upload load

1.後臺部分
import com.alibaba.fastjson.JSONObject;
import com.sekorm.flow.webentity.ResponseBean;
import org.apache.commons.lang3.StringUtils;
import org.apache.log4j.Logger;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.multipart.MultipartHttpServletRequest;
import org.springframework.web.multipart.commons.CommonsMultipartResolver;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.net.URLDecoder;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Iterator;
import java.util.List;
@Component
public class FileUtils {

    private static Logger log = Logger.getLogger(FileUtils.class);

    private static String uploadPath;

    @Value("${upload_path}")
    public  void setUploadPath(String uploadPath) {
        FileUtils.uploadPath = uploadPath;
    }
    public  String getUploadPath() {
        return uploadPath;
    }

    public static JSONObject upload(HttpServletRequest request , HttpServletResponse response){
        JSONObject responseBean = new JSONObject();
        responseBean.put("code", -1);
        try {
            //建立一個通用的多部分解析器
            CommonsMultipartResolver multipartResolver = new CommonsMultipartResolver(request.getSession().getServletContext());
            //判斷 request 是否有文件上傳,即多部分請求(即檢查form中是否有enctype="multipart/form-data")
            if(multipartResolver.isMultipart(request)){
                //轉換成多部分request
                MultipartHttpServletRequest multiRequest = (MultipartHttpServletRequest) request;
                //取得request中的全部input的name
                Iterator<String> iter = multiRequest.getFileNames();
                while(iter.hasNext()){
                    //取得一個input裏面全部的上傳文件
                    List<MultipartFile> list = multiRequest.getFiles(iter.next());
                    for(MultipartFile file : list){
                        if(file != null){
                            //取得當前上傳文件的文件名稱
                            String myFileName = file.getOriginalFilename();
                            //若是名稱不爲「」,說明該文件存在，不然說明該文件不存在
                            if(!StringUtils.isBlank(myFileName) && myFileName.trim() != null){
                                //重命名上傳後的文件名
                                Date date = new Date();
                                SimpleDateFormat sdf = new SimpleDateFormat("YYYYMMddHHmmss");
                                String saveName = myFileName.substring(0,myFileName.lastIndexOf("."))+"_"+sdf.format(date).toString() + myFileName.substring(myFileName.lastIndexOf("."));
                                //定義上傳路徑
                                File localFile = new File(uploadPath,saveName);
                                File pathIsExit = new File(uploadPath);
                                if(!pathIsExit.exists()  && !pathIsExit .isDirectory()){
                                    pathIsExit.mkdirs();
                                }
                                if(!localFile.exists()){
                                    localFile.createNewFile();
                                }
                                //保存
                                file.transferTo(localFile);
                                responseBean.put("data",saveName);
                            }
                        }
                    }
                }
            }
            responseBean.put("code",0);
        }catch (Exception e){
            log.error("上傳文件報錯->%",e);
            responseBean.put("msg","上傳文件報錯");
        }
        return  responseBean;
    }

    public static void load(HttpServletRequest request , HttpServletResponse response){
        try{
            //獲取網站部署路徑(經過ServletContext對象)，用於肯定下載文件位置，從而實現下載
            String path =uploadPath;
            String fileName=URLDecoder.decode(request.getParameter("fileName"),"UTF-8");
            //1.設置文件ContentType類型，這樣設置，會自動判斷下載文件類型
            response.setContentType("multipart/form-data");
            //2.設置文件頭：最後一個參數是設置下載文件名(假如咱們叫a.pdf)
            response.setHeader("Content-Disposition", "attachment;fileName="+java.net.URLEncoder.encode(fileName, "UTF-8"));
            ServletOutputStream out;
            //經過文件路徑得到File對象(假如此路徑中有一個download.pdf文件)
            File file = new File(path + fileName);
            out = response.getOutputStream();
            FileInputStream inputStream = new FileInputStream(file);
            try {
                //3.經過response獲取ServletOutputStream對象(out)
                int b = 0;
                byte[] buffer = new byte[1204];
                while ((b =inputStream.read(buffer))!= -1){
                    //4.寫到輸出流(out)中
                    out.write(buffer,0,b);
                    out.flush();
                }
            } catch (IOException e) {
                log.error("下載文件報錯->%",e);

            }finally {
                out.close();
                inputStream.close();
            }
        }catch (Exception e){
            log.error("下載文件報錯->%",e);

        }
    }
    }

2.js 部分

 //上傳文件事件
  $("#myFile").bind("change",function () {
      $("#dwform").attr("enctype","multipart/form-data");
      $.ajax({
          url:  $("#PageContext").val()+'/file/upload' ,
          type: 'POST',
          cache: false,
          data: new FormData($('#dwform')[0]),
          processData: false,
          contentType: false,
          dataType:"json",
          success : function(data) {
              console.log(data.code);
              if(data.code==0){
                  $("#fileName").val(data.data);
                  $("#loadFile").remove();
              }else{
                  layer.msg(data.msg);
              }
          }
      });
  })
});

  //下載文件
  function load(fileName) {
      var $ = layui.jquery;
      var url= $("#PageContext").val()+'/file/load?fileName='+encodeURI(encodeURI(fileName)) ;
      window.open(url);
  }
3.頁面部分
 <a onclick="javascript:load('迷你截圖_20190110140346.exe')">迷你截圖_20190110140346.exe</a>


4. controller 部分

@Controller@RequestMapping(value = "/file")public class FileController {    private static Logger log = Logger.getLogger(FileController.class);    @RequestMapping(value = "/upload")    @ResponseBody    public JSONObject upload(@ModelAttribute DW dw, HttpServletRequest request, HttpServletResponse resp) {        JSONObject responseBean = new JSONObject();        responseBean.put("code", -1);        try {           return  FileUtils.upload(request,resp);        }catch (Exception e) {            log.error("上傳文件失敗{}->",e);            responseBean.put("msg","上傳文件失敗");        }        return responseBean;    }    @RequestMapping(value = "/load")    @ResponseBody    public void load(@ModelAttribute DW dw, HttpServletRequest request, HttpServletResponse resp) {        try {            FileUtils.load(request,resp);        }catch (Exception e) {            log.error("下載文件失敗{}->",e);        }    }}