描述
Java ThreadGroup toString()方法返回此线程组的字符串表示形式。
声明
以下内容是java.lang.ThreadGroup.toString()方法的声明
public String toString()
参数
无
返回值
此方法返回返回此线程组的字符串表示形式。
异常
无
示例 1
以下内容该示例显示了在单个 ThreadGroup 对象的情况下 ThreadGroup toString() 方法的用法。我们创建了一个 ThreadGroup 对象并为其分配了一个名称。然后我们使用之前创建的线程组对象创建了两个线程。使用 toString() 方法，我们获取线程组对象的字符串表示形式。
package com.yxjc123;
public class ThreadGroupDemo implements Runnable {
public static void main(String[] args) {
ThreadGroupDemo tg = new ThreadGroupDemo();
tg.start();
}
public void start() {
try {
//创建一个ThreadGroup
ThreadGroup threadGroup = new ThreadGroup("ThreadGroup");
//创建一个线程
Thread t1 = new Thread(threadGroup, this);
System.out.println("Starting " + t1.toString() + "...");
t1.start();
//创建另一个线程
Thread t2 = new Thread(threadGroup, this);
System.out.println("Starting " + t2.toString() + "...");
t2.start();
//返回线程组的字符串表示
System.out.println("String representation of threadGroup = " + threadGroup.toString());
// 阻塞直到其他线程完成
t1.join();
t2.join();
} catch (InterruptedException ex) {
System.out.println(ex.toString());
}
}
// 实现 run()
public void run() {
for(int i = 0; i < 4;i++) {
i++;
try {
Thread.sleep(50);
} catch (InterruptedException e) {
// TODO 自动生成的 catch 块
e.printStackTrace();
}
}
System.out.println(Thread.currentThread().toString() + " finished executing.");
}
}
输出
让我们编译并运行上面的程序，这将产生以下结果−
Starting Thread[Thread-0,5,ThreadGroup]...
Starting Thread[Thread-1,5,ThreadGroup]...
String representation of threadGroup = java.lang.ThreadGroup[name=ThreadGroup,maxpri=10]
Thread[Thread-1,5,ThreadGroup] finished executing.
Thread[Thread-0,5,ThreadGroup] finished executing.
示例 2
以下示例显示了在多个 ThreadGroup 对象的情况下 ThreadGroup toString() 方法的用法。我们创建了一个 ThreadGroup 对象并为其分配了一个名称。接下来，我们创建了一个子 ThreadGroup 对象。然后我们使用之前创建的线程组对象创建了两个线程。使用 toString() 方法，我们打印每个线程组对象的字符串表示形式。
package com.yxjc123;
public class ThreadGroupDemo implements Runnable {
public static void main(String[] args) {
ThreadGroupDemo tg = new ThreadGroupDemo();
tg.start();
}
public void start() {
try {
//创建父ThreadGroup
ThreadGroup pThreadGroup = new ThreadGroup("parent ThreadGroup");
//为父ThreadGroup创建子ThreadGroup
ThreadGroup cThreadGroup = new ThreadGroup(pThreadGroup, "child ThreadGroup");
//创建一个线程
Thread t1 = new Thread(pThreadGroup, this);
System.out.println("Starting " + t1.toString() + "...");
t1.start();
//创建另一个线程
Thread t2 = new Thread(cThreadGroup, this);
System.out.println("Starting " + t2.toString() + "...");
t2.start();
//返回线程组的字符串表示形式
System.out.println("String representation of pThreadGroup = " + pThreadGroup.toString());
System.out.println("String representation of cThreadGroup = " + cThreadGroup.toString());
// 阻塞直到其他线程完成
t1.join();
t2.join();
} catch (InterruptedException ex) {
System.out.println(ex.toString());
}
}
// 实现 run()
public void run() {
for(int i = 0; i < 4;i++) {
i++;
try {
Thread.sleep(50);
} catch (InterruptedException e) {
// TODO 自动生成的 catch 块
e.printStackTrace();
}
}
System.out.println(Thread.currentThread().toString() + " finished executing.");
}
}
输出
让我们编译并运行上面的程序，这将产生以下结果 -
Starting Thread[Thread-0,5,parent ThreadGroup]...
Starting Thread[Thread-1,5,child ThreadGroup]...
String representation of pThreadGroup = java.lang.ThreadGroup[name=parent ThreadGroup,maxpri=10]
String representation of cThreadGroup = java.lang.ThreadGroup[name=child ThreadGroup,maxpri=10]
Thread[Thread-1,5,child ThreadGroup] finished executing.
Thread[Thread-0,5,parent ThreadGroup] finished executing.
示例 3
以下示例显示了 ThreadGroup toString() 方法在子 ThreadGroup 和孙 ThreadGroup 对象的情况下的用法。我们创建了一个 ThreadGroup 对象并为其分配了一个名称。接下来，我们创建了一个子 ThreadGroup 对象。然后，我们使用之前创建的子线程组对象和孙线程组对象创建了两个线程。使用 toString() 方法，我们打印每个线程组对象的字符串表示形式。
package com.yxjc123;
public class ThreadGroupDemo implements Runnable {
public static void main(String[] args) {
ThreadGroupDemo tg = new ThreadGroupDemo();
tg.start();
}
public void start() {
try {
//创建父ThreadGroup
ThreadGroup pThreadGroup = new ThreadGroup("Parent ThreadGroup");
//为父ThreadGroup创建子ThreadGroup
ThreadGroup cThreadGroup = new ThreadGroup(pThreadGroup, "Child ThreadGroup");
//为父ThreadGroup创建孙ThreadGroup
ThreadGroup gThreadGroup = new ThreadGroup(cThreadGroup, "GrandChild ThreadGroup");
//创建一个线程
Thread t1 = new Thread(cThreadGroup, this);
System.out.println("Starting " + t1.toString() + "...");
t1.start();
//创建另一个线程
Thread t2 = new Thread(gThreadGroup, this);
System.out.println("Starting " + t2.toString() + "...");
t2.start();
//返回线程组的字符串表示形式
System.out.println("String representation of pThreadGroup = " + pThreadGroup.toString());
System.out.println("String representation of cThreadGroup = " + cThreadGroup.toString());
System.out.println("String representation of gThreadGroup = " + gThreadGroup.toString());
// 阻塞直到其他线程完成
t1.join();
t2.join();
} catch (InterruptedException ex) {
System.out.println(ex.toString());
}
}
// 实现 run()
public void run() {
for(int i = 0; i < 4;i++) {
i++;
try {
Thread.sleep(50);
} catch (InterruptedException e) {
// TODO 自动生成的 catch 块
e.printStackTrace();
}
}
System.out.println(Thread.currentThread().toString() + " finished executing.");
}
}
输出
让我们编译并运行上面的程序，这将产生以下结果 -
Starting Thread[Thread-0,5,Child ThreadGroup]...
Starting Thread[Thread-1,5,GrandChild ThreadGroup]...
String representation of pThreadGroup = java.lang.ThreadGroup[name=Parent ThreadGroup,maxpri=10]
String representation of cThreadGroup = java.lang.ThreadGroup[name=Child ThreadGroup,maxpri=10]
String representation of gThreadGroup = java.lang.ThreadGroup[name=GrandChild ThreadGroup,maxpri=10]
Thread[Thread-0,5,Child ThreadGroup] finished executing.
Thread[Thread-1,5,GrandChild ThreadGroup] finished executing.