java实现图片上传功能，并返回图片保存路径

1、前端html

<div class="form-group">
    <label for="inputPassword3" class="col-sm-2 control-label">身份证正面照片:</label>
    <div class="col-sm-10">
    <input type="hidden" name="img"  id="photoUrl"/>
    <input type="file" name="logoFile" id="logoFile" onchange="setImg(this);">
    <span><img id="photourlShow" src="" width="300" height="197"/></span>
    </div>
</div>

2、js

//用于进行图片上传，返回地址
function setImg(obj){
    var f=$(obj).val();
    alert(f);
    console.log(obj);
    if(f == null || f ==undefined || f == ''){
        return false;
    }
    if(!/\.(?:png|jpg|bmp|gif|PNG|JPG|BMP|GIF)$/.test(f))
    {
        alert("类型必须是图片(.png|jpg|bmp|gif|PNG|JPG|BMP|GIF)");
        $(obj).val('');
        return false;
    }
    var data = new FormData();
    console.log(data);
    $.each($(obj)[0].files,function(i,file){
        data.append('file', file);
    });
    console.log(data);
    $.ajax({
        type: "POST",
        url: GLOBAL_INFO.WEBURL_PREFIX+"business/uploadImg.xhtml",
        data: data,
        cache: false,
        contentType: false,    //不可缺
        processData: false,    //不可缺
        dataType:"json",
        success: function(ret) {
            console.log(ret);
            if(ret.code==0){
                    $("#photoUrl").val(ret.result.url);//将地址存储好
                    $("#photourlShow").attr("src",ret.result.url);//显示图片
                    alertOk(ret.message);
            }else{
                alertError(ret.message);
                $("#url").val("");
                $(obj).val('');
            }
        },
        error: function(XMLHttpRequest, textStatus, errorThrown) {
            alert("上传失败，请检查网络后重试");
        }
    });
}

3、后台代码

import java.io.File;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import java.util.Random;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.multipart.MultipartFile;

import com.alibaba.fastjson.JSON;
import com.siyang.CommonUtil.BaseController;
import com.siyang.entity.ResponseResult;
/**
 * 照片上传工具类
 * @author admin
 *
 */
@Controller
@RequestMapping("/business")
public class UploaderController extends BaseController{
    @ResponseBody
    @RequestMapping("/uploadImg.xhtml")
    public void uploadPicture(@RequestParam(value="file",required=false)MultipartFile file,HttpServletRequest request,HttpServletResponse response){
        ResponseResult result = new ResponseResult();
        Map<String, Object> map = new HashMap<String, Object>();
        File targetFile=null;
        String url="";//返回存储路径
        int code=1;
        System.out.println(file);
        String fileName=file.getOriginalFilename();//获取文件名加后缀
        if(fileName!=null&&fileName!=""){
            String returnUrl = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort() + request.getContextPath() +"/upload/imgs/";//存储路径
            String path = request.getSession().getServletContext().getRealPath("upload/imgs"); //文件存储位置
            String fileF = fileName.substring(fileName.lastIndexOf("."), fileName.length());//文件后缀
            fileName=new Date().getTime()+"_"+new Random().nextInt(1000)+fileF;//新的文件名

            //先判断文件是否存在
            SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd");
            String fileAdd = sdf.format(new Date());
            //获取文件夹路径
            File file1 =new File(path+"/"+fileAdd);
            //如果文件夹不存在则创建
            if(!file1 .exists()  && !file1 .isDirectory()){
                file1 .mkdir();
            }
            //将图片存入文件夹
            targetFile = new File(file1, fileName);
            try {
                //将上传的文件写到服务器上指定的文件。
                file.transferTo(targetFile);
                url=returnUrl+fileAdd+"/"+fileName;
                code=0;
                result.setCode(code);
                result.setMessage("图片上传成功");
                map.put("url", url);
                result.setResult(map);
            } catch (Exception e) {
                e.printStackTrace();
                result.setMessage("系统异常，图片上传失败");
            }
        }
       writeJson(response, result);
    }
}

