文件读写问题
1，对同一文件，多个线程在读，同时有线程在写入，会发生冲突吗？
通过下面的测试代码看的话，貌似不会有问题：
static class ThreadReader implements Runnable{
@Override
public void run() {
// TODO Auto-generated method stub
File file = new File("d://1.txt");
try {
BufferedReader br = new BufferedReader(new FileReader(file));
String temp = br.readLine();
while(temp != null){
System.out.println(Thread.currentThread().getName()+",read:"+temp+",time:"+System.currentTimeMillis()+"\r\n");
temp = br.readLine();
Thread.sleep(25);
}
br.close();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
static class ThreadWriter implements Runnable{
@Override
public void run() {
// TODO Auto-generated method stub
File file = new File("d://1.txt");
if(!file.exists()){
try {
file.createNewFile();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
try {
BufferedWriter bw = new BufferedWriter(new FileWriter(file));
for(int i=0;i<100;i++){
bw.write(Thread.currentThread().getName()+",我是"+i+",time:"+System.currentTimeMillis()+"\r\n");
bw.flush();
Thread.sleep(20);
}
bw.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
public static void main(String[] args) throws InterruptedException {
new Thread(new ThreadWriter()).start();
Thread.sleep(25);
new Thread(new ThreadReader()).start();
new Thread(new ThreadReader()).start();
}
1.txt 中的内容
Thread-0,我是0,time:1389686561927 Thread-0,我是1,time:1389686561947 Thread-0,我是2,time:1389686561967 Thread-0,我是3,time:1389686561987 Thread-0,我是4,time:1389686562007 Thread-0,我是5,time:1389686562027 Thread-0,我是6,time:1389686562047 Thread-0,我是7,time:1389686562067 Thread-0,我是8,time:1389686562087 Thread-0,我是9,time:1389686562107 Thread-0,我是10,time:1389686562127 Thread-0,我是11,time:1389686562147 Thread-0,我是12,time:1389686562167 Thread-0,我是13,time:1389686562187 Thread-0,我是14,time:1389686562207 Thread-0,我是15,time:1389686562227 Thread-0,我是16,time:1389686562247 Thread-0,我是17,time:1389686562267 Thread-0,我是18,time:1389686562287 Thread-0,我是19,time:1389686562307 Thread-0,我是20,time:1389686562327 Thread-0,我是21,time:1389686562347 Thread-0,我是22,time:1389686562367 Thread-0,我是23,time:1389686562387 Thread-0,我是24,time:1389686562407 Thread-0,我是25,time:1389686562429 Thread-0,我是26,time:1389686562449 Thread-0,我是27,time:1389686562469 Thread-0,我是28,time:1389686562489 Thread-0,我是29,time:1389686562509 Thread-0,我是30,time:1389686562529 Thread-0,我是31,time:1389686562549 Thread-0,我是32,time:1389686562569 Thread-0,我是33,time:1389686562589 Thread-0,我是34,time:1389686562609 Thread-0,我是35,time:1389686562629 Thread-0,我是36,time:1389686562649 Thread-0,我是37,time:1389686562669 Thread-0,我是38,time:1389686562689 Thread-0,我是39,time:1389686562709 Thread-0,我是40,time:1389686562729 Thread-0,我是41,time:1389686562749 Thread-0,我是42,time:1389686562769 Thread-0,我是43,time:1389686562789 Thread-0,我是44,time:1389686562809 Thread-0,我是45,time:1389686562829 Thread-0,我是46,time:1389686562849 Thread-0,我是47,time:1389686562869 Thread-0,我是48,time:1389686562889 Thread-0,我是49,time:1389686562909 Thread-0,我是50,time:1389686562929 Thread-0,我是51,time:1389686562949 Thread-0,我是52,time:1389686562969 Thread-0,我是53,time:1389686562990 Thread-0,我是54,time:1389686563014 Thread-0,我是55,time:1389686563036 Thread-0,我是56,time:1389686563056 Thread-0,我是57,time:1389686563076 Thread-0,我是58,time:1389686563096 Thread-0,我是59,time:1389686563116 Thread-0,我是60,time:1389686563136 Thread-0,我是61,time:1389686563156 Thread-0,我是62,time:1389686563176 Thread-0,我是63,time:1389686563196 Thread-0,我是64,time:1389686563216 Thread-0,我是65,time:1389686563236 Thread-0,我是66,time:1389686563256 Thread-0,我是67,time:1389686563276 Thread-0,我是68,time:1389686563296 