuid,startdate,createtimefordw,status
    order by startdate,date(createtimefordw) desc
  </select>

4、sql语句

-- 创建aaa表用来验证增删改查的返回值
CREATE TABLE `reserve`.`aaa`  (
  `uuid` char(36) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL,
  `systemcode` varchar(8) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL,
  `status` varchar(1) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL,
  
  PRIMARY KEY (`uuid`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;

-- 新增
insert into aaa (uuid,systemcode,status)value ('1','2','2');
insert into aaa (uuid,systemcode,status)value ('2','2','2');
insert into aaa (uuid,systemcode,status)value ('3','2','2');
insert into aaa (uuid,systemcode,status)value ('4','2','2');
insert into aaa (uuid,systemcode,status)value ('5','2','2'),('6','2','2');

-- 删除
delete from aaa where uuid = '0';
delete from aaa where uuid != '1';
delete from aaa where uuid = '2';

-- 修改
UPDATE aaa SET systemcode = '3' WHERE uuid = '1';

UPDATE aaa SET uuid = '0' WHERE uuid = '2';

-- 查询
select * from aaa;


-- 创建bbb表用来关联aaa的uuid作外键
CREATE TABLE `reserve`.`bbb`  (
  `uuid` char(36) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL,
  `systemcode` varchar(8) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL,
  `status` varchar(1) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL,
  
  PRIMARY KEY (`uuid`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;

alter table bbb add constraint FK_T_POSITI_REFERENCE_T_COMPAN foreign key (uuid)references 
aaa (uuid);

insert into bbb (uuid,systemcode,status)value ('1','2','2');


-- 创建ccc表用来验证插入的为null的数据
CREATE TABLE `reserve`.`ccc`  (
  `uuid` char(36) CHARACTER SET utf8 COLLATE utf8_general_ci ,
  `systemcode` varchar(8) CHARACTER SET utf8 COLLATE utf8_general_ci ,
  `status` varchar(1) CHARACTER SET utf8 COLLATE utf8_general_ci 
  
) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;

insert into ccc (uuid,systemcode,status)value (NULL,NULL,NULL);

select *from ccc;

-- 创建ddd表用来验证查询结果为空时的返回值
CREATE TABLE `reserve`.`ddd`  (
  `uuid` INT  ,
  `systemcode` varchar(8) CHARACTER SET utf8 COLLATE utf8_general_ci ,
  `status` varchar(1) CHARACTER SET utf8 COLLATE utf8_general_ci 
  
) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;

insert into ddd (uuid,systemcode,status)value (1,'2','2');

select *from ddd;