图片处理

1. 常见的图片存储方案

方案一：使用nginx搭建图片服务器
方案二：使用开源的分布式文件存储系统，例如Fastdfs、HDFS等（需要运维搭建）
方案三：使用云存储，例如阿里云、七牛云等（目前最流行）

哪些图片需要部署到图片服务器上？

2. 七牛云图片存储

2.1 七牛云依赖坐标

<dependency>
    <groupId>com.qiniu</groupId>
    <artifactId>qiniu-java-sdk</artifactId>
    <version>7.2.0</version>
</dependency>

2.2 Java SDK操作七牛云

本章节我们就需要使用七牛云提供的Java SDK完成图片上传和删除，我们可以参考官方提供的例子。

上传文件案例

//构造一个带指定Zone对象的配置类
Configuration cfg = new Configuration(Zone.zone0());
//...其他参数参考类注释
UploadManager uploadManager = new UploadManager(cfg);
//...生成上传凭证，然后准备上传
String accessKey = "your access key";
String secretKey = "your secret key";
//存储空间的名称
String bucket = "your bucket name";
//如果是Windows情况下，格式是 D:\\qiniu\\test.png
String localFilePath = "/home/qiniu/test.png";
//默认不指定key的情况下，以文件内容的hash值（七牛云自己命名）作为文件名
//设置key的值后，以key值为文件名上传
String key = null;
Auth auth = Auth.create(accessKey, secretKey);
String upToken = auth.uploadToken(bucket);
try {
    Response response = uploadManager.put(localFilePath, key, upToken);
    //解析上传成功的结果
    DefaultPutRet putRet = new Gson().fromJson(response.bodyString(), DefaultPutRet.class);
    System.out.println(putRet.key);
    System.out.println(putRet.hash);
} catch (QiniuException ex) {
    Response r = ex.response;
    System.err.println(r.toString());
    try {
        System.err.println(r.bodyString());
    } catch (QiniuException ex2) {
        //ignore
    }
}

删除文件案例

//构造一个带指定Zone对象的配置类
Configuration cfg = new Configuration(Zone.zone0());
//...其他参数参考类注释
String accessKey = "your access key";
String secretKey = "your secret key";
String bucket = "your bucket name";
String key = "your file key";
Auth auth = Auth.create(accessKey, secretKey);
BucketManager bucketManager = new BucketManager(auth, cfg);
try {
    bucketManager.delete(bucket, key);
} catch (QiniuException ex) {
    //如果遇到异常，说明删除失败
    System.err.println(ex.code());
    System.err.println(ex.response.toString());
}