Thread-0,我是69,time:1389686563316 Thread-0,我是70,time:1389686563336 Thread-0,我是71,time:1389686563356 Thread-0,我是72,time:1389686563376 Thread-0,我是73,time:1389686563396 Thread-0,我是74,time:1389686563416 Thread-0,我是75,time:1389686563436 Thread-0,我是76,time:1389686563456 Thread-0,我是77,time:1389686563476 Thread-0,我是78,time:1389686563496 Thread-0,我是79,time:1389686563516 Thread-0,我是80,time:1389686563536 Thread-0,我是81,time:1389686563556 Thread-0,我是82,time:1389686563576 Thread-0,我是83,time:1389686563596 Thread-0,我是84,time:1389686563616 Thread-0,我是85,time:1389686563636 Thread-0,我是86,time:1389686563656 Thread-0,我是87,time:1389686563676 Thread-0,我是88,time:1389686563696 Thread-0,我是89,time:1389686563716 Thread-0,我是90,time:1389686563736 Thread-0,我是91,time:1389686563756 Thread-0,我是92,time:1389686563776 Thread-0,我是93,time:1389686563796 Thread-0,我是94,time:1389686563816 Thread-0,我是95,time:1389686563836 Thread-0,我是96,time:1389686563856 Thread-0,我是97,time:1389686563876 Thread-0,我是98,time:1389686563896 Thread-0,我是99,time:1389686563916
读出来的内容：
Thread-1,read:Thread-0,我是0,time:1389686561927,time:1389686561952 Thread-2,read:Thread-0,我是0,time:1389686561927,time:1389686561952 Thread-1,read:Thread-0,我是1,time:1389686561947,time:1389686561977 Thread-2,read:Thread-0,我是1,time:1389686561947,time:1389686561977 Thread-2,read:Thread-0,我是2,time:1389686561967,time:1389686562002 Thread-1,read:Thread-0,我是2,time:1389686561967,time:1389686562002 Thread-2,read:Thread-0,我是3,time:1389686561987,time:1389686562027 Thread-1,read:Thread-0,我是3,time:1389686561987,time:1389686562027 Thread-2,read:Thread-0,我是4,time:1389686562007,time:1389686562052 Thread-1,read:Thread-0,我是4,time:1389686562007,time:1389686562052 Thread-2,read:Thread-0,我是5,time:1389686562027,time:1389686562077 Thread-1,read:Thread-0,我是5,time:1389686562027,time:1389686562077 Thread-1,read:Thread-0,我是6,time:1389686562047,time:1389686562102 Thread-2,read:Thread-0,我是6,time:1389686562047,time:1389686562102 Thread-1,read:Thread-0,我是7,time:1389686562067,time:1389686562127 Thread-2,read:Thread-0,我是7,time:1389686562067,time:1389686562127 Thread-2,read:Thread-0,我是8,time:1389686562087,time:1389686562152 Thread-1,read:Thread-0,我是8,time:1389686562087,time:1389686562152 Thread-1,read:Thread-0,我是9,time:1389686562107,time:1389686562177 Thread-2,read:Thread-0,我是9,time:1389686562107,time:1389686562177 Thread-2,read:Thread-0,我是10,time:1389686562127,time:1389686562202 Thread-1,read:Thread-0,我是10,time:1389686562127,time:1389686562202 Thread-2,read:Thread-0,我是11,time:1389686562147,time:1389686562227 Thread-1,read:Thread-0,我是11,time:1389686562147,time:1389686562227 Thread-2,read:Thread-0,我是12,time:1389686562167,time:1389686562252 Thread-1,read:Thread-0,我是12,time:1389686562167,time:1389686562252 Thread-1,read:Thread-0,我是13,time:1389686562187,time:1389686562277 Thread-2,read:Thread-0,我是13,time:1389686562187,time:1389686562277 Thread-2,read:Thread-0,我是14,time:1389686562207,time:1389686562302 Thread-1,read:Thread-0,我是14,time:1389686562207,time:1389686562302 Thread-1,read:Thread-0,我是15,time:1389686562227,time:1389686562327 Thread-2,read:Thread-0,我是15,time:1389686562227,time:1389686562327 Thread-2,read:Thread-0,我是16,time:1389686562247,time:1389686562352 Thread-1,read:Thread-0,我是16,time:1389686562247,time:1389686562352 Thread-1,read:Thread-0,我是17,time:1389686562267,time:1389686562377 Thread-2,read:Thread-0,我是17,time:1389686562267,time:1389686562379 Thread-1,read:Thread-0,我是18,time:1389686562287,time:1389686562403 Thread-2,read:Thread-0,我是18,time:1389686562287,time:1389686562404 Thread-1,read:Thread-0,我是19,time:1389686562307,time:1389686562429 