springboot 通过filter修改请求体和响应体

1.新建ModifyRequestBodyWrapper.class

package com.example.my_project.filter;

import org.apache.commons.io.IOUtils;

import javax.servlet.ReadListener;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.nio.charset.StandardCharsets;

/**
 * 自定义HttpServletRequestWrapper 用于修改请求体
 */
public class ModifyRequestBodyWrapper extends HttpServletRequestWrapper {

    private String oldRequestBody;

    private String newRequestBody;

    public ModifyRequestBodyWrapper(HttpServletRequest request) throws IOException {
        super(request);
        this.oldRequestBody = IOUtils.toString(request.getInputStream(),request.getCharacterEncoding());
    }

    @Override
    public ServletInputStream getInputStream() throws IOException {
        return new ServletInputStream() {
            final ByteArrayInputStream bis = new ByteArrayInputStream(newRequestBody.getBytes(StandardCharsets.UTF_8));
            @Override
            public boolean isFinished() {
                return true;
            }

            @Override
            public boolean isReady() {
                return true;
            }

            @Override
            public void setReadListener(ReadListener readListener) {

            }

            @Override
            public int read() throws IOException {
                return bis.read();
            }
        };
    }

    public String getOldRequestBody() {
        return oldRequestBody;
    }

    public void setOldRequestBody(String oldRequestBody) {
        this.oldRequestBody = oldRequestBody;
    }

    public String getNewRequestBody() {
        return newRequestBody;
    }

    public void setNewRequestBody(String newRequestBody) {
        this.newRequestBody = newRequestBody;
    }
}

2.新建ModifyResponseBodyWrapper.class

package com.example.my_project.filter;

import javax.servlet.ServletOutputStream;
import javax.servlet.WriteListener;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServletResponseWrapper;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;

/**
 * 自定义HttpServletResponseWrapper 修改响应体
 */
public class ModifyResponseBodyWrapper extends HttpServletResponseWrapper {


    private ByteArrayOutputStream bos;

    public ModifyResponseBodyWrapper(HttpServletResponse response) {
        super(response);
        this.bos = new ByteArrayOutputStream();
    }

    @Override
    public ServletOutputStream getOutputStream() throws IOException {
        return new ServletOutputStream() {
            @Override
            public boolean isReady() {
                return true;
            }

            @Override
            public void setWriteListener(WriteListener writeListener) {

            }

            @Override
            public void write(int b) throws IOException {
                bos.write(b);
            }

            @Override
            public void write(byte[] b) throws IOException {
                bos.write(b);
            }
        };
    }

    @Override
    public PrintWriter getWriter() throws IOException {
        return new PrintWriter(new OutputStreamWriter(bos));
    }

    public String getResponseBody() throws IOException {
        ServletOutputStream outputStream = this.getOutputStream();
        outputStream.flush();

        PrintWriter writer = this.getWriter();
        writer.flush();

        return bos.toString(this.getCharacterEncoding());
    }
}

3.新建HttpRequestFilter.class

package com.example.my_project.filter;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.filter.OncePerRequestFilter;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.Map;

/**
 * 修改请求体响应体
 */
@Slf4j
public class HttpRequestFilter extends OncePerRequestFilter {

    @Override
    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException {
        ModifyRequestBodyWrapper modifyRequestBodyWrapper = new ModifyRequestBodyWrapper(request);
        String oldRequestBody = modifyRequestBodyWrapper.getOldRequestBody();
        log.info("path:{}",request.getRequestURI());
        log.info("oldRequestBody：{}",oldRequestBody);
        String newRequestBody = changeRequestBody(oldRequestBody);
        log.info("newRequestBody:{}",newRequestBody);
        modifyRequestBodyWrapper.setNewRequestBody(newRequestBody);

        ModifyResponseBodyWrapper modifyResponseBodyWrapper = new ModifyResponseBodyWrapper(response);
        filterChain.doFilter(modifyRequestBodyWrapper,modifyResponseBodyWrapper);
        String oldResponseBody = modifyResponseBodyWrapper.getResponseBody();
        log.info("oldResponseBody:{}",oldResponseBody);
        String newResponseBody = changeResponseBody(oldResponseBody);
        log.info("newResponseBody:{}",newResponseBody);
        response.setContentType(request.getContentType());
        byte[] responseBodyData = newResponseBody.getBytes(StandardCharsets.UTF_8);
        ServletOutputStream out = response.getOutputStream();
        out.write(responseBodyData);
    }

    /**
     * 修改请求体
     * @param oldRequestBody 修改前的请求体
     * @return 修改后的请求体
     */
    public String changeRequestBody(String oldRequestBody) throws JsonProcessingException {
        ObjectMapper objectMapper = new ObjectMapper();
        Map<String, String> stringStringMap =objectMapper.readValue(oldRequestBody, new TypeReference<Map<String, String>>() {
        });
        stringStringMap.put("password","34566");
        return objectMapper.writeValueAsString(stringStringMap);
    }

    /**
     * 修改响应体
     * @param oldResponseBody 修改前的响应体
     * @return 修改够的响应体
     */
    public String changeResponseBody(String oldResponseBody){
        return "00000000";
    }

}

4.新建FilterConfig.class

package com.example.my_project.config;

import com.example.my_project.filter.HttpRequestFilter;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import javax.servlet.Filter;
import java.util.List;

/**
 * 过滤器配置
 */
@Configuration
public class FilterConfig {

    @Bean
    public FilterRegistrationBean<Filter> filterFilterRegistrationBean(){
        FilterRegistrationBean<Filter> filterFilterRegistrationBean = new FilterRegistrationBean<>();
        filterFilterRegistrationBean.setFilter(new HttpRequestFilter());
        filterFilterRegistrationBean.setOrder(-1);
        //过滤的请求
        filterFilterRegistrationBean.setUrlPatterns(List.of("/*"));
        return filterFilterRegistrationBean;
    }
}