Java http下載損壞文件

Question

我有一個問題，我似乎無法解決... 我做了一個文件的http下載，但在服務器和客戶端上的文件的CRC32做不匹配。此外，該文件有不同的大小，所以顯然我必須做錯了什麼......當我通過Firefox下載時，文件大小沒問題......所以我猜這是在客戶端代碼中的某處。

我已經找到Corrupt file when using Java to download file，但這並沒有幫助我要麼...

下面的代碼：

private void downloadJar(String fileName, long crc32Server) throws IOException { 
    System.out.println("Downloading file '" + fileName + "' from server '" + mServer + "'."); 
    HttpURLConnection sourceConnection = null; 
    BufferedInputStream inputStream = null; 
    BufferedWriter fileWriter = null; 
    long crc32Client; 
    try { 
    URL sourceURL = new URL(fileName); 
    try { 
     sourceConnection = (HttpURLConnection)sourceURL.openConnection(); 
    } 
    catch (MalformedURLException exc) { 
     throw new RuntimeException("Configured URL caused a MalformedURLException: ", exc); 
    } 
    sourceConnection.setRequestProperty("Accept-Encoding", "zip, jar"); 
    sourceConnection.connect(); 
    inputStream = new BufferedInputStream(sourceConnection.getInputStream()); 
    fileWriter = new BufferedWriter(new FileWriter(targetFolder + File.separator + fileName)); 
    CRC32 crc32 = new CRC32(); 
    for (int singleByte = inputStream.read(); singleByte != -1; singleByte = inputStream.read()) { 
     fileWriter.write(singleByte); 
     crc32.update(singleByte); 
    } 
    crc32Client = crc32.getValue(); 
    } 
    finally { 
    if (inputStream != null) { 
     inputStream.close(); 
    } 
    if (fileWriter != null) { 
     fileWriter.flush(); 
     fileWriter.close(); 
    } 
    if (sourceConnection != null) { 
     sourceConnection.disconnect(); 
    } 
    } 
    if (crc32Client != crc32Server) { 
    //  deleteFile(fileName); 
    throw new IOException("CRC32 did not match for file '" + fileName + "': " + crc32Client + "!=" 
     + crc32Server); 
    } 
} 

Answer 1

您應該使用BufferedOutputStream，而不是一個FileWriter/BufferedWriter。一般來說，*Streams處理原始二進制數據，而*Writers處理字符數據（這是解釋給定字符編碼的原始二進制數據）。