Java线程类void setContextClassLoader（ClassLoader loader）方法，带示例

线程类void setContextClassLoader(ClassLoader loader) (Thread Class void setContextClassLoader(ClassLoader loader))

This method is available in package java.lang.Thread.setContextClassLoader(ClassLoader loader).
软件包java.lang.Thread.setContextClassLoader(ClassLoader loader)中提供了此方法。
This method is used to sets the context ClassLoader for this(Current)Thread.
此方法用于为此(当前)线程设置上下文ClassLoader。
The context ClassLoader can be set at the time of thread creation by which thread creator could access the thread and provide appropriate the class loader to code run in the program at the time of class loading.
可以在创建线程时设置上下文ClassLoader，通过该上下文，线程创建者可以访问线程并提供适当的类加载器，以在类加载时在程序中运行代码。
This method is not static so this method is accessible with Thread class object it is not accessible with the class name.
此方法不是静态的，因此该方法可通过Thread类对象访问，而无法通过类名称访问。
The return type of this method is void so it does not return anything.
此方法的返回类型为void，因此它不返回任何内容。
This method raises an exception (SecurityException) if this thread could not set the context ClassLoader.
如果此线程无法设置上下文ClassLoader，则此方法引发异常(SecurityException)。

Syntax:

句法：

    void setContextClassLoader(ClassLoader loader){
}

Parameter(s):

参数：

We pass only one object as a parameter in the method of the Thread and the parameter is the context ClassLoader for this thread.

我们仅在Thread方法中传递一个对象作为参数，并且该参数是该线程的上下文ClassLoader。

Return value:

返回值：

The return type of this method is void, it does not return anything.

此方法的返回类型为void ，它不返回任何内容。

Java程序演示setContextClassLoader()方法的示例 (Java program to demonstrate example of setContextClassLoader() method)

/*  We will use Thread class methods so we are importing 
the package but it is not mandate because 
it is imported by default
*/
import java.lang.Thread;
class SetContextClassLoader extends Thread {
// Override run() of Thread class
public void run() {
//Display a message for the end user 	
System.out.println("The name of this thread is " + " " + Thread.currentThread().getName());
}
public static void main(String[] args) {
// Creating an object of SetContextClassLoader class
SetContextClassLoader ccl = new SetContextClassLoader();
// Creating an object of Thread class
Thread th = new Thread(ccl);
// Thread class start() method will call and it will ultimately 
th.start();
// getContextClassLoader() will return context ClassLoader 
// and create a reference of ClassLoader
ClassLoader cl = th.getContextClassLoader();
// By using setContextClassLoader(ClassLoader cl) sets 
// the context ClassLoader for this thread th
th.setContextClassLoader(cl);
System.out.println("The Context ClassLoader for this thread th is = " + cl);
System.out.println("The Parent of the ClassLoader is = " + cl.getParent());
System.out.println("The Class of the ClassLoader is = " + cl.getClass());
}
}

Output

输出量

E:\Programs>javac SetContextClassLoader.java
E:\Programs>java SetContextClassLoader
The Context ClassLoader for this thread th is = [email protected]
The name of this thread is  Thread-1
The Parent of the ClassLoader is = [email protected]
The Class of the ClassLoader is = class sun.misc.Launcher$AppClassLoader