-----------------------------类1----------------------------------------
public class SerialNum{// The next serial number to be assigned
private static int nextSerialNum = 0;private static ThreadLocal serialNum = new ThreadLocal(){protected synchronized Object initialValue(){return new Integer(nextSerialNum++);}};
public static int get(){return ((Integer) (serialNum.get())).intValue();}}
---------------------------------------类2-------------------------------
public class SerialNum{// The next serial number to be assigned
private static int nextSerialNum = 0;public static int get(){ return nextSerialNum;}}
==============================================
两个类在运行时有什么区别?
请写出测试用例.............
public class SerialNum{// The next serial number to be assigned
private static int nextSerialNum = 0;private static ThreadLocal serialNum = new ThreadLocal(){protected synchronized Object initialValue(){return new Integer(nextSerialNum++);}};
public static int get(){return ((Integer) (serialNum.get())).intValue();}}
---------------------------------------类2-------------------------------
public class SerialNum{// The next serial number to be assigned
private static int nextSerialNum = 0;public static int get(){ return nextSerialNum;}}
==============================================
两个类在运行时有什么区别?
请写出测试用例.............
解决方案 »
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return nextSerialNum;
应该为
return nextSerialNum++;
么?
下面的测试代码可以看出区别:public class Test implements Runnable{
private int id=0;
public Test(int id) {
this.id=id;
}
public void run(){
for (int i=0;i<10;i++){
System.out.println("线程"+id+":"+SerialNum.get());
}
}
public static void main(String[] args) {
Test test = new Test(1);
(new Thread(test)).start();
test = new Test(2);
(new Thread(test)).start();
test = new Test(3);
(new Thread(test)).start();
}
}