文章目錄

• 第二步：在tomcat伺服器下webapps/ROOT目錄下建立如下兩個xml檔案
• 1. clientaccesspolicy.xml
• 2. crossdomain.xml
• 第三步：修改Tomcat伺服器下conf/web.xml，或者專案WEB-INF/web.xml，

兩個專案 ，同一域名不同埠 分別跑在同一臺機器的兩個tomcat中，構成跨域。

1. 首先需要進行cros配置,詳見下面說明（這裡使用了cors-filter jar包方式）

2. 意圖跨域訪問的請求不需要session驗證：跨域訪問在進行session驗證時可利用請求頭Referer引數判斷請求來源，若是來自允許的域則直接通過。

完成後，前端可直接使用ajax post請求 跨域提取資料(測試瀏覽器:chrome).

第一步：頁面js程式碼：

function createCORSRequest(method, url){
    var xhr = new XMLHttpRequest();
    if ("withCredentials" in xhr){
        xhr.open(method, url, true);
    }
 
 else if (typeof XDomainRequest != "undefined"){
        xhr = new XDomainRequest();
        xhr.open(method, url);
    } else {
        xhr = null;
    }
    return xhr;
}

var request = createCORSRequest("get", "http://192.168.5.221:8080/");
if (request){
    request.onreadystatechange = function(){
        if
 
 (request.readyState == 4 && request.status == 200) {
            var response = request.responseText;
            console.log(response)
        }   
    request.send();
}

第二步：在tomcat伺服器下webapps/ROOT目錄下建立如下兩個xml檔案

1. clientaccesspolicy.xml

<?xml version="1.0" encoding="utf-8" ?>
<access-policy>
  <cross-domain-access>
    <policy>  
      <allow-from http-request-headers="*">  
        <domain uri="*"/>  
      </allow-from>  
      <grant-to>  
        <resource path="/" include-subpaths="true"/>  
      </grant-to>  
    </policy>  
  </cross-domain-access>  
</access-policy>  

2. crossdomain.xml

<?xml version="1.0"?>  
  
<cross-domain-policy>  
  
<allow-access-from domain="*" />  
  
</cross-domain-policy>

第三步：修改Tomcat伺服器下conf/web.xml，或者專案WEB-INF/web.xml，

我選擇的是在專案下配置過濾器。我驗證了兩個，一個是tomcat下自帶的cors過濾器，一個是cors-filter-1.7.jar下的過濾器。兩個我都測試了，沒問題。

應用tomcat的filter配置如下：引數cors.allowOrigin可以指定具體的源來訪問

<filter>
  <filter-name>CorsFilter</filter-name>
  <filter-class>org.apache.catalina.filters.CorsFilter</filter-class>
  <init-param>
    <param-name>cors.allowed.origins</param-name>
    <param-value>*</param-value>
  </init-param>
  <init-param>
    <param-name>cors.allowed.methods</param-name>
    <param-value>GET,POST,HEAD,OPTIONS,PUT</param-value>
  </init-param>
  <init-param>
    <param-name>cors.allowed.headers</param-name>
    <param-value>Content-Type,X-Requested-With,accept,Origin,Access-Control-Request-Method,Access-Control-Request-Headers</param-value>
  </init-param>
  <init-param>
    <param-name>cors.exposed.headers</param-name>
    <param-value>Access-Control-Allow-Origin,Access-Control-Allow-Credentials</param-value>
  </init-param>
  <init-param>
    <param-name>cors.support.credentials</param-name>
    <param-value>true</param-value>
  </init-param>
  <init-param>
    <param-name>cors.preflight.maxage</param-name>
    <param-value>10</param-value>
  </init-param>
</filter>
<filter-mapping>
  <filter-name>CorsFilter</filter-name>
  <url-pattern>/*</url-pattern>
</filter-mapping>

或者應用cors-filter-1.7.jar，還需要java-property-utils-1.9.jar，可以在http://mvnrepository.com/artifact/com.thetransactioncompany/cors-filter 選擇某個版本匯入pom.xml中，自動匯入jar包。

配置如下：引數cors.allowOrigin可以指定具體的源來訪問

<filter>
    <filter-name>CORS</filter-name>
    <filter-class>com.thetransactioncompany.cors.CORSFilter</filter-class>
    <init-param>
     <param-name>cors.allowOrigin</param-name>
        <param-value>*</param-value>
    </init-param>
    <init-param>
     <param-name>cors.supportedMethods</param-name>
        <param-value>GET, POST, HEAD, PUT, DELETE</param-value>
    </init-param>
    <init-param>
     <param-name>cors.supportedHeaders</param-name>
        <param-value>Accept, Origin, X-Requested-With, Content-Type, Last-Modified</param-value>
    </init-param>
    <init-param>
        <param-name>cors.exposedHeaders</param-name>
        <param-value>Set-Cookie</param-value>
    </init-param>
    <init-param>
        <param-name>cors.supportsCredentials</param-name>
        <param-value>true</param-value>
    </init-param>
</filter>
<filter-mapping>
    <filter-name>CORS</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>