[游戏开发]学习黑马教程之内部类和集合

内部类

匿名内部类

API

public static void main(String[] args) {
    int[] ar = {30, 55, 2, 656, 80};
    System.out.println(style(ar));
    //第x次循环
    for (int j = 0; j < ar.length - 1; j++) {
        for (int i = 0; i < ar.length - 1-j; i++) {
            if (ar[i] > ar[i + 1]) {
                int temp = ar[i + 1];
                ar[i + 1] = ar[i];
                ar[i] = temp;
            }
        }
        System.out.println(style(ar));

    }
}

public static String style(int[] ar) {
    StringBuilder sb = new StringBuilder();
    sb.append("[");
    for (int i = 0; i < ar.length; i++) {
        if (i == ar.length - 1) {
            sb.append(ar[i]);
        } else {
            sb.append(ar[i]).append(",");
        }
    }
    sb.append("]");
    String s = sb.toString();
    return s;
}

Arrays

基本类类型包装类

Integer类

基本类型包装类

案例：字符串中数据排序

 public static void main(String[] args) {
        String s="22 35 33 2 64 16";
        //用空格分隔长度
       String [] tr=s.split(" ");
//        System.out.println(tr.length);
        //String类型转换成int类型
        int [] n=new int[tr.length];
        for(int i=0;i<n.length;i++){
          n[i]=Integer.parseInt(tr[i]);
        }
//        for(int i=0;i<n.length;i++){
//            System.out.print(n[i]);
//        }
        //排序
        Arrays.sort(n);
        //有格式输出
        StringBuilder sb=new StringBuilder();
        for(int i=0;i<n.length;i++){
            if(i==n.length-1){
                sb.append(n[i]);
            }else{
                sb.append(n[i]).append(" ");
            }
        }
        String str=sb.toString();
        System.out.println(str);
    }

装箱和拆箱

Date

public static void main(String[] args) {
    Calendar c=Calendar.getInstance();
    int i = c.get(Calendar.YEAR);
    int i1 = c.get(Calendar.MARCH);
    int i2 = c.get(Calendar.DATE);
    System.out.println(i+"年"+i1+"月"+i2+"日");
}

案例：二月天

public static void main(String[] args) {
    //输入任意年份
    Scanner in=new Scanner(System.in);
    System.out.println("输入年份");
    int year=in.nextInt();
    //设置对象的年月日
    Calendar c=Calendar.getInstance();
    c.set(year,2,1);
    c.add(Calendar.DATE,-1);
    int i = c.get(Calendar.DATE);
    System.out.println("二月份共有："+i);
}

集合

案例

存储字符串并遍历

public static void main(String[] args) {
    ArrayList<String> ar=new ArrayList<String>();
    ar.add("xuge");
    ar.add("yuge");
    ar.add("儿子建");
    ar.add("死鬼懂");
    for (int i=0;i<ar.size();i++){
        System.out.println(ar.get(i));
    }
}

存储学生对象并遍历

存储学生对象并遍历

public class Student1 {
    private String name;
    private int age;
 /* public Student1(String name,int age){
      this.name =name;
      this.age=age;
  }*/

    public String getName() {
        return name;
    }

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

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }
}

import java.util.ArrayList;
import java.util.Scanner;

public class ArrayListDome4 {
    public static void main(String[] args) {
        /*Scanner in=new Scanner(System.in);
        System.out.println("请输入名字：");
        String name=in.nextLine();
        System.out.println("请输入年龄：");
        int age=in.nextInt();
        Student1 sc=new Student1();
        sc.setName(name);
        sc.setAge(age);
        ArrayList<Student1> array=new ArrayList<Student1>();
        array.add(sc);*/
        ArrayList<Student1> array=new ArrayList<Student1>();
        addStudent(array);
        addStudent(array);
        addStudent(array);
        for(int i=0;i<array.size();i++){
            Student1 s = array.get(i);
            System.out.println(s.getName()+","+s.getAge());

