问个import的问题 为什么上面的创建一个对象比下面的要省内存资源?import java.util.Date;public class Test {
Date a;
Date b;
// setter getter
}public class Test {
java.util.Date a;
java.util.Date b;
// setter getter
}
Date a;
Date b;
// setter getter
}public class Test {
java.util.Date a;
java.util.Date b;
// setter getter
}
今天公司的同事用虚拟内存监控工具测试的时候 发现我写的bean中 java.util.Date a; 的方式比import方式创建一个对象会增加内存消耗 我也不知道怎么得出来的
Test2下面的
public class Test3 { /**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub System.gc();
long total1 = Runtime.getRuntime().totalMemory(); // byte
long m1 = Runtime.getRuntime().freeMemory();
System.out.println("before:" + (total1 - m1));
Test1 t1 = new Test1();
long total11 = Runtime.getRuntime().totalMemory();
long m11 = Runtime.getRuntime().freeMemory();
System.out.println("after:" + (total11 - m11));
System.gc();
long total2 = Runtime.getRuntime().totalMemory(); // byte
long m2 = Runtime.getRuntime().freeMemory();
System.out.println("before:" + (total2 - m2));
Test2 t2 = new Test2();
long total22 = Runtime.getRuntime().totalMemory();
long m22 = Runtime.getRuntime().freeMemory();
System.out.println("after:" + (total22 - m22));
}}
after:832856
before:172424
after:502808