1查询并返回list
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别名映射->实体类：resultClass |
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<select id=" selectAll" resultClass="AppLog"> select ID as id, TYPE as type, DESCR as descr from APP_LOG where ID = #id# </select> |
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List list = sqlMapper.queryForList("selectAll"); for (int i = 0; i < list.size(); i ) { AppLog log = (AppLog) list.get(i); //add your code here; } |
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别名映射->Map类：resultClass |
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<select id=" selectAll" resultClass="java.util.HashMap"> select ID as id, TYPE as type, DESCR as descr from APP_LOG where ID = #id# </select> |
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List list = sqlMapper.queryForList("selectAll"); for (int i = 0; i < list.size(); i ) { Map map = (Map) list.get(i); String id = (String) map.get("id"); String type = (String) map.get("type"); String descr = (String) map.get("descr"); //add your code here; } |
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显式映射->实体类：resultMap |
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<resultMap id="AppLogResult" class="AppLog"> <result property="id" column="ID"/> <result property="type" column="Type"/> <result property="descr" column="DESCR"/> </resultMap> <select id="selectAll" resultMap="AppLogResult"> select * from APP_LOG </select> |
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List list = sqlMapper.queryForList("selectAll"); for (int i = 0; i < list.size(); i ) { AppLog log = (AppLog) list.get(i); //add your code here; } |
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显式映射->Map类：resultMap |
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<resultMap id="map-result" class="java.util.HashMap"> <result property="id" column="ID"/> <result property="type" column="Type"/> <result property="descr" column="DESCR"/> </resultMap> <select id="selectAll2" resultMap="map-result"> select * from APP_LOG </select> |
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List list = sqlMapper.queryForList("selectAll2"); for (int i = 0; i < list.size(); i ) { Map map = (Map) list.get(i); String id = (String) map.get("id"); String type = (String) map.get("type"); String descr = (String) map.get("descr"); } |
2,Unknown tag (c:forEach) 未知的标签
需要在
<%@ page language="Java" import="java.util.*" pageEncoding="utf-8"%>下面加一句
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
3<c:foreach>
<c:forEach>标签，需要与el表达式联合使用
<c:forEach>标签的语法定义如下所示。
<c:forEach var="每个变量名字" items="要迭代的list" varStatus="每个对象的状态"
begin="循环从哪儿开始" end="循环到哪儿结束" step="循环的步长">
循环要输出的东西
</c:forEach>
例如
<table border="1">
<tr><th>用户名</th> <th>密码</th> <th>操作</th></tr>
<c:forEach var="userlist" items="${userlist}">
<tr><th>${userlist.username}</th>
<th>${userlist.password}</th>
<th><a href="">修改</a> <a href="">删除</a> </th></tr>
</c:forEach>
</table>