java - 扫描仪在给出最终输出之前请求多个输入

Question

所以我是 Java 新手，正在尝试将变量从扫描仪传递到我的 getter/setter 方法，以便根据输入的数字对数组进行不同的排序。

我已经知道了列表的排序位置；问题是我的扫描仪会重复，您必须多次输入您的选择才能显示列表。

我知道问题与调用“int c = allocate_6.choice()”有关。如果我硬编码一个数字，那没问题，但它似乎对 choice() 函数进行了多次调用。

我尝试将函数移出主函数，并删除 setter/getter 文件中的 Comparable，还删除快速排序并使用数组和集合。这些都不起作用。
我觉得这可能是我犯的一个愚蠢的错误，并且由于不太了解 Java 而错过了它。可以使用帮助来解决这个问题。

这是我的输出:

nter number 1,2 or 3: 1
Enter number 1,2 or 3: 1
Enter number 1,2 or 3: 1
Enter number 1,2 or 3: 1
Enter number 1,2 or 3: 1
Enter number 1,2 or 3: 1
Enter number 1,2 or 3: 1
Enter number 1,2 or 3: 1
Enter number 1,2 or 3: 1
Enter number 1,2 or 3: 1
contacts [age=20, state=Alabama, firstname=Pickles, lastname=Cattle]
contacts [age=35, state=New York, firstname=George, lastname=Constanza]
contacts [age=90, state=Florida, firstname=Adam, lastname=Tree]
contacts [age=32, state=Illinois, firstname=Mary, lastname=Upton]
contacts [age=58, state=Washington, firstname=Bob, lastname=Wiseman]

代码:

    import java.util.Scanner;

public class test_6 {

    public static void main(String[] args) {


        Contacts[] a = {
                new Contacts(32, "Illinois", "Mary", "Upton"),
                new Contacts(58, "Washington", "Bob", "Wiseman"),
                new Contacts(20, "Alabama", "Pickles", "Cattle"),
                new Contacts(35, "New York", "George", "Constanza"),
                new Contacts(90, "Florida", "Adam", "Tree"),
                };

        Quick.sort(a);
        for (Contacts contacts:a){
            System.out.println(contacts);
        }
    }

    public static int choice() {
        System.out.print("Enter number 1,2 or 3: ");
        Scanner sc = new Scanner(System.in);
        int i = sc.nextInt();
        return i;
    }
}

    public class Contacts implements Comparable<Contacts>{

    Integer age;
    String state;
    String firstname;
    String lastname;
    int c = test_6.choice();

    public Contacts(Integer age, String state, String firstname, String lastname){
        this.age = age;
        this.state = state;
        this.firstname = firstname;
        this.lastname = lastname;
    }
    public Integer getAge() {
        return age;
    }
    public void setAge(Integer age) {
        this.age = age;
    }
    public String getState() {
        return state;
    }
    public void setState(String state) {
        this.state = state;
    }
    public String getFirstname() {
        return firstname;
    }
    public void setFirstname(String firstname) {
        this.firstname = firstname;
    }
    public String getLastname() {
        return lastname;
    }
    public void setLastname(String lastname) {
        this.lastname = lastname;
    }
        public int compareTo(Contacts contacts) {

            if (c == 1){
                return this.getLastname().compareTo(contacts.getLastname());
            }
            else if (c == 2){
                return this.getState().compareTo(contacts.getState());
            }
            else if (c == 3){
                return this.getAge().compareTo(contacts.getAge());
            }
            else return 0;

        }
        @Override
        public String toString() {
            return "contacts [age=" + age + ", state=" + state + ", firstname=" + firstname + ", lastname=" + lastname
                    + "]";
        }
}

Answer 1

我不完全确定，您可以调试，但这可能与在全局范围内分配您的函数有关。您最好将静态函数 choice() 移动到您的 Contacts 类/对象中。

然后从初始化器 Contacts 内部调用 choice() 函数。例如:

import java.util.Scanner;

public class test_6 {

    public static void main(String[] args) {


        Contacts[] a = {
                new Contacts(32, "Illinois", "Mary", "Upton"),
                new Contacts(58, "Washington", "Bob", "Wiseman"),
                new Contacts(20, "Alabama", "Pickles", "Cattle"),
                new Contacts(35, "New York", "George", "Constanza"),
                new Contacts(90, "Florida", "Adam", "Tree"),
                };

        Quick.sort(a);
        for (Contacts contacts:a){
            System.out.println(contacts);
        }
    }

    //Function Choice Moved to Contacts.choice()
}

    public class Contacts implements Comparable<Contacts>{

    Integer age;
    String state;
    String firstname;
    String lastname;
    int c;

    public Contacts(Integer age, String state, String firstname, String lastname){
        this.age = age;
        this.state = state;
        this.firstname = firstname;
        this.lastname = lastname;
        this.c = choice();
    }
    public Integer getAge() {
        return age;
    }
    public void setAge(Integer age) {
        this.age = age;
    }
    public String getState() {
        return state;
    }
    public void setState(String state) {
        this.state = state;
    }
    public String getFirstname() {
        return firstname;
    }
    public void setFirstname(String firstname) {
        this.firstname = firstname;
    }
    public String getLastname() {
        return lastname;
    }
    public void setLastname(String lastname) {
        this.lastname = lastname;
    }
    public int compareTo(Contacts contacts) {

        if (c == 1){
            return this.getLastname().compareTo(contacts.getLastname());
        }
        else if (c == 2){
            return this.getState().compareTo(contacts.getState());
        }
        else if (c == 3){
            return this.getAge().compareTo(contacts.getAge());
        }
        else return 0;

    }
    public static int choice() {
        System.out.print("Enter number 1,2 or 3: ");
        Scanner sc = new Scanner(System.in);
        int i = sc.nextInt();
        return i;
    }
    @Override
    public String toString() {
        return "contacts [age=" + age + ", state=" + state + ", firstname=" + firstname + ", lastname=" + lastname
                + "]";
    }
}