java关于IO输入的问题
[code=Java][/code]import java.io.*;
public class TestPriority {
public static void main(String [] args) {
Thread t1 = new Thread(new T1() );
T2 t2 = new T2("T2");
//t2.setPriority(Thread.NORM_PRIORITY+3);
t1.start();t2.start();
}
}

class T1 implements Runnable {
public void run() {
try {
PrintWriter fw = new PrintWriter(new FileWriter("d:/bak/TestPriority.txt"),true);
for(int i = 1;i<50;i++) {
System.out.println("T1: " + i);
fw.println("T1: " + i);
fw.flush();
}
fw.close();
}catch(IOException x) {
x.printStackTrace();
}
}
}

class T2 extends Thread {
T2(String s) {
super(s);
}
public void run() {
try {
PrintWriter fws = new PrintWriter(new FileWriter("d:/bak/TestPriority.txt"),true);
for(int i = 1;i<50;i++) {
//if(i%10 == 0) this.yield();
System.out.println("---------" + this.getName() + ": " + i);
fws.println("---------" + this.getName() + ": " + i);
fws.flush();
}
fws.close();
}catch(IOException x) {
x.printStackTrace();
}
}
}这是我写的一个小程序，里面两个线程同时向屏幕打印和文件写入一些内容，可是运行后发现屏幕上打印的内容和预期是一样的，而文件中写入的内容有些问题，求解？
屏幕的内容：
T1: 1
T1: 2
T1: 3
---------T2: 1
---------T2: 2
---------T2: 3
---------T2: 4
---------T2: 5
T1: 4
T1: 5
T1: 6
T1: 7
T1: 8
T1: 9
T1: 10
---------T2: 6
---------T2: 7
---------T2: 8
---------T2: 9
---------T2: 10
---------T2: 11
---------T2: 12
T1: 11
T1: 12
T1: 13
T1: 14
T1: 15
T1: 16
T1: 17
---------T2: 13
---------T2: 14
---------T2: 15
---------T2: 16
---------T2: 17
---------T2: 18
---------T2: 19
---------T2: 20
T1: 18
T1: 19
T1: 20
T1: 21
T1: 22
T1: 23
T1: 24
---------T2: 21
---------T2: 22
---------T2: 23
---------T2: 24
---------T2: 25
---------T2: 26
T1: 25
T1: 26
T1: 27
T1: 28
T1: 29
T1: 30
T1: 31
---------T2: 27
---------T2: 28
---------T2: 29
---------T2: 30
---------T2: 31
---------T2: 32
---------T2: 33
T1: 32
T1: 33
T1: 34
T1: 35
T1: 36
T1: 37
T1: 38
T1: 39
---------T2: 34
---------T2: 35
---------T2: 36
---------T2: 37
---------T2: 38
---------T2: 39
---------T2: 40
T1: 40
T1: 41
T1: 42
T1: 43
T1: 44
T1: 45
T1: 46
T1: 47
T1: 48
---------T2: 41
---------T2: 42
---------T2: 43
---------T2: 44
---------T2: 45
---------T2: 46
T1: 49
---------T2: 47
---------T2: 48
---------T2: 49
文件中的内容：

---------T2: 1T1: 3
T1: 4
T1: 5
T1: 6
T1: 7
T1: 8
T1: 9
T1: 10
T1: 11
T1: 12
T1: 13
T1: 14
T1: 15
T1: 16
T1: 17
T1: 18
T1: 19
T1: 20
T1: 21
T1: 22
T1: 23
T1: 24
T1: 25
T1: 26
T1: 27
T1: 28
T1: 29
T1: 30
T1: 31
T1: 32
T1: 33
T1: 34
T1: 35
T1: 36
T1: 37
T1: 38
T1: 39
T1: 40
T1: 41
T1: 42
T1: 43
T1: 44
T1: 45
T1: 46
T1: 47
T1: 48
T1: 49
--------T2: 24
---------T2: 25
---------T2: 26
---------T2: 27
---------T2: 28
---------T2: 29
---------T2: 30
---------T2: 31
---------T2: 32
---------T2: 33
---------T2: 34
---------T2: 35
---------T2: 36
---------T2: 37
---------T2: 38
---------T2: 39
---------T2: 40
---------T2: 41
---------T2: 42
---------T2: 43
---------T2: 44
---------T2: 45