全网最细笔记java与kotlin的一些异同

本文主要介绍java与kotlin的一些异同

后面可能还会继续比较kotlin和dart 期待吗？

打印日志

• Java

System.out.print("Amit Shekhar");
System.out.println("Amit Shekhar");

• Kotlin

print("Amit Shekhar")
println("Amit Shekhar")

常量与变量

• Java

String name = "Amit Shekhar";
final String name = "Amit Shekhar";

• Kotlin

var name = "Amit Shekhar"
val name = "Amit Shekhar"

null声明

• Java

String otherName;
otherName = null;

• Kotlin

var otherName : String?
otherName = null

空判断

• Java

if (text != null) {
    int length = text.length();
}

• Kotlin

text?.let {
    val length = text.length
}
// or simply
val length = text?.length

字符串拼接

• Java

String firstName = "Amit";
String lastName = "Shekhar";
String message = "My name is: " + firstName + " " + lastName;

• Kotlin

val firstName = "Amit"
val lastName = "Shekhar"
val message = "My name is: $firstName $lastName"

换行

• Java

String text = "First Line\n" +
              "Second Line\n" +
              "Third Line";

• Kotlin

val text = """
        |First Line
        |Second Line
        |Third Line
        """.trimMargin()

三元表达式

• Java

String text = x > 5 ? "x > 5" : "x  5"
           else "x