跨域，前端開發中常常遇到的問題。Angularjs實現跨域方式類似於Ajax，使用CORS機制。以下闡述一下Angularjs中使用$http實現跨域請求資料。

AngularJS XMLHttpRequest：$http用於讀取遠端server的資料

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

一、$http.jsonp【實現跨域】

1. 指定callback和回撥函式名，函式名為JSON_CALLBACK時，會呼叫success回撥函式。JSON_CALLBACK必須全為大寫。
2. 指定其他回撥函式，但必須是定義在window下的全域性函式。url中必須加上callback。

二、$http.get【實現跨域】

1、 在server端設定同意在其它域名下訪問

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

2、 AngularJS端使用$http.get()

三、$http.post【實現跨域】

1、 在server端設定同意在其它域名下訪問，及響應型別、響應頭設定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()，同一時候設定請求頭資訊

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

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四、實現方式

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。須要使用相應callback方法接收，但怎樣置於$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端支援跨域請求
public String execute(){
	response.setHeader("Access-Control-Allow-Origin", "*"); //同意哪些url能夠跨域請求到本域
	response.setHeader("Access-Control-Allow-Methods","POST"); //同意的請求方法，通常是GET,POST,PUT,DELETE,OPTIONS
	response.setHeader("Access-Control-Allow-Headers","x-requested-with,content-type"); //同意哪些請求頭能夠跨域
	
	SiteHandlerAction SiteHandler = (SiteHandlerAction) BeansFactory.getBean(SiteHandlerAction.class);
	List<IndustryCategory> list = SiteHandler.getAllIndustryCategory(); //全部的分類集合
	JSONArray jsonArray = JSONArray.fromObject(list); //將list轉為json
	String json = jsonArray.toString(); //轉為json字串
	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>