Java - 使用 FTP 连接上传时 JPG 损坏？

Question

以下代码用于在 JAVA 中使用 FTP 上传三个 JPG 图像文件。\n文件已上传并通过“成功”消息进行确认，但文件已损坏。小缩略图文件部分可读（上四分之一）。

\n\n

我尝试搜索网络并添加

\n\n

setFileType(FTPClient.BINARY_FILE_TYPE);\n

\n\n

但问题仍然出现:(

\n\n

有人可以看一下并给我提示或建议吗？

\n\n

代码：

\n\n

package de.immozukunft.programs;\n\nimport java.io.*;\nimport java.util.Locale;\nimport java.util.ResourceBundle;\n\nimport org.apache.commons.net.ftp.FTPClient;\n\n/**\n * This class enables the ability to connect and trasfer data to the FTP server\n */\n\npublic class FtpUpDown {\n\n    static Locale locale = new Locale("de"); // Locale is set to "de" for\n                                                // Germany\n    static ResourceBundle r = ResourceBundle.getBundle("Strings", locale); // ResourceBundle\n                                                                            // for\n                                                                            // different\n                                                                            // languages\n                                                                            // and\n                                                                            // String\n                                                                            // Management\n\n    // FTP-Connection properties\n    static String host = "IP-address"; //Host\n    static String username = "username"; // Username\n    static int port = 21; //Port\n    static String password = "password"; // Password\n\n    /**\n     * <h3>FTP-connection tester</h3>\n     * \n     */\n\n    public static boolean connect() {\n\n        FTPClient ftpClient = new FTPClient();\n\n        try {\n            ftpClient.setFileType(FTPClient.BINARY_FILE_TYPE);\n            ftpClient.connect(host, port);\n            ftpClient.login(username, password);\n            ftpClient.logout();\n            ftpClient.disconnect();\n        } catch (Exception e) {\n            // e.printStackTrace();\n            System.err.println("Unable to connect"); // TODO String einf\xc3\xbcgen\n            return (false);\n        }\n        System.out.println("Connection established"); // TODO String einf\xc3\xbcgen\n        return (true);\n    }\n\n    /**\n     * <h3>FTP-Status</h3>\n     * \n     * @return\n     * @throws IOException\n     */\n    static public String getStatus() {\n        if (connect()) {\n            return (r.getString("successConnectFTP"));\n        } else {\n            return (r.getString("unableToConnectFTP"));\n        }\n    }\n\n    /**\n     * <h3>FTP-filelist</h3>\n     * \n     * @return String-Array der Dateinamen auf dem FTP-Server\n     */\n\n    public static String[] list() throws IOException {\n        FTPClient ftpClient = new FTPClient();\n        String[] filenameList;\n\n        try {\n            ftpClient.connect(host, port);\n            ftpClient.login(username, password);\n            filenameList = ftpClient.listNames();\n            ftpClient.logout();\n        } finally {\n            ftpClient.disconnect();\n        }\n\n        return filenameList;\n    }\n\n    /**\n     * <h3>FTP-Client-Download:</h3>\n     * \n     * @return true falls ok\n     */\n    public static boolean download(String localResultFile,\n            String remoteSourceFile, boolean showMessages) throws IOException {\n        FTPClient ftpClient = new FTPClient();\n        FileOutputStream fos = null;\n        boolean resultOk = true;\n\n        try {\n            ftpClient.connect(host, port);\n            if (showMessages) {\n                System.out.println(ftpClient.getReplyString());\n            }\n            resultOk &= ftpClient.login(username, password);\n            if (showMessages) {\n                System.out.println(ftpClient.getReplyString());\n            }\n            fos = new FileOutputStream(localResultFile);\n            resultOk &= ftpClient.retrieveFile(remoteSourceFile, fos);\n            if (showMessages) {\n                System.out.println(ftpClient.getReplyString());\n            }\n            resultOk &= ftpClient.logout();\n            if (showMessages) {\n                System.out.println(ftpClient.getReplyString());\n            }\n        } finally {\n            try {\n                if (fos != null) {\n                    fos.close();\n                }\n            } catch (IOException e) {/* nothing to do */\n            }\n            ftpClient.disconnect();\n        }\n\n        return resultOk;\n    }\n\n    /**\n     * <h3>FTP-Client-Upload:</h3>\n     * \n     * @param localSourceFile\n     *            The source of local file\n     * @param remoteResultFile\n     *            Set the destination of the file\n     * @param showMessages\n     *            If set on TRUE messages will be displayed on the console\n     * @return true Returns If successfully transfered it will return TRUE, else\n     *         FALSE\n     */\n    public static boolean upload(String localSourceFile,\n            String remoteResultFile, boolean showMessages) throws IOException {\n\n        FTPClient ftpClient = new FTPClient();\n        FileInputStream fis = null;\n        boolean resultOk = true;\n\n        try {\n            ftpClient.connect(host, port);\n            if (showMessages) {\n                System.out.println(ftpClient.getReplyString());\n            }\n            resultOk &= ftpClient.login(username, password);\n            if (showMessages) {\n                System.out.println(ftpClient.getReplyString());\n            }\n            fis = new FileInputStream(localSourceFile);\n            resultOk &= ftpClient.storeFile(remoteResultFile, fis);\n            if (showMessages) {\n                System.out.println(ftpClient.getReplyString());\n            }\n            resultOk &= ftpClient.logout();\n            if (showMessages) {\n                System.out.println(ftpClient.getReplyString());\n            }\n        } finally {\n            try {\n                if (fis != null) {\n                    fis.close();\n                }\n            } catch (IOException e) {/* nothing to do */\n            }\n            ftpClient.disconnect();\n        }\n\n        return resultOk;\n    }\n\n    // Setter and Getter-methods\n    public static String getHost() {\n        return host;\n    }\n\n    public static void setHost(String host) {\n        FtpUpDown.host = host;\n    }\n\n    public static String getUsername() {\n        return username;\n    }\n\n    public static void setUsername(String username) {\n        FtpUpDown.username = username;\n    }\n\n    public static int getPort() {\n        return port;\n    }\n\n    public static void setPort(int port) {\n        FtpUpDown.port = port;\n    }\n\n    public static String getPassword() {\n        return password;\n    }\n\n    public static void setPassword(String password) {\n        FtpUpDown.password = password;\n    }\n}\n

