CSDN的ASK频道，看到关于struts2返回json数据的问题，整理了下struts2的简单demo,完成JSON数据的展示。
public class ValidateAction extends ActionSupport {
private static final long serialVersionUID = 1L;
private String username;
public Map<String, Object> result = new HashMap<String, Object>();
public Map<String, Object> getResult() {
return result;
}
public String execute() throws Exception {
if ("zhangsan".equals(username)) {
result.put("message", "success结果");
return Action.SUCCESS;
}else {
System.out.println("error结果");
result.put("message", "error结果");
return Action.ERROR;
}
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
}
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.1//EN" "http://struts.apache.org/dtds/struts-2.1.dtd">
<struts>
<package name="default" extends="json-default">
<action name="validate" class="ValidateAction">
<result type="json" />
<result name="error" type="json"></result>
</action>
</package>
</struts>
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme() + "://"
+ request.getServerName() + ":" + request.getServerPort()
+ path + "/";
%>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-type" content="text/html; charset=utf-8" />
<title>Welcome to BoadVedio</title>
<script type='text/javascript' src="<%=basePath%>resource/js/jquery-1.8.3.js"></script>
<script type="text/javascript">
var basePath = '<%=basePath%>';
function validate(){
var username = document.getElementById("username").value;
$.ajax({
url:basePath+"validate.action",
type:"post",
dataType:"json",
data:{username:username},
success:function(data){
var message = data.result.message;
$('#message').html(message);
},
error : function(XMLHttpRequest, textStatus, errorThrown) {
alert("error when insert.");
}
});
}
</script>
</head>
<body>
<input type="text" name="username" id="username"/>
<input type="button" value="提交" onclick="validate();"/>
<div id="message"></div>
</body>
</html> 测试基本功能没有问题。只是对于Action的返回值是SUCCESS还是ERROR，对页面是有影响的。上述配置，action配置中的success和error类型都是JSON，这样不管Action走入的是return SUCCESS还是ERROR分支，都会把成员变量result对象转化成JSON返回给页面的，ajax请求都是走入success分支中的。但是如果把error类型配置成一个jsp，那么，此时ajax的请求返回时是进入了error分支了<struts>
<package name="default" extends="json-default">
<action name="validate" class="ValidateAction">
<result type="json" />
<result name="error" >/error.jsp</result>
</action>
</package>
</struts> 而且浏览器并没有自动跳转到error.jsp页面去。那么问题来了：为什么配置error为error.jsp的时候，ajax请求走入了error分支呢？这个应该是ajax请求的dataType类型设置成了json，如果此时Action返回了error.jsp，那么ajax会视为异常。原文地址：http://blog.csdn.net/wojiushiwo945you/article/details/45247391
