java - 如何删除/不显示空值？

Question

所以我的问题是我如何删除/不显示空值、未找到的多余值以及运行程序时的 0，以及“运行”时 Student201 的最后两个属性，它以相反的顺序显示，这意味着首先显示空值或未找到的多余值或零。

另外我如何添加学生“预定义”

This is my preferred output or display as much as possible w/o the not found

This is not what I want, the not founds are printed first before the desired output

Main.java

public class Main {
        public static void main(String[] args) {
        // TODO Auto-generated method stub

        //Student a1=new Student();
        //a1.choosy();

        Student201 a2 =new Student201();
        a2.studinfo();
        a2.findstud("2000000001);
    }

}

Student201.java

public class Student201 {

    Student [] studarray = new Student[13];
    int x;
    public void studinfo()
    {



        for (x=0;x<studarray.length;x++) {

            studarray[x]= new Student();

        }


        Student estudyante1 = new Student();
        Student estudyante2 = new Student ();
        Student estudyante3 = new Student ();
        Student estudyante4 = new Student ();
        Student estudyante5 = new Student ();

        estudyante1.getStudName("Yves Francisco");
        estudyante1.getStudNum(2000000001);
        estudyante1.getYrLvl(5);
        estudyante1.getKors("CpE");
        estudyante1.getGender("Male");

        estudyante2.getStudName("Lance Eco");
        estudyante2.getStudNum(2000000002);
        estudyante2.getYrLvl(5);
        estudyante2.getKors("CpE");
        estudyante2.getGender("Male");

        estudyante3.getStudName("Karlos Castillo");
        estudyante3.getStudNum(2000000003);
        estudyante3.getYrLvl(5);
        estudyante3.getKors("CpE");
        estudyante3.getGender("Male");

        estudyante4.getStudName("Glenn Bordonada");
        estudyante4.getStudNum(2000000004);
        estudyante4.getYrLvl(4);
        estudyante4.getKors("ECE");
        estudyante4.getGender("Male");

        estudyante5.getStudName("Tim Tolentino");
        estudyante5.getStudNum(2000000005);
        estudyante5.getYrLvl(4);
        estudyante5.getKors("ECE");
        estudyante5.getGender("Male");

        studarray[0]=estudyante1;
        studarray[1]=estudyante2;
        studarray[2]=estudyante3;
        studarray[3]=estudyante4;
        studarray[4]=estudyante5;


    }
    public void findstud (String query) //String query for searching 

    {

    int ercatch=0;

    try{

         ercatch=Integer.parseInt(query);
       }

        catch (NumberFormatException m)
       {


       }

    for (x=0;x<studarray.length;x++) 
    {

        if (query.equalsIgnoreCase(studarray[x].setStudName())) //query.equalsIgnorecase for case sensitive inputs
        {
            System.out.println(studarray[x].setStudName()+"\n"+studarray[x].setStudNum()+"\n"+studarray[x].setYrLvl()+"\n"+studarray[x].setKors()+"\n"+studarray[x].setGender()+"\n");
            System.out.println("\n");
        }




    }

    for (x=0;x<studarray.length;x++) 
    {
        if (ercatch == studarray[x].setStudNum()) //Integer.parseInt for int data types
        { 

            System.out.println(studarray[x].setStudName()+"\n"+studarray[x].setStudNum()+"\n"+studarray[x].setYrLvl()+"\n"+studarray[x].setKors()+"\n"+studarray[x].setGender());
            System.out.println("\n");
        }

        else if (ercatch != studarray[x].setStudNum()) 
        {

            System.out.println("Not Found!");
        }


    }

    for (x=0;x<studarray.length;x++) 
    {

        if (ercatch == studarray[x].setYrLvl()) 
        {
            System.out.println(studarray[x].setStudName()+"\n"+studarray[x].setStudNum()+"\n"+studarray[x].setYrLvl()+"\n"+studarray[x].setKors()+"\n"+studarray[x].setGender());
            System.out.println("\n");
        }

        else if (ercatch != studarray[x].setYrLvl())
        {
            System.out.println("Not Found!");
        }

    }

    for (x=0;x<studarray.length;x++)
    {

        if (query.equalsIgnoreCase(studarray[x].setKors())) 
        {

            System.out.println(studarray[x].setStudName()+"\n"+studarray[x].setStudNum()+"\n"+studarray[x].setYrLvl()+"\n"+studarray[x].setKors()+"\n"+studarray[x].setGender());
            System.out.println("\n");
        }


    }

    for (x=0;x<studarray.length;x++) 
    {
        if (query.equalsIgnoreCase(studarray[x].setGender())) 
        {

            System.out.println(studarray[x].setStudName()+"\n"+studarray[x].setStudNum()+"\n"+studarray[x].setYrLvl()+"\n"+studarray[x].setKors()+"\n"+studarray[x].setGender());
            System.out.println("\n");
        }


    }



 }

    public void addstud (String query) 

    {


    }

}

学生.Java

public class Student {


    private String StudName;
    private int StudNum;
    private int YrLvl;
    private String Kors;
    private String Gender;

