当我们客户端与服务端进行数据传输时需要走流量，为了节省流量我们常常需要写一个压缩类对数据进行压缩。    <pre class="brush:java; toolbar: true; auto-links: false;">import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.util.zip.GZIPInputStream; import java.util.zip.GZIPOutputStream;  /**  * GZIP压缩解压类  */ public class MessageGZIP {          private static String encode = "utf-8";//"ISO-8859-1"          public String getEncode() {         return encode;     }      /*      * 设置 编码，默认编码：UTF-8      */     public void setEncode(String encode) {         MessageGZIP.encode = encode;     }      /*      * 字符串压缩为字节数组      */     public static byte[] compressToByte(String str){         if (str == null || str.length() == 0) {             return null;         }         ByteArrayOutputStream out = new ByteArrayOutputStream();         GZIPOutputStream gzip;         try {             gzip = new GZIPOutputStream(out);             gzip.write(str.getBytes(encode));             gzip.close();         } catch (IOException e) {             e.printStackTrace();         }         return out.toByteArray();     }      /*      * 字符串压缩为字节数组      */     public static byte[] compressToByte(String str,String encoding){         if (str == null || str.length() == 0) {             return null;         }         ByteArrayOutputStream out = new ByteArrayOutputStream();         GZIPOutputStream gzip;         try {             gzip = new GZIPOutputStream(out);             gzip.write(str.getBytes(encoding));             gzip.close();         } catch (IOException e) {             e.printStackTrace();         }         return out.toByteArray();     }      /*      * 字节数组解压缩后返回字符串      */     public static String uncompressToString(byte[] b) {         if (b == null || b.length == 0) {             return null;         }         ByteArrayOutputStream out = new ByteArrayOutputStream();         ByteArrayInputStream in = new ByteArrayInputStream(b);          try {             GZIPInputStream gunzip = new GZIPInputStream(in);             byte[] buffer = new byte[256];             int n;             while ((n = gunzip.read(buffer)) >= 0) {                 out.write(buffer, 0, n);             }         } catch (IOException e) {             e.printStackTrace();         }         return out.toString();     }      /*      * 字节数组解压缩后返回字符串      */     public static String uncompressToString(byte[] b, String encoding) {         if (b == null || b.length == 0) {             return null;         }         ByteArrayOutputStream out = new ByteArrayOutputStream();         ByteArrayInputStream in = new ByteArrayInputStream(b);          try {             GZIPInputStream gunzip = new GZIPInputStream(in);             byte[] buffer = new byte[256];             int n;             while ((n = gunzip.read(buffer)) >= 0) {                 out.write(buffer, 0, n);             }             return out.toString(encoding);         } catch (IOException e) {             e.printStackTrace();         }         return null;     } }</pre>