原理分析：迅雷的thunder://地址就是将普通url地址加前缀‘AA’、后缀‘ZZ’，再base64编码后得到的字符串

实现：

步骤1，添加工具类Base64 编码和解码：Base64.java

package th;

import java.io.*;

/**

* Base64 编码和解码。

*

* @author 宋立君

* @date 2014年07月03日

*/

public class Base64 {

public Base64() {

}

/**

* 功能：编码字符串

*

* @author 宋立君

* @date 2014年07月03日

* @param data

* 源字符串

* @return String

*/

public static String encode(String data) {

return new String(encode(data.getBytes()));

}

/**

* 功能：解码字符串

*

* @author 宋立君

* @date 2014年07月03日

* @param data

* 源字符串

* @return String

*/

public static String decode(String data) {

return new String(decode(data.toCharArray()));

}

/**

* 功能：编码byte[]

*

* @author 宋立君

* @date 2014年07月03日

* @param data

* 源

* @return char[]

*/

public static char[] encode(byte[] data) {

char[] out = new char[((data.length + 2) / 3) * 4];

for (int i = 0, index = 0; i < data.length; i += 3, index += 4) {

boolean quad = false;

boolean trip = false;

int val = (0xFF & (int) data[i]);

val <<= 8;

if ((i + 1) < data.length) {

val |= (0xFF & (int) data[i + 1]);

trip = true;

}

val <<= 8;

if ((i + 2) < data.length) {

val |= (0xFF & (int) data[i + 2]);

quad = true;

}

out[index + 3] = alphabet[(quad ? (val & 0x3F) : 64)];

val >>= 6;

out[index + 2] = alphabet[(trip ? (val & 0x3F) : 64)];

val >>= 6;

out[index + 1] = alphabet[val & 0x3F];

val >>= 6;

out[index + 0] = alphabet[val & 0x3F];

}

return out;

}

/**

* 功能：解码

*

* @author 宋立君

* @date 2014年07月03日

* @param data

* 编码后的字符数组

* @return byte[]

*/

public static byte[] decode(char[] data) {

int tempLen = data.length;

for (int ix = 0; ix < data.length; ix++) {

if ((data[ix] > 255) || codes[data[ix]] < 0) {

--tempLen; // ignore non-valid chars and padding

}

}

// calculate required length:

// -- 3 bytes for every 4 valid base64 chars

// -- plus 2 bytes if there are 3 extra base64 chars,

// or plus 1 byte if there are 2 extra.

int len = (tempLen / 4) * 3;

if ((tempLen % 4) == 3) {

len += 2;

}

if ((tempLen % 4) == 2) {

len += 1;

}

byte[] out = new byte[len];

int shift = 0; // # of excess bits stored in accum

int accum = 0; // excess bits

int index = 0;

// we now go through the entire array (NOT using the 'tempLen' value)

for (int ix = 0; ix < data.length; ix++) {

int value = (data[ix] > 255) ? -1 : codes[data[ix]];

if (value >= 0) { // skip over non-code

accum <<= 6; // bits shift up by 6 each time thru

shift += 6; // loop, with new bits being put in

accum |= value; // at the bottom.

if (shift >= 8) { // whenever there are 8 or more shifted in,

shift -= 8; // write them out (from the top, leaving any

out[index++] = // excess at the bottom for next iteration.

(byte) ((accum >> shift) & 0xff);

}

}

}

// if there is STILL something wrong we just have to throw up now!

if (index != out.length) {

throw new Error("Miscalculated data length (wrote " + index

+ " instead of " + out.length + ")");

}

return out;

}

/**

* 功能：编码文件

*

* @author 宋立君

* @date 2014年07月03日

* @param file

* 源文件

*/

public static void encode(File file) throws IOException {

if (!file.exists()) {

System.exit(0);

}

else {

byte[] decoded = readBytes(file);

char[] encoded = encode(decoded);

writeChars(file, encoded);

}

file = null;

}

/**

* 功能：解码文件。

*

* @author 宋立君

* @date 2014年07月03日

* @param file

* 源文件

* @throws IOException

*/

public static void decode(File file) throws IOException {

if (!file.exists()) {

System.exit(0);

} else {

char[] encoded = readChars(file);

byte[] decoded = decode(encoded);

writeBytes(file, decoded);

}

file = null;

}

//

// code characters for values 0..63

//

private static char[] alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/="

.toCharArray();

