java - 使用 ISO 字符集压缩文件时线程 "main"java.util.zip.ZipException : Not in GZIP format. 中的异常

Question

我在我的程序中尝试使用 GZIP 流压缩/解压缩数据，当使用字符集“ISO-8859-1”时，一切正常，但当将字符集更改为“UTF-8”时，我得到错误消息“线程“主”java.util.zip.ZipException 中的异常:不是 GZIP 格式”。这是我的代码:

public static String compress(String str) throws IOException { 
       if (str == null || str.length() == 0) { 
           return str; 
       } 
       System.out.println("String length : " + str.length()); 
       ByteArrayOutputStream out = new ByteArrayOutputStream(); 
       GZIPOutputStream gzip = new GZIPOutputStream(out); 
       gzip.write(str.getBytes()); 
       gzip.close(); 
       String outStr = out.toString("UTF-8"); 
       System.out.println("Output String lenght : " + outStr.length()); 
       System.out.println("Output : " + outStr.toString()); 
       return outStr; 
} 

public static String decompress(String str) throws IOException { 
       if (str == null || str.length() == 0) { 
          return str; 
       } 
       System.out.println("Input String length : " + str.length()); 
       GZIPInputStream gis = new GZIPInputStream(new ByteArrayInputStream(str.getBytes("UTF-8"))); 
       BufferedReader bf = new BufferedReader(new InputStreamReader(gis, "UTF-8")); 
       String outStr = ""; 
       String line; 
       while ((line=bf.readLine())!=null) { 
             outStr += line; 
       } 
       System.out.println("Output String lenght : " + outStr.length()); 
       return outStr; 
} 

public static void main(String[] args) throws IOException { 
       String string = "my data"; 
       System.out.println("after compress:"); 
       String compressed = compress(string); 
       System.out.println(compressed); 
       System.out.println("after decompress:"); 
       String decomp = decompress(compressed); 
       System.out.println(decomp); 
} 

Answer 1

String outStr = out.toString("UTF-8");这个“输出”是压缩字节流，将它编码为字符串然后从字符串解码它会丢失一些字节。这可能是 java 的一个错误。要解决它，你可以在compress()中将字节编码为String返回，例如:

String infoBase64Encode = new String(Base64.encodeBase64(out.toByteArray()))

在decompress()中将String解码为bytes返回，如:

String infoBase64Decode = Base64.decodeBase64(decryptAESinfo)

完整代码如下:

public static String compress(String str) throws IOException { 
           if (str == null || str.length() == 0) { 
               return str; 
           } 
           System.out.println("String length : " + str.length()); 
           ByteArrayOutputStream out = new ByteArrayOutputStream(); 
           GZIPOutputStream gzip = new GZIPOutputStream(out); 
           gzip.write(str.getBytes()); 
           gzip.close(); 
           String outStr = new String(Base64.encodeBase64(out.toByteArray()));
           System.out.println("Output String lenght : " + outStr.length()); 
           System.out.println("Output : " + outStr.toString()); 
           return outStr; 
    } 

    public static String decompress(String str) throws IOException { 
           if (str == null || str.length() == 0) { 
              return str; 
           } 
           System.out.println("Input String length : " + str.length()); 
           GZIPInputStream gis = new GZIPInputStream(new ByteArrayInputStream(Base64.decodeBase64(str))); 
           String outStr = ""; 
           ByteArrayOutputStream out = new ByteArrayOutputStream();
           byte[] buffer = new byte[256];
           int n;
           while ((n = gis.read(buffer)) >= 0) {
               out.write(buffer, 0, n);
           }
           System.out.println("Output String lenght : " + outStr.length()); 
           return new String(out.toByteArray()); 
    } 

    public static void main(String[] args) throws IOException { 
           String string = "my data"; 
           System.out.println("after compress:"); 
           String compressed = compress(string); 
           System.out.println(compressed); 
           System.out.println("after decompress:"); 
           String decomp = decompress(compressed); 
           System.out.println(decomp); 
    }