SpringBoot过滤器获取响应的参数

一、背景

在项目开发过程中，需要对于某些接口统一处理。
这时候就需要获取响应的报文，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 WebResponseWrapper.java
重写 HttpServletResponseWrapper，处理json报文请求

package com.config.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;
import java.io.UnsupportedEncodingException;public class WebResponseWrapper extends HttpServletResponseWrapper {private ByteArrayOutputStream buffer = null;private ServletOutputStream out = null;private PrintWriter writer = null;public WebResponseWrapper(HttpServletResponse response) throws IOException {super(response);buffer = new ByteArrayOutputStream();out = new WrapperOutputStream(buffer);writer = new PrintWriter(new OutputStreamWriter(buffer,this.getCharacterEncoding()));}@Overridepublic ServletOutputStream getOutputStream() throws IOException {return out;}@Overridepublic PrintWriter getWriter() throws UnsupportedEncodingException {return writer;}@Overridepublic void flushBuffer() throws IOException {if (out != null) {out.flush();}if (writer != null) {writer.flush();}}@Overridepublic void reset() {buffer.reset();}public byte[] getResponseData() throws IOException {flushBuffer();return buffer.toByteArray();}private class WrapperOutputStream extends ServletOutputStream {private ByteArrayOutputStream bos = null;public WrapperOutputStream(ByteArrayOutputStream stream)throws IOException {bos = stream;}@Overridepublic void write(int b) throws IOException {bos.write(b);}@Overridepublic void write(byte[] b) throws IOException {bos.write(b, 0, b.length);}@Overridepublic boolean isReady() {return false;}@Overridepublic void setWriteListener(WriteListener writeListener) {}}}

新建WebResponseFilter.java，响应过滤器处理参数，加密、字符串替、添加响应参数等等。

package com.config.filter;import com.Utils;
import org.springframework.stereotype.Component;
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 java.io.IOException;
import java.io.PrintWriter;@Component
public class WebResponseFilter implements Filter {@Overridepublic void init(FilterConfig filterConfig) 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(httpRequest, httpResponse);} else {response.setContentType("application/json; charset=utf-8");response.setCharacterEncoding("UTF-8");WebResponseWrapper webResponseWrapper = new WebResponseWrapper((HttpServletResponse) response);chain.doFilter(request, webResponseWrapper);byte[] resData = webResponseWrapper.getResponseData();PrintWriter out = response.getWriter();String encrypt = Utils.handleResponse(new String(resData, "UTF-8"));out.print(encrypt.replaceAll("[\\s*\t\n\r]", ""));out.flush();out.close();}}private boolean checkPath(String url){if(!"on".equals(ENCRYPT_SWITCH)) return true;for (String path : RESPONSE_LIST) {if(url.contains(path)) return true;}return false;}@Overridepublic void destroy() {}}

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

相关链接：
SpringBoot过滤器获取请求的参数：https://blog.csdn.net/qq_38254635/article/details/136041159
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！☺☺☺