spring+dwr

DWR（Direct Web Remoting）是一个用于改善web页面与Java类交互的远程服务器端Ajax开源框架,可以帮助开发人员开发包含AJAX技术的网站.它可以允许在浏览器里的代码使用运行在WEB服务器上的JAVA函数,就像它就在浏览器里一样。

以下模拟一个简单的dwr入门案例，重点理解dwr是如何跟java后台服务器打交道的

模拟效果如下

该功能说明了dwr是怎么跟后台服务器打交道的

模拟从服务器加载下拉列表数据

模拟保存功能

模拟查询功能

接下来为dwr+spring集成步骤：

1、新建一个web工程，导入dwr+spring所需jar，如下图

目录结构图

修改web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4" 
    xmlns="http://java.sun.com/xml/ns/j2ee" 
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee 
    http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">  <!-- Spring上下文 -->
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:resource/app*.xml</param-value>
    </context-param>
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
    <!-- 配置DWR前端控制器 -->
    <servlet>
        <servlet-name>dwrServlet</servlet-name>
        <servlet-class>org.directwebremoting.servlet.DwrServlet</servlet-class>
        <!-- 指定配置文件 -->
        <init-param>
            <param-name>config</param-name>
            <!-- 如果有多个用","分开 -->
            <param-value>
                /WEB-INF/classes/config/dwr.xml                
            </param-value>
        </init-param>
        <init-param>
            <param-name>debug</param-name>
            <param-value>true</param-value>
        </init-param>
    </servlet>
    <servlet-mapping>
        <servlet-name>dwrServlet</servlet-name>
        <url-pattern>/dwr/*</url-pattern>
    </servlet-mapping>
</web-app>

新建实体类Dept

package entity; public class Dept { private Long id; private String name; public Dept() {

    } public Dept(Long id, String name) { this.id = id; this.name = name;
    } public Long getId() { return id;
    } public void setId(Long id) { this.id = id;
    } public String getName() { return name;
    } public void setName(String name) { this.name = name;
    }

}

新建业务逻辑类

DeptServices类

package services; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import entity.Dept;

@SuppressWarnings("unchecked") public class DeptServices { public List findDept() { throw new RuntimeException("查找失败!");
    } public void deleteDept(Long id) {
        System.out.println("Delete dept " + id);
    } public List getDeptsForPo() {
        List depts = new ArrayList();
        depts.add(new Dept(1l, "教质部"));
        depts.add(new Dept(2l, "学术部"));
        depts.add(new Dept(3l, "就业部"));
        depts.add(new Dept(4l, "咨询部")); return depts;
    } public void saveDept(List<Dept> depts) { // System.out.println(dept.getId() + ":" + dept.getName());  System.out.println(depts);
    } public List getDepts() {
        List depts = new ArrayList();
        Map map = new HashMap();
        map.put("id", "01");
        map.put("name", "教质部");
        depts.add(map);

        map = new HashMap();
        map.put("id", "02");
        map.put("name", "学术部");
        depts.add(map);

        map = new HashMap();
        map.put("id", "03");
        map.put("name", "就业部");
        depts.add(map);

        map = new HashMap();
        map.put("id", "04");
        map.put("name", "咨询部");
        depts.add(map); try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        } return depts;
    }
}

HelloServices类

package services; /** * @author dlwu
 * */ public class HelloServices { public String sayHello(String name){
        System.out.println("Hello now!"); return "Hello " + name + "!";
    }
}

LoginService类

package services; import org.directwebremoting.WebContext; import org.directwebremoting.WebContextFactory; public class LoginService { public void checkUserLogin(String userid, String pwd){
        WebContext ctx = WebContextFactory.get();
        ctx.getSession().setAttribute("userid", userid);
    } public String getLoginUser(){
        WebContext ctx = WebContextFactory.get(); return (String)ctx.getSession().getAttribute("userid");
    }
}

配置applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<!--
    配置系统基础环境
 -->
<beans
    xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd"
    >            
    <bean id="deptServices" class="services.DeptServices"></bean>
    <bean id="loginSrv" class="services.LoginService"></bean>
</beans>

