Java 확장 메서드를 만드는 방법

/// 扩展方法
public static class ExpandMethod {
    /// 两个数相加
    public static int Sum(this int num,int num2) {
        return num + num2;
    }
}
public class Program {
    static void Main(string[] args) {
        /// 调用位置
        Console.WriteLine(3.Sum(2));
    }
}

Imports System.Runtime.CompilerServices
Module Module3
    Sub Main()
        Dim ex As New ExampleClass
        ' 调用位置
        ex.ExampleMethod("Extension method")
    End Sub 
    Class ExampleClass
        ' Define an instance method named ExampleMethod. 
        Public Sub ExampleMethod()
            Console.WriteLine("Instance method")
        End Sub 
    End Class
    <Extension()> 
    Sub ExampleMethod(ByVal ec As ExampleClass, 
            ByVal stringParameter As String)
        Console.WriteLine(stringParameter)
    End Sub 
End Module

// 扩展函数(本类中扩展方法)
class Test1 {
    var name: String = "boyi.chen"
}
fun Test1.temp() {
    println("增加扩展函数,打印扩展类的属性name=${this.name}")
}
fun main(args: Array<String>) {
    // 调用位置
    Test1().temp()
}

/**
 * lombok测试
 *
 * @author reboot
 */
@ExtensionMethod(StringUtil.class)
public class LombokTest {
    public static void main(String[] args) {
        System.out.println("".isBlank());
    }
    /**
     * 字符串工具
     *
     * @author reboot
     */
    public static class StringUtil {
        /**
         * 字符串判空
         *
         * @param targetStr 目标str
         * @return boolean
         */
        public static boolean isBlank(String targetStr) {
            return targetStr == null || "".equals(targetStr);
        }
    }
}