AJAX跨域访问（从Tomcat8到Apache）

1.在Tomcat的Root目录下放入如下的文件

apache-tomcat-8.0.12X64\webapps\ROOT

clientaccesspolicy.xml文件

<?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>

crossdomain.xml

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

2.在项目的web.xml中加入如下的代码

apache-tomcat-8.0.12X64\webapps\test\WEB-INF

web.xml

<?xml version="1.0" encoding="ISO-8859-1"?>

<web-app xmlns="http://java.sun.com/xml/ns/j2ee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"
         version="2.4">
  <display-name></display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
  </welcome-file-list>

  <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>
    <!--
    <filter>
      <filter-name>CorsFilter</filter-name>
      <filter-class>org.apache.catalina.filters.CorsFilter</filter-class>
    </filter>
    <filter-mapping>
      <filter-name>CorsFilter</filter-name>
      <url-pattern>/*</url-pattern>
    </filter-mapping>
    -->
</web-app>

3.在Apache的httpd.conf中取消LoadModule headers_module modules/mod_headers.so 前面的注释

Apache\conf

4.修改Apache的httpd.conf中<Directory>配置节

Apache\conf

<Directory "D:/Project/Resource/">
    AllowOverride None   
    Require all granted
    Header set Access-Control-Allow-Origin *
    Header set Access-Control-Allow-Headers "*"
    Header set Access-Control-Allow-Methods "POST, GET, OPTIONS, DELETE, PUT"   
</Directory>

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在tomcat工程的HTML页面中可以应用AJAX来访问Apache中的数据

var url = http://127.0.0.1/resource/JavaScript/gis/Z_QPF_20140831000000.F060.bin.bz2;

function loadData()
{
    var xhr = new XMLHttpRequest();
    if ("withCredentials" in xhr){
        xhr.open("get", url, true);
        console.log("withCredentials");
    } else if (typeof XDomainRequest != "undefined"){
        xhr = new XDomainRequest();
        xhr.open("get", url);
        console.log("XDomainRequest");
    } else {
        xhr = null;
    }
    xhr.responseType = "arraybuffer";
    xhr.onload = function() {
        if (this.status == 200) {
            var arrayBuffer = this.response;
            //......
        }
    }
}