mybatis接受mysql存储过程out的值

这是题目的实体类

    private Integer id;
    private Integer type;//题型    单选，多选
    private String category;//类型    数据字典配置
    private String problem;//问题
    private String choose1;//选择1
    private String choose2;
    private String choose3;
    private String choose4;
    private String choose5;
    private String choose6;
    private String choose7;
    private String choose8;
    private String answer;//答案

卷子的实体类

    private Integer id;
    private String title;
    private String problemNo;//题目，逗号分割
    private Integer extract;//抽题个数

需求：已经录入若干提，其中每题的类型不完全相同，例如有的题目是语文，有的是数学之类的。

抽取其中若干题，必然是小于录入题的，必须保证每种类型的题都被抽取到，且希望能根据不同类型的题目均匀抽取；

例如录入40题，抽取10题。

假如语文，数学，物理，化学各是16，12，8，4。那么抽取语文，数学，物理，化学应当各是4，3，2，1道题。

假如语文，数学，物理，化学各是19，19，1，1。那么抽取语文，数学，物理，化学应当各是4，4，1，1道题。

作出最优解。

 表结构：

CREATE TABLE `tb_multi_question_problem` (
  `id` int(10) NOT NULL AUTO_INCREMENT COMMENT 'ID',
  `type` tinyint(4) DEFAULT NULL COMMENT '题型',
  `category` varchar(32) COLLATE utf8mb4_unicode_ci DEFAULT NULL COMMENT '类型',
  `problem` varchar(512) COLLATE utf8mb4_unicode_ci NOT NULL COMMENT '问题',
  `choose1` varchar(128) COLLATE utf8mb4_unicode_ci DEFAULT NULL COMMENT '选择1',
  `choose2` varchar(128) COLLATE utf8mb4_unicode_ci DEFAULT NULL COMMENT '选择2',
  `choose3` varchar(128) COLLATE utf8mb4_unicode_ci DEFAULT NULL COMMENT '选择3',
  `choose4` varchar(128) COLLATE utf8mb4_unicode_ci DEFAULT NULL COMMENT '选择4',
  `choose5` varchar(128) COLLATE utf8mb4_unicode_ci DEFAULT NULL COMMENT '选择5',
  `choose6` varchar(128) COLLATE utf8mb4_unicode_ci DEFAULT NULL COMMENT '选择6',
  `choose7` varchar(128) COLLATE utf8mb4_unicode_ci DEFAULT NULL COMMENT '选择7',
  `choose8` varchar(128) COLLATE utf8mb4_unicode_ci DEFAULT NULL COMMENT '选择8',
  `answer` varchar(32) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `update_time` datetime DEFAULT NULL COMMENT '更新时间',
  `create_time` datetime DEFAULT NULL COMMENT '创建时间',
  `update_user` varchar(32) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `create_user` varchar(32) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `del_flag` char(1) COLLATE utf8mb4_unicode_ci NOT NULL DEFAULT '0',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=58 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
CREATE TABLE `tb_multi_questionnaire` (
  `id` int(10) NOT NULL AUTO_INCREMENT,
  `title` varchar(128) DEFAULT NULL,
  `description` text,
  `imgurl` varchar(128) DEFAULT NULL,
  `problem_no` varchar(512) DEFAULT NULL,
  `parent_area` varchar(32) DEFAULT NULL,
  `area` varchar(32) DEFAULT NULL,
  `committee` varchar(32) DEFAULT NULL,
  `start_time` datetime DEFAULT NULL,
  `end_time` datetime DEFAULT NULL,
  `duration` int(10) DEFAULT NULL COMMENT '时长',
  `number` tinyint(4) DEFAULT NULL,
  `extract` tinyint(4) DEFAULT NULL,
  `url1` varchar(256) DEFAULT NULL,
  `url2` varchar(256) DEFAULT NULL,
  `url3` varchar(256) DEFAULT NULL,
  `update_time` datetime DEFAULT NULL COMMENT '更新时间',
  `create_time` datetime DEFAULT NULL COMMENT '创建时间',
  `update_user` varchar(32) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `create_user` varchar(32) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `del_flag` char(1) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci NOT NULL DEFAULT '0',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=20 DEFAULT CHARSET=utf8;

