小知识点集锦

1：建立数据库表的时候，
注解标签：
@Entity
@Table(name=”表名”)
//生成的ID为随机数
@Id
@GeneratedValue(generator = “system-uuid”)
@GenericGenerator(name = “system-uuid”, strategy = “uuid”)
@Column(length = 32)

2.查询数据库语句：
string hql=“from 表的model where 列名=？”

3.js获取选中单选框按钮的value
var check=$(“input[name=”单选框的name值”]:checked”).val();

4.map

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%><%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %><h1 align="center">问卷调查</h1>    <script type="text/javascript">    var j=0;</script><form readonly="true"><c:if test="${!empty investigateAnswerList }">        <c:forEach items="${investigateAnswerList }" varStatus="status" var="investigateAnswer">        <input type="hidden" id="iqqid_${status.index+1}" value=${investigateAnswer.answer }>                 <div>问题：${investigateAnswer.question.question }                    <br>                     <input name="iqqname_${status.index+1}" type="radio" value="optionA" readonly="true" disabled/>A：${investigateAnswer.question.optionA}                     <input name="iqqname_${status.index+1}" type="radio" value="optionB" readonly="true" disabled/>B：${investigateAnswer.question.optionB}                     <br>                    <input name="iqqname_${status.index+1}" type="radio" value="optionC" readonly="true" disabled/>C：${investigateAnswer.question.optionC}                     <input name="iqqname_${status.index+1}" type="radio" value="optionD" readonly="true" disabled/>D：${investigateAnswer.question.optionD}                 </div>                <script language="javascript">                $(function(){                    j++;                    var returnstr =$("#iqqid_"+j).attr("value");//获取单选框的value值                    var name="iqqname_"+${status.index+1};                                 var radios = document.getElementsByName(name);//获取单选框                    for(i=0;i<radios.length;i++){          //循环单选框                    if(radios[i].value == returnstr)   //判断是否等于单选框的值                    radios[i].checked = true;          //选中单选框                    }                 });                </script>        </c:forEach>    </c:if></form>

6.spilt(“字符串”)根据字符串截取值；

7，request.setAttribute（“字符串名”，取得的对象），将对象传到字符串，送到前台。

8.@ResponseBody注解标签，将数据转化为JSon。