Thread-2,read:Thread-0,我是19,time:1389686562307,time:1389686562429 Thread-2,read:Thread-0,我是20,time:1389686562327,time:1389686562454 Thread-1,read:Thread-0,我是20,time:1389686562327,time:1389686562454 Thread-2,read:Thread-0,我是21,time:1389686562347,time:1389686562479 Thread-1,read:Thread-0,我是21,time:1389686562347,time:1389686562479 Thread-2,read:Thread-0,我是22,time:1389686562367,time:1389686562504 Thread-1,read:Thread-0,我是22,time:1389686562367,time:1389686562504 Thread-1,read:Thread-0,我是23,time:1389686562387,time:1389686562529 Thread-2,read:Thread-0,我是23,time:1389686562387,time:1389686562529 Thread-1,read:Thread-0,我是24,time:1389686562407,time:1389686562554 Thread-2,read:Thread-0,我是24,time:1389686562407,time:1389686562554 Thread-2,read:Thread-0,我是25,time:1389686562429,time:1389686562579 Thread-1,read:Thread-0,我是25,time:1389686562429,time:1389686562579 Thread-1,read:Thread-0,我是26,time:1389686562449,time:1389686562604 Thread-2,read:Thread-0,我是26,time:1389686562449,time:1389686562604 Thread-1,read:Thread-0,我是27,time:1389686562469,time:1389686562629 Thread-2,read:Thread-0,我是27,time:1389686562469,time:1389686562629 Thread-2,read:Thread-0,我是28,time:1389686562489,time:1389686562654 Thread-1,read:Thread-0,我是28,time:1389686562489,time:1389686562654 Thread-2,read:Thread-0,我是29,time:1389686562509,time:1389686562679 Thread-1,read:Thread-0,我是29,time:1389686562509,time:1389686562679 Thread-1,read:Thread-0,我是30,time:1389686562529,time:1389686562704 Thread-2,read:Thread-0,我是30,time:1389686562529,time:1389686562704 Thread-2,read:Thread-0,我是31,time:1389686562549,time:1389686562729 Thread-1,read:Thread-0,我是31,time:1389686562549,time:1389686562729 Thread-2,read:Thread-0,我是32,time:1389686562569,time:1389686562754 Thread-1,read:Thread-0,我是32,time:1389686562569,time:1389686562754 Thread-1,read:Thread-0,我是33,time:1389686562589,time:1389686562779 Thread-2,read:Thread-0,我是33,time:1389686562589,time:1389686562779 Thread-1,read:Thread-0,我是34,time:1389686562609,time:1389686562804 Thread-2,read:Thread-0,我是34,time:1389686562609,time:1389686562804 Thread-1,read:Thread-0,我是35,time:1389686562629,time:1389686562829 Thread-2,read:Thread-0,我是35,time:1389686562629,time:1389686562829 Thread-2,read:Thread-0,我是36,time:1389686562649,time:1389686562854 Thread-1,read:Thread-0,我是36,time:1389686562649,time:1389686562854 Thread-1,read:Thread-0,我是37,time:1389686562669,time:1389686562879 Thread-2,read:Thread-0,我是37,time:1389686562669,time:1389686562879 Thread-2,read:Thread-0,我是38,time:1389686562689,time:1389686562904 Thread-1,read:Thread-0,我是38,time:1389686562689,time:1389686562904 Thread-1,read:Thread-0,我是39,time:1389686562709,time:1389686562929 Thread-2,read:Thread-0,我是39,time:1389686562709,time:1389686562929 Thread-1,read:Thread-0,我是40,time:1389686562729,time:1389686562954 Thread-2,read:Thread-0,我是40,time:1389686562729,time:1389686562954 Thread-2,read:Thread-0,我是41,time:1389686562749,time:1389686562979 Thread-1,read:Thread-0,我是41,time:1389686562749,time:1389686562981 Thread-2,read:Thread-0,我是42,time:1389686562769,time:1389686563005 Thread-1,read:Thread-0,我是42,time:1389686562769,time:1389686563006 Thread-2,read:Thread-0,我是43,time:1389686562789,time:1389686563033 Thread-1,read:Thread-0,我是43,time:1389686562789,time:1389686563033 Thread-2,read:Thread-0,我是44,time:1389686562809,time:1389686563058 Thread-1,read:Thread-0,我是44,time:1389686562809,time:1389686563058 Thread-2,read:Thread-0,我是45,time:1389686562829,time:1389686563083 Thread-1,read:Thread-0,我是45,time:1389686562829,time:1389686563083 Thread-1,read:Thread-0,我是46,time:1389686562849,time:1389686563108 