Huffman编码算法之Java实现(三)
t;
do {
Character c = binaryList.removeFirst();
if (c.charValue() == '0') {
node = node.leftNode;
} else {
node = node.rightNode;
}
} while (!node.isLeaf());
buffer.append(node.chars);
}
return buffer.toString();
}
测试以及比较
以下测试Huffman编码的正确性(先编码，后解码，包括中文)，以及Huffman编码与常见的字符编码的二进制字符串比较。代码如下:
[java]
public static void main(String[] args) {
String oriStr = "Huffman codes compress data very effectively: savings of 20% to 90% are typical, "
+ "depending on the characteristics of the data being compressed. 中华崛起";
Map statistics = statistics(oriStr.toCharArray());
String encodedBinariStr = encode(oriStr, statistics);
String decodedStr = decode(encodedBinariStr, statistics);
System.out.println("Original sstring: " + oriStr);
System.out.println("Huffman encoed binary string: " + encodedBinariStr);
System.out.println("decoded string from binariy string: " + decodedStr);
System.out.println("binary string of UTF-8: "
+ getStringOfByte(oriStr, Charset.forName("UTF-8")));
System.out.println("binary string of UTF-16: "
+ getStringOfByte(oriStr, Charset.forName("UTF-16")));
System.out.println("binary string of US-ASCII: "
+ getStringOfByte(oriStr, Charset.forName("US-ASCII")));
System.out.println("binary string of GB2312: "
+ getStringOfByte(oriStr, Charset.forName("GB2312")));
}
public static String getStringOfByte(String str, Charset charset) {
if (str == null || str.equals("")) {
return "";
}
byte[] byteArray = str.getBytes(charset);
int size = byteArray.length;
StringBuffer buffer = new StringBuffer();
for (int i = 0; i < size; i++) {
byte temp = byteArray[i];
buffer.append(getStringOfByte(temp));
}
return buffer.toString();
}
public static String getStringOfByte(byte b) {
StringBuffer buffer = new StringBuffer();
for (int i = 7; i >= 0; i--) {
byte temp = (byte) ((b >> i) & 0x1);
buffer.append(String.valueOf(temp));
}
return buffer.toString();
}