6. 这是处理密码的两个类,我网上找的
import java.io.*;
import java.util.*;
/**
* This class prompts the user for a password and attempts to mask input with "*"
*/
public class PasswordField {
/**
*@param input stream to be used (e.g. System.in)
*@param prompt The prompt to display to the user.
*@return The password as entered by the user.
*/
public static final char[] getPassword(InputStream in, String prompt) throws IOException {
MaskingThread maskingthread = new MaskingThread(prompt);
Thread thread = new Thread(maskingthread);
thread.start();
char[] lineBuffer;
char[] buf;
int i;
buf = lineBuffer = new char[128];
int room = buf.length;
int offset = 0;
int c;
loop: while (true) {
switch (c = in.read()) {
case -1:
case '\n':
break loop;
case '\r':
int c2 = in.read();
if ((c2 != '\n') && (c2 != -1)) {
if (!(in instanceof PushbackInputStream)) {
in = new PushbackInputStream(in);
}
((PushbackInputStream)in).unread(c2);
} else {
break loop;
}
default:
if (--room < 0) {
buf = new char[offset + 128];
room = buf.length - offset - 1;
System.arraycopy(lineBuffer, 0, buf, 0, offset);
Arrays.fill(lineBuffer, ' ');
lineBuffer = buf;
}
buf[offset++] = (char) c;
break;
}
}
maskingthread.stopMasking();
if (offset == 0) {
return null;
}
char[] ret = new char[offset];
System.arraycopy(buf, 0, ret, 0, offset);
Arrays.fill(buf, ' ');
return ret;
}
}
import java.io.*;
/**
* This class attempts to erase characters echoed to the console.
*/
class MaskingThread extends Thread {
** volatile boolean stop;
** char echochar = '*';
/**
*@param prompt The prompt displayed to the user
*/
public MaskingThread(String prompt) {
System.out.print(prompt);
}
/**
* Begin masking until asked to stop.
*/
public void run() {
int priority = Thread.currentThread().getPriority();
Thread.currentThread().setPriority(Thread.MAX_PRIORITY);
try {
stop = true;
while(stop) {
System.out.print("\010" + echochar);
try {
// attempt masking at this rate
Thread.currentThread().sleep(1);
}catch (InterruptedException iex) {
Thread.currentThread().interrupt();
return;
}
}
} finally { // restore the original priority
Thread.currentThread().setPriority(priority);
}
}
/**
* Instruct the thread to stop masking.
*/
public void stopMasking() {
this.stop = false;
}
}