Thread-2,read:Thread-0,我是46,time:1389686562849,time:1389686563108 Thread-1,read:Thread-0,我是47,time:1389686562869,time:1389686563133 Thread-2,read:Thread-0,我是47,time:1389686562869,time:1389686563133 Thread-1,read:Thread-0,我是48,time:1389686562889,time:1389686563158 Thread-2,read:Thread-0,我是48,time:1389686562889,time:1389686563158 Thread-2,read:Thread-0,我是49,time:1389686562909,time:1389686563183 Thread-1,read:Thread-0,我是49,time:1389686562909,time:1389686563183 Thread-1,read:Thread-0,我是50,time:1389686562929,time:1389686563208 Thread-2,read:Thread-0,我是50,time:1389686562929,time:1389686563208 Thread-1,read:Thread-0,我是51,time:1389686562949,time:1389686563233 Thread-2,read:Thread-0,我是51,time:1389686562949,time:1389686563233 Thread-2,read:Thread-0,我是52,time:1389686562969,time:1389686563258 Thread-1,read:Thread-0,我是52,time:1389686562969,time:1389686563258 Thread-1,read:Thread-0,我是53,time:1389686562990,time:1389686563283 Thread-2,read:Thread-0,我是53,time:1389686562990,time:1389686563283 Thread-2,read:Thread-0,我是54,time:1389686563014,time:1389686563308 Thread-1,read:Thread-0,我是54,time:1389686563014,time:1389686563308 Thread-2,read:Thread-0,我是55,time:1389686563036,time:1389686563333 Thread-1,read:Thread-0,我是55,time:1389686563036,time:1389686563333 Thread-1,read:Thread-0,我是56,time:1389686563056,time:1389686563358 Thread-2,read:Thread-0,我是56,time:1389686563056,time:1389686563358 Thread-2,read:Thread-0,我是57,time:1389686563076,time:1389686563383 Thread-1,read:Thread-0,我是57,time:1389686563076,time:1389686563383 Thread-1,read:Thread-0,我是58,time:1389686563096,time:1389686563408 Thread-2,read:Thread-0,我是58,time:1389686563096,time:1389686563408 Thread-2,read:Thread-0,我是59,time:1389686563116,time:1389686563433 Thread-1,read:Thread-0,我是59,time:1389686563116,time:1389686563433 Thread-2,read:Thread-0,我是60,time:1389686563136,time:1389686563458 Thread-1,read:Thread-0,我是60,time:1389686563136,time:1389686563458 Thread-1,read:Thread-0,我是61,time:1389686563156,time:1389686563483 Thread-2,read:Thread-0,我是61,time:1389686563156,time:1389686563483 Thread-1,read:Thread-0,我是62,time:1389686563176,time:1389686563508 Thread-2,read:Thread-0,我是62,time:1389686563176,time:1389686563508 Thread-1,read:Thread-0,我是63,time:1389686563196,time:1389686563533 Thread-2,read:Thread-0,我是63,time:1389686563196,time:1389686563533 Thread-2,read:Thread-0,我是64,time:1389686563216,time:1389686563558 Thread-1,read:Thread-0,我是64,time:1389686563216,time:1389686563558 Thread-1,read:Thread-0,我是65,time:1389686563236,time:1389686563583 Thread-2,read:Thread-0,我是65,time:1389686563236,time:1389686563583 Thread-2,read:Thread-0,我是66,time:1389686563256,time:1389686563608 Thread-1,read:Thread-0,我是66,time:1389686563256,time:1389686563608 Thread-2,read:Thread-0,我是67,time:1389686563276,time:1389686563633 Thread-1,read:Thread-0,我是67,time:1389686563276,time:1389686563633 Thread-1,read:Thread-0,我是68,time:1389686563296,time:1389686563658 Thread-2,read:Thread-0,我是68,time:1389686563296,time:1389686563658 Thread-2,read:Thread-0,我是69,time:1389686563316,time:1389686563683 Thread-1,read:Thread-0,我是69,time:1389686563316,time:1389686563683 Thread-2,read:Thread-0,我是70,time:1389686563336,time:1389686563708 Thread-1,read:Thread-0,我是70,time:1389686563336,time:1389686563708 Thread-1,read:Thread-0,我是71,time:1389686563356,time:1389686563733 Thread-2,read:Thread-0,我是71,time:1389686563356,time:1389686563733 Thread-2,read:Thread-0,我是72,time:1389686563376,time:1389686563758 Thread-1,read:Thread-0,我是72,time:1389686563376,time:1389686563758 