DWR3.0 如何应用的简单介绍（有实例）

DWR3.0 dwr 返回值(数组,集合,Map)
示例代码如下：

首先导入项目所需要的包，如下：dwr.jar，commons-logging-1.0.4.jar，版本可以调整；

1.web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="2.4"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee  http://java.sun.com/xml/ns/j2ee/web-app_2_4.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>
   <load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
   <servlet-name>dwr-invoker</servlet-name>
   <url-pattern>/dwr/*</url-pattern>
</servlet-mapping>

</web-app>

2.DWRTest.java
package com.micro;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

@SuppressWarnings("unchecked")
public class DWRTest {

/**
   * 第一个简单调用
   */
public String getStr() {
    return "第一个dwr示例，调用成功";
}

/**
   * 带传递参数的调用，返回String
   */
public String getInfo(String name, int age, String address) {
    return "我的名字叫" + name + ",现年" + age + "岁," + "来自" + address;
}

/**
   * 返回数组Array
   */
public String[] getStrArray() {
    return new String[] { "one", "two", "three", "go!" };
}

/**
   * 返回集合List
   */
public List getList() {
    List list = new ArrayList();
    list.add("welcome");
    list.add("to");
    list.add("BeiJing");
    return list;
}

/**
   * 返回Map类型
   */
public Map getMap() {
    Map map = new HashMap();
    map.put("name", "周星星");
    map.put("hobby", "逃课");
    return map;
}

/**
   * 返回二维数组类型
   */
public List getArrayList() {
    List list = new ArrayList();
    list.add(new String[] { "1", "2", "3" });
    list.add(new String[] { "one", "two", "three", "four", "five" });
    return list;
}

/**
   * Exception处理
   */
public List getListTest(List list) {
    try {
      list.get(0);
    } catch (Exception e) {
      throw new NullPointerException("数据位空");
    }
    return list;
}

}

3.dwr.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE dwr PUBLIC
    "-//GetAhead Limited//DTD Direct Web Remoting 2.0//EN"
    "http://getahead.org/dwr/dwr20.dtd">

<dwr>
<allow>
   <!-- 调用不同的方法，返回不同的数据类型 -->
   <create javascript="dwr" creator="new">
    <param name="class" value="com.micro.DWRTest" />
   </create>

   <!-- 类型转换为JavaBean的处理 -->
   <create javascript="dwrBean" creator="new" scope="request">
    <param name="class" value="com.micro.UserRs" />
   </create>
   <convert match="com.micro.User" converter="bean">
    <param name="include" value="name,pass" />
   </convert>

   <!-- 异常Exception的处理 ,默认情况下dwr对异常的处理就是一个弹出框提示为Error-->
   <create javascript="dwrException" creator="new">
    <param name="class" value="com.micro.DWRTest" />
   </create>
   <convert match="java.lang.NullPointerException" converter="exception" />

</allow>

</dwr>

4.mydwr.js
/**
* 无参数
*/
function invoke1(){
dwr.getStr(
   function(value){
    alert(value);
   }
);
}

/**
* 有参数
*/
function invoke2(){
dwr.getInfo("长江七号",3,"火星",
   function(value){
    alert(value);
   }
);
}

/**
* 返回数组
*/
function invoke3(){
dwr.getStrArray(
   function(array){
    var str="";
    for(var i=0;i<array.length;i++){
     str += array[i]+" ";
    }
    alert(str);
   }
);
}

/**
* 返回集合（集合和数组的处理方式一样）
*/
function invoke4(){
dwr.getList(
   function(list){
    var str="";
    for(var i=0;i<list.length;i++){
     str += list[i];
    }
    alert(str);
   }
);
}
/**
* 返回Map
*/
function invoke5(){
dwr.getMap(

//有如下两种处理方式
   /*1)已知map的key*/
   function(map){
    alert("姓名:"+map.name+",爱好:"+map.hobby);
   }
   /*2).遍历的方式
    function(map){
    for(var key in map){
     alert(key+":"+map[key]);
    }
   }*/
);
}

/**
* 返回数组的集合(二维数组)
*/
function invoke6(){
dwr.getArrayList(
   function(arrayList){
    var str="";
    for(var i=0;i<arrayList.length;i++){
     for(var j=0;j<arrayList[i].length;j++){
      str += arrayList[i][j];
     }
     str+="\n\r";
    }
    alert(str);
   }
);
}

/**
* 同步设置
*/
function invoke7(){
dwr.engine.setAsync(false);//设置同步，那么后续的方法才能按照顺序执行
invoke1();
invoke2();
}

/**
* 批处理batch（按照先后顺序执行）
*/
function invoke8(){
dwr.engine.beginBatch();
invoke1();
invoke2();
dwr.engine.endBatch();
}

5.index.jsp
<%@ page language="java" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
   <script type='text/javascript' src='http://yangchao20020.blog.163.com/blog/dwr/engine.js'></script>
   <script type='text/javascript' src='http://yangchao20020.blog.163.com/blog/dwr/util.js'></script>
   <script type='text/javascript' src='http://yangchao20020.blog.163.com/blog/dwr/interface/dwr.js'></script>
   <script type="text/javascript" src="http://yangchao20020.blog.163.com/blog/mydwr.js"></script>
</head>

