Java文件下载，Java通用文件下载，Java文件下载中文乱码

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©Copyright 蕃薯耀 2020-01-07

https://www.cnblogs.com/fanshuyao/

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URLDecoder;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.UUID;

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

import org.apache.commons.io.FileUtils;
import org.apache.commons.lang.StringUtils;
import org.apache.log4j.Logger;
import org.springframework.util.FileCopyUtils;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.multipart.MultipartHttpServletRequest;
import org.springframework.web.multipart.commons.CommonsMultipartResolver;



public class FileAction extends BaseAction{

    private Logger log = Logger.getLogger(FileAction.class);
    
    
    /**
     * 通用文件下载方法
     * @param request HttpServletRequest
     * @param response HttpServletResponse
     * @param absoluteFilePath String 文件的绝对路径，如：c:/a/a.txt
     * @param fileDownloadName String 自定义文件下载显示的名称
     * @param isDeleteAfterDownload boolean 用户下载文件后是否删除服务器的源文件，true删除，其它否
     */
    public void downloadFile(HttpServletRequest request, HttpServletResponse response, 
            String absoluteFilePath, String fileDownloadName, boolean isDeleteAfterDownload){
        InputStream is = null;
        OutputStream os = null;
        File file = null;
        try{
            log.info("开始时间："+System.currentTimeMillis());
            
            
            file = new File(absoluteFilePath);
            if(!file.exists()){
                throw new RuntimeException("文件不存在："+file.getAbsolutePath());
            }
            is = new BufferedInputStream(new FileInputStream(file));
            
            String suffix = absoluteFilePath.substring(absoluteFilePath.lastIndexOf("."));
            if(".xls".equalsIgnoreCase(suffix) || ".xlsx".equalsIgnoreCase(suffix)){
                response.setContentType("application/vnd.ms-excel");
            }else if(".doc".equalsIgnoreCase(suffix) || ".docx".equalsIgnoreCase(suffix)){
                response.setContentType("application/vnd.msword");
            }else if(".exe".equalsIgnoreCase(suffix)){
                response.setContentType("application/octet-stream");
            }else if(".jpe".equalsIgnoreCase(suffix) || ".jpeg".equalsIgnoreCase(suffix) || ".jpg".equalsIgnoreCase(suffix)){
                response.setContentType("image/jpeg");
            }else if(".png".equalsIgnoreCase(suffix)){
                response.setContentType("image/png");
            }else if(".gif".equalsIgnoreCase(suffix)){
                response.setContentType("image/gif");
            }else if(".mp3".equalsIgnoreCase(suffix)){
                response.setContentType("audio/x-mpeg");
            }else if(".mp4".equalsIgnoreCase(suffix) || ".mpg4".equalsIgnoreCase(suffix)){
                response.setContentType("video/mp4");
            }else if(".wm".equalsIgnoreCase(suffix)){
                response.setContentType("video/x-ms-wm");
            }else if(".wmv".equalsIgnoreCase(suffix)){
                response.setContentType("audio/x-ms-wmv");
            }else if(".rm".equalsIgnoreCase(suffix) || ".rmvb".equalsIgnoreCase(suffix)){
                response.setContentType("audio/x-pn-realaudio");
            }else if(".xml".equalsIgnoreCase(suffix)){
                response.setContentType("text/xml");
            }else if(".gz".equalsIgnoreCase(suffix)){
                response.setContentType("application/x-gzip");
            }else if(".gtar".equalsIgnoreCase(suffix)){
                response.setContentType("application/x-gtar");
            }else if(".tar".equalsIgnoreCase(suffix) || ".taz".equalsIgnoreCase(suffix)){
                response.setContentType("application/x-tar");
            }else if(".rar".equalsIgnoreCase(suffix)){
                response.setContentType("application/x-rar-compressed");
            }else if(".zip".equalsIgnoreCase(suffix)){
                response.setContentType("application/zip");
            }else{
                response.setContentType("multipart/form-data");
            }
            
            //处理自定义文件名，如果自定义文件名，使用原来的文件名进行下载
            if(StringUtils.isBlank(fileDownloadName)){//org.apache.commons.lang.StringUtils
                fileDownloadName = file.getName().substring(0, file.getName().lastIndexOf("."));;
            }else{
                if(fileDownloadName.indexOf(".") > -1){
                    fileDownloadName = fileDownloadName.substring(0, fileDownloadName.lastIndexOf("."));
                }
            }
            
            //文件名编码，解决中文乱码问题
            String userAgent = request.getHeader("User-Agent").toLowerCase();
            if(userAgent.contains("msie") 
                    || userAgent.contains("trident") 
                    || userAgent.contains("edge")){//IE浏览器
                
                fileDownloadName = URLEncoder.encode(fileDownloadName, "UTF-8");
                fileDownloadName = fileDownloadName.replaceAll("\+", "%20");//处理文件名多余的加号（+）
            }else{//其它浏览器
                fileDownloadName = new String(fileDownloadName.getBytes("UTF-8"), "ISO-8859-1");
            }
            
            response.setCharacterEncoding("UTF-8");
            response.addHeader("Content-Disposition", "attachment;filename="" + fileDownloadName + suffix + """);
            response.addHeader("Content-Length", "" + file.length());
            
            os = response.getOutputStream();
            
            byte[] buffer = new byte[1024];
            int length = 0;
            while((length = is.read(buffer)) > 0){
                os.write(buffer, 0, length);
            }
            log.info("结束时间："+System.currentTimeMillis());
        }catch(Exception e){
            e.printStackTrace();
            log.info("下载文件出错："+e.getCause());
        }finally{
            try {
                if(os != null){
                    //os.flush();
                    os.close();
                }
                if(is != null){
                    is.close();
                }
                if(isDeleteAfterDownload){
                    if(file != null){
                        //org.apache.commons.io.FileUtils
                        FileUtils.deleteQuietly(file);
                    }
                }
            } catch (Exception ex) {
                ex.printStackTrace();
            }
        }
    }
    
    
}

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©Copyright 蕃薯耀 2020-01-07

https://www.cnblogs.com/fanshuyao/