spring boot上传 下载图片。

buildscript {

    repositories {

        mavenCentral()

    }

    dependencies {

        classpath('org.springframework.boot:spring-boot-gradle-plugin:1.5.9.RELEASE')

    }

}

group "com.li"

version "1.0-SNAPSHOT"

apply plugin: "java"                           //java 插件

apply plugin: "org.springframework.boot"   //spring boot 插件

apply plugin: "io.spring.dependency-management"

apply plugin: "application"   //应用

//mainClassName = "Main.Application"

sourceCompatibility = 1.8

repositories {

    mavenCentral()

}

dependencies {

    compile("org.springframework.boot:spring-boot-starter-web",

            "org.springframework.boot:spring-boot-starter-activemq",

            "org.springframework.boot:spring-boot-starter-test",

            "org.springframework.boot:spring-boot-starter-cache",

            "org.springframework.boot:spring-boot-devtools")

    runtime ("org.apache.tomcat.embed:tomcat-embed-jasper")

    testCompile group: 'junit', name: 'junit', version: '4.12'

}

    //上传的方法

    @RequestMapping(method = RequestMethod.POST, value = "/upload")

    public String handleFileUpload(@RequestParam("file") MultipartFile file,

                                   RedirectAttributes redirectAttributes, HttpServletRequest request) {

//        System.out.println(request.getParameter("member"));

        if (!file.isEmpty()) {

            try {

                Files.copy(file.getInputStream(), Paths.get(ROOT, file.getOriginalFilename()));

                redirectAttributes.addFlashAttribute("message",

                        "You successfully uploaded " + file.getOriginalFilename() + "!");

            } catch (IOException|RuntimeException e) {

                redirectAttributes.addFlashAttribute("message", "Failued to upload " + file.getOriginalFilename() + " => " + e.getMessage());

            }

        } else {

            redirectAttributes.addFlashAttribute("message", "Failed to upload " + file.getOriginalFilename() + " because it was empty");

        }

        return "redirect:/";

    }

package com.li.controller;

import static org.springframework.hateoas.mvc.ControllerLinkBuilder.linkTo;

import static org.springframework.hateoas.mvc.ControllerLinkBuilder.methodOn;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.core.io.ResourceLoader;

import org.springframework.http.ResponseEntity;

import org.springframework.stereotype.Controller;

import org.springframework.ui.Model;

import org.springframework.web.bind.annotation.*;

import org.springframework.web.multipart.MultipartFile;

import org.springframework.web.servlet.mvc.support.RedirectAttributes;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import java.io.*;

import java.nio.file.Files;

import java.nio.file.Paths;

import java.util.UUID;

import java.util.stream.Collectors;

@Controller

public class FileUploadController {

//    private static final Logger log = LoggerFactory.getLogger(FileUploadController.class);

    public static final String ROOT = "d://upload-dir";

    private final ResourceLoader resourceLoader;

    @Autowired

    public FileUploadController(ResourceLoader resourceLoader) {

        this.resourceLoader = resourceLoader;

    }

    @RequestMapping(method = RequestMethod.GET, value = "/")

    public String provideUploadInfo(Model model) throws IOException {

        model.addAttribute("files", Files.walk(Paths.get(ROOT))

                .filter(path -> !path.equals(Paths.get(ROOT)))

                .map(path -> Paths.get(ROOT).relativize(path))

                .map(path -> linkTo(methodOn(FileUploadController.class).getFile(path.toString())).withRel(path.toString()))

                .collect(Collectors.toList()));

        return "uploadForm";

    }

    //显示图片的方法关键 匹配路径像 localhost:8080/b7c76eb3-5a67-4d41-ae5c-1642af3f8746.png

    @RequestMapping(method = RequestMethod.GET, value = "/{filename:.+}")

    @ResponseBody

    public ResponseEntity<?> getFile(@PathVariable String filename) {

        try {

            return ResponseEntity.ok(resourceLoader.getResource("file:" + Paths.get(ROOT, filename).toString()));

        } catch (Exception e) {

            return ResponseEntity.notFound().build();

        }

    }

    //上传的方法

    @RequestMapping(method = RequestMethod.POST, value = "/upload")

    public String handleFileUpload(@RequestParam("file") MultipartFile file,

                                   RedirectAttributes redirectAttributes, HttpServletRequest request) {

//        System.out.println(request.getParameter("member"));

        if (!file.isEmpty()) {

            try {

                Files.copy(file.getInputStream(), Paths.get(ROOT, file.getOriginalFilename()));

                redirectAttributes.addFlashAttribute("message",

                        "You successfully uploaded " + file.getOriginalFilename() + "!");

            } catch (IOException|RuntimeException e) {

                redirectAttributes.addFlashAttribute("message", "Failued to upload " + file.getOriginalFilename() + " => " + e.getMessage());

            }

        } else {

            redirectAttributes.addFlashAttribute("message", "Failed to upload " + file.getOriginalFilename() + " because it was empty");

        }

        return "redirect:/";

    }

//    @RequestMapping("/save")

//    public String save(@RequestParam(value = "file") MultipartFile file, userInfo uf, RedirectAttributes attributes, HttpServletRequest request) {

//        if (uf != null) {

//            if (!file.isEmpty()) {

//                String fileName = UUID.randomUUID().toString().replaceAll("-", "") + file.getOriginalFilename().substring(file.getOriginalFilename().lastIndexOf("."));

//                String filePath ="/Users/thomas-wu/upload/" + fileName;

//                System.out.println(filePath);

//                try {

//                    file.transferTo(new File(filePath));

//                } catch (IOException e) {

//                    e.printStackTrace();

//                }

//                uf.setHead_href("getimgs?address="+filePath);

//            }

//

//        }

//        String result = userService.saveUser(uf);

//        JSONObject jb = JSONObject.fromObject(result);

//        if (jb.getInt("status") == 1 && "信息保存成功".equals(jb.getString("msg"))) {

//            attributes.addFlashAttribute("error", "信息保存成功");

//            return "redirect:/user";

//        }

//        attributes.addFlashAttribute("error", "信息保存失败");

//        return "redirect:/edit";

//    }

    @RequestMapping("/getimgs")

    public void getimg(String address, HttpServletRequest request, HttpServletResponse response) throws IOException{

        try {

            FileInputStream hFile=new FileInputStream(address);

            int i=hFile.available();

            byte data[]=new byte[i];

            hFile.read(data);

            hFile.close();

            response.setContentType("image/*");

            OutputStream toClient=response.getOutputStream();

            toClient.write(data);

            toClient.close();

        }catch (IOException e){

            PrintWriter toClient=response.getWriter();

            response.setContentType("text/html;charset=gb2312");

            toClient.write("无法打开图片");

            toClient.close();

        }

    }

}