4、结果集实体类

package com.siyang.entity;

import java.util.Map;

public class ResponseResult {
    private Integer code;

    private String message;

    private Map<String, Object> result;

    public Integer getCode() {
        return this.code;
    }

    public void setCode(Integer code) {
        this.code = code;
    }

    public String getMessage() {
        return this.message;
    }

    public void setMessage(String message) {
        this.message = message;
    }

    public Map<String, Object> getResult() {
        return this.result;
    }

    public void setResult(Map<String, Object> result) {
        this.result = result;
    }

}

5、向页面返回结果

package com.siyang.CommonUtil;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;

import javax.servlet.http.HttpServletResponse;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.gson.Gson;

public class BaseController {
     protected Logger logger = LoggerFactory.getLogger(getClass());
        /**
         * 输出JSON数据
         *
         * @param response
         * @param jsonStr
         */
        public void writeJson(HttpServletResponse response, String jsonStr) {
            response.setContentType("text/json;charset=utf-8");
            response.setHeader("Pragma", "No-cache");
            response.setHeader("Cache-Control", "no-cache");
            response.setDateHeader("Expires", 0);
            PrintWriter pw = null;
            try {
                pw = response.getWriter();
                pw.write(jsonStr);
                pw.flush();
            } catch (Exception e) {
                logger.info("输出JSON数据异常", e);
            }finally{
                if(pw!=null){
                    pw.close();
                }
            }
        }
        /**
         *
         * 向页面响应json字符数组串流.
         *
         * @param response
         * @param jsonStr
         * @throws IOException
         * @return void
         * @author 蒋勇
         * @date 2015-1-14 下午4:18:33
         */
        public void writeJsonStr(HttpServletResponse response, String jsonStr) throws IOException {

            OutputStream outStream = null;
            try {
                response.reset();
                response.setCharacterEncoding("UTF-8");
                outStream = response.getOutputStream();
                outStream.write(jsonStr.getBytes("UTF-8"));
                outStream.flush();
            } catch (IOException e) {
                logger.info("输出JSON数据异常(writeJsonStr)", e);
            } finally {
                if(outStream!=null){
                    outStream.close();
                }
            }
        }

        public void writeJsonStr(HttpServletResponse response, InputStream in) throws IOException {

            if(null == in ){
                return ;
            }
            OutputStream outStream = null;
            try {
                response.reset();
                response.setCharacterEncoding("UTF-8");
                response.setHeader("Pragma", "No-cache");
                response.setHeader("Cache-Control", "no-cache");
                response.setDateHeader("Expires", 0);
                outStream = response.getOutputStream();
                int len = 0;
                byte[] byt = new byte[1024];
                while ((len = in.read(byt)) != -1) {
                    outStream.write(byt, 0, len);
                }
                outStream.flush();

            } catch (IOException e) {

                logger.info("输出JSON数据异常(writeJsonStr)", e);
            } finally {
                if(outStream!=null){
                    outStream.close();
                    in.close();
                }
            }
        }

        /**
         * 输出JSON数据
         *
         * @param response
         * @param jsonStr
         */
        public void writeJson(HttpServletResponse response, Object obj) {
            response.setContentType("text/json;charset=utf-8");
            response.setHeader("Pragma", "No-cache");
            response.setHeader("Cache-Control", "no-cache");
            response.setDateHeader("Expires", 0);
            PrintWriter pw = null;
            Gson gson = new Gson();
            try {
                pw = response.getWriter();
                pw.write(gson.toJson(obj));

                pw.flush();
            } catch (Exception e) {
                logger.info("输出JSON数据异常", e);
            }finally{
                if(pw!=null){
                    pw.close();
                }
            }
        }

       public void writeHtml(HttpServletResponse response, String html) {
            response.setContentType("text/html;;charset=utf-8");
            response.setHeader("Pragma", "No-cache");
            response.setHeader("Cache-Control", "no-cache");
            response.setDateHeader("Expires", 0);
            PrintWriter pw = null;
            try {
                pw = response.getWriter();
                pw.write(html);
                pw.flush();
            } catch (Exception e) {
                logger.info("输出HTML数据异常", e);
            }finally{
                if(pw!=null){
                    pw.close();
                }
            }
        }
}

摘自：https://blog.csdn.net/weixin_40050532/article/details/80799708