记录一次代码优化

 1  String eventId = "";
 2  String aTime = "";
 3  for (UserEvent event : userEventList) {
 4       eventId = event.getEventId();
 5   
 6       // 获取业务B信息
 7       List<EntityB> listB = mapperB.selectBInfoByEventId(eventId);
 8       event.setListB(listB);
 9   
10      // 获取业务C信息
11      List<EntityC> listC = mapperC.selectCInfoByEventId(eventId);
12      event.setListC(listC);
13  
14      // 查看是否有业务B处理
15      EntityB entityB = mapperB.selectBInfoByPrimary(phone, eventId);
16      event.setIsActionB(null == entityB ? "false" : "true");
17  
18      // 获取业务A和用户信息
19      User userInfo = mapperA.selectEventUserInfoByEventId(eventId);
20      if(null != userInfo){
21          aTime = userInfo.getTime();
22          event.setTime(aTime == null ? "" : sdfMd.format(sdfYmd.parse(aTime)));
23                      event.setUserInfo(userInfo);
24       }
25  }

 1   <select id="selectBInfoByEventId" parameterType="String" resultType="EntityA">
 2     SELECT
 3       B.phone     AS phone,
 4       B.time      AS time,
 5       U.name      AS userName
 6     FROM table_b B
 7     LEFT JOIN user U ON U.phone = B.phone
 8     WHERE B.event_id = #{eventId}
 9     ORDER BY B.time ASC
10   </select>
11   <select id="selectCInfoByEventId" parameterType="String" resultType="EntityC">
12     SELECT
13       C.cmtId,
14       C.referId,
15       C.time,
16       U.name   AS userName
17       ( SELECT TU.name FROM table_c TC
18         LEFT JOIN user TU ON TU.phone = TC.phone
19         WHERE TC.cmt_id = TC.refer_id
20        ) AS referName
21     FROM table_c C
22       LEFT JOIN user U ON C.phone = U.phone
23     WHERE C.event_id = #{eventId}
24     ORDER BY C.time ASC
25   <select id="selectEventUserInfoByEventId" parameterType="java.lang.String" resultType="User">
26       SELECT
27           U.name,
28           U.picId,
29           A.time
30        FROM table_a A
31        LEFT JOIN user U ON U.phone = A.phone
32       WHERE A.event_id = #{eventId}
33   </select>

  int eventSize = userEventList.size();
  List<String> eventIds = new ArrayList<String>(); 
  // 如果考虑去掉重复数据，可以使用集合Set，但是作为Mybatis的出入参数，最后还是需要将Set转化为List。
   // 此处直接使用List，因为在业务上排除了重复数据的可能性。
  for (int i = 0; i < eventSize; i++) {
     eventIds.add(userEventList.get(i).getEventId());
  }
  Map<String, Object> paramsMap = new HashMap<String, Object>();
  paramsMap.put("eventIds", eventIds);
  paramsMap.put("phone", phone);
  List<UserEvent> eventInfoList = eventMapper.selectUserEventInfo(paramsMap);
                
  // 将查询结果转化为Map存储，方便调用
  Map<String, UserEvent> eventInfoMap = new HashMap<String, UserEvent>();
  for(UserEvent event : eventInfoList){
     eventInfoMap.put(event.getEventId(), event);
  }
  UserEvent newEvent = null;
  String aTime = null;
  for(UserEvent event : roadEventList){ // 从查询结果Map中取出补充信息，保存到原UserEvent对象中
     newEvent =eventInfoMap.get(event.getEventId());
     if(null != newEvent ){
         aTime = newEvent.getTime();
         event.setTime(aTime == null ? "" : sdfMd.format(sdfYmd.parse(aTime )));
         event.setIsActionB(newEvent.getIsActionB() == null ? "false" : newEvent.getIsActionB());
         event.setUserInfo(newEvent.getUserInfo());
         event.setListB(newEvent.getListB());
         event.setListC(newEvent.getListC());
     }
 }
             

    <resultMap id="UserMap" type="User">
        <result column="name" property="name" />
        <result column="picId" property="picId" />
        <result column="time" property="time" />
    </resultMap>
    
    <resultMap id="BMap" type="EntityB">
        <id column="bPhone" property="phone" />
        <result column="bUserName" property="userName" />
         <result column="bTime" property="time" />
     </resultMap>
    
     <resultMap id="CMap" type="EntityC">
         <id column="cmtId" property="cmtId" />
         <result column="referId" property="referId" />
         <result column="cUserName" property="userName" />
         <result column="referName" property="referName" />
         <result column="cTime" property="time" />
     </resultMap>
    
     <resultMap id="EventResultMap" type="com.xxxx.bean.UserEvent">
         <id column="eventId" property="eventId" />
         <result column="time" property="time" />
         <result column="isActionB" property="isActionB" />
         <association property="userInfo" resultMap="UserMap" />
         <collection property="listB" resultMap="BMap" />
         <collection property="listC" resultMap="CMap" />
     </resultMap>
 
     <select id="selectUserEventInfo" resultMap="EventResultMap">
       SELECT
           A.eventId,
           A.time,
           A.name,
           A.picId,
           CASE WHEN B.phone = #{phone} THEN "true" ELSE "false" END AS isActionB,
           B.phone          AS bPhone,
           B.userName       AS bUserName,
           B.time           AS bTime,
           C.cmtId,
           C.referId,
           C.userName       AS cUserName,
           C.referName      AS referName,
           C.time           AS cTime
        FROM v_table_a A
        LEFT JOIN v_table_b B ON B.eventId = A.eventId
        LEFT JOIN v_table_c C ON C.eventId = A.eventId
       <where>
           A.event_id in
           <foreach collection="eventIds" index="" item="eventId" 
　　　　　　　　　　　　open="(" separator="," close=")">
                 #{eventId}
           </foreach>
       </where>;
   </select>