Java 中的方法类| isDefault()方法
原文:https://www . geesforgeks . org/method-class-is default-method-in-Java/
Java . lang . reflect. Method . isdefault()方法用于检查 Method 对象的方法是否为默认方法:。如果方法对象是默认方法，则返回 true，否则返回 false。
默认方法:一种公共的非抽象静态方法，其主体在接口类型中声明。
语法:
public boolean isDefault()
返回值:该方法返回一个布尔值。如果方法对象是 JVM 规范的默认方法，则返回真，否则返回假。
下面的程序说明了方法类的 isDefault()方法:
例 1:
/*
* Program Demonstrate isDefault() method
* of Method Class.
*/
import java.lang.reflect.Method;
public class GFG {
// create main method
public static void main(String args[])
{
try {
// create class object for interface Shape
Class c = Shape.class;
// get list of Method object
Method[] methods = c.getMethods();
// print Default Methods
for (Method m : methods) {
// check whether the method is Default Method or not
if (m.isDefault())
// Print
System.out.println("Method: "
+ m.getName()
+ " is Default Method");
}
}
catch (Exception e) {
e.printStackTrace();
}
}
private interface Shape {
default int
draw()
{
return 0;
}
void paint();
}
}
Output:
Method: draw is Default Method
例 2:
/*
* Program Demonstrate isDefault() method
* of Method Class.
* This program checks all default method in Comparator interface
*/
import java.lang.reflect.Method;
import java.util.Comparator;
public class Main6 {
// create main method
public static void main(String args[])
{
try {
// create class object for Interface Comparator
Class c = Comparator.class;
// get list of Method object
Method[] methods = c.getMethods();
System.out.println("Default Methods of Comparator Interface");
for (Method method : methods) {
// check whether method is Default Method or not
if (method.isDefault())
// print Method name
System.out.println(method.getName());
}
}
catch (Exception e) {
e.printStackTrace();
}
}
}
Output:
Default Methods of Comparator Interface
reversed
thenComparing
thenComparing
thenComparing
thenComparingInt
thenComparingLong
thenComparingDouble
参考: https://docs . Oracle . com/javase/8/docs/API/Java/lang/reflect/method . html # isDefault–
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