Thread-2,read:Thread-0,我是73,time:1389686563396,time:1389686563783 Thread-1,read:Thread-0,我是73,time:1389686563396,time:1389686563783 Thread-1,read:Thread-0,我是74,time:1389686563416,time:1389686563808 Thread-2,read:Thread-0,我是74,time:1389686563416,time:1389686563808 Thread-1,read:Thread-0,我是75,time:1389686563436,time:1389686563833 Thread-2,read:Thread-0,我是75,time:1389686563436,time:1389686563833 Thread-2,read:Thread-0,我是76,time:1389686563456,time:1389686563858 Thread-1,read:Thread-0,我是76,time:1389686563456,time:1389686563858 Thread-1,read:Thread-0,我是77,time:1389686563476,time:1389686563883 Thread-2,read:Thread-0,我是77,time:1389686563476,time:1389686563883 Thread-1,read:Thread-0,我是78,time:1389686563496,time:1389686563908 Thread-2,read:Thread-0,我是78,time:1389686563496,time:1389686563908 Thread-1,read:Thread-0,我是79,time:1389686563516,time:1389686563933 Thread-2,read:Thread-0,我是79,time:1389686563516,time:1389686563933 Thread-1,read:Thread-0,我是80,time:1389686563536,time:1389686563958 Thread-2,read:Thread-0,我是80,time:1389686563536,time:1389686563958 Thread-2,read:Thread-0,我是81,time:1389686563556,time:1389686563983 Thread-1,read:Thread-0,我是81,time:1389686563556,time:1389686563983 Thread-2,read:Thread-0,我是82,time:1389686563576,time:1389686564008 Thread-1,read:Thread-0,我是82,time:1389686563576,time:1389686564008 Thread-2,read:Thread-0,我是83,time:1389686563596,time:1389686564033 Thread-1,read:Thread-0,我是83,time:1389686563596,time:1389686564033 Thread-1,read:Thread-0,我是84,time:1389686563616,time:1389686564058 Thread-2,read:Thread-0,我是84,time:1389686563616,time:1389686564058 Thread-2,read:Thread-0,我是85,time:1389686563636,time:1389686564083 Thread-1,read:Thread-0,我是85,time:1389686563636,time:1389686564083 Thread-1,read:Thread-0,我是86,time:1389686563656,time:1389686564108 Thread-2,read:Thread-0,我是86,time:1389686563656,time:1389686564108 Thread-1,read:Thread-0,我是87,time:1389686563676,time:1389686564133 Thread-2,read:Thread-0,我是87,time:1389686563676,time:1389686564133 Thread-1,read:Thread-0,我是88,time:1389686563696,time:1389686564158 Thread-2,read:Thread-0,我是88,time:1389686563696,time:1389686564158 Thread-2,read:Thread-0,我是89,time:1389686563716,time:1389686564183 Thread-1,read:Thread-0,我是89,time:1389686563716,time:1389686564183 Thread-2,read:Thread-0,我是90,time:1389686563736,time:1389686564208 Thread-1,read:Thread-0,我是90,time:1389686563736,time:1389686564208 Thread-1,read:Thread-0,我是91,time:1389686563756,time:1389686564233 Thread-2,read:Thread-0,我是91,time:1389686563756,time:1389686564233 Thread-2,read:Thread-0,我是92,time:1389686563776,time:1389686564258 Thread-1,read:Thread-0,我是92,time:1389686563776,time:1389686564258 Thread-2,read:Thread-0,我是93,time:1389686563796,time:1389686564283 Thread-1,read:Thread-0,我是93,time:1389686563796,time:1389686564283 Thread-1,read:Thread-0,我是94,time:1389686563816,time:1389686564308 Thread-2,read:Thread-0,我是94,time:1389686563816,time:1389686564308 Thread-1,read:Thread-0,我是95,time:1389686563836,time:1389686564333 Thread-2,read:Thread-0,我是95,time:1389686563836,time:1389686564333 Thread-2,read:Thread-0,我是96,time:1389686563856,time:1389686564358 Thread-1,read:Thread-0,我是96,time:1389686563856,time:1389686564358 Thread-1,read:Thread-0,我是97,time:1389686563876,time:1389686564383 Thread-2,read:Thread-0,我是97,time:1389686563876,time:1389686564383 Thread-1,read:Thread-0,我是98,time:1389686563896,time:1389686564408 Thread-2,read:Thread-0,我是98,time:1389686563896,time:1389686564408 Thread-2,read:Thread-0,我是99,time:1389686563916,time:1389686564433 Thread-1,read:Thread-0,我是99,time:1389686563916,time:1389686564433
2，为什么在静态方法中调用的内部类也必须是静态的？