如何在另一個類中使用一個類的字符串值？

Question

我對Java很新，希望有些幫助！當我編譯/運行「Driver.java」時，它會要求用戶鍵入他們的名字。而程序應該做的就是將這個名字傳遞給「Greeter.java」中的類以打印出最終的消息。

我想實現一個接受字符串參數的構造函數，表示我的程序正在問候的人的名字。我必須使用此參數來初始化我在「Greeter」類中聲明的私有實例變量。這是我卡住了，但這裏是我到目前爲止有：

這裏是我的 「Driver.java」：

import java.util.Scanner; 

public class Driver 
{ 
    public static void main(String[] args) 
    { 
     Scanner scanner = new Scanner(System.in); 
     System.out.print("What is your name? "); 
     String name = scanner.nextLine(); 
     Greeter greeter = new Greeter(name); 
     String greeting = greeter.greet(); 
     System.out.println(greeting); 
    } 
} 

這是我的Greeter.java：

public class Greeter 
{ 
    String inputName; (This is where I got stuck) 

    public string greet() 
    { 
     return "Hello " + inputName; 
    } 

}

Answer 1

您缺少構造函數

嘗試

public class Greeter 
{ 
    String inputName; 

    public Greeter (String inputName) { 
    this.inputName = inputName; 
    } 

    public String greet() 
    { 
     return "Hello " + inputName; 
    } 
} 

Answer 2

改變你Greeter類。

public class Greeter{ 
    private String inputName;  

    public Greeter(){ 

    } 

    public Greeter (String inputName) { 
    this.inputName = inputName; 
    } 

    public String greet() 
    { 
     return "Hello " + inputName; 
    } 

} 

Answer 3

你需要做的構造函數，將採取的論點，即會在主類中使用：

public Greeter (String inputName) { // constructor with parameter that ll be called when Greeter's instance ll be created. 
    this.inputName = inputName; 
} 

在任何地方Greeter greeter = new Greeter(字符串「）; will be called then inputName`變量會被初始化

所以每當你使用參數構造函數創建類的實例時，它都會初始化inputName變量。

public class Driver 
{ 
    public static void main(String[] args) 
    { 
     Scanner scanner = new Scanner(System.in); 
     System.out.print("What is your name? "); 
     String name = scanner.nextLine(); 
     Greeter greeter = new Greeter(name); 
     String greeting = greeter.greet(); 
     System.out.println(greeting); 
    } 
} 

Answer 4

Greeter greeter = new Greeter(name); 

要做到這一點，你需要它接受一個String變量作爲輸入參數在Greeter類

public class Greeter { 
String inputName; 

public Greeter(String inputName) { // matching constructor 
    this.inputName = inputName; 
} 

public String greet() { 
    return "Hello " + inputName; 
} 
} 

Answer 5

經過以下代碼構造，

public class Greeter { 

    private String name; 

    public Greeter() { } 

    public Greeter(String name) { 
     this.name = name; 
    } 

    public String getName() { 
     return name; 
    } 

    public void setName(String name) { 
     this.name = name; 
    } 

    public String greet(){ 
     return "Hello "+ getName(); 
    } 

}

public class Driver { 

    public static void main(String[] args) { 

     Scanner input = new Scanner(System.in); 
     System.out.print("Enter your name : "); 
     Greeter greeter = new Greeter(input.nextLine()); 
     System.out.println(greeter.greet()); 

    } 

}

祝你好運!!!