最近有一个银行数据漂白系统,要求操作人员在页面调用远端Linux服务器的shell,并将shell输出的信息保存到一个日志文件,前台页面要实时显示日志文件的内容.这个问题难点在于如何判断哪些数据是新增加的,通过查看JDK
的帮助文档,java.io.RandomAccessFile
可以解决这个问题.为了模拟这个问题,编写LogSvr和 LogView类,LogSvr不断向mock.log日志文件写数据,而
LogView则实时输出日志变化部分的数据.
代码1:日志产生类
-
package
com.bill99.seashell.domain.svr; -
-
import
java.io.File; -
import
java.io.FileWriter; -
import
java.io.IOException; -
import
java.io.Writer; -
import
java.text.SimpleDateFormat; -
import
java.util.Date; -
import
java.util.concurrent.Executors; -
import
java.util.concurrent.ScheduledExecutorService ; -
import
java.util.concurrent.TimeUnit; -
-
public
class LogSvr { -
-
private SimpleDateFormat dateFormat = -
new SimpleDateFormat("yyyy-MM-dd HH:mm:ss" ); -
-
-
public void logMsg(File logFile,String mesInfo) throws IOException{ -
if(logFile == null) { -
throw new IllegalStateException("logFile can );not be null!" -
} -
Writer txtWriter = new FileWriter(logFile,true); -
txtWriter.write(dateFormat.format(new Date()) +" "+mesInfo+" "); -
txtWriter.flush(); -
} -
-
public static void main(String[] args) throws Exception{ -
-
final LogSvr logSvr = new LogSvr(); -
final File tmpLogFile = new File("mock.log"); -
if(!tmpLogFile.exists()) { -
tmpLogFile.createNewFile(); -
} -
//启动一个线程每5秒钟向日志文件写一次数据 -
ScheduledExecutorService exec = -
Executors.newScheduledThreadPool(1); -
exec.scheduleWithFixedDelay(new Runnable(){ -
public void run() { -
try { -
logSvr.logMsg(tmpLogFile, " 99bill );test !" -
} catch (IOException e) { -
throw new RuntimeException(e); -
} -
} -
}, 0, 5, TimeUnit.SECONDS); -
} -
}
-
package
com.bill99.seashell.domain.client; -
-
import
java.io.File; -
import
java.io.IOException; -
import
java.io.RandomAccessFile; -
import
java.util.concurrent.Executors; -
import
java.util.concurrent.ScheduledExecutorService ; -
import
java.util.concurrent.TimeUnit; -
-
public
class LogView { -
private long lastTimeFileSize = 0; //上次文件大小 -
-
public void realtimeShowLog(File logFile) throws IOException{ -
//指定文件可读可写 -
final RandomAccessFile randomFile = new RandomAccessFile(logFile,"rw"); -
//启动一个线程每10秒钟读取新增的日志信息 -
ScheduledExecutorService exec = -
Executors.newScheduledThreadPool(1); -
exec.scheduleWithFixedDelay(new Runnable(){ -
public void run() { -
try { -
//获得变化部分的 -
randomFile.seek(lastTimeFileSize); -
String tmp = ""; -
while( (tmp = randomFile.readLine())!= null) { -
System.out.println(new String(tmp.getBytes("ISO8859-1"))); -
} -
lastTimeFileSize = randomFile.length(); -
} catch (IOException e) { -
throw new RuntimeException(e); -
} -
} -
}, 0, 1, TimeUnit.SECONDS); -
} -
-
public static void main(String[] args) throws Exception { -
LogView view = new LogView(); -
final File tmpLogFile = new File("mock.log"); -
view.realtimeShowLog(tmpLogFile); -
} -
-
}
执行LogSvr类,LogSvr类会启动一个线程,每5秒钟向mock.log日志文件写一次数据,然后再执行LogView类,LogView每隔1秒钟读一次,如果数据有变化则输出变化的部分.
结果输出:
2010-06-19 17:25:54
2010-06-19 17:25:59
2010-06-19 17:26:04
2010-06-19 17:26:09
2010-06-19 17:26:14
2010-06-19 17:26:19
PS: