一、背景

在项目开发过程中，需要对于某些接口统一处理。
这时候就需要获取请求的报文，再对获取的报文进行统一处理。

二、了解过滤器

首先了解一下过滤器拦截器的区别：
JAVA中的拦截器、过滤器：https://blog.csdn.net/qq_38254635/article/details/131201519

三、代码

新建 WebRequestWrapper.java
重写 HttpServletRequestWrapper，处理json报文请求

package com.config.filter;import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import javax.servlet.ReadListener;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import org.springframework.util.StreamUtils;public class WebRequestWrapper extends HttpServletRequestWrapper{private byte[] body;public WebRequestWrapper(HttpServletRequest request) throws IOException {super(request);body = StreamUtils.copyToByteArray(request.getInputStream());}@Overridepublic BufferedReader getReader() throws IOException {return new BufferedReader(new InputStreamReader(getInputStream()));}@Overridepublic ServletInputStream getInputStream() throws IOException {final ByteArrayInputStream bais = new ByteArrayInputStream(body);return new ServletInputStream() {@Overridepublic int read() throws IOException {return bais.read();}@Overridepublic boolean isFinished() {return false;}@Overridepublic boolean isReady() {return false;}@Overridepublic void setReadListener(ReadListener listener) {}};}public byte[] getBody() {return body;}public void setBody(byte[] body) {this.body = body;}}

新建WebRequestFilter.java，请求过滤器处理参数，解密、字符串替、添加请求参数等等。

package com.config.filter;import java.io.BufferedReader;
import java.io.IOException;
import java.util.List;
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 com.Utils;
import org.springframework.stereotype.Component;@Component
public class WebRequestFilter implements Filter {@Overridepublic void init(FilterConfig arg0) throws ServletException {}@Overridepublic void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {HttpServletRequest httpRequest = (HttpServletRequest) request;HttpServletResponse httpResponse = (HttpServletResponse) response;if (checkPath(httpRequest.getRequestURI())) {chain.doFilter(request, response);} else {WebRequestWrapper requestWrapper = new WebRequestWrapper((HttpServletRequest) request);BufferedReader br = requestWrapper.getReader();String line = null;StringBuilder sb = new StringBuilder();while ((line = br.readLine()) != null) {sb.append(line);}String original = sb.toString();String handle = Utils.handleRequest(original);requestWrapper.setBody(handle.getBytes("UTF-8"));chain.doFilter(requestWrapper, response);}}private boolean checkPath(String url){if(!"on".equals(ENCRYPT_SWITCH)) return true;for (String path : REQUEST_LIST) {if(url.contains(path)) return true;}return false;}@Overridepublic void destroy() {}}

说明：
ENCRYPT_SWITCH：开关配置
REQUEST_LIST：忽略处理路径配置，如一些导入的操作。
Utils.handleRequest()：需要对报文进行的处理操作。

新建 WebRequestConfig.java 配置过滤器的执行顺序。
order属性控制过滤器加载顺序：数字越小，加载越早

package com.config.filter;import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;@Configuration
public class WebRequestConfig {@Beanpublic FilterRegistrationBean ValidatorFilterRegistration() {FilterRegistrationBean<WebRequestFilter> registration = new FilterRegistrationBean<WebRequestFilter>();registration.setFilter(new WebRequestFilter());registration.addUrlPatterns("/*");registration.setOrder(Integer.MAX_VALUE-10);return registration;}
}

相关链接：
SpringBoot过滤器获取响应的参数：https://blog.csdn.net/qq_38254635/article/details/136041183
JAVA中的拦截器、过滤器：https://blog.csdn.net/qq_38254635/article/details/131201519

OK，就这些吧。

有什么不对的还望指正，书写不易，觉得有帮助就点个赞吧！☺☺☺

参考链接:https://www.jb51.net/article/221072.html