//

// lookup table for converting base64 characters to value in range 0..63

//

private static byte[] codes = new byte[256];

static {

for (int i = 0; i < 256; i++) {

codes[i] = -1;

// LoggerUtil.debug(i + "&" + codes[i] + " ");

}

for (int i = 'A'; i <= 'Z'; i++) {

codes[i] = (byte) (i - 'A');

// LoggerUtil.debug(i + "&" + codes[i] + " ");

}

for (int i = 'a'; i <= 'z'; i++) {

codes[i] = (byte) (26 + i - 'a');

// LoggerUtil.debug(i + "&" + codes[i] + " ");

}

for (int i = '0'; i <= '9'; i++) {

codes[i] = (byte) (52 + i - '0');

// LoggerUtil.debug(i + "&" + codes[i] + " ");

}

codes['+'] = 62;

codes['/'] = 63;

}

private static byte[] readBytes(File file) throws IOException {

ByteArrayOutputStream baos = new ByteArrayOutputStream();

byte[] b = null;

InputStream fis = null;

InputStream is = null;

try {

fis = new FileInputStream(file);

is = new BufferedInputStream(fis);

int count = 0;

byte[] buf = new byte[16384];

while ((count = is.read(buf)) != -1) {

if (count > 0) {

baos.write(buf, 0, count);

}

}

b = baos.toByteArray();

} finally {

try {

if (fis != null)

fis.close();

if (is != null)

is.close();

if (baos != null)

baos.close();

} catch (Exception e) {

System.out.println(e);

}

}

return b;

}

private static char[] readChars(File file) throws IOException {

CharArrayWriter caw = new CharArrayWriter();

Reader fr = null;

Reader in = null;

try {

fr = new FileReader(file);

in = new BufferedReader(fr);

int count = 0;

char[] buf = new char[16384];

while ((count = in.read(buf)) != -1) {

if (count > 0) {

caw.write(buf, 0, count);

}

}

} finally {

try {

if (caw != null)

caw.close();

if (in != null)

in.close();

if (fr != null)

fr.close();

} catch (Exception e) {

System.out.println(e);

}

}

return caw.toCharArray();

}

private static void writeBytes(File file, byte[] data) throws IOException {

OutputStream fos = null;

OutputStream os = null;

try {

fos = new FileOutputStream(file);

os = new BufferedOutputStream(fos);

os.write(data);

} finally {

try {

if (os != null)

os.close();

if (fos != null)

fos.close();

} catch (Exception e) {

System.out.println(e);

}

}

}

private static void writeChars(File file, char[] data) throws IOException {

Writer fos = null;

Writer os = null;

try {

fos = new FileWriter(file);

os = new BufferedWriter(fos);

os.write(data);

} finally {

try {

if (os != null)

os.close();

if (fos != null)

fos.close();

} catch (Exception e) {

e.printStackTrace();

}

}

}

}

步骤2,编写迅雷地址转普通地址的类及方法：ThunderSiteConverUtil.java

package th;

/**

* 迅雷地址转普通地址

*

Title: ThunderSiteConverUtil

*

Description:

*

Company: www.itcast.com

* @author入云龙

* @date2017年3月6日下午2:11:32

* @version 1.0

*/

public class ThunderSiteConverUtil {

/**

* 迅雷thunder://地址与普通url地址转换

其实迅雷的thunder://地址就是将普通url地址加前缀‘AA’、后缀‘ZZ’，再base64编码后得到的字符串

*

Title: t1

*

Description:

* @param url

* @return

*/

public String conver(String url){

String newUrl="";

//s＝s.substring(int begin，int end);截取s中从begin开始至end结束时的字符串，并将其赋值给s;

//去掉迅雷地址前缀

url=url.substring(10, url.length());

//解密

newUrl=Base64.decode(url);

//去掉头AA，尾ZZ

newUrl=newUrl.substring(2, newUrl.length()-2);

return newUrl;

}

}

步骤3，建立测试类：TestTh.java

package th;

import org.junit.Test;

/*

* 迅雷地址转普通地址测试

*/

public class TestTh {

@Test

public void test1(){

String url="thunder://QUFodHRwOi8vdG9vbC5sdS90ZXN0LnppcFpa";

System.out.println("迅雷地址："+url);

url=new ThunderSiteConverUtil().conver(url);

System.out.println("普通地址："+url);

}

}

运行Junit测试test1，控制台输出：

迅雷地址：thunder://QUFodHRwOi8vdG9vbC5sdS90ZXN0LnppcFpa

普通地址：http://tool.lu/test.zip