How to use Java server to process image uploads

1. Brief description

First: Implementation of browser uploading images;

Second: Implementation of WeChat applet uploading images;

Second. Implementation of image upload function

1. Implementation of processing H5 single file upload:

package cn.ncist.tms.attachment.controller;
 
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
 
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.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.multipart.MultipartFile;
 
/**
 * 附件上传类
 * 
 * @author Fxh
 *
 */
@RequestMapping(value = "/fileUpload")
@Controller
public class AttachmentUpload {
    
    /**
     * 上传文件功能，以Post请求发送请求，
     * 
     * @param request:请求对象
     * @param reponse:响应对象
     * @param file:上传的文件对象
     * @return JSON串 : {"code":"S","msg":"服务调用成功"}
     * @throws IOException 
     */
    @RequestMapping(value = "/doFileUpload",method = RequestMethod.POST)
    @ResponseBody
    public Map<String,Object> doFileUpload(HttpServletRequest request,
            HttpServletResponse reponse,
            @RequestParam("file") MultipartFile srcFile) throws IOException{
        
        /*
         * 注意:传入参数时，文件的注解@ReuqestParam("variable") -->variable指:前端的h6的控件的name值.
         * 
         * 文件处理功能: 1.将获取的字节数组转化为文件对象，并保存在本地目录中;
         * 
         * 文件处理思路: 1.将获取的(source)file对象，通过函数获取字节数组；
         *                 2.实例化文件对象和文件输出流；
         *                 3.将字节数组写入文件即可.
         * 
         * 功能难度: 简单.
         */
        
        //1.变量声明
        Map<String,Object> result = null;// 返回结果变量
        FileOutputStream fos = null;     //写入文件的变量
        File destFile = null;    //写入的目的地文件(distination)
        
        try {
            result = new HashMap<String,Object>();
            
            //2.参数验证
            if(srcFile == null){
                throw new RuntimeException("上传文件不存在");
            }
            if(srcFile.getBytes().length == 0){
                throw new RuntimeException("上传文件内容为空");
            }
            
            //3.操作文件对象，写入本地目录的文件中
            
            //3.1 截取文件后缀
            String ext = srcFile.getOriginalFilename().substring(srcFile.getContentType().lastIndexOf( ".")+1);
            //3.2 实例化目标文件，根据当前的操作系统，指定目录文件,
            destFile = new File("D:"+File.separator+"descFolder"+File.separator+"descFile."+ext);
            //3.3 实例化流
            fos = new FileOutputStream(destFile);
            //3.4 获取写入的字节数组,并写入文件    
            byte[] srcBytes = srcFile.getBytes();
            fos.write(srcBytes);
            fos.flush();
            //4.对输入、输出流进行统一管理
            //已在文件finally代码块处理
            
            result.put( "code", "S");
            result.put( "msg", "服务调用成功");
            result.put( "path", destFile.getAbsolutePath());
            return result;
        } catch (Exception e) {
            // TODO: handle exception
            e.printStackTrace();
            result = new HashMap<String,Object>();
            result.put( "code", "F");
            result.put( "msg", "服务调用失败");
            result.put( "path", null);
            return result;
        } finally{
            //关闭系统资源,避免占用资源.
            if(fos != null){
                fos.close();
            }
        }
    }
}

2. Code implementation of uploading image files on WeChat or mobile APP:

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
 
import javax.annotation.Resource;
import javax.servlet.ServletInputStream;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
import org.jboss.netty.handler.codec.http.HttpRequest;
import org.springframework.mock.web.MockMultipartFile;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.multipart.MultipartHttpServletRequest;
 
import com.hlinkcloud.ubp.core.constant.RedisKeyConstant;
import com.hlinkcloud.ubp.core.service.RedisService;
import com.hlinkcloud.ubp.core.util.BaseStringUtil;
import com.hlinkcloud.ubp.facade.bean.common.FastDFSFile;
import com.hlinkcloud.ubp.facade.bean.common.FileManagerConfig;
import com.hlinkcloud.ubp.facade.service.common.FileInfoService;
import com.hlinkcloud.ubp.facade.service.permission.UserService;
import com.hlinkcloud.ubp.facade.util.DictionaryCommUtil;
 
import fr.opensagres.xdocreport.core.io.internal.ByteArrayOutputStream;
 
