DWR是一個開源的服務器端ajax框架,js通過直接調用普通java類中的方法實現服務器端數據處理。原理:框架根據配置在加載頁面的時候自動生成ajax代碼供前端調用。
該框架只需一個jar包 csdn有下載:dwr(免費)
web.xml
<listener><!--配置監聽器 默認啓動時加載dwr.xml(後面有配置) 路徑和web.xml一致-->
<listener-class>org.directwebremoting.servlet.DwrListener</listener-class>
</listener>
<servlet><!-- 配置servlet和映射路徑 下面有相關參數 比如fileUploadMaxBytes是允許文件上傳的大小-->
<servlet-name>dwr-invoker</servlet-name>
<servlet-class>org.directwebremoting.servlet.DwrServlet</servlet-class>
<init-param>
<param-name>fileUploadMaxBytes</param-name>
<param-value>25000000000000</param-value>
</init-param>
<init-param>
<param-name>debug</param-name>
<param-value>true</param-value>
</init-param>
<init-param>
<param-name>accessLogLevel</param-name>
<param-value>runtimeexception</param-value>
</init-param>
<init-param>
<param-name>activeReverseAjaxEnabled</param-name>
<param-value>true</param-value>
</init-param>
<init-param>
<param-name>initApplicationScopeCreatorsAtStartup</param-name>
<param-value>true</param-value>
</init-param>
<init-param>
<param-name>jsonRpcEnabled</param-name>
<param-value>true</param-value>
</init-param>
<init-param>
<param-name>jsonpEnabled</param-name>
<param-value>true</param-value>
</init-param>
<init-param>
<param-name>preferDataUrlSchema</param-name>
<param-value>false</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>
dwr.xml(與web.xml在同一目錄)
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE dwr PUBLIC "-//GetAhead Limited//DTD Direct Web Remoting 3.0//EN" "http://getahead.org/dwr/dwr30.dtd">
<dwr>
<allow>
<create creator="new" javascript="mytest"><!-普通java類-->
<param name="class" value="org.ITschool.dwr.utilcontroller.mytest"/>
</create>
<!-- this is a bad idea for live, but can be useful in testing -->
<!-- <create creator="spring" javascript="User_Service">
<param name="BeanName" value="User_Service" />
</create>-->
<create javascript="User_Service" creator="spring"><!--使用Spring配置中的bean-->
<param name="beanName" value="User_Service"/>
</create>
<create creator="new" javascript="Uploadprocess">
<param name="class" value="org.ITschool.dwr.utilcontroller.Uploadprocess"/>
</create>
<create creator="new" javascript="uploadFile">
<param name="class" value="org.ITschool.dwr.utilcontroller.uploadFile"/>
</create>
<convert converter="exception" match="java.lang.Exception"/>
<convert converter="bean" match="java.lang.StackTraceElement"/>
</allow>
</dwr>
現在看下上面mytest.java文件的代碼(以我項目中的代碼爲例)
package org.ITschool.dwr.utilcontroller;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import org.directwebremoting.WebContext;
import org.directwebremoting.WebContextFactory;
import net.sf.json.JSON;
import net.sf.json.JSONObject;
public class mytest {
public JSON getInfo(String info1){
JSONObject json=new JSONObject();
json.put("name", "XXXX");
json.put("name1", info1);
return json;
}}
最後看下前端調用了(引入必要的js)
<script type='text/javascript' src='dwr/engine.js'></script><!--必須引入的 js代碼由框架自動生成-->
<script type='text/javascript' src='dwr/util.js'></script><!--必須引入的 js代碼由框架自動生成-->
<script type='text/javascript' src='dwr/interface/mytest.js'></script><!---dwr.xml中配置的mytest java類->
再看調用
<script type='text/javascript'>
mytest.getInfo(“方法參數”,function(data){//前一個是方法參數 後面是回調函數
alert(data.name)
});
</script>
運行結果:彈出 XXXX內容的提示框架。