Java Method类 getDeclaringClass()用法及代码示例

Method类的java.lang.reflect.Method.getDeclaringClass()方法返回该类或接口的Class对象，该对象定义了我们应用此getDeclaringClass()方法的方法。

用法:

public Class<?> getDeclaringClass()

返回值：此方法返回在其中声明方法的Class对象。

以下示例程序旨在说明Method类的getDeclaringClass()方法：

程序1:通过应用getDeclaringClass()方法来查找定义该方法的Object类的详细信息。

在下面的程序中，创建了带有某些方法的Demo类。创建类对象后，通过调用类对象的getMethods()函数来创建方法对象的列表。然后，它们遍历列表，并打印每个方法的声明类的详细信息。
该程序的输出还显示除类对象中定义的方法以外的方法对象的结果，例如，wait，equals，toString，hashCode，getClass，notify和notifyAll。这些方法是按类对象从java.lang包的超类对象继承的。

// Program Demonstrate getDeclaringClass() method 
// of Method Class. 
  
import java.lang.reflect.Method; 
  
// sample class containing some method 
class GFGDemoClass { 
  
    // create attributes 
    private String field1; 
    private String field2; 
  
    // create methods 
    public String getField1() 
    { 
        return field1; 
    } 
    public void setField1(String field1) 
    { 
        this.field1 = field1; 
    } 
    public String getField2() 
    { 
        return field2; 
    } 
    public void setField2(String field2) 
    { 
        this.field2 = field2; 
    } 
} 
  
// class containing the Main method 
public class GFG { 
    public static void main(String[] args) 
    { 
  
        // get array Method objects of GFGDemoClass 
        Method[] methods = GFGDemoClass.class.getMethods(); 
  
        // print getDeclaringclass for every Method object 
        // looping through a list of method objects 
        for (Method m:methods) { 
  
            // get a class object which declares the current method 
            // by declaringClass() method 
            Class declaringClass = m.getDeclaringClass(); 
  
            // print Method name and class name 
            System.out.println("Method Name:" + m.getName()); 
            System.out.println("Declaring class Name:"
                               + declaringClass.getName()); 
        } 
    } 
}

输出：

Method Name:getField1
Declaring class Name:GFGDemoClass
Method Name:setField1
Declaring class Name:GFGDemoClass
Method Name:getField2
Declaring class Name:GFGDemoClass
Method Name:setField2
Declaring class Name:GFGDemoClass
Method Name:wait
Declaring class Name:java.lang.Object
Method Name:wait
Declaring class Name:java.lang.Object
Method Name:wait
Declaring class Name:java.lang.Object
Method Name:equals
Declaring class Name:java.lang.Object
Method Name:toString
Declaring class Name:java.lang.Object
Method Name:hashCode
Declaring class Name:java.lang.Object
Method Name:getClass
Declaring class Name:java.lang.Object
Method Name:notify
Declaring class Name:java.lang.Object
Method Name:notifyAll
Declaring class Name:java.lang.Object

程序2:通过应用getDeclaringClass()方法来查找Object类方法的详细信息。

// Program Demonstrate getDeclaringClass() method 
// of Method Class. 
  
import java.lang.reflect.Method; 
  
// sample class containing some method 
class BasicOperations { 
  
    // create attributes 
    int a; 
    int b; 
  
    // create methods 
    public int add() 
    { 
        return a + b; 
    } 
  
    public int multiply() 
    { 
        return a * b; 
    } 
  
    public int subtract() 
    { 
        return a - b; 
    } 
  
    public int division() 
    { 
        return a / b; 
    } 
} 
  
public class GFG { 
    public static void main(String[] args) 
    { 
  
        // get array Method objects 
        Method[] methods = BasicOperations.class.getMethods(); 
  
        // print getDeclaringclass for every Method object 
        for (Method m:methods) { 
  
            // get class object by declaringClass() method 
            Class declaringClass = m.getDeclaringClass(); 
  
            // checks whether the method belong to 
            // BasicOperations class or not 
            // and if yes then print method name 
            // along with declaring class name. 
            if (declaringClass.getName().equals("BasicOperations")) { 
  
                // print Method name and class name 
                System.out.println("Method Name:" + m.getName()); 
                System.out.println("Declaring class Name:"
                                   + declaringClass.getName()); 
            } 
        } 
    } 
}

输出：

Method Name:multiply
Declaring class Name:BasicOperations
Method Name:subtract
Declaring class Name:BasicOperations
Method Name:division
Declaring class Name:BasicOperations
Method Name:add
Declaring class Name:BasicOperations

参考： https://docs.oracle.com/javase/8/docs/api/java/lang/reflect/Method.html#getDeclaringClass-

相关用法

注：本文由纯净天空筛选整理自AmanSingh2210大神的英文原创作品 Method Class | getDeclaringClass() method in Java。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。