<body>
   <input type="button" value="DRW1" onclick="invoke1()" />
   <br />
   <input type="button" value="DRW2" onclick="invoke2()" />
   <br />
   <input type="button" value="DRW3" onclick="invoke3()" />
   <br />
   <input type="button" value="DRW4" onclick="invoke4()" />
   <br />
   <input type="button" value="DRW5" onclick="invoke5()" />
   <br />
   <input type="button" value="DRW6" onclick="invoke6()" />
   <br />
   <input type="button" value="DRW7" onclick="invoke7()" />
   <br />
   <input type="button" value="批处理测试" onclick="invoke8()" />
</body>
</html>

上述，index.jsp页面就对上述各种dwr的返回类型和批处理(batch)做了处理，做了简单的测试，Ok，测试通过，下面再介绍几个页面，
对dwr其他功能的一些简单测试：

6.异常处理：exception.jsp
<%@ page language="java" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
   <script type='text/javascript' src='http://yangchao20020.blog.163.com/blog/dwr/engine.js'></script>
   <script type='text/javascript' src='http://yangchao20020.blog.163.com/blog/dwr/util.js'></script>
   <script type='text/javascript' src='http://yangchao20020.blog.163.com/blog/dwr/interface/dwrException.js'></script>
   <script type="text/javascript" src="http://yangchao20020.blog.163.com/blog/mydwr.js"></script>
  
   <script type="text/javascript">
    function convert(){
     var list;
     dwrException.getListTest(list,
      {
       exceptionHandler:function(msg){
        alert(msg);
       },
       callback:function(data){
        alert(data);
       }
      }
     );
    }
   
   </script>
</head>

<body>
   <input type="button" value="异常测试" onclick="convert()"/>
</body>
</html>

7.dwr.util.getValue()调用，dwrfunc.jsp
<%@ page language="java" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
   <script type='text/javascript' src='http://yangchao20020.blog.163.com/blog/dwr/engine.js'></script>
   <script type='text/javascript' src='http://yangchao20020.blog.163.com/blog/dwr/util.js'></script>
   <script type='text/javascript' src='http://yangchao20020.blog.163.com/blog/dwr/interface/dwr.js'></script>
   <script type="text/javascript" src="http://yangchao20020.blog.163.com/blog/mydwr.js"></script>
</head>

<body>
   <input type="text" name="name" id="nameid" />
   <br/>
   <input type="button" value="EL通过id取值" onclick="alert(${'nameid'}.value)" />
   <br />
  
   //如果要是有dwr.util提供的功能，必须引入dwr/util.js文件,dwr3之后，有写函数内写name或id都可以
   <br/>
   <input type="button" value="dwr.util通过id" onclick="alert($('nameid').value)" />
   <br />
   <input type="button" value="dwr.util通过name" onclick="alert($('name').value)" />
   <br />
   <input type="button" value="dwr.util通过name/id" onclick="alert(dwr.util.getValue('name'))" />
   <br />

</body>
</html>

8.对JavaBean的传递和返回
User.java:
package com.micro;

public class User {

private String name;;
private String pass;

//get/set方法....
}

UserRs.java:
package com.micro;

public class UserRs {

public User convertUser(User user) {
    user.setName("admin");
    user.setPass("123456");
    return user;
}
}
bean.jsp:
<%@ page language="java" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
   <script type='text/javascript' src='http://yangchao20020.blog.163.com/blog/dwr/engine.js'></script>
   <script type='text/javascript' src='http://yangchao20020.blog.163.com/blog/dwr/util.js'></script>
   <script type='text/javascript' src='http://yangchao20020.blog.163.com/blog/dwr/interface/dwrBean.js'></script>
   <script type="text/javascript" src="http://yangchao20020.blog.163.com/blog/mydwr.js"></script>
  
   <script type="text/javascript">
    function convert(){
     var uname = $("name").value;
     var upass = $("pass").value;
     var obj = {name:uname,pass:upass};
    
     dwrBean.convertUser(obj,function(data){
      $("uname").value = data.name;
      $("upass").value = data.pass;
     });
    }
   
   </script>
</head>

<body>
   <input type="text" name="name" id="uname" value="you name"/><br/>
   <input type="text" name="pass" id="upass" value="your password"/><br/>
   <input type="button" value="测试处理" onclick="convert()"/>
</body>
</html>

这些，只是对dwr的简单应用，其中的配置都在dwr.xml中，大家可以举一反三，通常情况下，dwr和spring要结合使用，下面给出一个简单的配置说明：
比如：
<!-- 验证登陆名是否存在 -->
<create creator="spring" javascript="loginServiceDWR" scope="request">
   <param name="beanName" value="coreLoginService" />
   <include method="checkLogin" />
</create>
其中，creator="spring"，表明由spring来创建该对象，javascript="loginServiceDWR"，说明客户端的调用名称叫"loginServiceDWR"，<param name="beanName" value="coreLoginService" />指明了spring配置文件中，id为"coreLoginService"的这么一个bean，<include method="checkLogin" />，对外公开的方法是"checkLogin" ，调用过程同上述其他类型调用相同，不同就是配置而已。上述代码，仅供参考。

注意：引入dwr的js文件的顺序不能错了，如：

   <script type='text/javascript' src='http://yangchao20020.blog.163.com/blog/dwr/engine.js'></script>
   <script type='text/javascript' src='http://yangchao20020.blog.163.com/blog/dwr/util.js'></script>
   <script type='text/javascript' src='http://yangchao20020.blog.163.com/blog/dwr/interface/dwrBean.js'></script>

先引入dwr自身的，再引入自己的。