对Java并发常见的工具类进行从使用到原理的详解,
包括CAS+AQS+ThreadLocal+ConcurrentHashMap+线程池+各种锁+并发综合实战项目
下载:链接:https://pan.baidu.com/s/1u6xXLnNUd7jBqw7dxoymeQ
提取码:9voy
package threadlocal; import java.text.SimpleDateFormat; import java.util.Date; /** * 描述: 两个线程打印日期 */ public class ThreadLocalNormalUsage00 { public static void main(String[] args) { new Thread(new Runnable() { @Override public void run() { String date = new ThreadLocalNormalUsage00().date(10); System.out.println(date); } }).start(); new Thread(new Runnable() { @Override public void run() { String date = new ThreadLocalNormalUsage00().date(104707); System.out.println(date); } }).start(); } public String date(int seconds) { //参数的单位是毫秒,从1970.1.1 00:00:00 GMT计时 Date date = new Date(1000 * seconds); SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); return dateFormat.format(date); } }
下载:链接:https://pan.baidu.com/s/1u6xXLnNUd7jBqw7dxoymeQ
提取码:9voy
package threadlocal; import java.text.SimpleDateFormat; import java.util.Date; /** * 描述: 10个线程打印日期 */ public class ThreadLocalNormalUsage01 { public static void main(String[] args) throws InterruptedException { for (int i = 0; i < 30; i++) { int finalI = i; new Thread(new Runnable() { @Override public void run() { String date = new ThreadLocalNormalUsage01().date(finalI); System.out.println(date); } }).start(); Thread.sleep(100); } } public String date(int seconds) { //参数的单位是毫秒,从1970.1.1 00:00:00 GMT计时 Date date = new Date(1000 * seconds); SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); return dateFormat.format(date); } }
package threadlocal; import java.text.SimpleDateFormat; import java.util.Date; import java.util.concurrent.Executor; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; /** * 描述: 1000个打印日期的任务,用线程池来执行 */ public class ThreadLocalNormalUsage02 { public static ExecutorService threadPool = Executors.newFixedThreadPool(10); public static void main(String[] args) throws InterruptedException { for (int i = 0; i < 1000; i++) { int finalI = i; threadPool.submit(new Runnable() { @Override public void run() { String date = new ThreadLocalNormalUsage02().date(finalI); System.out.println(date); } }); } threadPool.shutdown(); } public String date(int seconds) { //参数的单位是毫秒,从1970.1.1 00:00:00 GMT计时 Date date = new Date(1000 * seconds); SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); return dateFormat.format(date); } }
package threadlocal; import java.text.SimpleDateFormat; import java.util.Date; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; /** * 描述: 加锁来解决线程安全问题 */ public class ThreadLocalNormalUsage04 { public static ExecutorService threadPool = Executors.newFixedThreadPool(10); static SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); public static void main(String[] args) throws InterruptedException { for (int i = 0; i < 1000; i++) { int finalI = i; threadPool.submit(new Runnable() { @Override public void run() { String date = new ThreadLocalNormalUsage04().date(finalI); System.out.println(date); } }); } threadPool.shutdown(); } public String date(int seconds) { //参数的单位是毫秒,从1970.1.1 00:00:00 GMT计时 Date date = new Date(1000 * seconds); String s = null; synchronized (ThreadLocalNormalUsage04.class) { s = dateFormat.format(date); } return s; } }
package threadlocal; import java.text.SimpleDateFormat; import java.util.Date; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; /** * 描述: 利用ThreadLocal,给每个线程分配自己的dateFormat对象,保证了线程安全,高效利用内存 */ public class ThreadLocalNormalUsage05 { public static ExecutorService threadPool = Executors.newFixedThreadPool(10); public static void main(String[] args) throws InterruptedException { for (int i = 0; i < 1000; i++) { int finalI = i; threadPool.submit(new Runnable() { @Override public void run() { String date = new ThreadLocalNormalUsage05().date(finalI); System.out.println(date); } }); } threadPool.shutdown(); } public String date(int seconds) { //参数的单位是毫秒,从1970.1.1 00:00:00 GMT计时 Date date = new Date(1000 * seconds); // SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); SimpleDateFormat dateFormat = ThreadSafeFormatter.dateFormatThreadLocal2.get(); return dateFormat.format(date); } } class ThreadSafeFormatter { public static ThreadLocal<SimpleDateFormat> dateFormatThreadLocal = new ThreadLocal<SimpleDateFormat>() { @Override protected SimpleDateFormat initialValue() { return new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); } }; public static ThreadLocal<SimpleDateFormat> dateFormatThreadLocal2 = ThreadLocal .withInitial(() -> new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")); }
package threadlocal; /** * 描述: 演示ThreadLocal用法2:避免传递参数的麻烦 */ public class ThreadLocalNormalUsage06 { public static void main(String[] args) { new Service1().process(""); } } class Service1 { public void process(String name) { User user = new User("超哥"); UserContextHolder.holder.set(user); new Service2().process(); } } class Service2 { public void process() { User user = UserContextHolder.holder.get(); ThreadSafeFormatter.dateFormatThreadLocal.get(); System.out.println("Service2拿到用户名:" + user.name); new Service3().process(); } } class Service3 { public void process() { User user = UserContextHolder.holder.get(); System.out.println("Service3拿到用户名:" + user.name); UserContextHolder.holder.remove(); } } class UserContextHolder { public static ThreadLocal<User> holder = new ThreadLocal<>(); } class User { String name; public User(String name) { this.name = name; } }
下载:链接:https://pan.baidu.com/s/1u6xXLnNUd7jBqw7dxoymeQ
提取码:9voy