圖片的上傳與預覽（三行代碼實現）

第一步：建立一個springboot項目

第二步：編寫controller層

package com.atzhongruan.springboot_pngupload.controller;

import org.apache.tomcat.util.http.fileupload.IOUtils;
import org.springframework.core.io.InputStreamResource;
import org.springframework.core.io.Resource;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
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 java.io.*;

/**
 * @Author jose
 * date 2019
 */
@RestController
public class UploadController {
    /**
     * 圖片上傳
     * @param file
     * @throws IOException
     */
    @RequestMapping("/upload")
    public void upload(@RequestParam("file")MultipartFile file)throws IOException {
        File saveFile = new File("D:\\11.png");
        FileOutputStream outputStream = new FileOutputStream(saveFile);
        IOUtils.copy(file.getInputStream(),outputStream);
        outputStream.close();
    }

    /**
     * 圖片預覽
     * @return
     * @throws FileNotFoundException
     */
    @RequestMapping(value = "/image/preview",produces = MediaType.IMAGE_PNG_VALUE)
    public ResponseEntity<Resource> preview()throws FileNotFoundException {
        FileInputStream inputStream = new FileInputStream(new File("D:\\23.png"));
        InputStreamResource inputStreamResource = new InputStreamResource(inputStream);
        HttpHeaders httpHeaders = new HttpHeaders();
        return  new ResponseEntity<>(inputStreamResource,httpHeaders, HttpStatus.OK);
    }
}

第三步：post請求