配置dwr.xml,dwr.xml是前台js跟java服务器沟通的桥梁

<?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">
<!-- 通用dwr配置 -->
<dwr>
    <allow>
        <!-- 建立JS对象，将目标对象的方法转换成JS对象的方法 -->
        <create javascript="helloSrv" creator="new">
            <param name="class" value="services.HelloServices"></param>
        </create>
        <!-- 从Spring中获取Java对象 -->
        <create javascript="deptSrv" creator="spring">
            <param name="beanName" value="deptServices"></param>
            <!-- 禁止执行 -->
            <exclude method="deleteDept" />
        </create>
        <create javascript="loginSrv" creator="spring">
            <param name="beanName" value="loginSrv"></param>
        </create>
        <!-- 指定针对于特定对象的转换器 -->
        <convert match="entity.*" converter="bean"></convert>
        <convert match="java.lang.Throwable" converter="bean">
            <param name="include" value="message"></param>
        </convert>
    </allow>
</dwr>

页面

hello.jsp页面

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>My JSP 'hello.jsp' starting page</title>
    
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">    
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
  </head>
  <!-- 记得引入js，测试地址： http://localhost:8083/dwrweb/dwr/ -->  <script type="text/javascript" src="dwr/engine.js"></script>
  <script type="text/javascript" src="dwr/interface/helloSrv.js"></script>
  <script type="text/javascript" src="dwr/util.js"></script>
  <script type="text/javascript">
          function hello(){ //方法一 //返回处理后的结果信息  /*var fn = function(result){
                $("msg").innerHTML = result;
            }
            helloSrv.sayHello($("name").value, fn);*/ //方法二  helloSrv.sayHello($("name").value, function(result){
                $("msg").innerHTML=result;
            }); //方法三 //使用如下的好处为：不用导入如上三个js //第一个参数: dwr访问路径，在web.xml中配置，如： <url-pattern>/dwr/*</url-pattern> //第二个参数: dwr与java服务器通信变量，在dwr.xml中声明 //第三个参数: 服务器方法名 //第四个参数: 页面请求参数，即服务器方法名得参数 //第五个参数: 回调函数 //dwr.engine._execute("dwr", 'helloSrv', 'sayHello', $("name").value, fn);  }
  </script>
  <body>
      <div id="msg"></div>
    <input type="text" id="name" />
    <input type="button" value="Hello" onclick="hello();" />
  </body>
</html>

dept.jsp页面

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>My JSP 'hello.jsp' starting page</title>
    
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">    
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">

  </head>
  <!-- 记得引入js，测试地址： http://localhost:8083/dwrweb/dwr/ -->  <script type="text/javascript" src="dwr/engine.js"></script>
  <script type="text/javascript" src="dwr/interface/helloSrv.js"></script>
  <script type="text/javascript" src="dwr/util.js"></script>
  <script type="text/javascript">
          function loadDept(){ //说明已经加载，不必重新加载  if($('depts').options.length > 0){ return;
              }
              DWRUtil.addOptions('depts', [{id:'',name:'正在下载...'}], 'id', 'name');
              dwr.engine._execute("dwr", 'deptSrv', 'getDepts', function(depts){
                  DWRUtil.removeAllOptions('depts');
                  DWRUtil.addOptions('depts', depts, 'id', 'name');
              });
          }
          function loadDept2(){ if($('depts2').options.length > 0){ return;
              }
              DWRUtil.addOptions('depts2', [{id:'',name:'正在下载...'}], 'id', 'name');
              dwr.engine._execute("dwr", 'deptSrv', 'getDeptsForPo', function(depts){
                  DWRUtil.removeAllOptions('depts2');
                  DWRUtil.addOptions('depts2', depts, 'id', 'name');
              });
          }
          function saveDept(){ //声明dept对象  var dept = {
                  id:$("deptid").value, 
                  name:$("deptname").value
              };
              dwr.engine._execute("dwr", 'deptSrv', 'saveDept', [dept], function(){
                  alert('保存成功!');
              });
              
          }
          function find(){
              dwr.engine._execute("dwr", 'deptSrv', 'findDept', {
                  callback:function(results){
                      alert('查询成功!');
                  },
                  errorHandler:function(e){
                      alert("查询失败:" + e);
                  }
              });
              
          }
  </script>
  <body>
      <select id="depts" onclick="loadDept();"></select>
      <select id="depts2" onclick="loadDept2();"></select>
      <hr/>
      ID:<input id="deptid" type="text" size="8"/>
      Name:<input id="deptname" type="text" size="8"/>
      <input value="保存部门" type="button" onclick="saveDept();"/>
      <input value="查找" type="button" onclick="find();"/>
  </body>
</html>