Struts2中 ajax交互

<span style="font-size:18px;"><strong>Struts.xml</strong>配置文件

<!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN" "http://struts.apache.org/dtds/struts-2.0.dtd">
<struts>
	<include file="struts-default.xml"></include>
	
	
	
	<package name="ajax" extends="struts-default">
		<action name="ajax_*" class="com.test.action.AjaxAction" method="{1}">
			<result name="SUCCESS">/ajax.jsp</result>
			<result type="stream">
				<param name="inputName">inputStream</param>
			</result>
		</action>
	</package>
	
</struts></span>


AjaxAction

package com.test.action;

import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.StringBufferInputStream;
import java.io.StringReader;
import java.io.UnsupportedEncodingException;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.struts2.ServletActionContext;

import com.opensymphony.xwork2.ActionSupport;

public class AjaxAction extends ActionSupport {

	private InputStream inputStream;

	public InputStream getInputStream() {
		return inputStream;
	}

	public String execute() throws Exception {
		return SUCCESS;
	}

	public String checkUser() throws Exception {
		HttpServletRequest request = ServletActionContext.getRequest();
		// 获取 ajax 传递的 name 参数值
		Object name = request.getParameter("name");
		Object password = request.getParameter("password");
		System.out.println("name=>" + name);
		// 返回 StringBufferInputStream 对象，新的 jdk 里面已经不推荐使用，但推荐使用的 StringReader
		// 并不是 InputStream 接口的实现类，这个比较蛋疼，可以使用下面 test 里面其他的实现类来传递
		inputStream = new StringBufferInputStream(transcoding("哈哈,"+name +password));
		return SUCCESS;
	}
	
	public String test() throws Exception {
		// 返回 ByteArrayInputStream 对象至前台，注意跟上面的编码上的区别
		inputStream = new ByteArrayInputStream("乱码测试".getBytes("utf-8"));
		return SUCCESS;
	}
	
	private String transcoding(String str) {
		try {
			return new String(str.getBytes("utf-8"), "iso-8859-1");
		} catch (UnsupportedEncodingException e) {
			e.printStackTrace();
		}
		return str;
	}
}


ajax.jsp

<span style="font-size:18px;"><%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>ajax</title>
</head>
<body>
	<form>
		用户名：<input type="text" id="nameId"/><br/>
		密码：<input type="text" id="passwordId"/><br/>
		<span id="nameId2"><span></span></span><br/>
		<span id="msgId"></span><br/>
		<input type="button" onclick="checkUserName()" value="提交"/>
	</form>
</body>
</html>

<script type="text/javascript">
var xhr ;

// 初始化 xhr 对象
// return value : 1 : IE , 2 , Mozila , 0 : create xhr error ;
function createXHR(){
	// 1,创建xhr 对象 .
	if( window.ActiveXObject ){
		xhr = new ActiveXObject( "Microsoft.XMLHTTP" ) ;
		return 1 ;
	}else if( window.XMLHttpRequest ){
		xhr = new XMLHttpRequest();
		return 2 ;	
	}else{
		return 0 ;
	}	   
}   
  
// ////////// 验证用户名是否存在 ////////////////////

// 将用户填写的用户名发送给服务器端验证
function checkUserName(){
	var ret = createXHR();
	if( ret == 0 ){
		alert( "create xhr error" ) ;
	}else{
		// 在xhr中注册用于处理应答的函数(handleCheck)
		xhr.onreadystatechange = handleCheck ;
		/*
		 * //使用Get方式向服务器发送请求 . 
		 * var url = makeQueryString( "/ajax/reg.jsp" ); 
		 * xhr.open( "get" , url ) ; 
		 * xhr.send( null );
		 */
		  
		// 通过Post 形式向服务器发送数据 .
		var url = "http://localhost:8080/ajax/ajax_checkUser.action" ;
		xhr.open( "post" , url ) ;   
		xhr.setRequestHeader( "Content-Type" , "application/x-www-form-urlencoded" ) ;
		xhr.send( makeQueryString( null ) ) ;
	}   
}   
  
// 在指定的URL上添加参数
function makeQueryString( url ){
	var name = document.getElementById( "nameId" ).value ;
	var password = document.getElementById( "passwordId" ).value ;
	var queryString ;
	if( url == null ){
		return "name=" + name ;	
	}else{
		return url + "?name=" + name +"&password=" + password;	
	}
}   

function handleCheck(){  
	document.getElementById( "nameId2" ).firstChild.innerHTML="用户名不能为空";
	// 通信过程结束 .
	// readyState : 1: 初始化阶段 2 ：连接建立阶段 3 : 通信中阶段 4 ： 通信结束
	if( xhr.readyState == 4 ){   
		// status==200,表示服务器运行正常,其他值代表错误
		if( xhr.status == 200 ){
			processResult();
		}else if(document.getElementById( "nameId" ).value==""){
			document.getElementById( "nameId2" ).firstChild.nodeValue="用户名不能为空";
			document.getElementById( "nameId2" ).color="red";	
		}
	}
}
  
function processResult(){
	// 获得应答内容 ,把应答内容显示在网页上
	var span = document.getElementById( "msgId" ) ;
	span.innerHTML = xhr.responseText ;	
}

</script></span>

web.xml

<span style="font-size:18px;"><?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
	

	<filter>
		<filter-name>struts2</filter-name>
		<filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
	</filter>
	
	<filter>
        <filter-name>struts-cleanup</filter-name>
        <filter-class>
            com.test.filter.SetCharacterEncodingFilter
        </filter-class>
        <init-param>
        	<param-name>encoding</param-name>
        	<param-value>utf-8</param-value>
        </init-param>
    </filter>  
    <filter-mapping>
        <filter-name>struts-cleanup</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

	<filter-mapping>
		<filter-name>struts2</filter-name>
		<url-pattern>*.action</url-pattern>
	</filter-mapping>

</web-app></span>


SetCharacterEncodingFilter

<span style="font-size:18px;">package com.test.filter;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

public class SetCharacterEncodingFilter implements Filter {

    protected String encoding = null;

    protected FilterConfig filterConfig = null;

    protected boolean ignore = true;

    public void destroy() {

        this.encoding = null;
        this.filterConfig = null;

    }

    public void doFilter(ServletRequest request, ServletResponse response,
                         FilterChain chain)
    throws IOException, ServletException {

        if (ignore || (request.getCharacterEncoding() == null)) {
            String encoding = selectEncoding(request);
            if (encoding != null)
                request.setCharacterEncoding(encoding);
        }

        chain.doFilter(request, response);

    }

    public void init(FilterConfig filterConfig) throws ServletException {

    this.filterConfig = filterConfig;
        this.encoding = filterConfig.getInitParameter("encoding");
        String value = filterConfig.getInitParameter("ignore");
        if (value == null)
            this.ignore = true;
        else if (value.equalsIgnoreCase("true"))
            this.ignore = true;
        else if (value.equalsIgnoreCase("yes"))
            this.ignore = true;
        else
            this.ignore = false;

    }

    protected String selectEncoding(ServletRequest request) {
        return (this.encoding);
    }
}
</span>


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原文地址：https://www.cnblogs.com/laohuihui/p/5308752.html