Springboot 之 Filter 实现 Gzip 压缩超大 json 对象

标签：return Springboot bytes Filter json new import byte public

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

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

标签：return,Springboot,bytes,Filter,json,new,import,byte,public
From： https://www.cnblogs.com/happyhuangjinjin/p/16759500.html