解决方案，因为涉及到类型，且类型未均匀分布。避免多次访问数据库，使用存储过程；

CREATE DEFINER=`root`@`localhost` PROCEDURE `rand_question`(in pid int, out idstr VARCHAR(128))
begin
declare pno VARCHAR(128);
declare qp VARCHAR(32);
DECLARE ques_ext int DEFAULT 1;
DECLARE ques_sum int DEFAULT 0;
DECLARE qpid VARCHAR(32);
DECLARE qpCategory VARCHAR(32) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
DECLARE qpSum INT(10);
DECLARE q_sum INT(10) DEFAULT 0;
DECLARE rem INT(10) DEFAULT 0;
DECLARE lim INT(10) DEFAULT 0;
declare done int default -1;
DECLARE qp_cursor CURSOR FOR SELECT qp.category,COUNT(1) FROM tb_multi_question_problem qp WHERE del_flag = '0' and FIND_IN_SET(qp.id,(SELECT q.problem_no FROM tb_multi_questionnaire q WHERE del_flag = '0' and q.id = pid)) GROUP BY qp.category;
DECLARE CONTINUE HANDLER FOR NOT found SET done = 1;
SELECT q.problem_no INTO pno FROM tb_multi_questionnaire q WHERE del_flag = '0' and q.id = pid;
SELECT q.extract into ques_ext FROM tb_multi_questionnaire q WHERE del_flag = '0' and q.id = pid;
SELECT COUNT(1) into ques_sum FROM tb_multi_question_problem qp WHERE del_flag = '0' and FIND_IN_SET(qp.id,(SELECT q.problem_no FROM tb_multi_questionnaire q WHERE del_flag = '0' and q.id = pid));
set idstr = '';
OPEN qp_cursor;
qpLoop : LOOP
    FETCH qp_cursor INTO qpCategory,qpSum;
    IF done = 1 THEN
    LEAVE qpLoop;
    END IF;
    set rem = floor(qpSum*ques_ext/ques_sum);
    IF rem < 1 THEN
    SET rem = 1;
    END IF;
    SELECT group_concat(id) INTO qpid FROM (SELECT id FROM tb_multi_question_problem WHERE del_flag = '0' and category = qpCategory and FIND_IN_SET(id,pno) and id >= (SELECT FLOOR(RAND()*(SELECT MAX(id) FROM tb_multi_question_problem WHERE del_flag = '0' and category = qpCategory))) order by rand() LIMIT rem) as a;
    set idstr = CONCAT(idstr,qpid,',');
END LOOP qpLoop;
CLOSE qp_cursor;
select length(idstr)-length(replace(idstr,',','')) INTO q_sum;
    WHILE  q_sum < ques_ext DO
    SET lim = ques_ext-q_sum;
    SELECT ques_ext,q_sum,lim;
    SELECT group_concat(a.id) INTO qpid FROM (SELECT * FROM tb_multi_question_problem WHERE del_flag = '0' and !FIND_IN_SET(id,idstr) and id >= (SELECT FLOOR(RAND()*(SELECT MAX(id) FROM tb_multi_question_problem WHERE del_flag = '0'))) order by rand() LIMIT lim) as a WHERE FIND_IN_SET(a.id,pno);
    set idstr = CONCAT(idstr,qpid,',');
    select length(idstr)-length(replace(idstr,',','')) INTO q_sum;
    END WHILE;
end

得到所得的值有两种方法，第一种：

使用map传递接受参数

mapper.xml

<resultMap type="java.util.HashMap" id="resultMap">
       <result column="id" property="id" javaType="java.lang.Integer" jdbcType="INTEGER"/>
       <result column="idstr" property="idstr" javaType="java.lang.String" jdbcType="VARCHAR"/>
    </resultMap>

    <select id="randomList" statementType="CALLABLE" parameterType="java.util.HashMap" resultMap="resultMap">
        {
            call rand_question(
            #{id,jdbcType=INTEGER,mode=IN},
            #{idstr, jdbcType=VARCHAR,mode=OUT})
        }
    </select>

service

public List<QuestionProblem> randomList(Map<String, Object> param) {
        questionProblemDao.randomList(param);
        return questionProblemDao.getListByIds((String)param.get("idstr"));
    }

如上，通过param传参，也通过param接受参数；

类似于selectkey，我之前写的博客https://www.cnblogs.com/zhengyuanyuan/p/10616616.html

第二种通过javabean,有时间再补充

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原文地址：https://www.cnblogs.com/zhengyuanyuan/p/10731317.html