ClassLoader類findLoadedClass()方法 (ClassLoader Class findLoadedClass() method)

• findLoadedClass() method is available in java.lang package.

  findLoadedClass()方法在java.lang包中可用。

• findLoadedClass() method is used to return the Class with the given binary class name when this loader has been recorded by JVM as initializing the loader of the class with that binary name.

  當JVM在使用該二進制名稱初始化類的加載器時記錄了該加載器時，將使用findLoadedClass()方法返回具有給定二進制類名稱的Class。

• findLoadedClass() method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.

  findLoadedClass()方法是一個非靜態方法，只能通過類對象訪問，如果嘗試使用類名稱訪問該方法，則會收到錯誤消息。

• findLoadedClass() method may throw an exception at the time of loading Class object.

  在加載Class對象時， findLoadedClass()方法可能會引發異常。

Syntax:

句法：

    protected Class findLoadedClass(String class_name);

Parameter(s):

參數：

• String class_name – represents the binary name of the class.

  字符串class_name –表示類的二進制名稱。

Return value:

返回值：

The return type of this method is Class, it returns Class object when the class has been recorded otherwise it returns null, when the class has not been recorded.

該方法的返回類型為Class ，當記錄了該類時，它將返回Class對象；否則，當未記錄該類時，它將返回null。

Example:

例：

// Java program to demonstrate the example 
// of Class findLoadedClass(String class_name)
// method of ClassLoader 
class FindLoadedClass extends ClassLoader {
void loadedClass() {
// It checks whether the given class is loaded
// or not by using the findLoadedClass()
Class cl1 = super.findLoadedClass("java.lang.String");
// If cl1 not null that means cl1 is loaded
// then don't need to load again
if (cl1 != null)
System.out.println(" Class already loaded!!!");
else
System.out.println("Ready to load the given class by using loadClass()!!!");
}
}
public class Main {
public static void main(String[] args) throws Exception {
// Creating an instance of FindLoadedClass
FindLoadedClass lc = new FindLoadedClass();
lc.loadedClass();
}
}

Output

輸出量

Ready to load the given class by using loadClass()!!!

翻譯自: https://www.includehelp.com/java/classloader-findloadedclass-method-with-example.aspx