        }
    }
    //增加学生方法
    public static void addStudent(ArrayList<Student1> array){
        Scanner in=new Scanner(System.in);
        System.out.println("请输入名字：");
        String name=in.nextLine();
        System.out.println("请输入年龄：");
        int age=in.nextInt();
        Student1 sc=new Student1();
        sc.setName(name);
        sc.setAge(age);
        array.add(sc);
    }
}

学生管理系统

思路

public class Student {
    private String id;
    private String name;
    private String age;
    private String address;

    public Student() {
    }

    public Student(String id, String name, String age, String address) {
        this.id = id;
        this.name = name;
        this.age = age;
        this.address = address;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

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

    public String getAge() {
        return age;
    }

    public void setAge(String age) {
        this.age = age;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }
}

public class Manager {
    public static void main(String[] args) {
        while (true){
        System.out.println("欢迎来到学生管理系统");
        System.out.println("1.添加学生");
        System.out.println("2.删除学生");
        System.out.println("3.修改学生");
        System.out.println("4.查看所有学生");
        System.out.println("5。退出");
        System.out.println("请输入你的选择：");
        Scanner in =new Scanner(System.in);
        String s=in.nextLine();
        switch (s) {
            case "1":
                System.out.println("添加学生");
                break;
            case "2":
                System.out.println("删除学生");
                break;
            case "3":
                System.out.println("修改学生");
                break;
            case "4":
                System.out.println("查看所有学生");
                break;
            case "5":
                System.out.println("退出");
                System.exit(0);
            default:
                System.out.println("你输入有误");
        }
        }

    }
   }

public static void addStudent(ArrayList<Student> array){
    //输入学生信息
    Scanner in=new Scanner(System.in);
    System.out.println("请输入添加的学号");
    String id=in.nextLine();
    System.out.println("请输入姓名");
    String name=in.nextLine();
    System.out.println("请输入年龄");
    String age=in.nextLine();
    System.out.println("请输入地址");
    String address=in.nextLine();
    //添加学生信息赋值给成员变量
    Student sc=new Student();
    sc.setId(id);
    sc.setName(name);
    sc.setAge(age);
    sc.setAddress(address);
    //将学生对象添加到集合中
    array.add(sc);
    //给出成功添加提示
    System.out.println("添加成功");


}

public static void findAllStudent(ArrayList<Student>array){
    System.out.println("学号\t\t姓名\t年龄\t地址");
     for (int i=0;i<array.size();i++){
        Student s = array.get(i);
        System.out.println(s.getId()+"\t"+s.getName()+"\t"+s.getAge()+"\t"+s.getAddress());
    }
}

public static void delectStudent(ArrayList<Student> array){
    Scanner in=new Scanner(System.in);
    System.out.println("请输入你要删除的学号：");
    String id=in.nextLine();
    for(int i=0;i<array.size();i++){
        Student s = array.get(i);
        if(s.getId().equals(id)){
            array.remove(i);
            break;
        }
    }
    System.out.println("删除成功");

}

public static void updateStudent(ArrayList<Student> array){
    //输入要修改的学生信息
    Scanner in=new Scanner(System.in);
    System.out.println("输入要修改的学生ID");
    String id=in.nextLine();

    System.out.println("输入要修改的学生姓名");
    String name=in.nextLine();
    System.out.println("输入要修改的学生年龄");
    String age=in.nextLine();
    System.out.println("输入要修改的学生地址");
    String address=in.nextLine();
    //创建学生对象
    Student student=new Student();
    student.setId(id);
    student.setName(name);
    student.setAge(age);
    student.setAddress(address);
    //遍历集合修改对应学生信息
    for(int i=0;i<array.size();i++){
        Student s = array.get(i);

        if(s.getId().equals(id)){
            array.set(i,student);
            break;
        }
    }
    System.out.println("修改成功");
}

public static void delectStudent(ArrayList<Student> array){
    Scanner in=new Scanner(System.in);
    System.out.println("请输入你要删除的学号：");
    String id=in.nextLine();

    int index=-1;
    for(int i=0;i<array.size();i++){
        Student s = array.get(i);
        if(s.getId().equals(id)){
           index=i;
            break;
        }
    }
    if (index==-1){
        System.out.println("你输入有误，请重新输入");
    }else{
        array.remove(index);
        System.out.println("删除成功");
    }


}