Springboot 之 Filter 实现 Gzip 压缩超大 json 对象

简介

在项目中，存在传递超大 json 数据的场景。直接传输超大 json 数据的话，有以下两个弊端

• 占用网络带宽，而有些云产品就是按照带宽来计费的，间接浪费了钱
• 传输数据大导致网络传输耗时较长 为了避免直接传输超大 json 数据，可以对 json 数据进行 Gzip 压缩后，再进行网络传输。
• 请求头添加 Content-Encoding 标识，传输的数据进行过压缩
• Servlet Filter 拦截请求，对压缩过的数据进行解压
• HttpServletRequestWrApper 包装，把解压的数据写入请求体

GzipUtils 类提供压缩解压相关方法

package com.olive.utils;import com.alibaba.fastjson2.JSON;import com.olive.vo.ArticleRequestVO;import lombok.extern.slf4j.Slf4j;import org.apache.commons.io.FileUtils;import JAVA.io.*;import java.util.zip.GZIPInputStream;import java.util.zip.GZIPOutputStream;@Slf4jpublic class GzipUtils {private static final String GZIP_ENCODE_UTF_8 = "UTF-8";* 字符串压缩为GZIP字节数组* @param str* @returnpublic static byte[] compress(String str) {return compress(str, GZIP_ENCODE_UTF_8);* 字符串压缩为GZIP字节数组* @param str* @param encoding* @returnpublic static byte[] compress(String str, String encoding) {if (str == null || str.length() == 0) {return null;ByteArrayOutputStream out = new ByteArrayOutputStream();GZIPOutputStream gzip = null;try {gzip = new GZIPOutputStream(out);gzip.write(str.getBytes(encoding));} catch (IOException e) {log.error("compress>>", e);}finally {if(gzip!=null){try {gzip.close();} catch (IOException e) {return out.toByteArray();* GZIP解压缩* @param bytes* @returnpublic static byte[] uncompress(byte[] bytes) {if (bytes == null || bytes.length == 0) {return null;ByteArrayOutputStream out = new ByteArrayOutputStream();ByteArrayInputStream in = new ByteArrayInputStream(bytes);GZIPInputStream unGzip = null;try {unGzip = new GZIPInputStream(in);byte[] buffer = new byte[256];int n;while ((n = unGzip.read(buffer)) >= 0) {out.write(buffer, 0, n);} catch (IOException e) {log.error("uncompress>>", e);}finally {if(unGzip!=null){try {unGzip.close();} catch (IOException e) {return out.toByteArray();* 解压并返回String* @param bytes* @returnpublic static String uncompressToString(byte[] bytes) throws IOException {return uncompressToString(bytes, GZIP_ENCODE_UTF_8);* @param bytes* @returnpublic static byte[] uncompressToByteArray(byte[] bytes) throws IOException {return uncompressToByteArray(bytes, GZIP_ENCODE_UTF_8);* 解压成字符串* @param bytes 压缩后的字节数组* @param encoding 编码方式* @return 解压后的字符串public static String uncompressToString(byte[] bytes, String encoding) throws IOException {byte[] result = uncompressToByteArray(bytes, encoding);return new String(result);* 解压成字节数组* @param bytes* @param encoding* @returnpublic static byte[] uncompressToByteArray(byte[] bytes, String encoding) throws IOException {if (bytes == null || bytes.length == 0) {return null;ByteArrayOutputStream out = new ByteArrayOutputStream();ByteArrayInputStream in = new ByteArrayInputStream(bytes);GZIPInputStream unGzip = null;try {unGzip = new GZIPInputStream(in);byte[] buffer = new byte[256];int n;while ((n = unGzip.read(buffer)) >= 0) {out.write(buffer, 0, n);return out.toByteArray();} catch (IOException e) {log.error("uncompressToByteArray>>", e);throw new IOException("解压缩失败！");}finally {if(unGzip!=null){unGzip.close();* 将字节流转换成文件* @param filename* @param data* @throws Exceptionpublic static void saveFile(String filename, byte[] data) throws Exception {FileOutputStream fos = null;try {if (data != null) {String filepath = "/" + filename;File file = new File(filepath);if (file.exists()) {file.delete();fos = new FileOutputStream(file);fos.write(data, 0, data.length);fos.flush();System.out.println(file);}catch (Exception e){throw e;}finally {if(fos!=null){fos.close();对Request进行包装

