Java 上传和下载文件（附加密和解密）

使用 jersey 服务器实现上传，使用 http 请求实现下载

引入依赖

在 pom.xml 中添加 jersey 相关依赖

<dependency>
    <groupid>com.sun.jersey</groupid>
    <artifactid>jersey-client</artifactid>
    <version>1.18.1</version>
</dependency>

创建工具类

import com.sun.jersey.api.client.client;
import com.sun.jersey.api.client.clienthandlerexception;
import com.sun.jersey.api.client.uniforminterfaceexception;
import com.sun.jersey.api.client.webresource;
import org.springframework.web.context.request.requestcontextholder;
import org.springframework.web.context.request.servletrequestattributes;
import org.springframework.web.multipart.multipartfile;

import javax.servlet.http.httpservletrequest;
import java.io.*;
import java.net.httpurlconnection;
import java.net.url;
import java.util.uuid;

public class fileutils {

    // 加密/解密文件的密钥
    public static final int crypto_secret_key = 0x99;

    public static int file_data = 0;

    /**
     * 加密/解密 文件
     * @param srcfile 原文件
     * @param encfile 加密/解密后的文件
     * @throws exception
     */
    public static void cryptofile(file srcfile, file encfile) throws exception {

        inputstream inputstream = new fileinputstream(srcfile);
        outputstream outputstream = new fileoutputstream(encfile);
        while ((file_data = inputstream.read()) > -1) {
            outputstream.write(file_data ^ crypto_secret_key);
        }
        inputstream.close();
        outputstream.flush();
        outputstream.close();
    }

    /**
     * multipartfile 生成临时文件
     * @param multipartfile
     * @param tempfilepath 临时文件路径
     * @return file 临时文件
     */
    public static file multipartfiletofile(multipartfile multipartfile, string tempfilepath) {

        file file = new file(tempfilepath);
        // 获取文件原名
        string originalfilename = multipartfile.getoriginalfilename();
        // 获取文件后缀
        string suffix = originalfilename.substring(originalfilename.lastindexof("."));
        if (!file.exists()) {
            file.mkdirs();
        }
        // 创建临时文件
        file tempfile = new file(tempfilepath + "\\" + uuid.randomuuid().tostring().replaceall("-", "") + suffix);
        try {
            if (!tempfile.exists()) {
                // 写入临时文件
                multipartfile.transferto(tempfile);
            }
        } catch (ioexception e) {
            e.printstacktrace();
        }
        return tempfile;
    }

    /**
     * 上传文件
     * @param fileserverpath	文件服务器地址
     * @param folderpath    存放的文件夹路径（比如存放在文件服务器的 upload 文件夹下，即 ”/upload“）
     * @param uploadfile	需要上传的文件
     * @param iscrypto	是否加密
     * @return string	文件上传后的全路径
     */
    public static string uploadbyjersey(string fileserverpath, string folderpath, file uploadfile, boolean iscrypto) {

        string suffix = uploadfile.getname().substring(uploadfile.getname().lastindexof("."));
        string randomfilename = uuid.randomuuid().tostring().replaceall("-", "") + suffix;
        string fullpath = fileserverpath + folderpath + "/" + randomfilename;
        try {
            if (iscrypto) {
                // 创建加密文件
                file cryptofile = new file(uploadfile.getpath().substring(0, uploadfile.getpath().lastindexof(".")) + "crypto" + uploadfile.getpath().substring(uploadfile.getpath().lastindexof(".")));
                // 执行加密
                cryptofile(uploadfile, cryptofile);
                // 保存加密后的文件
                uploadfile = cryptofile;
            }
            // 创建 jersey 服务器
            client client = client.create();
            webresource wr = client.resource(fullpath);
            // 上传文件
            wr.put(string.class, filetobyte(uploadfile));
        } catch (exception e) {
            e.printstacktrace();
        }
        return fullpath;
    }

