文件下载

前端：

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>

<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
      <p>被下载的文件名</p>
       <a href="${pageContext.request.contextPath }/down?filename=${name}">${name}</a>
      
</body>
</html>

后端代码：

package controller;

import java.io.File;
import java.io.FileInputStream;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;

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

import org.apache.commons.logging.LogFactory;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;

import sun.rmi.runtime.Log;

/**
 * 文件下载
 * @author jiyiyuan
 *
 */
@Controller
public class FileDownController {
   
    /**
     * 显示要下载的文件
     */
    @RequestMapping(value="/showDownFiles")
    public String show(HttpServletRequest request, Model model) {
        // 从 workspace\.metadata\.plugins\org.eclipse.wst.server.core\
        // tmp0\wtpwebapps\springMVCDemo11\下载
        String realpath = request.getServletContext()
                .getRealPath("uploadfiles");
        System.out.println(realpath);
        File dir = new File(realpath);
        File files[] = dir.listFiles();
        // 获取该目录下的所有文件名
        ArrayList<String> fileName = new ArrayList<String>();
        for (int i = 0; i < files.length; i++) {
            fileName.add(files[i].getName());
        }
        model.addAttribute("name", fileName.get(1));
        return "showDownFiles";
    }
    /**
     * 执行下载
     */
    @RequestMapping("down")
    public String down(@RequestParam String filename,
            HttpServletRequest request, HttpServletResponse response) {
        String aFilePath = null; // 要下载的文件路径
        FileInputStream in = null; // 输入流
        ServletOutputStream out = null; // 输出流
        try {
            // 从workspace\.metadata\.plugins\org.eclipse.wst.server.core\
            // tmp0\wtpwebapps下载
            aFilePath = request.getServletContext().getRealPath("uploadfiles");
            // 设置下载文件使用的报头
            response.setHeader("Content-Type", "application/x-msdownload");
            response.setHeader("Content-Disposition", "attachment; filename="
                    + toUTF8String(filename));
            // 读入文件
            in = new FileInputStream(aFilePath + "\\" + filename);
            // 得到响应对象的输出流，用于向客户端输出二进制数据
            out = response.getOutputStream();
            out.flush();
            int aRead = 0;
            byte b[] = new byte[1024];
            while ((aRead = in.read(b)) != -1 & in != null) {
                out.write(b, 0, aRead);
            }
            out.flush();
            in.close();
            out.close();
        } catch (Throwable e) {
            e.printStackTrace();
        }
         System.out.println("下载成功！！！");
        return null;
    }
    /**
     * 下载保存时中文文件名的字符编码转换方法
     */
    public String toUTF8String(String str) {
        StringBuffer sb = new StringBuffer();
        int len = str.length();
        for (int i = 0; i < len; i++) {
            // 取出字符中的每个字符
            char c = str.charAt(i);
            // Unicode码值为0~255时，不做处理
            if (c >= 0 && c <= 255) {
                sb.append(c);
            } else { // 转换 UTF-8 编码
                byte b[];
                try {
                    b = Character.toString(c).getBytes("UTF-8");
                } catch (UnsupportedEncodingException e) {
                    e.printStackTrace();
                    b = null;
                }
                // 转换为%HH的字符串形式
                for (int j = 0; j < b.length; j++) {
                    int k = b[j];
                    if (k < 0) {
                        k &= 255;
                    }
                    sb.append("%" + Integer.toHexString(k).toUpperCase());
                }
            }
        }
        return sb.toString();
    }
}

 

posted @ 2020-05-29 15:24  一场屠夫的战争  阅读(160)  评论(0)    收藏  举报