js脚本中执行java后台代码

使用场景：关闭页面弹窗时执行sql语句。

其实js里执行sql语句有多种方式。

方式一：直接在js代码里调用sql语句，原则上不能使用，因为这将sql直接暴露在客户端，安全性极差。

方式二：在js里运用ajax技术，调用后台方法执行sql语句。

方式三：运用dwr框架，其实是对ajax技术进行了封装。

一、首先编写一个dwr.xml文件

 <?xml version="1.0" encoding="utf-8"?>
 <!DOCTYPE dwr PUBLIC "-//GetAhead Limited//DTD Direct Web Remoting 2.0//EN" "http://www.getahead.ltd.uk/dwr//dwr20.dtd">
 <dwr>
     <allow>
         <!-- 对呼叫类型的操作 -->
         <create javascript="CallTypeOpDwr" creator="new">
             <param name="class"
                 value="cn.etcom.jfgl.tel.fee.callType.CallTypeOpDwr" />
             <include method="addCallType" />
             <include method="modifyCallType" />
             <include method="deleteCallType" />
             <include method="updateSp" />
         </create>

     </allow>
     <!-- 用户信息管理操作中用到的map配置 -->
     <signatures>
         <![CDATA[
             import java.util.List;
             import cn.etcom.jfgl.customer.tel.userInfo.UserInfoManageOpDwr;
             UserInfoManageOpDwr.addUsersInfo(String,String,String,String,String,String,String,String,String,String,String,String,String,String,String,String,String,String,String,String,String,String,String,String,Map<String,String>);
             UserInfoManageOpDwr.addUserInfo(String,String,String,String,String,String,String,String,String,String,String,String,String,String,String,String,String,String,String,String,String,String,String,String,Map<String,String>);
             ]]>
     </signatures>
 </dwr>

二、在web.xml文件里配置servlet

 <!-- DWR相关配置 -->
     <servlet>
         <servlet-name>dwr-invoker</servlet-name>
         <servlet-class>uk.ltd.getahead.dwr.DWRServlet</servlet-class>
         <init-param>
             <param-name>debug</param-name>
             <param-value>false</param-value>
         </init-param>
         <init-param>
             <param-name>
                 allowGetForSafariButMakeForgeryEasier
             </param-name>
             <param-value>true</param-value>
         </init-param>
         <init-param>
             <param-name>crossDomainSessionSecurity</param-name>
             <param-value>false</param-value>
         </init-param>
         <load-on-startup>1</load-on-startup>
     </servlet>
     <servlet-mapping>
         <servlet-name>dwr-invoker</servlet-name>
         <url-pattern>/dwr/*</url-pattern>
     </servlet-mapping>

三、写一个普通的JAVA类

 package cn.etcom.jfgl.tel.fee.callType;

 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.util.ArrayList;
 import java.util.List;

 import javax.servlet.http.HttpServletRequest;

 import org.json.JSONException;
 import org.json.JSONObject;

 import cn.etcom.common.utility.DBUtil;
 import cn.etcom.common.utility.RsHandler;
 import cn.etcom.common.utility.SqlActuator;
 import cn.etcom.common.utility.StringUtil;

 /*******************************************************************************
  *
  * @author 刘彦宁 2011-08-12
  *
  */
 // 处理呼叫类型的dwr
 public class CallTypeOpDwr {

     /***************************************************************************
      * DWR 方法，执行存储过程。
      *
      */
     public String updateSp() {
         String sql = "exec Pub_Sp_UpdateFieldMemo ?";
         Connection conn = DBUtil.getConnection();
         PreparedStatement psmt = null;
         try {
             psmt = conn.prepareStatement(sql);
             psmt.setString(1, "CALL");
             boolean a = psmt.execute();
             DBUtil.close(null, psmt, conn);
             conn = DBUtil.getConnection();
             psmt = conn.prepareStatement(sql);
             psmt.setString(1, "USER");
             boolean b = psmt.execute();
             System.out.println(a);
             System.out.println(b);
             System.out.println("关闭弹窗执行存储过程 >> "+sql);
         } catch (SQLException e) {
             e.printStackTrace();
         }finally {
             DBUtil.close(null, psmt, conn);
         }
         return null;
     }
 }

四、写一个JSP页面，主要导入engine.js和相应的java类映射的js文件，然后编写js即可调用。

 //以下为jsp的引入js文件部分
 <script type="text/javascript">
     //设置根路径，放在 tab.js 前
     var glbRootPath = "<%=basePath%>";
 </script>
 <script src="<%=basePath%>js/lhgdialog/lhgcore.min.js" type="text/javascript"></script>
 <script src="<%=basePath%>js/lhgdialog/lhgdialog.js" type="text/javascript"></script>

五、js文件里调用后台代码

 var basePath = "";
     if(typeof(glbRootPath) != "undefined"){
         basePath = glbRootPath;
         document.write("<script type='text/javascript' src='"+basePath+"\/dwr\/engine.js'><\/script><script type='text/javascript' src='"+basePath+"\/dwr\/interface\/CallTypeOpDwr.js'><\/script>");
     }
 /*
 中间省略若干代码
 */
 .
 .
 .
 if(typeof(glbRootPath) != "undefined"&&$(this).parent().children().eq(0).text()=="呼叫类型设置"){
                 console.log("进来了");
                 DWREngine.setAsync(false);
                 CallTypeOpDwr.updateSp();
             }