android开发之synchronized的用法
来源:互联网 发布:javascript 或运算 编辑:程序博客网 时间:2024/06/14 16:19
ndroid开发之synchronized的用法
public synchronized void synMethod() {
//方法体
}
public int synMethod(int a1){
synchronized(a1) {
//一次只能有一个线程进入
}
}
public class MyThread implements Runnable {
public static void main(String args[]) {
MyThread mt = new MyThread();
Thread t1 = new Thread(mt, "t1");
Thread t2 = new Thread(mt, "t2");
Thread t3 = new Thread(mt, "t3");
Thread t4 = new Thread(mt, "t4");
Thread t5 = new Thread(mt, "t5");
Thread t6 = new Thread(mt, "t6");
t1.start();
t2.start();
t3.start();
t4.start();
t5.start();
t6.start();
}
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
public void run() {
synchronized (this) {
System.out.println(Thread.currentThread().getName());
}
}
}
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628171.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628171.gif)
vc+01rLatcS3vbeooaPOqsqyw7TSqr2r1fu49rbUz/O2vMnPy/ijrLb4srvUytDtxuTL+8/fs8y2zNTdtdjKudPDttTP89bQxuTL+82ssr23vbeowLS3w87KubLP7dfK1LSjv8jnufvSu7j2ttTP89O109C24Lj218rUtKOsvs2yu9Do0qrWu86qwcvIw9K7uPbP37PMyrnTw8bk1tDSu7K/t9bXytS0o6y+zb2ry/nT0M/fs8y2vMv41NrN4sPmoaPTydPaw7+49rbUz/O2vNPQy/ijrL/J0tTI58/Cy/nKvsq508PQ6cTittTP88C0yc/L+KO6PC9wPgo8cD4KIDwvcD4KCjxpbWcgaWQ9"Codehighlighter1_21_474_Open_Image" src="http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627166.gif" align="top" alt="\"> class FineGrainLock {
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
MyMemberClass x, y;
Object xlock = new Object(), ylock = new Object();
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
public void foo() {
synchronized(xlock) {
//access x here
}
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
//do something here - but don"t use shared resources
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
synchronized(ylock) {
//access y here
}
}
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
public void bar() {
synchronized(this) {
//access both x and y here
}
//do something here - but don"t use shared resources
}
}
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628171.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628171.gif)
class ArrayWithLockOrder{
private static long num_locks = 0;
private long lock_order;
private int[] arr;
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
public ArrayWithLockOrder(int[] a)
{
arr = a;
synchronized(ArrayWithLockOrder.class) {//-----这里
num_locks++; // 锁数加 1。
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
lock_order = num_locks; // 为此对象实例设置唯一的 lock_order。
}
}
public long lockOrder()
{
return lock_order;
}
public int[] array()
{
return arr;
}
}
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628171.gif)
class SomeClass implements Runnable
{
public int sumArrays(ArrayWithLockOrder a1,
ArrayWithLockOrder a2)
{
int value = 0;
ArrayWithLockOrder first = a1; // 保留数组引用的一个
ArrayWithLockOrder last = a2; // 本地副本。
int size = a1.array().length;
if (size == a2.array().length)
{
if (a1.lockOrder() > a2.lockOrder()) // 确定并设置对象的锁定
{ // 顺序。
first = a2;
last = a1;
}
synchronized(first) { // 按正确的顺序锁定对象。
synchronized(last) {
int[] arr1 = a1.array();
int[] arr2 = a2.array();
for (int i=0; i
value += arr1[i] + arr2[i];
}
}
}
return value;
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
}
public void run() {
//![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628172.gif)
}
}
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628171.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628171.gif)
在android开发中synchronized主要有四种用法。第一是在方法声明时使用;第二是在对某一代码块时使用;第三是对某一对象使用;第四是对某一类使用。具体的实现代码如下:
1.方法声明时使用
放在范围操作符(public等)之后,返回类型声明(void等)之前.这时,线程获得的是成员锁,即一次只能有一个线程进入该方法,其他线程要想在此时调用该方法,只能排队等候,当前线程(就是在synchronized方法内部的线程)执行完该方法后,别的线程才能进入.
例如:
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627166.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627168.gif)
2.对某一代码块使用
synchronized后跟括号,括号里是变量,这样,一次只有一个线程进入该代码块.此时,线程获得的是成员锁.例如:
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627166.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627169.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628170.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627168.gif)
3.对某一对象使用
synchronized后面括号里是一对象,此时,线程获得的是对象锁.例如:
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627166.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627169.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628170.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627169.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627169.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628170.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628170.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627168.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628171.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628171.gif)
![](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628171.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627169.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627169.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628170.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627169.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628170.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628170.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627169.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627169.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628170.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628170.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627168.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628171.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628171.gif)
4.对类使用时
synchronized后面括号里是类,此时,线程获得的是对象锁.例如:
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627166.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627169.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627169.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628170.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628170.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627169.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628170.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627169.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628170.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627168.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628171.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628171.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627166.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627169.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627169.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627169.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628170.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627169.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627169.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628170.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628170.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628170.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628170.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627169.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627167.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628172.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628170.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084627168.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628171.gif)
![\](http://www.2cto.com/uploadfile/Collfiles/20150207/20150207084628171.gif)
对于4,如果线程进入,则线程在该类中所有操作不能进行,包括静态变量和静态方法,实际上,对于含有静态方法和静态变量的代码块的同步,我们通常用4来加锁.
以上为synchronized的四种用法。
0 0
- android开发之synchronized的用法
- android开发之synchronized的用法
- android开发之synchronized的用法
- Android应用开发之synchronized
- java线程之synchronized的用法详解
- android synchronized 关键字用法
- Android synchronized用法
- Android synchronized用法一
- Android synchronized用法二
- Android synchronized用法
- android开发之AsyncTask的用法
- android开发之ToggleButton的用法实现
- android开发之interpolator的用法详解
- android开发之interpolator的用法详解
- android开发之interpolator的用法详解
- android开发之interpolator的用法详解
- android开发之interpolator的用法详解
- Android开发之AlarmManager的用法详解
- 转发重定向的区别
- 20个正则表达式
- [从头学声学] 第214节 声音的升频
- 优化Privoxy的打开和关闭
- 01.C++ STL简介
- android开发之synchronized的用法
- iOS中如何在欢迎界面中动态加载广告
- 重建二叉树
- servlet写的文件上传
- rtmp协议相关知识
- 启动Hbase,HMaster进程可以启动,但是HRegionServer启动不成功
- win 10 修改资源管理器默认打开为我的电脑
- alsa-utils工具的使用
- MyBatis结果映射与MyBatis缓存初探学习记录