Java通過過濾器修改header

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1、問題所在

　　項目需要在聚合層做header重寫，於是搜集了很多資料，最終確定了使用filter來實現。

2、代碼片段

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、執行效果

4、參考網站

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