筑基DWR

最新推荐文章于 2024-09-26 13:54:19 发布

原创最新推荐文章于 2024-09-26 13:54:19 发布 · 1.1k 阅读

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#dwr #javascript #string #integer #button

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本文介绍如何使用DWR框架实现Java服务器端与JavaScript客户端之间的交互，包括配置web.xml、创建DWR配置文件、生成JavaScript文件及在页面中调用服务器端方法。

完整版见https://jadyer.github.io/

这是一个Web Project

首先是web.xml文件

<?xml version="1.0" encoding="UTF-8"?> <web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"> <servlet> <servlet-name>dwr-invoker</servlet-name> <servlet-class>org.directwebremoting.servlet.DwrServlet</servlet-class>       <init-param> <param-name>debug</param-name> <param-value>true</param-value> </init-param> </servlet> <servlet-mapping> <servlet-name>dwr-invoker</servlet-name> <url-pattern>/dwr/*</url-pattern> </servlet-mapping> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> </web-app>

然后是DWR的配置文件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="JSHello">  <param name="class" value="com.jadyer.dwr.Hello" />  <include method="sayHello" /> </create> <create creator="new" javascript="JSPersonManager"> <param name="class" value="com.jadyer.dwr.PersonManager" /> </create>  <convert match="com.jadyer.model.Ghoul" converter="bean" /> <convert match="com.jadyer.model.Person" converter="bean" /> </allow> </dwr>

接着是用于测试并显示DWR效果的index.jsp页面

<%@ page language="java" pageEncoding="UTF-8"%> <script type='text/javascript' src="/dwr_demo/dwr/interface/JSHello.js"></script> <script type='text/javascript' src="/dwr_demo/dwr/interface/JSPersonManager.js"></script> <script type='text/javascript' src="/dwr_demo/dwr/engine.js"></script> <script type='text/javascript' src="/dwr_demo/dwr/util.js"></script> <script type="text/javascript"> /** * 返回字符串 */ function sayHello(){ //文件名.方法名。。文件名即生成的js文件名。。方法名即dwr.xml指定的方法名 //第一个参数就是方法参数。。若该方法不需要传入参数，即可省略 //第二个参数就是回调函数 JSHello.sayHello(callbackForSayHello); JSHello.sayHello("玄玉", callbackForSayHello); } //回调函数的参数，就是服务器端返回的字符串，即sayHello()方法的返回值 //这里的serverReturnString就类似于xmlHttpRequest.responseText function callbackForSayHello(serverReturnString){ alert(serverReturnString); } /** * 返回数组 */ function getArray(){ JSPersonManager.getArray(callbackForGetArray); } function callbackForGetArray(array){ var array = eval(array); alert(array.length + " " + array[0] + " " + array[1] + " " + array[2]); } /** * 返回集合 */ function getList(){ JSPersonManager.getList(callbackForGetList); } function callbackForGetList(list){ var ghouls = eval(list); /* var example = document.getElementById("example"); for(var i=0; i<ghouls.length; i++){ example.options[i] = new Option(ghouls[i].name, ghouls[i].id); } */ //dwr.util是DWR框架提供的工具对象，是在util.js中定义的 //以前它叫做DWRUtil，不过现在已经改为dwr.util了 dwr.util.removeAllOptions("example"); //移除下拉框中的所有信息 dwr.util.addOptions("example", ghouls, "id", "name"); //添加下拉框信息。参数分别为<option>的id、集合数据、value、text } /** * 返回对象 */ function getPerson(){ JSPersonManager.getPerson(callbackForGetPerson); } function callbackForGetPerson(Object){ var person = eval(Object); var ghouls = person.ghouls; dwr.util.removeAllOptions("example"); dwr.util.addOptions("example", ghouls, "id", "name"); } </script> <input type="button" value="返回字符串" onclick="sayHello()"/> <input type="button" value="返回数组" onclick="getArray()"/> <input type="button" value="返回集合" onclick="getList()"/> <input type="button" value="返回对象" onclick="getPerson()"/> 案例：<select id="example"></select>

下面是所用到的两个JavaBean类

package com.jadyer.model; /** * 盗墓笔记人员名单 */ public class Ghoul { private Integer id; private String name; /* 两个属性的setter和getter略 */ public Ghoul(){} public Ghoul(Integer id, String name){ this.id = id; this.name = name; } } /** * 这是当前Web Project所用到的两个JavaBean类 */ package com.jadyer.model; import java.util.Set; /** * 复杂对象 */ public class Person { private Integer id; private String name; private Set<Ghoul> ghouls; /* 三个属性的setter和getter略 */ public Person(){} public Person(Integer id, String name){ this.id = id; this.name = name; } }

这是一个需要由DWR发布的普通Java类

package com.jadyer.dwr; public class Hello { public String sayHello(String name){ System.out.println("------sayHello is invoked------"); if(null == name){ return "你好，无名氏"; }else{ return "你好，" + name; } } }

最后一个是需要由DWR发布的包含了复杂Java对象的类

package com.jadyer.dwr; import java.util.ArrayList; import java.util.HashSet; import java.util.List; import java.util.Set; import com.jadyer.model.Ghoul; import com.jadyer.model.Person; public class PersonManager { /** * 获取数组 */ public String[] getArray(){ return new String[]{"张起灵", "汪藏海", "铁面生"}; } /** * 获取java.util.List */ public List<Ghoul> getList(){ List<Ghoul> ghouls = new ArrayList<Ghoul>(); ghouls.add(new Ghoul(1, "陈文锦")); ghouls.add(new Ghoul(2, "吴三省")); ghouls.add(new Ghoul(3, "谢连环")); return ghouls; } /** * 获取复杂对象 */ public Person getPerson(){ Person person = new Person(28, "玄玉"); Set<Ghoul> ghouls = new HashSet<Ghoul>(); ghouls.add(new Ghoul(1, "吴邪")); ghouls.add(new Ghoul(2, "齐羽")); ghouls.add(new Ghoul(3, "霍玲")); person.setGhouls(ghouls); return person; } }