UnZipRequestWrapper 读取输入流，然进行解压；解压完后，再把解压出来的数据封装到输入流中。

package com.olive.filter;import com.olive.utils.GzipUtils;import lombok.extern.slf4j.Slf4j;import javax.servlet.ReadListener;import javax.servlet.ServletInputStream;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletRequestWrapper;import java.io.*;* Json String 经过压缩后保存为二进制文件 -> 解压缩后还原成 Jso nString转换成byte[]写回body中@Slf4jpublic class UnZipRequestWrapper extends HttpServletRequestWrapper {private final byte[] bytes;public UnZipRequestWrapper(HttpServletRequest request) throws IOException {super(request);try (BufferedInputStream bis = new BufferedInputStream(request.getInputStream());ByteArrayOutputStream baos = new ByteArrayOutputStream()) {final byte[] body;byte[] buffer = new byte[1024];int len;while ((len = bis.read(buffer)) > 0) {baos.write(buffer, 0, len);body = baos.toByteArray();if (body.length == 0) {log.info("Body无内容，无需解压");bytes = body;return;this.bytes = GzipUtils.uncompressToByteArray(body);} catch (IOException ex) {log.error("解压缩步骤发生异常！", ex);throw ex;@Overridepublic ServletInputStream getInputStream() throws IOException {final ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(bytes);return new ServletInputStream() {@Overridepublic boolean isFinished() {return false;@Overridepublic boolean isReady() {return false;@Overridepublic void setReadListener(ReadListener readListener) {public int read() throws IOException {return byteArrayInputStream.read();@Overridepublic BufferedReader getReader() throws IOException {return new BufferedReader(new InputStreamReader(this.getInputStream()));定义GzipFilter对请求进行拦截

GzipFilter 拦截器根据请求头是否包含Content-Encoding=application/gzip，如果包含就对数据进行解压；否则就直接放过。

package com.olive.filter;import lombok.extern.slf4j.Slf4j;import org.springframework.stereotype.Component;import javax.servlet.*;import javax.servlet.http.HttpServletRequest;import java.io.IOException;* 解压filter@Slf4j@Componentpublic class GzipFilter implements Filter {private static final String CONTENT_ENCODING = "Content-Encoding";private static final String CONTENT_ENCODING_TYPE = "application/gzip";@Overridepublic void init(FilterConfig filterConfig) throws ServletException {log.info("init GzipFilter");@Overridepublic void doFilter(ServletRequest request, ServletResponse response, FilterChAIn chain) throws IOException, ServletException {long start = System.currentTimeMillis();HttpServletRequest httpServletRequest = (HttpServletRequest)request;String encodeType = httpServletRequest.getHeader(CONTENT_ENCODING);if (encodeType!=null && CONTENT_ENCODING_TYPE.equals(encodeType)) {log.info("请求:{} 需要解压", httpServletRequest.getRequestURI());UnZipRequestWrapper unZipRequest = new UnZipRequestWrapper(httpServletRequest);chain.doFilter(unZipRequest, response);}else {log.info("请求:{} 无需解压", httpServletRequest.getRequestURI());chain.doFilter(request,response);log.info("耗时：{}ms", System.currentTimeMillis() - start);@Overridepublic void destroy() {log.info("destroy GzipFilter");注册 GzipFilter 拦截器package com.olive.config;import com.olive.filter.GzipFilter;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.boot.web.servlet.FilterRegistrationBean;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;* 注册filter@Configurationpublic class FilterRegistration {@Autowiredprivate GzipFilter gzipFilter;@Beanpublic FilterRegistrationBean gzipFilterRegistrationBean() {FilterRegistrationBean registration = new FilterRegistrationBean<>();//Filter可以new，也可以使用依赖注入Beanregistration.setFilter(gzipFilter);//过滤器名称registration.setName("gzipFilter");//拦截路径registration.addUrlPatterns("/*");//设置顺序registration.setOrder(1);return registration;定义 Controller

该 Controller 非常简单，主要是输入请求的数据

package com.olive.controller;import java.util.HashMap;import java.util.Map;import com.alibaba.fastjson2.JSON;import com.olive.vo.ArticleRequestVO;import org.springframework.web.bind.annotation.RequestBody;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RestController;@RestControllerpublic class TestController {@RequestMapping("/getArticle")public Map getArticle(@RequestBody ArticleRequestVO articleRequestVO){Map result = new HashMap<>();result.put("code", 200);result.put("msg", "success");System.out.println(JSON.toJSONString(articleRequestVO));return result;

Controller 参数接收VO

package com.olive.vo;import lombok.Data;import java.io.Serializable;@Datapublic class ArticleRequestVO implements Serializable {private Long id;private String title;private String content;定义 Springboot 引导类package com.olive;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;@SpringBootApplicationpublic class Application {public static void main(String[] args) {SpringApplication.run(Application.class);测试

• 非压缩请求测试

• 压缩请求测试

不要直接将压缩后的 byte[] 数组当作字符串进行传输，否则压缩后的请求数据比没压缩后的还要大得多！ 项目中一般采用以下两种传输压缩后的 byte[] 的方式：

• 将压缩后的 byet[] 进行 Base64 编码再传输字符串，这种方式会损失掉一部分 GZIP 的压缩效果，适用于压缩结果要存储在 redis 中的情况
• 将压缩后的 byte[] 以二进制的形式写入到文件中，请求时直接在 body 中带上文件即可，用这种方式可以不损失压缩效果

小编测试采用第二种方式，采用以下代码把原始数据进行压缩

public static void main(String[] args) {ArticleRequestVO vo = new ArticleRequestVO();vo.setId(1L);vo.setTitle("bug弄潮儿");try {byte[] bytes = FileUtils.readFileToByteArray(new File("C:\Users\2230\Desktop\凯平项目资料\改装车项目\CXSSBOOT_DB_DDL-1.0.9.sql"));vo.setContent(new String(bytes));byte[] dataBytes = compress(JSON.toJSONString(vo));saveFile("d:/vo.txt", dataBytes);} catch (Exception e) {e.printStackTrace();

压缩后数据存储到d:/vo.txt，然后在 postman 中安装下图选择