<?xml version="1.0" encoding="UTF-8"?>
<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">
    <parent>
        <artifactId>leyou</artifactId>
        <groupId>com.leyou.parent</groupId>
        <version>1.0.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.leyou.service</groupId>
    <artifactId>ly-upload</artifactId>
    <version>1.0.0-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
    </dependencies>
</project>

編寫配置

server:
  port: 8082
spring:
  application:
    name: upload-service
  servlet:
    multipart:
      max-file-size: 5MB # 限制文件上傳的大小
# Eureka
eureka:
  client:
    service-url:
      defaultZone: http://127.0.0.1:10086/eureka
  instance:
    lease-renewal-interval-in-seconds: 5 # 每隔5秒發(fā)送一次心跳
    lease-expiration-duration-in-seconds: 10 # 10秒不發(fā)送就過期
    prefer-ip-address: true
    ip-address: 127.0.0.1
    instance-id: ${spring.application.name}:${server.port}

需要注意的是，我們應(yīng)該添加了限制文件大小的配置

2.1.4.啟動(dòng)類

@SpringBootApplication
@EnableDiscoveryClient
public class LyUploadService {
    public static void main(String[] args) {
        SpringApplication.run(LyUploadService.class, args);
    }
}

結(jié)構(gòu)：

編寫上傳功能

controller

編寫controller需要知道4個(gè)內(nèi)容：

請求方式：上傳肯定是POST
請求路徑：/upload/image
請求參數(shù)：文件，參數(shù)名是file，SpringMVC會(huì)封裝為一個(gè)接口：MultipleFile
返回結(jié)果：上傳成功后得到的文件的url路徑

代碼如下：

package com.leyou.upload.web;

import com.leyou.upload.service.UploadService;
import org.apache.commons.lang3.StringUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;

@RestController
@RequestMapping("upload")
public class UploadController {
    @Autowired
    private UploadService uploadService;
    /**
     * 上傳圖片功能
     * @param file
     * @return
     */
    @PostMapping("image")
    public ResponseEntity<String> uploadImage(@RequestParam("file") MultipartFile file){
        String url = uploadService.uploadImage(file);
        if(StringUtils.isBlank(url)){
            // url為空，證明上傳失敗
            return new ResponseEntity<>(HttpStatus.BAD_REQUEST);
        }
        // 返回200，并且攜帶url路徑
        return ResponseEntity.ok(url);
    }
}

service

在上傳文件過程中，我們需要對上傳的內(nèi)容進(jìn)行校驗(yàn)：

校驗(yàn)文件大小
校驗(yàn)文件的媒體類型
校驗(yàn)文件的內(nèi)容

文件大小在Spring的配置文件中設(shè)置，因此已經(jīng)會(huì)被校驗(yàn)，我們不用管。

具體代碼：

package com.leyou.upload.service;

import com.leyou.common.enums.ExceptionEnum;
import com.leyou.common.exception.LyException;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;
import org.springframework.web.multipart.MultipartFile;
import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.Arrays;
import java.util.List;

@Service
@Slf4j
public class UploadService {

    private static final List<String> ALLOW_TYPES = Arrays.asList("image/png", "image/jpeg", "image/bmg");

    public String uploadImage(MultipartFile file) {
        try {
            //校驗(yàn)文件類型
            String contentType = file.getContentType();
            if(!ALLOW_TYPES.contains(contentType)){
                throw new LyException(ExceptionEnum.INVALID_FILE_TYPE);
            }
            //校驗(yàn)文件的內(nèi)容
            BufferedImage image = ImageIO.read(file.getInputStream());
            if(image == null){
                throw new LyException(ExceptionEnum.INVALID_FILE_TYPE);
            }
            //準(zhǔn)備目標(biāo)路徑
            File dest = new File("E:\黑馬程序員57期\09 微服務(wù)電商【黑馬樂優(yōu)商城】\upload\",file.getOriginalFilename());
            file.transferTo(dest);
            //返回路徑
            return "http://image.leyou.com/"+file.getOriginalFilename();
        } catch (IOException e) {
            log.error("上傳文件失敗",e);
            throw new LyException(ExceptionEnum.UPLOAD_FILE_ERROR);
        }

    }
}

這里有一個(gè)問題：為什么圖片地址需要使用另外的url？

圖片不能保存在服務(wù)器內(nèi)部，這樣會(huì)對服務(wù)器產(chǎn)生額外的加載負(fù)擔(dān)

一般靜態(tài)資源都應(yīng)該使用獨(dú)立域名，這樣訪問靜態(tài)資源時(shí)不會(huì)攜帶一些不必要的cookie，減小請求的數(shù)據(jù)量

測試上傳

我們通過RestClient工具來測試：