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@L_502_0@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
模拟从服务器加载下拉列表数据
模拟保存功能
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-@H_404_42@class>org.springframework.web.context.ContextLoaderListener</listener-@H_404_42@class> </listener> <!-- 配置DWR前端控制器 --> <servlet> <servlet-name>dwrServlet</servlet-name> <servlet-@H_404_42@class>org.directwebremoting.servlet.DwrServlet</servlet-@H_404_42@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>@H_404_42@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
@H_404_42@package entity; @H_404_42@public @H_404_42@class Dept { @H_404_42@private Long id; @H_404_42@private String name; @H_404_42@public Dept() { } @H_404_42@public Dept(Long id,String name) { @H_404_42@this.id = id; @H_404_42@this.name = name; } @H_404_42@public Long getId() { @H_404_42@return id; } @H_404_42@void setId(Long id) { @H_404_42@this.id = id; } @H_404_42@public String getName() { @H_404_42@return name; } @H_404_42@void setName(String name) { @H_404_42@this.name = name; } }
新建业务逻辑类
DeptServices类
@H_404_42@package services; @H_404_42@import java.util.ArrayList; @H_404_42@import java.util.HashMap; @H_404_42@import java.util.List; @H_404_42@import java.util.Map; @H_404_42@import entity.Dept; @SuppressWarnings("unchecked") @H_404_42@class DeptServices { @H_404_42@public List findDept() { @H_404_42@throw @H_404_42@new RuntimeException("查找失败!"); } @H_404_42@void deleteDept(Long id) { System.out.println("Delete dept " + id); } @H_404_42@public List getDeptsForPo() { List depts = @H_404_42@new ArrayList(); depts.add(@H_404_42@new Dept(1l,"教质部")); depts.add(@H_404_42@new Dept(2l,"学术部")); depts.add(@H_404_42@new Dept(3l,"就业部")); depts.add(@H_404_42@new Dept(4l,"咨询部")); @H_404_42@return depts; } @H_404_42@void saveDept(List<Dept> depts) { System.out.println(dept.getId() + ":" + dept.getName()); System.out.println(depts); } @H_404_42@public List getDepts() { List depts = @H_404_42@new ArrayList(); Map map = @H_404_42@new HashMap(); map.put("id","01"); map.put("name","教质部"); depts.add(map); map = 404_42@try { Thread.sleep(1000); } @H_404_42@catch (InterruptedException e) { e.printStackTrace(); } @H_404_42@return depts; } }
HelloServices类
/** * @author dlwu * */ @H_404_42@class HelloServices { @H_404_42@public String sayHello(String name){ System.out.println("Hello now!"); @H_404_42@return "Hello " + name + "!"; } }
LoginService类
@H_404_42@import org.directwebremoting.WebContext; @H_404_42@import org.directwebremoting.WebContextFactory; @H_404_42@class LoginService { @H_404_42@void checkUserLogin(String userid,String pwd){ WebContext ctx = WebContextFactory.get(); ctx.getSession().setAttribute("userid",userid); } @H_404_42@public String getLoginUser(){ WebContext ctx = WebContextFactory.get(); @H_404_42@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" @H_404_42@class="services.DeptServices"></bean> <bean id="loginSrv" @H_404_42@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>
hello.jsp页面
<%@ page language="java" @H_404_42@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,0)"> } </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" Meta http-equiv="description" content="This is my page"> </head> <!-- 记得引入js,测试地址: http: <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 @H_404_42@if($('depts').options.length > 0){ @H_404_42@return; } DWRUtil.addOptions('depts',[{id:'',name:'正在下载...'}],'id','name'); dwr.engine._execute("dwr",'deptSrv','getDepts',function(depts){ DWRUtil.removeAllOptions('depts'); DWRUtil.addOptions('depts',depts,'name'); }); } function loadDept2(){ @H_404_42@if($('depts2').options.length > 0){ @H_404_42@return; } DWRUtil.addOptions('depts2','getDeptsForPo',function(depts){ DWRUtil.removeAllOptions('depts2'); DWRUtil.addOptions('depts2','name'); }); } function saveDept(){ 声明dept对象 var dept = { id:$("deptid").value,name:$("deptname").value }; dwr.engine._execute("dwr",'saveDept',[dept],function(){ alert('保存成功!'); }); } function find(){ dwr.engine._execute("dwr",'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>