/**
 * 微信上传图片业务
 * 
 * @author FengQi
 *
 */
@Controller
@RequestMapping("/wx_upload")
public class WxUploadImgBusiness {
 
    @Resource
    private UserService userService;
 
    @Resource
    private RedisService redisService;
 
    @Resource(name = "commonUtil")
    private DictionaryCommUtil commUtil;
 
    @Resource
    private FileInfoService fileService; /* 文件服务 */
    
    @RequestMapping("/getUploadFilePath")
    @ResponseBody
    public Map<String, Object> doWxUploadFile(HttpServletRequest request, HttpServletResponse response) {
 
        HashMap<String, Object> map = new HashMap<String, Object>();
        
        try {
            
            /*
             * // 注释:该部分是使用在没有使用sprinvMVC的架构下的图片上传. // 1.磁盘文件条目工厂
             * DiskFileItemFactory factory = new DiskFileItemFactory();
             * 
             * //2.1 高速的文件上传处理类 ServletFileUpload sfu = new
             * ServletFileUpload(factory);
             * 
             * List<FileItem> list = sfu.parseRequest(request); FileItem picture
             * = null; if(list != null && list.size() > 0){ for(FileItem item :
             * list){ if(!item.isFormField()){ picture = item; } } }
             */
 
            // 1.将请求转化为操作流的请求对象.
            MultipartHttpServletRequest req = (MultipartHttpServletRequest) request;
            MultipartFile picture = req.getFile("file");
            
            if(picture != null && picture.getBytes().length != 0){
                // 2.将图片上传到服务器
                byte[] bytes = picture.getBytes();
                String ext = picture.getOriginalFilename().substring(
                        picture.getOriginalFilename().lastIndexOf(".") + 1
                        );
                // (备注:下列代码为内部业务代码，可根据公司自身的需求，进行更改)
                
                
                map.put("code", "S");
                map.put( "msg", "服务调用成功");
                map.put("statusCode", 200);
                map.put("data", filePath);
            }else{
                throw new RuntimeException("上传图片异常或空图片!");
            }
        } catch (IOException e) {
            e.printStackTrace();
            map.put("code", "F");
            map.put("msg", "服务调用失败");
            map.put("statusCode", 500);
            map.put("data", null);
        }
        return map;
    }
    
    /**
     * 当不知道手机、微信传入前端的参数是什么时，
     * 
     * 可调用该接口进行判断.
     * 
     * @param request
     * @param response
     * @return
     * @throws IOException
     */
    @RequestMapping(value = "/doUploadFileOfCI" , method = RequestMethod.POST )
    public @ResponseBody Map<String,Object> doUploadFile(
            HttpServletRequest request,//请求对象
            HttpServletResponse response) throws IOException{//响应对象
        
        System.out.println("doTestMultipartFile:");
        
        MultipartHttpServletRequest req = (MultipartHttpServletRequest) request;
        //此时说明请求对象是MultipartHttpServletRequest对象
        MultipartFile picture = req.getFile("UploadedImage");
        
        //遍历请求得到所有的数据.
        if(req != null){
            
            //获取所有属性名
            Enumeration enume= req.getAttributeNames();
            while(enume.hasMoreElements()){
                System.out.println("enume:"+enume.nextElement());
            }
            
            //获取所有文件名
            Iterator<String> fileNames = req.getFileNames();
            while(fileNames.hasNext()){
                System.out.println("fileNames:"+fileNames.next());
            }
            
            //获取操作文件的map
            Map<String,MultipartFile> fileMap =  req.getFileMap();
            if(fileMap != null && fileMap.size() > 0){
                Set<String> set = fileMap.keySet();
                for(String key:set){
                    System.out.println("String:"+key);
                }
            }
            
            //获取请求流
            InputStream is = req.getInputStream();
            System.out.println("InputStream:"+is);
            int length = -1;
            while( (length = is.read()) != -1 ){
                System.err.println("data:"+length);
            }
            
            //获取所有请求参数
            Enumeration enumee = req.getParameterNames();
            while(enumee.hasMoreElements()){
                System.out.println("enumee:"+enumee.nextElement());
            }
        }
        
        System.out.println(picture);
        
        
        return null;
    }
 
}

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