Java杂烩，

Java杂烩，

查看内存

import java.lang.management.*;

public class MemTest{
public static void main(String[] args){
java.util.List<MemoryPoolMXBean> mpools =
ManagementFactory.getMemoryPoolMXBeans();

MemoryPoolMXBean mp = mpools.get(0);
float usedMemory = mp.getUsage().getUsed();
float totalMemory = mp.getUsage().getMax();
System.out.println(usedMemory/1000 + "K used");
System.out.println(totalMemory/1000 +"K total" );
}
}

 

打包WAR jar cvf wileyapp.war *

得到列名,列数ResultSetMetaData

让cmd报错时停住 键盘上有个pause break,按这个就行

java.util.Date date=new java.util.Date();
 date.setYear(date.getYear()-1);
 java.sql.Date sqldate=new java.sql.Date(date.getTime());