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