GZIP壓縮解壓類

    針對一些與APP交互的網站，常常用json格式，這樣明文有些不安全以及很容易被爬，且數據量大，所以用gzip來進行壓縮並用base64編碼，避免上述問題，直接上代碼：

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;

/**
 * GZIP壓縮解壓類
 */
public class StringGZIP {

	private static String encode = "UTF-8";

	private static final String CODES = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+-/=";

	/**
	 * base64解密
	 * 
	 * @param input
	 * @return
	 */
	public static byte[] base64Decode(String input) {
		if (input.length() % 4 != 0) {
			throw new IllegalArgumentException("Invalid base64 input");
		}
		byte decoded[] = new byte[((input.length() * 3) / 4)
				- (input.indexOf('=') > 0 ? (input.length() - input.indexOf('=')) : 0)];
		char[] inChars = input.toCharArray();
		int j = 0;
		int b[] = new int[4];
		for (int i = 0; i < inChars.length; i += 4) {
			// This could be made faster (but more complicated) by precomputing
			// these index locations.
			b[0] = CODES.indexOf(inChars[i]);
			b[1] = CODES.indexOf(inChars[i + 1]);
			b[2] = CODES.indexOf(inChars[i + 2]);
			b[3] = CODES.indexOf(inChars[i + 3]);
			decoded[j++] = (byte) ((b[0] << 2) | (b[1] >> 4));
			if (b[2] < 64) {
				decoded[j++] = (byte) ((b[1] << 4) | (b[2] >> 2));
				if (b[3] < 64) {
					decoded[j++] = (byte) ((b[2] << 6) | b[3]);
				}
			}
		}
		return decoded;
	}

	/**
	 * base64加密
	 * 
	 * @param in
	 * @return
	 */
	public static String base64Encode(byte[] in) {
		StringBuilder out = new StringBuilder((in.length * 4) / 3);
		int b;
		for (int i = 0; i < in.length; i += 3) {
			b = (in[i] & 0xFC) >> 2;
			out.append(CODES.charAt(b));
			b = (in[i] & 0x03) << 4;
			if (i + 1 < in.length) {
				b |= (in[i + 1] & 0xF0) >> 4;
				out.append(CODES.charAt(b));
				b = (in[i + 1] & 0x0F) << 2;
				if (i + 2 < in.length) {
					b |= (in[i + 2] & 0xC0) >> 6;
					out.append(CODES.charAt(b));
					b = in[i + 2] & 0x3F;
					out.append(CODES.charAt(b));
				} else {
					out.append(CODES.charAt(b));
					out.append('=');
				}
			} else {
				out.append(CODES.charAt(b));
				out.append("==");
			}
		}
		return out.toString();
	}

	public String getEncode() {
		return encode;
	}

	/*
	 * 設置 編碼，默認編碼：UTF-8
	 */
	public void setEncode(String encode) {
		StringGZIP.encode = encode;
	}

	/**
	 * 字符串壓縮爲字節數組,默認UTF-8編碼
	 * 
	 * @param str
	 * @return
	 */
	public static String compress(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 base64Encode(out.toByteArray());
	}

	/**
	 * 字符串壓縮爲字節數組
	 * 
	 * @param str
	 * @param encoding
	 * @return
	 */
	public static String compress(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 base64Encode(out.toByteArray());
	}

	/**
	 * 字節數組解壓縮後返回字符串，默認編碼爲UTF-8
	 * 
	 * @param zipText
	 * @return
	 */
	public static String decompress(String zipText) {
		byte[] b = base64Decode(zipText);
		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();
	}

	/**
	 * 字節數組解壓縮後返回字符串
	 * 
	 * @param zipText
	 * @param encoding
	 * @return
	 */
	public static String decompress(String zipText, String encoding) {
		byte[] b = base64Decode(zipText);
		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;
	}
}

    使用案例：

@Test
    public void decompress1() {
        String tempString = "sdfji漢字測試";
        String compress = StringGZIP.compress(tempString);
        System.out.println(compress);
        String decompress = StringGZIP.decompress(compress);
        System.out.println(decompress);
        tempString = "sdfji漢字測試sdfji漢字測試sdfji漢字測試sdfji漢字測試sdfji漢字測試sdfji漢字測試sdfji漢字測試sdfji漢字測試sdfji漢字測試sdfji漢字測試";
         compress = StringGZIP.compress(tempString);
        System.out.println(compress);
         decompress = StringGZIP.decompress(compress);
        System.out.println(decompress);
    }

    測試輸出：

H4sIAAAAAAAAACtOScvKfLax8+na6c+2dr9YPxUAoOKrwBEAAAA=
sdfji漢字測試
H4sIAAAAAAAAACtOScvKfLax8+na6c+2dr9YP7V4sAoAAO-IIA6qAAAA
sdfji漢字測試sdfji漢字測試sdfji漢字測試sdfji漢字測試sdfji漢字測試sdfji漢字測試sdfji漢字測試sdfji漢字測試sdfji漢字測試sdfji漢字測試

 

    對於重複字段越多，壓縮率越高！