\n\n

问候

\n\n

THE-E

\n

Answer 1

所以我终于弄清楚问题出在哪里了。

\n\n

该问题是由 的顺序引起的setFileType(FTPClient.BINARY_FILE_TYPE)。它需要放置在upload()-method 的后面fis = new FileInputStream(localSourceFile)和之前ftpClient.storeFile(remoteResultFile, fis)

\n\n

所以完整的工作代码是：

\n\n

import java.io.*;\nimport java.util.Locale;\nimport java.util.ResourceBundle;\n\nimport org.apache.commons.net.ftp.FTPClient;\n\n/**\n * This class enables the ability to connect and trasfer data to the FTP server\n */\n\npublic class FtpUpDown {\n\n    static Locale locale = new Locale("de"); // Locale is set to "de" for\n                                                // Germany\n    static ResourceBundle r = ResourceBundle.getBundle("Strings", locale); // ResourceBundle\n                                                                            // for\n                                                                            // different\n                                                                            // languages\n                                                                            // and\n                                                                            // String\n                                                                            // Management\n\n    // FTP-Connection properties\n    static String host = "IP-Address"; // IP-address\n    static String username = "username"; // Username\n    static int port = 21; // Port\n    static String password = "password"; // Password\n\n    /**\n     * <h3>FTP-connection tester</h3>\n     * \n     */\n\n    public static boolean connect() {\n\n        FTPClient ftpClient = new FTPClient();\n\n        try {\n            ftpClient.connect(host, port);\n            ftpClient.login(username, password);\n            ftpClient.logout();\n            ftpClient.disconnect();\n        } catch (Exception e) {\n            // e.printStackTrace();\n            System.err.println("Unable to connect"); // TODO String einf\xc3\xbcgen\n            return (false);\n        }\n        System.out.println("Connection established"); // TODO String einf\xc3\xbcgen\n        return (true);\n    }\n\n    /**\n     * <h3>FTP-Status</h3>\n     * \n     * @return\n     * @throws IOException\n     */\n    static public String getStatus() {\n        if (connect()) {\n            return (r.getString("successConnectFTP"));\n        } else {\n            return (r.getString("unableToConnectFTP"));\n        }\n    }\n\n    /**\n     * <h3>FTP-filelist</h3>\n     * \n     * @return String-Array der Dateinamen auf dem FTP-Server\n     */\n\n    public static String[] list() throws IOException {\n        FTPClient ftpClient = new FTPClient();\n        String[] filenameList;\n\n        try {\n            ftpClient.connect(host, port);\n            ftpClient.login(username, password);\n            filenameList = ftpClient.listNames();\n            ftpClient.logout();\n        } finally {\n            ftpClient.disconnect();\n        }\n\n        return filenameList;\n    }\n\n    /**\n     * <h3>FTP-Client-Download:</h3>\n     * \n     * @return true falls ok\n     */\n\n    public static boolean download(String localResultFile,\n            String remoteSourceFile, boolean showMessages) throws IOException {\n        FTPClient ftpClient = new FTPClient();\n        FileOutputStream fos = null;\n        boolean resultOk = true;\n\n        try {\n            ftpClient.connect(host, port);\n            ftpClient.setFileType(FTPClient.BINARY_FILE_TYPE);\n            if (showMessages) {\n                System.out.println(ftpClient.getReplyString());\n            }\n            resultOk &= ftpClient.login(username, password);\n            if (showMessages) {\n                System.out.println(ftpClient.getReplyString());\n            }\n            fos = new FileOutputStream(localResultFile);\n            resultOk &= ftpClient.retrieveFile(remoteSourceFile, fos);\n            if (showMessages) {\n                System.out.println(ftpClient.getReplyString());\n            }\n            resultOk &= ftpClient.logout();\n            if (showMessages) {\n                System.out.println(ftpClient.getReplyString());\n            }\n        } finally {\n            try {\n                if (fos != null) {\n                    fos.close();\n                }\n            } catch (IOException e) {/* nothing to do */\n            }\n            ftpClient.disconnect();\n        }\n\n        return resultOk;\n    }\n\n\n    /**\n     * <h3>FTP-Client-Upload:</h3>\n     * \n     * @param localSourceFile\n     *            The source of local file\n     * @param remoteResultFile\n     *            Set the destination of the file\n     * @param showMessages\n     *            If set on TRUE messages will be displayed on the console\n     * @return true Returns If successfully transfered it will return TRUE, else\n     *         FALSE\n     */\n    public static boolean upload(String localSourceFile,\n            String remoteResultFile, boolean showMessages) throws IOException {\n\n        FTPClient ftpClient = new FTPClient();\n        FileInputStream fis = null;\n        boolean resultOk = true;\n\n        try {\n            ftpClient.connect(host, port);\n\n            if (showMessages) {\n                System.out.println(ftpClient.getReplyString());\n            }\n            resultOk &= ftpClient.login(username, password);\n            if (showMessages) {\n                System.out.println(ftpClient.getReplyString());\n            }\n\n            fis = new FileInputStream(localSourceFile);\n            ftpClient.setFileType(FTPClient.BINARY_FILE_TYPE);\n\n            resultOk &= ftpClient.storeFile(remoteResultFile, fis);\n            if (showMessages) {\n                System.out.println(ftpClient.getReplyString());\n            }\n            resultOk &= ftpClient.logout();\n            if (showMessages) {\n                System.out.println(ftpClient.getReplyString());\n            }\n        } finally {\n            try {\n                if (fis != null) {\n                    fis.close();\n                }\n                ftpClient.disconnect();\n            } catch (IOException e) {/* nothing to do */\n            }\n        }\n\n        return resultOk;\n    }   \n\n\n    // Setter and Getter-methods\n    public static String getHost() {\n        return host;\n    }\n\n    public static void setHost(String host) {\n        FtpUpDown.host = host;\n    }\n\n    public static String getUsername() {\n        return username;\n    }\n\n    public static void setUsername(String username) {\n        FtpUpDown.username = username;\n    }\n\n    public static int getPort() {\n        return port;\n    }\n\n    public static void setPort(int port) {\n        FtpUpDown.port = port;\n    }\n\n    public static String getPassword() {\n        return password;\n    }\n\n    public static void setPassword(String password) {\n        FtpUpDown.password = password;\n    }\n}\n

\n