Cors实现java后端完全跨域实例

https://www.jb51.net/article/114838.htm这篇文章很详细的介绍了JS的跨域，给出的解决方案是springboot的方式，假如不用spring boot 或者 spring版本低于4.2就需要自己实现；

参考了spring boot的实现方式，并有所简化，代码如下：

package com.lvluo.web.filter.CorsFilter;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.http.HttpHeaders;

public class CorsFilter implements Filter {

public static final String ACCESS_CONTROL_REQUEST_METHOD = "Access-Control-Request-Method";

public static final String OPTIONS = "OPTIONS";

public void doFilter(ServletRequest request, ServletResponse response,
 FilterChain chain) throws IOException, ServletException {

HttpServletRequest httpRequest = (HttpServletRequest) request;
HttpServletResponse httpResponse = (HttpServletResponse) response;

if (isCorsRequest(httpRequest)) {
 httpResponse.setHeader("Access-Control-Allow-Origin", "*");
 httpResponse.setHeader("Access-Control-Allow-Methods",
  "POST, GET, PUT, DELETE");
 httpResponse.setHeader("Access-Control-Allow-Credentials", "true");
 // response.setIntHeader("Access-Control-Max-Age", 1728000);
 httpResponse
  .setHeader(
   "Access-Control-Allow-Headers",
   "Origin, X-Requested-With, Content-Type, Accept, Accept-Encoding, Authorization");
 if (isPreFlightRequest(httpRequest)) {
 return;
 }
}
chain.doFilter(request, response);
}

public void init(FilterConfig filterConfig) {
}

public void destroy() {
}

public boolean isCorsRequest(HttpServletRequest request) {
return (request.getHeader(HttpHeaders.ORIGIN) != null);
}

/**
* Returns {@code true} if the request is a valid CORS pre-flight one.
*/
public boolean isPreFlightRequest(HttpServletRequest request) {
return (isCorsRequest(request) && OPTIONS.equals(request.getMethod()) && request
 .getHeader(ACCESS_CONTROL_REQUEST_METHOD) != null);
}
}

接着在web.xml配置filter即可

<filter>
 <filter-name>corsFilter</filter-name>
 <filter-class>com.lvluo.web.filter.CorsFilter</filter-class>
</filter>
<filter-mapping>
 <filter-name>corsFilter</filter-name>
 <url-pattern>/api/*</url-pattern>
</filter-mapping>

前端测试的JS代码，其中客户端的

$.ajax({
 headers : {
  'Authorization' :'Bearer iBoxSO9QdrHR0'
 },
 url: 'http://localhost:8080/service/api/ping',
 type: 'GET',
 dataType: 'json',
 success : function(result){
  $("#result").html(result.code);
 }
 })

来源：https://my.oschina.net/lifereader/blog/909524