微信小程序上传文件Java后台实现

微信小程序上传文件

开发环境：微信开发者工具+eclipse+Tomcat+Mysql

1、过程描述

Mysql中存放的是文档的记录（如文档名、存放的地址等），而不是文档中实际的内容。
文档实际存放在本地磁盘的某个文件夹中
微信开发者工具提供接口，访问eclipse中的Java项目地址，在对应的Java项目中将读到的内容写入磁盘。

2、代码

前台

.wxml

<form bindsubmit="submit">
<view>
<input placeholder='请输入文件名,如:张三-论文' name="fileName" />
<view class='button'>
<button type='primary' form-type='submit'>确定</button>
</view>
</view>
<view class="br"></view>
<view class="weui-uploader__input-box">
 <view class="weui-uploader__input" bindtap="upload"></view>
</view>
</form>

.js

var account;
var fileName;
Page({
  data: {
    files: []
  },
  submit:function(e){    
    var objData = e.detail.value;
    fileName=objData.fileName;
    if (fileName==''){
      wx.showToast({
        title: '请输入文件名',
        duration: 2000,
      })
    }
  },
  upload: function(e) {
    if(fileName==''){
      wx.showToast({
        title: '请输入文件名',
      })
    }
    if (fileName == ''||fileName == undefined) {
      wx.showToast({
        title: '请确定',
      })
    }
    else{
      var account = wx.getStorageSync('account');
      var that = this;
      wx.chooseMessageFile({
        count: 10,
        type: 'file',
        success(res) {     
          wx.uploadFile({
            url: 'http://192.168.x.xxx:8080/GraduateDesign/StuUploadPaper',
            filePath: res.tempFiles[0].path,
            name: 'file',
            header: {
              'content-type': 'multipart/form-data'
            },
            formData:{
              fileName:fileName,
              account:account
            },
            success(res) {
              if(res.data==1)
              wx.showToast({
                title: '上传成功',
              })
              else{
                wx.showToast({
                  title: '文件已存在',
                })
              }
            }
          })
        }
      })
    }
 }
})

.json

{
  "navigationBarTitleText": "提交论文"
}

.wxss

input{
border: 1px solid #ccc;
height: 40px;
margin-left: 10px;
margin-right: 10px;
}
.button{
  margin-top: 10px;
  margin-left: 10px;
}
.weui-uploader__input-box{
  margin-bottom: 40px;
  margin-left: 100px;
  width:120px;
  height: 120px;
}
.br{
  width: 20px;
  height: 20px;
}

后台

（只贴了关键部分）

package GraduateDesign.servlet;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.Writer;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;

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

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

import GraduateDesign.domain.StuFile;
import GraduateDesign.service.StuFileService;

public class StuUploadPaper extends HttpServlet {
 private static final long serialVersionUID = 1L;
 public StuUploadPaper() {
        super();
        // TODO Auto-generated constructor stub
    }
 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  // TODO Auto-generated method stub
  request.setCharacterEncoding("utf-8");
  response.setContentType("text/html;charset=utf-8");
  response.setHeader("Access-Control-Allow-Origin", "*"); 
  response.setHeader("Access-Control-Allow-Methods", "GET,POST");
  String fname=null;          //前台传过来的文件名（不带后缀）
  String account=null;       //教师工号
  String value=null;         //前台传的formdata中的值，有两个：file、account，要遍历取出
  String fileName=null;      //最终的文件名称(带后缀)
  String destPath=null;      //上传的文件的完整地址
  String path ="D:/eclipse-workspace/GraduateDesign/WebContent/WEB-INF/paper";   //这是我在磁盘上存放文件的地址
  File dir = new File(path);
  /*如果指定目录不存在就创建*/
  if (!dir.exists()) {
       dir.mkdir();
   }
  DiskFileItemFactory factory=new DiskFileItemFactory();
  factory.setRepository(dir);
  //设置缓存的大小，当上传文件的容量超过该缓存时，直接放到暂时存储室
  factory.setSizeThreshold(1024 * 1024);
  //高水平的API文件上传处理
  ServletFileUpload upload=new ServletFileUpload(factory);
  upload.setHeaderEncoding("utf-8");//解决前台传过来的值乱码问题
  try {
         List<FileItem> list=upload.parseRequest(request);
         FileItem file=null;
         for(FileItem item : list){
             if (item.isFormField()) {
                    //获取用户具体输入的字符串,分别取出文件名fname和学生学号account              
              value = item.getString("utf-8");
                    if(fname==null){
                     fname=value;
                     continue;                     
                    }
                    if(account==null){
                     account=value;
                    }
                } else {
                    file = item;
                }             
            }
       fileName = account+"-"+fname + ".doc";
       destPath = path + "/" + fileName;
       //真正写到磁盘上
       //System.out.println(destPath);
       File f = new File(destPath);
       OutputStream out = new FileOutputStream(f);
       InputStream in = file.getInputStream();
       int length = 0;
       byte[] buf = new byte[1024];
       // in.read(buf) 每次读到的数据存放在buf 数组中
       while ((length = in.read(buf)) != -1) {
       //在buf数组中取出数据写到（输出流）磁盘上
       out.write(buf, 0, length);
       }
       in.close();
       out.close();
  } catch (FileUploadException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }

/*更新数据库中记录*/
  Date date=new Date();
  SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
  String time=df.format(date);
  StuFile sf=new StuFile();
  sf.setFileName(fileName);
  sf.setFileUrl(destPath);
  sf.setSno(account);
  sf.setDate(time);
  StuFileService sfs=new StuFileService();
  boolean b=sfs.upload(sf);
    
/*向前台返回是否成功标志位*/ 
  String flag;
  if(b==true)
    flag="1";
   else
    flag="0";
   Writer out = response.getWriter();
   out.write(flag);
   out.flush();
 }

  protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
      doGet(request, response);
  }
 
}

3、运行结果

数据库中记录
本地磁盘记录

附：
两个jar包（io包、fileupload包），百度网盘https://pan.baidu.com/s/1-xdFZSsCJo7Ai3f
提取码:8mvg