DWR之初尝

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准备公工作

1.去官网下载jar和war

开发工具

eclipse

开始开发:gogogo

1:建立一个可以跑起来的javaweb项目,最基本的就可以了.

2:导入commons-logging-1.0.4.jar,dwr.jar

3:在web.xml里配置一下

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="http://java.sun.com/xml/ns/javaee"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
    id="WebApp_ID" version="3.0">
    <display-name>Girl_dwr</display-name>
    <welcome-file-list>
        <welcome-file>index.jsp</welcome-file>
    </welcome-file-list>

    <servlet>
        <servlet-name>dwr</servlet-name>
        <servlet-class>uk.ltd.getahead.dwr.DWRServlet</servlet-class>
        <init-param>
            <param-name>activeReverseAjaxEnabled</param-name>
            <param-value>true</param-value>
        </init-param>

        <init-param>
            <param-name>corssDomainSessionSecurity</param-name>
            <param-value>false</param-value>
        </init-param>

        <init-param>
            <param-name>allowScriptTagRemoting</param-name>
            <param-value>true</param-value>
        </init-param>

    </servlet>
    <servlet-mapping>
        <servlet-name>dwr</servlet-name>
        <url-pattern>/js/dwr/*</url-pattern>
    </servlet-mapping>
</web-app>

4:配置dwr.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE dwr PUBLIC "-//GetAhead Limited//DTD Direct Web Remoting 3.0//EN" "http://getahead.org/dwr/dwr30.dtd">
<dwr>
  <allow>
  
      <create creator="new" javascript="DWRPush">
          <param name="class" value="fz.song.girl.util.DWRPush"/>
       </create>

  </allow>
</dwr>

5:配置一个java类DWRPush

package fz.song.girl.util;

import java.util.Collection;

import org.directwebremoting.ScriptBuffer;
import org.directwebremoting.ScriptSession;
import org.directwebremoting.WebContext;
import org.directwebremoting.WebContextFactory;
import org.directwebremoting.proxy.dwr.Util;

public class DWRPush {

    public void send(String msg) {
        WebContext context = WebContextFactory.get();
        Collection<ScriptSession> session = context.getAllScriptSessions();

        ScriptBuffer sb = new ScriptBuffer();
        sb.appendScript("callback(");
        sb.appendScript("""+msg+""");
        sb.appendScript(")");

        Util util = new Util(session);
        util.addScript(sb);
    }

}

6:写一个jsp

<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<script type="text/javascript" src="${pageContext.request.contextPath}/js/dwr/engine.js"></script>
<script type="text/javascript" src="${pageContext.request.contextPath}/js/dwr/util.js"></script>
<script type="text/javascript" src="${pageContext.request.contextPath}/js/dwr/interface/DWRPush.js"></script>
<script type="text/javascript" src="${pageContext.request.contextPath}/js/jquery-3.1.1.min.js"></script>
<title>DWR_Test</title>
<script type="text/javascript">
    $(document).ready(function() {
        dwr.engine.setActiveReverseAjax(true);

        $("#sing").click(function() {
            var val = $("#message").val();
            DWRPush.send(val);
        });
    });

    function callback(msg) {
        $("#ul").append("<li>"+msg+"</li>");
    }
</script>

</head>
<body>
    <ul id="ul" style="color: red; font-size: 60px">

    </ul>
    <input type="text" id="message" name="message" size="30"
        style="height: 60px; font-size: 35px">
    <input type="button" id="sing" value="发布信息">

</body>
</html>

这里的几个坑要指出来一下;

在java类中那个msg要用引号包裹,否则会出问题.

jsp中那两个js和你的web.xml里的配置路劲一致.

就是这样,一个简单的demo就写好了.记下来,怕自己忘了.

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原文地址:https://www.cnblogs.com/songfahzun/p/6422777.html