如何从java中的命令行对姓氏进行排序

Question

我正在尝试编写一个程序，该程序按照姓氏排序，并在应用“排序”条件时输入名字。输入将从命令行提供。我已经开始这种方式，但不知道如何使其工作。

输入：排序 “约翰主”， “抢班”， “鲍勃·公羊”

输出：类，抢主，约翰RAM，BOB

public static void main(String[] args) 
{ 
    String[] args_name = new String[args.length-1]; 
    System.arraycopy(args, 1, args_name, 0, args.length-1); 

    if(args[0].equals("sort")) 
    { 
     String firstName = name.substring(args_name,name.indexOf(" ")); 
     String lastName = name.substring(name.indexOf(" ")+1); 
     String slst = lastName + ", " + firstName; 

     Arrays.sort(slst); 

     for (String s: slst) System.out.print(s); 
    } 
} 

Answer 1

尝试使用比较排序您的输入。为了简单起见，我删除了您的参数相关的代码。您仍然需要重新正确添加它。

所需导入

import java.util.ArrayList; 
import java.util.Arrays; 
import java.util.Comparator; 
import java.util.List; 

的名称

class Name{ 
    public static final String FULL_NAME_DELIMITER = " "; 
    public static final String PRINT_DELIMITER = ", "; 

    private String firstName; 
    private String lastName; 

    public Name(String firstName, String lastName){ 
     this.firstName = firstName; 
     this.lastName = lastName; 
    } 

    public static String[] getName(String fullName){ 
     return fullName.split(FULL_NAME_DELIMITER); 
    } 

    public String getLastName(){ 
     return this.lastName; 
    } 

    @Override 
    public String toString(){ 
     return String.join(PRINT_DELIMITER , this.lastName, this.firstName); 
    } 

    public void print(){ 
     System.out.println(this); 
    } 
} 

的比较

class NameComparator implements Comparator<Name>{ 
    @Override 
    public int compare(Name a, Name b) { 
     return a.getLastName().compareTo(b.getLastName()); // ASC: a to b or DESC: b to a 
    } 
} 

使用

public class Main { 
    // Holds the sorted names 
    private static List<Name> names = new ArrayList<>(); 

    public static void main(String[] args) { 
     // The input names 
     String[] input = new String[]{ 
       "john main", 
       "rob class", 
       "bob ram" 
     }; 

     // Prepare list for sorting 
     String firstName; 
     String lastName; 
     String[] completeName; 

     for (String fullName : input) { 
      completeName = Name.getName(fullName); 
      firstName = completeName[0]; 
      lastName = completeName[1]; 
      names.add(new Name(firstName, lastName)); 
     } 

     // Actually sort 
     names.sort(new NameComparator()); 

     // Print 
     names.forEach(System.out::println); 
    } 
} 

---

编辑

要在命令行中使用的输入，在ARGS参数是要使用的东西。

与命令行输入使用

public class Main { 
    // Holds the sorted names 
    private static List<Name> names = new ArrayList<>(); 

    public static void main(String[] args) { 
     // The method (in case something else than "sort" is desired) 
     String method = args[0]; 

     // Check for valid method 
     if(!method.equals("sort")) return; 

     // The input names 
     String[] input = Arrays.copyOfRange(args, 1, args.length); 

     // Prepare list for sorting 
     String firstName; 
     String lastName; 
     String[] completeName; 

     for (String fullName : input) { 
      completeName = Name.getName(fullName); 
      firstName = completeName[0]; 
      lastName = completeName[1]; 
      names.add(new Name(firstName, lastName)); 
     } 

     // Actually sort 
     names.sort(new NameComparator()); 

     // Print 
     names.forEach(System.out::println); 
    } 
} 

---

EDIT 2

要使用的第一个名字，而不是姓氏，只是改变比较。

class NameComparator implements Comparator<Name>{ 
    @Override 
    public int compare(Name a, Name b) { 
     return a.getFirstName().compareTo(b.getFirstName()); // ASC: a to b or DESC: b to a 
    } 
} 

当然，你需要调整名称类以及通过增加：

public String getFirstName(){ 
    return this.firstName; 
} 

Answer 2

如果我明白你的问题以及这里是我的代码，解决这个问题

public static void shortName(String shortName){ 

    System.out.println("please enter yout name : "); 
    Scanner scanner = new Scanner(System.in); 
    String fullName = scanner.nextLine(); 

    if(shortName.equals("sort")){ 
     String [] nameArr = fullName.split(" "); 
     int lastNameIndex = nameArr.length - 1; 
     String name = nameArr[0] +" "+ nameArr[lastNameIndex]; 
     System.out.println("welcome : "+name); 
    } 
    else { 
     System.out.println("welcome : "+fullName); 

    } 

} 
public static void main(String[] args) { 

    shortName("sort"); 
}