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
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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
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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
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Servlet Filter 拦截请求，对压缩过的数据进行解压
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HttpServletRequestWrapper 包装，把解压的数据写入请求体
pom.xml 引入依赖
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.olive</groupId> <artifactId>request-uncompression</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>request-uncompression</name> <url>http://maven.apache.org</url> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.5.14</version> <relativePath /> <!-- lookup parent from repository --> </parent> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <maven.compiler.source>8</maven.compiler.source> <maven.compiler.target>8</maven.compiler.target> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>com.alibaba.fastjson2</groupId> <artifactId>fastjson2</artifactId> <version>2.0.14</version> </dependency> <dependency> <groupId>commons-io</groupId> <artifactId>commons-io</artifactId> <version>2.9.0</version> </dependency> </dependencies> </project> 创建压缩工具类
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; @Slf4j public 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 * @return */ public 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 * @return */ public 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 * @return */ public 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 * @return */ public static String uncompressToString(byte[] bytes) throws IOException { return uncompressToString(bytes, GZIP_ENCODE_UTF_8); } /** * @param bytes * @return */ public 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 * @return */ public 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 Exception */ public 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 */ @Slf4j public 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; } } @Override public ServletInputStream getInputStream() throws IOException { final ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(bytes); return new ServletInputStream() { @Override public boolean isFinished() { return false; } @Override public boolean isReady() { return false; } @Override public void setReadListener(ReadListener readListener) { } public int read() throws IOException { return byteArrayInputStream.read(); } }; } @Override public 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 @Component public class GzipFilter implements Filter { private static final String CONTENT_ENCODING = "Content-Encoding"; private static final String CONTENT_ENCODING_TYPE = "application/gzip"; @Override public void init(FilterConfig filterConfig) throws ServletException { log.info("init GzipFilter"); } @Override public 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); } @Override public 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 */ @Configuration public class FilterRegistration { @Autowired private GzipFilter gzipFilter; @Bean public FilterRegistrationBean<GzipFilter> gzipFilterRegistrationBean() { FilterRegistrationBean<GzipFilter> registration = new FilterRegistrationBean<>(); //Filter可以new，也可以使用依赖注入Bean registration.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; @RestController public class TestController { @RequestMapping("/getArticle") public Map<String, Object> getArticle(@RequestBody ArticleRequestVO articleRequestVO){ Map<String, Object> 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; @Data public 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; @SpringBootApplication public class Application { public static void main(String[] args) { SpringApplication.run(Application.class); } } 测试
- 非压缩请求测试
curl -X POST http://127.0.0.1:8080/getArticle -H 'content-type: application/json' -d '{ "id":1, "title": "java乐园", "content":"xxxxxxxxxx" }' - 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
