基于SpringBoot实现图片上传与显示

<dependencies>
 <!--FreeMarker模板视图依赖-->
    <dependency>
      <groupId>org.spring work.boot</groupId>
      <artifactId>spring-boot-starter-freemarker</artifactId>
    </dependency>

    <dependency>
      <groupId>org.spring work.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

    <dependency>
      <groupId>org.spring work.boot</groupId>
      <artifactId>spring-boot-starter-test</artifactId>
      <scope>test</scope>
    </dependency>
</dependencies>

server.port=8102

### FreeMarker 配置
spring.freemarker.allow-request-override=false
#Enable template caching.启用模板缓存。
spring.freemarker.cache=false
spring.freemarker.check-template-location=true
spring.freemarker.charset=UTF-8
spring.freemarker.content-type=text/html
spring.freemarker.expose-request-attributes=false
spring.freemarker.expose-session-attributes=false
spring.freemarker.expose-spring-macro-helpers=false
#设置面板后缀
spring.freemarker.suffix=.ftl

# 设置单个文件最大内存
multipart.maxFileSize=50Mb
# 设置所有文件最大内存
multipart.maxRequestSize=50Mb
# 自定义文件上传路径
web.upload-path=E:/Develop/Files/Photos/

package com.wu.demo.fileupload.demo.util;

public class FileNameUtils {

  /**
   * 获取文件后缀
   * @param fileName
   * @return
   */
  public static String getSuffix(String fileName){
    return fileName.substring(fileName.lastIndexOf("."));
  }

  /**
   * 生成新的文件名
   * @param fileOriginName 源文件名
   * @return
   */
  public static String getFileName(String fileOriginName){
    return UUIDUtils.getUUID() + FileNameUtils.getSuffix(fileOriginName);
  }

}

import java.util.UUID;

/**
 * 生成文件名
 */
public class UUIDUtils {

  public static String getUUID(){
    return UUID.randomUUID().toString().replace("-", "");
  }

}

package com.wu.demo.fileupload.demo.util;

import org.spring work.web.multipart.MultipartFile;

import java.io.File;
import java.io.IOException;

/**
 * 文件上传工具包
 */
public class FileUtils {

  /**
   *
   * @param file 文件
   * @param path 文件存放路径
   * @param fileName 源文件名
   * @return
   */
  public static boolean upload(MultipartFile file, String path, String fileName){

    // 生成新的文件名
    //String realPath = path + "/" + FileNameUtils.getFileName(fileName);

    //使用原文件名
    String realPath = path + "/" + fileName;

    File dest = new File(realPath);

    //判断文件父目录是否存在
    if(!dest.getParentFile().exists()){
      dest.getParentFile().mkdir();
    }

    try {
      //保存文件
      file.transferTo(dest);
      return true;
    } catch (IllegalStateException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
      return false;
    } catch (IOException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
      return false;
    }

  }
}

package com.wu.demo.fileupload.demo.controller;

import com.wu.demo.fileupload.demo.util.FileUtils;
import org.spring work.beans.factory.annotation.Autowired;
import org.spring work.beans.factory.annotation.Value;
import org.spring work.core.io.ResourceLoader;
import org.spring work.http.ResponseEntity;
import org.spring work.stereotype.Controller;
import org.spring work.web.bind.annotation.RequestMapping;
import org.spring work.web.bind.annotation.RequestParam;
import org.spring work.web.multipart.MultipartFile;

import javax.servlet.http.HttpServletResponse;
import java.util.Map;

@Controller
public class TestController {

  private final ResourceLoader resourceLoader;

  @Autowired
  public TestController(ResourceLoader resourceLoader) {
    this.resourceLoader = resourceLoader;
  }

  @Value("${web.upload-path}")
  private String path;

  /**
   * 跳转到文件上传页面
   * @return
   */
  @RequestMapping("test")
  public String toUpload(){
    return "test";
  }

  /**
   *
   * @param file 要上传的文件
   * @return
   */
  @RequestMapping("fileUpload")
  public String upload(@RequestParam("fileName") MultipartFile file, Map<String,  > map){

    // 要上传的目标文件存放路径
    String localPath = "E:/Develop/Files/Photos";
    // 上传成功或者失败的提示
    String msg = "";

    if (FileUtils.upload(file, localPath, file.getOriginalFilename())){
      // 上传成功，给出页面提示
      msg = "上传成功！";
    }else {
      msg = "上传失败！";

    }

    // 显示图片
    map.put("msg", msg);
    map.put("fileName", file.getOriginalFilename());

    return "forward:/test";
  }

  /**
   * 显示单张图片
   * @return
   */
  @RequestMapping("show")
  public ResponseEntity showPhotos(String fileName){

    try {
      // 由于是读取本机的文件，file是一定要加上的， path是在application配置文件中的路径
      return ResponseEntity.ok(resourceLoader.getResource("file:" + path + fileName));
    } catch (Exception e) {
      return ResponseEntity.notFound().build();
    }
  }

}

<!DOCTYPE html>
<head>
  <  charset="UTF-8" />
  < >图片上传Demo</ >
</head>
<body>
<h1 >图片上传Demo</h1>
<form action="fileUpload" method="post" enctype="multipart/form-data">
  <p>选择文件: <input type="file" name="fileName"/></p>
  <p><input type="submit" value="提交"/></p>
</form>
<#--判断是否上传文件-->
<#if msg??>
  <span>${msg}</span><br>
<#else >
  <span>${msg!("文件未上传")}</span><br>
</#if>
<#--显示图片，一定要在img中的src发请求给controller，否则直接跳转是乱码-->
<#if fileName??>
<img src="/show?fileName=${fileName}" style="width: 200px"/>
<#else>
<img src="/show" style="width: 100px"/>
</#if>
</body>
</html>