    //this just for naming convention for the get and set
    public void getStudName (String name) {

        this.StudName=name;
    }


    public String setStudName() {

        return StudName;
    }

    public void getStudNum (int numero) {

        this.StudNum=numero;
    }

    public int setStudNum() {

        return StudNum;
    }

    public void getYrLvl (int yrlvl) {

        this.YrLvl=yrlvl;
    }

    public int setYrLvl()
    {
        return YrLvl;
    }

    public void getKors (String korse) {

        this.Kors=korse;
    }

    public String setKors() {

        return Kors;
    }

    public void getGender (String sex)
    {
        this.Gender=sex;
    }

    public String setGender() {

        return Gender;
    }

    public void choosy() {

        System.out.println("Here is the list and the information of the Students \n");


    }

    /*public static void main(String[] args) {
        // TODO Auto-generated method stub

    }*/

}

Answer 1

首先，你完全混淆了 getters 和 setters，getters 应该返回不带任何参数的值，而 setters 使用参数将字段设置为值，如下所示

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

public String getStudName() {
    return StudName;
}

public void setStudNum (int numero) {
    this.StudNum=numero;
}

public int getStudNum() {
    return StudNum;
}

由于您不想显示“未找到”结果，因此我将其删除，这是您的 Student201 类。

public class Student201 {

Student[] studarray = new Student[13];
int x;

public void studinfo() {

    for (x = 0; x < studarray.length; x++) {

        studarray[x] = new Student();

    }

    Student estudyante1 = new Student();
    Student estudyante2 = new Student();
    Student estudyante3 = new Student();
    Student estudyante4 = new Student();
    Student estudyante5 = new Student();

    estudyante1.setStudName("Yves Francisco");
    estudyante1.setStudNum(2000000001);
    estudyante1.setYrLvl(5);
    estudyante1.setKors("CpE");
    estudyante1.setGender("Male");

    estudyante2.setStudName("Lance Eco");
    estudyante2.setStudNum(2000000002);
    estudyante2.setYrLvl(5);
    estudyante2.setKors("CpE");
    estudyante2.setGender("Male");

    estudyante3.setStudName("Karlos Castillo");
    estudyante3.setStudNum(2000000003);
    estudyante3.setYrLvl(5);
    estudyante3.setKors("CpE");
    estudyante3.setGender("Male");

    estudyante4.setStudName("Glenn Bordonada");
    estudyante4.setStudNum(2000000004);
    estudyante4.setYrLvl(4);
    estudyante4.setKors("ECE");
    estudyante4.setGender("Male");

    estudyante5.setStudName("Tim Tolentino");
    estudyante5.setStudNum(2000000005);
    estudyante5.setYrLvl(4);
    estudyante5.setKors("ECE");
    estudyante5.setGender("Male");

    studarray[0] = estudyante1;
    studarray[1] = estudyante2;
    studarray[2] = estudyante3;
    studarray[3] = estudyante4;
    studarray[4] = estudyante5;

}

public void findstud(String query) //String query for searching 
{

    int ercatch = 0;

    try {
        ercatch = Integer.parseInt(query);
    } catch (NumberFormatException m) {
    }

    for (x = 0; x < studarray.length; x++) {

        if (query.equalsIgnoreCase(studarray[x].getStudName())) //query.equalsIgnorecase for case sensitive inputs
        {
            System.out.println(studarray[x].getStudName() + "\n" + studarray[x].getStudNum() + "\n" + studarray[x].getYrLvl() + "\n" + studarray[x].getKors() + "\n" + studarray[x].getGender() + "\n");
            System.out.println("\n");
        }

    }

    for (x = 0; x < studarray.length; x++) {
        if (ercatch == studarray[x].getStudNum()) //Integer.parseInt for int data types
        {

            System.out.println(studarray[x].getStudName() + "\n" + studarray[x].getStudNum() + "\n" + studarray[x].getYrLvl() + "\n" + studarray[x].getKors() + "\n" + studarray[x].getGender());
            System.out.println("\n");
        }

    }

    for (x = 0; x < studarray.length; x++) {

        if (ercatch == studarray[x].getYrLvl()) {
            System.out.println(studarray[x].getStudName() + "\n" + studarray[x].getStudNum() + "\n" + studarray[x].getYrLvl() + "\n" + studarray[x].getKors() + "\n" + studarray[x].getGender());
            System.out.println("\n");
        }

    }

    for (x = 0; x < studarray.length; x++) {

        if (query.equalsIgnoreCase(studarray[x].getKors())) {

            System.out.println(studarray[x].getStudName() + "\n" + studarray[x].getStudNum() + "\n" + studarray[x].getYrLvl() + "\n" + studarray[x].getKors() + "\n" + studarray[x].getGender());
            System.out.println("\n");
        }

    }

    for (x = 0; x < studarray.length; x++) {
        if (query.equalsIgnoreCase(studarray[x].getGender())) {

            System.out.println(studarray[x].getStudName() + "\n" + studarray[x].getStudNum() + "\n" + studarray[x].getYrLvl() + "\n" + studarray[x].getKors() + "\n" + studarray[x].getGender());
            System.out.println("\n");
        }

    }
}

public void addstud(String query) {

}

}