AngularJS实现跨域请求

跨域，前端开发中经常遇到的问题，AngularJS实现跨域方式类似于Ajax，使用CORS机制。
下面阐述一下AngularJS中使用$http实现跨域请求数据。
AngularJS XMLHttpRequest：$http用于读取远程服务器的数据

$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. 指定其它回调函数，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. 在服务器端设置允许在其他域名下访问

response.setHeader("Access-Control-Allow-Origin", "*"); //允许所有域名访问
response.setHeader("Access-Control-Allow-Origin", "http://www.123.com"); //允许www.123.com访问

2. AngularJS端使用$http.get()

三、$http.post【实现跨域】

1. 在服务器端设置允许在其他域名下访问，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()，同时设置请求头信息

$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，需要使用对应callback方法接收，但如何置于$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", "*"); //允许哪些url可以跨域请求到本域
  response.setHeader("Access-Control-Allow-Methods","POST"); //允许的请求方法，一般是GET,POST,PUT,DELETE,OPTIONS
  response.setHeader("Access-Control-Allow-Headers","x-requested-with,content-type"); //允许哪些请求头可以跨域
  
  SiteHandlerAction SiteHandler = (SiteHandlerAction) BeansFactory.getBean(SiteHandlerAction.class);
  List<IndustryCategory> list = SiteHandler.getAllIndustryCategory(); //所有的分类集合
  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>