    /**
     * 下载文件
     * @param url   文件路径
     * @param filepath  文件保存路径
     * @param filename	文件名称（包含文件后缀）
     * @param iscrypto  是否解密
     * @return file
     */
    public static file downloadbyurl(string url, string filepath, string filename, boolean iscrypto) {

        file file = new file(filepath);
        if (!file.exists()) {
            file.mkdirs();
        }
        fileoutputstream fileout;
        httpurlconnection httpurlconnection;
        inputstream inputstream;
        try {
            url httpurl = new url(url);
            httpurlconnection = (httpurlconnection) httpurl.openconnection();
            httpurlconnection.setdoinput(true);
            httpurlconnection.setdooutput(true);
            httpurlconnection.setusecaches(false);
            httpurlconnection.connect();
            inputstream = httpurlconnection.getinputstream();
            bufferedinputstream bufferedinputstream = new bufferedinputstream(inputstream);
            if (!filepath.endswith("\\")) {
                filepath += "\\";
            }
            file = new file(filepath + filename);
            fileout = new fileoutputstream(file);
            bufferedoutputstream bufferedoutputstream = new bufferedoutputstream(fileout);
            byte[] bytes = new byte[4096];
            int length = bufferedinputstream.read(bytes);
            //保存文件
            while (length != -1) {
                bufferedoutputstream.write(bytes, 0, length);
                length = bufferedinputstream.read(bytes);
            }
            bufferedoutputstream.close();
            bufferedinputstream.close();
            httpurlconnection.disconnect();
        } catch (exception e) {
            e.printstacktrace();
        }
        if (iscrypto) {
            try {
                // 创建解密文件
                file cryptofile = new file(((servletrequestattributes) requestcontextholder.getrequestattributes()).getrequest().getservletcontext().getrealpath("/") +  "\\temp\\" + uuid.randomuuid().tostring().replaceall("-", "") + file.getname().substring(file.getname().lastindexof(".")));
                // 执行解密
                cryptofile(file, cryptofile);
                // 删除下载的原文件
                file.delete();
                // 保存解密后的文件
                file = cryptofile;
            } catch (exception e) {
                e.printstacktrace();
            }
        }
        return file;
    }

    /**
     * 删除文件服务器上的文件
     * @param url 文件路径
     * @return boolean
     */
    public static boolean deletebyjersey(string url) {

        try {
            client client = new client();
            webresource webresource = client.resource(url);
            webresource.delete();
            return true;
        } catch (uniforminterfaceexception e) {
            e.printstacktrace();
        } catch (clienthandlerexception e) {
            e.printstacktrace();
        }
        return false;
    }

    /**
     * file转bytes
     * @param file
     * @return byte[]
     */
    public static byte[] filetobyte(file file) {

        byte[] buffer = null;
        try {
            fileinputstream fileinputstream = new fileinputstream(file);
            bytearrayoutputstream bytearrayoutputstream = new bytearrayoutputstream();
            byte[] bytes = new byte[1024];
            int n;
            while ((n = fileinputstream.read(bytes)) != -1) {
                bytearrayoutputstream.write(bytes, 0, n);
            }
            fileinputstream.close();
            bytearrayoutputstream.close();
            buffer = bytearrayoutputstream.tobytearray();
        } catch (filenotfoundexception e) {
            e.printstacktrace();
        } catch (ioexception e) {
            e.printstacktrace();
        }
        return buffer;
    }
}

测试上传

/**
 * @param multipartfile 上传文件
 * @param iscrypto 是否加密文件
 * @return
 */
@test
public string upload(multipartfile multipartfile, boolean iscrypto) {

    httpservletrequest request = ((servletrequestattributes) requestcontextholder.getrequestattributes()).getrequest();
    // 生成临时文件
    file tempfile = fileutil.multipartfiletofile(multipartfile, request.getservletcontext().getrealpath("/") + "\\static\\temp");
    // 上传文件并返回文件路径
    string uploadfilepath = fileutil.uploadbyjersey("http://localhost:8080", "/upload", tempfile, iscrypto);
    if (uploadfilepath != null) {
        return "上传成功";
    }
    else {
        return "上传失败";
    }
}

• 文章作者：彭超
• 本文首发于个人博客：https://antoniopeng.com/2019/04/09/java/java%e4%b8%8a%e4%bc%a0%e5%92%8c%e4%b8%8b%e8%bd%bd%e6%96%87%e4%bb%b6-%e9%99%84%e5%8a%a0%e5%af%86%e5%92%8c%e8%a7%a3%e5%af%86/
• 版权声明：本博客所有文章除特别声明外，均采用 cc by-nc-sa 4.0 许可协议。转载请注明来自 彭超 | blog！