Java通过过滤器修改header

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1、问题所在

　　项目需要在聚合层做header重写，于是搜集了很多资料，最终确定了使用filter来实现。

2、代码片段

 package com.filter;

 import org.springframework.stereotype.Component;
 import org.springframework.web.filter.OncePerRequestFilter;

 import javax.servlet.FilterChain;
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletRequestWrapper;
 import javax.servlet.http.HttpServletResponse;
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.Enumeration;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;

 @Component
 public class HeadFilter extends OncePerRequestFilter {

     @Override
     protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain chain) throws ServletException, IOException {
         HeaderRequestWrapper httpServletRequestWrapper = new HeaderRequestWrapper(request);
         httpServletRequestWrapper.addHeader("headerTest", "headerTest");
         chain.doFilter(httpServletRequestWrapper, response);
     }

     private class HeaderRequestWrapper extends HttpServletRequestWrapper {

         public HeaderRequestWrapper(HttpServletRequest request) {
             super(request);
         }

         private Map<String, String> headerMap = new HashMap<>();

         public void addHeader(String name, String value) {
             this.headerMap.put(name, value);
         }

         @Override
         public String getHeader(String name) {
             String headerValue = super.getHeader(name);
             if (this.headerMap.containsKey(name)) {
                 headerValue = this.headerMap.get(name);
             }
             return headerValue;
         }

         @Override
         public Enumeration<String> getHeaderNames() {
             List<String> names = Collections.list(super.getHeaderNames());
             for (String name : this.headerMap.keySet()) {
                 names.add(name);
             }
             return Collections.enumeration(names);
         }

         @Override
         public Enumeration<String> getHeaders(String name) {
             List<String> values = Collections.list(super.getHeaders(name));
             if (this.headerMap.containsKey(name)) {
                 values = Arrays.asList(this.headerMap.get(name));
             }
             return Collections.enumeration(values);
         }

     }

 }

3、执行效果

4、参考网站

https://bbs.csdn.net/topics/392205676