封装工具类

为了方便操作七牛云存储服务，我们可以将官方提供的案例简单改造成一个工具类QiniuUtils

package com.itheima.util;
import com.google.gson.Gson;
import com.qiniu.common.QiniuException;
import com.qiniu.common.Zone;
import com.qiniu.http.Response;
import com.qiniu.storage.BucketManager;
import com.qiniu.storage.Configuration;
import com.qiniu.storage.UploadManager;
import com.qiniu.storage.model.DefaultPutRet;
import com.qiniu.util.Auth;
/**
 * 七牛云工具类
 */
public class QiniuUtils {
    public  static String accessKey = "dulF9Wze9bxujtuRvu3yyYb9JX1Sp23jzd3tO708";
    public  static String secretKey = "vZkhW7iot3uWwcWz9vXfbaP4JepdWADFDHVLMZOe";
    public  static String bucket = "qiniutest";
    public static void upload2Qiniu(String filePath,String fileName){
        //构造一个带指定Zone对象的配置类
        Configuration cfg = new Configuration(Zone.zone0());
        UploadManager uploadManager = new UploadManager(cfg);
        Auth auth = Auth.create(accessKey, secretKey);
        String upToken = auth.uploadToken(bucket);
        try {
            Response response = uploadManager.put(filePath, fileName, upToken);
            //解析上传成功的结果
            DefaultPutRet putRet = new Gson().fromJson(response.bodyString(), DefaultPutRet.class);
        } catch (QiniuException ex) {
            Response r = ex.response;
            try {
                System.err.println(r.bodyString());
            } catch (QiniuException ex2) {
                //ignore
            }
        }
    }
    //上传文件
    public static void upload2Qiniu(byte[] bytes, String fileName){
        //构造一个带指定Zone对象的配置类
        Configuration cfg = new Configuration(Zone.zone0());
        //...其他参数参考类注释
        UploadManager uploadManager = new UploadManager(cfg);
        //默认不指定key的情况下，以文件内容的hash值作为文件名
        String key = fileName;
        Auth auth = Auth.create(accessKey, secretKey);
        String upToken = auth.uploadToken(bucket);
        try {
            Response response = uploadManager.put(bytes, key, upToken);
            //解析上传成功的结果
            DefaultPutRet putRet = new Gson().fromJson(response.bodyString(), DefaultPutRet.class);
            System.out.println(putRet.key);
            System.out.println(putRet.hash);
        } catch (QiniuException ex) {
            Response r = ex.response;
            System.err.println(r.toString());
            try {
                System.err.println(r.bodyString());
            } catch (QiniuException ex2) {
                //ignore
            }
        }
    }
    //删除文件
    public static void deleteFileFromQiniu(String fileName){
        //构造一个带指定Zone对象的配置类
        Configuration cfg = new Configuration(Zone.zone0());
        String key = fileName;
        Auth auth = Auth.create(accessKey, secretKey);
        BucketManager bucketManager = new BucketManager(auth, cfg);
        try {
            bucketManager.delete(bucket, key);
        } catch (QiniuException ex) {
            //如果遇到异常，说明删除失败
            System.err.println(ex.code());
            System.err.println(ex.response.toString());
        }
    }
}

3. 图片上传代码实现

3.1 图片上传并回显流程

3.2 在Controller层接收上传的文件

package com.itheima.controller;
import com.alibaba.dubbo.config.annotation.Reference;
import com.itheima.constant.MessageConstant;
import com.itheima.entity.PageResult;
import com.itheima.entity.QueryPageBean;
import com.itheima.entity.Result;
import com.itheima.pojo.CheckGroup;
import com.itheima.pojo.Setmeal;
import com.itheima.service.CheckGroupService;
import com.itheima.service.SetmealService;
import com.itheima.utils.QiniuUtils;
import org.springframework.web.bind.annotation.RequestBody;
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;
import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import java.io.File;
import java.util.List;
import java.util.UUID;
/**
 * 套餐管理
 */
@RestController
@RequestMapping("/setmeal")
public class SetmealController {
    @Reference
    private SetmealService setmealService;
      //图片上传
    @RequestMapping("/upload")
    public Result upload(@RequestParam("imgFile")MultipartFile imgFile){
        try{
            //获取原始文件名
            String originalFilename = imgFile.getOriginalFilename();
            int lastIndexOf = originalFilename.lastIndexOf(".");
            //获取文件后缀
            String suffix = originalFilename.substring(lastIndexOf);
            //使用UUID随机产生文件名称，防止同名文件覆盖
            String fileName = UUID.randomUUID().toString() + suffix;
            QiniuUtils.upload2Qiniu(imgFile.getBytes(),fileName);
            //图片上传成功
            Result result = new Result(true, MessageConstant.PIC_UPLOAD_SUCCESS);
            result.setData(fileName);
            return result;
        }catch (Exception e){
            e.printStackTrace();
            //图片上传失败
            return new Result(false,MessageConstant.PIC_UPLOAD_FAIL);
        }
    }
}

文件上传时，需要对文件名进行处理，保证文件名是唯一的，防止被覆盖。(实现方案：文件名使用UUID)

注意：别忘了在spring配置文件中配置文件上传组件

<!--文件上传组件-->
<bean id="multipartResolver" 
      class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
  <property name="maxUploadSize" value="104857600" />
  <property name="maxInMemorySize" value="4096" />
  <property name="defaultEncoding" value="UTF-8"/>
</bean>