AngularJS实现跨域请求

跨域，前端开发中常常遇到的问题。AngularJS实现跨域方式类似于Ajax。使用CORS机制。

以下阐述一下AngularJS中使用$http实现跨域请求数据。

AngularJS XMLHttpRequest：$http用于读取远程server的数据

$http.post(url, data, [config]).success(function(){ ... });
$http.get(url, [config]).success(function(){ ... });
$http.get(url, [config]).success(function(){ ... });

一、$http.jsonp【实现跨域】

1. 指定callback和回调函数名，函数名为JSON_CALLBACK时，会调用success回调函数。JSON_CALLBACK必须全为大写。 
2. 指定其他回调函数，但必须是定义在window下的全局函数。url中必须加上callback。 

二、$http.get【实现跨域】

1. 在server端设置同意在其它域名下訪问

response.setHeader("Access-Control-Allow-Origin", "*"); //同意全部域名訪问
response.setHeader("Access-Control-Allow-Origin", "http://www.123.com"); //同意www.123.com訪问

2. AngularJS端使用$http.get()

三、$http.post【实现跨域】

1. 在server端设置同意在其它域名下訪问，及响应类型、响应头设置

response.setHeader("Access-Control-Allow-Origin", "*");
response.setHeader("Access-Control-Allow-Methods","POST");
response.setHeader("Access-Control-Allow-Headers","x-requested-with,content-type");

2. AngularJS端使用$http.post()，同一时候设置请求头信息

$http.post('http://localhost/ajax/getAllIndustryCategoty.pt',{languageColumn:'name_eu'},{'Content-Type':'application/x-www-form-urlencoded'}).success(function(data){
		$scope.industries = data;
	});

四、实现方式

跨域方式一【JSONP】：

方法一：

$http.jsonp("http://localhost/sitesettings/getBadgeInfo.pt?jsonp=JSON_CALLBACK&siteid=137bd406").success(function(data){ ... });
//  The name of the callback should be the string JSON_CALLBACK.

方法二【返回值。须要使用相应callback方法接收，但怎样置于$scope??

?】：

$http.jsonp("http://localhost/sitesettings/getBadgeInfo.pt?jsonp=badgeabc&siteid=137bd406");
function badgeabc(data){ ... }

public String execute() throws Exception {	
	String result = FAIL;
	response.setHeader("", "");
	SiteHandlerAction siteHandlerAction = (SiteHandlerAction)BeansFactory.getBean(SiteHandlerAction.class);
	BadgeHandlerAction badgeHandlerAction = (BadgeHandlerAction)BeansFactory.getBean(BadgeHandlerAction.class);
	if("".equals(siteid) || siteid == null || StringUtils.isBlank("jsonp")){
		result = FAIL;
	}else{
		Site site = siteHandlerAction.find(siteid);
		UserBadgeStatus userBadgeStatus = badgeHandlerAction.getUserBadgeStatus(site.getId());
		if(userBadgeStatus != null){
			result = "{"t":"+userBadgeStatus.getStyle()+","l":"+userBadgeStatus.getSuspend_location()+","s":"+site.getId()+"}";
			JSONObject jsonObj = JSONObject.fromObject(result);
			String json = jsonObj.toString();
			result = jsonp + "(" + json + ")";
		}
	}
	PrintWriter write = response.getWriter();
	write.print(result);
	write.flush();
	write.close();
	return NONE;
}

跨域方式二【$http.get()】：

function getAdustryController($scope,$http){
	$http.get('http://localhost/ajax/getAllIndustryCategoty.pt?languageColumn=name_eu').success(function(data){
		$scope.industries = data;
	});
}

跨域方式三【$http.post()】：

function getAdustryController($scope,$http){
	$http.post('http://localhost/ajax/getAllIndustryCategoty.pt',{languageColumn:'name_eu'},{'Content-Type':'application/x-www-form-urlencoded'}).success(function(data){
		$scope.industries = data;
	});
}

// java端支持跨域请求
public String execute(){
	response.setHeader("Access-Control-Allow-Origin", "*"); //同意哪些url能够跨域请求到本域
	response.setHeader("Access-Control-Allow-Methods","POST"); //同意的请求方法，通常是GET,POST,PUT,DELETE,OPTIONS
	response.setHeader("Access-Control-Allow-Headers","x-requested-with,content-type"); //同意哪些请求头能够跨域
	
	SiteHandlerAction SiteHandler = (SiteHandlerAction) BeansFactory.getBean(SiteHandlerAction.class);
	List<IndustryCategory> list = SiteHandler.getAllIndustryCategory(); //全部的分类集合
	JSONArray jsonArray = JSONArray.fromObject(list); //将list转为json
	String json = jsonArray.toString(); //转为json字符串
	try {
		PrintWriter write = response.getWriter();
		write.print(json);
		write.close();
	} catch (IOException e) {
		e.printStackTrace();
	}
	return NONE;
}

<table ng-controller="getAdustryController">
	<tr ng-repeat='industry in industries'>
		<td>{{ industry.id }}</td>
		<td>{{ industry.name_ch }}</td>
		<td>{{ industry.name_eu }}</td>
		<td>{{ industry.name_jp }}</td>
	</tr>
</table>