javaWeb之json的简单使用

AJAX步骤

function sendRequest() {

CreateXHR();

if(XHR) {

/* 
var name = document.getElementById("name").value;
var password = document.getElementById("password").value; */
var uri = "http://localhost:8080/TestStruts2/userJson.action";
XHR.open("GET", uri, true);

XHR.onreadystatechange = resultHander;

XHR.send(null);

}
}

首先执行 CreateXHR（）方法

function CreateXHR() {
try {
XHR = new ActiveXObject("msxm12.XMLHTTP");
} catch(e1) {
try {
XHR = new ActiveXObject("microsoft.XMLHTTP");
} catch(e2) {
try {
XHR = new XMLHttpRequest();
} catch (e3) {
XHR = false;
}
}
}
}

然后判断XHR

if(XHR) {

/* 
var name = document.getElementById("name").value;
var password = document.getElementById("password").value; */
var uri = "http://localhost:8080/TestStruts2/userJson.action";
XHR.open("GET", uri, true);

XHR.onreadystatechange = resultHander;

XHR.send(null);

}

状态改变即可触发onreadysyayechange方法，方法如下

function resultHander() {
if(XHR.readyState == 4 && XHR.status == 200) {
var userObj = JSON.parse(XHR.responseText);

alert(XHR.status);
alert(XHR.readyState);
var userStr = "<table border=0>";
userStr += ('<tr><td><b>Name</b></td><td>' + userObj.USER.name + '</td></tr>');
userStr += ('<tr><td><b>Age</b></td><td>' + userObj.USER.age + '</td></tr>');
userStr += "</table>";
document.getElementById("jsonDiv").innerHTML = userStr;
}
}

在UserAction中，使用如下JSON即可将User调用改成USER调用 userStr += ('<tr><td><b>Name</b></td><td>' + userObj.USER.name + '</td></tr>');

@JSON(name="USER")
public User getUser() {
return user;
}

JSON需导入的包struts2-json-plugin-2.3.16.3.jar