项目所用技术回顾之DWR

什么是DWR？

DWR是一个Open Source的 java项目,可以让JavaScript调用运行JAVA程序。

配置实例

1.首先将dwr.jar放到lib目录下面

2.在web.xml中添加关于dwr的Servlet配置信息

<?xml version="1.0" encoding="UTF-8"?><web-app version="2.5" <span style="white-space:pre"></span>xmlns="http://java.sun.com/xml/ns/javaee" <span style="white-space:pre"></span>xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" <span style="white-space:pre"></span>xsi:schemaLocation="http://java.sun.com/xml/ns/javaee <span style="white-space:pre"></span>http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"><span style="white-space:pre"></span><span style="white-space:pre"></span><!-- Struts2配置信息 --><span style="white-space:pre"></span><filter><span style="white-space:pre"></span><filter-name>struts2</filter-name><span style="white-space:pre"></span><filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class><span style="white-space:pre"></span></filter><span style="white-space:pre"></span><span style="white-space:pre"></span><filter-mapping><span style="white-space:pre"></span><filter-name>struts2</filter-name><span style="white-space:pre"></span><url-pattern>/*</url-pattern><span style="white-space:pre"></span></filter-mapping><span style="white-space:pre"></span><span style="white-space:pre"></span><!-- Spring配置信息 --><span style="white-space:pre"></span><context-param><span style="white-space:pre"></span><param-name>contextConfigLocation</param-name><span style="white-space:pre"></span><param-value><span style="white-space:pre"></span>classpath*:app*.xml<span style="white-space:pre"></span></param-value><span style="white-space:pre"></span></context-param><span style="white-space:pre"></span><listener><span style="white-space:pre"></span><listener-class>org.springframework.web.context.ContextLoaderListener</listener-class><span style="white-space:pre"></span></listener><span style="white-space:pre"></span><span style="white-space:pre"></span><!-- DWR配置信息 --><span style="white-space:pre"></span><servlet><span style="white-space:pre"></span><servlet-name>dwr-invoker</servlet-name><span style="white-space:pre"></span><servlet-class>org.directwebremoting.servlet.DwrServlet</servlet-class><span style="white-space:pre"></span><init-param><span style="white-space:pre"></span><param-name>debug</param-name><span style="white-space:pre"></span><param-value>true</param-value><span style="white-space:pre"></span></init-param><span style="white-space:pre"></span></servlet><span style="white-space:pre"></span><span style="white-space:pre"></span><servlet-mapping><span style="white-space:pre"></span><servlet-name>dwr-invoker</servlet-name><span style="white-space:pre"></span><url-pattern>/dwr/*</url-pattern><span style="white-space:pre"></span></servlet-mapping><span style="white-space:pre"></span>  <welcome-file-list>    <welcome-file>index.jsp</welcome-file>  </welcome-file-list></web-app><?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"><filter><filter-name>struts2</filter-name><filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class></filter><filter-mapping><filter-name>struts2</filter-name><url-pattern>/*</url-pattern></filter-mapping><!-- DWR配置信息 --><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>

3.添加dwr.xml的配置文件 
在WEB-INF下面添加dwr.xml文件,dwr.xml是DWR的配置文件，所有需要在JavaScript中调用的java的类都必须在这个文件中描述 (必须与web.xml同级)

<?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><!-- 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>        <convert match="com.ssh.test.Dept" converter="bean"></convert>        <create javascript="loginSrv" creator="spring">            <param name="beanName" value="loginSrv"></param>        </create></allow></dwr>  

<create javascript="deptSrv" creator="spring">是指由spring实例化配置文件中deptServices，并且将其转换为名称为deptSrv的javascript库。在函数的调用过程中我们需要传递参数，这样我们就需要将本地的javascript变量转变成对应的java类型变量。这个就是Convertor的作用。DWR内部为我们编写了一些JAVA主要类型的Convertor.默认下面的数据类型会自动转换：boolean, byte, short, int, long, float, double, char, java.lang.Boolean, java.lang.Byte, java.lang.Short, java.lang.Integer, java.lang.Long, java.lang.Float, java.lang.Double, java.lang.Character, java.math.BigInteger, java.math.BigDecimal and java.lang.String.但是假如我们有这样一个方法A.setB(B b)，现在我们要在javascript脚本中调用该方法，我们需要传递java类型为B的参数，这个时候我们就需要配B配置Convertor。

本实例的代码下载地址http://download.csdn.net/detail/yurujun/7827289