Java学习笔记
一个Student类
public class Student {
private String sid;
private String name;
private String age;
private String address;
public Student() {
}
public Student(String sid, String name, String age, String address) {
this.sid = sid;
this.name = name;
this.age = age;
this.address = address;
}
public String getSid() {
return sid;
}
public void setSid(String sid) {
this.sid = sid;
}
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;
}
}
一个Student的测试类
import java.util.ArrayList;
import java.util.Scanner;
public class Student_Demo {
public static void main(String[] args) {
ArrayList<Student> array = new ArrayList<>();
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 修改学生");
System.out.println("3 删除学生");
System.out.println("4 查看所有学生");
System.out.println("5 退出系统");
System.out.println("请输入您的选择:");
Scanner sc = new Scanner(System.in);
String line = sc.nextLine();
switch (line) {
case "1":
// System.out.println("添加学生成功");
addStudent(array);
break;
case "2":
// System.out.println("修改学生成功");
modifyStudent(array);
break;
case "3":
// System.out.println("删除学生成功");
delStudent(array);
break;
case "4":
// System.out.println("查看学生成功");
showStudent(array);
break;
case "5":
System.out.println("谢谢使用");
// break;
return;
// System.exit(0);
}
}
}
// 添加学生
// 传入参数是学生数组,添加学生对象,不返回
public static void addStudent(ArrayList<Student> array) {
Scanner sc = new Scanner(System.in);
System.out.println("请输入学号:");
String sid = sc.nextLine();
boolean flag = false;
for (int i = 0; i < array.size(); i++) {
if (sid.equals(array.get(i).getSid())) {
flag = true;
}
}
if (flag) {
System.out.println("有内鬼,停止交易!");
} else {
System.out.println("请输入姓名:");
String name = sc.nextLine();
System.out.println("请输入年龄:");
String age = sc.nextLine();
System.out.println("请输入地址:");
String address = sc.nextLine();
Student student = new Student();
student.setSid(sid);
student.setName(name);
student.setAge(age);
student.setAddress(address);
array.add(student);
System.out.println("添加学生成功!");
}
}
// 删除学生
// 传入的参数是学生数组,删除学生对象,不返回
public static void delStudent(ArrayList<Student> array){
Scanner sc = new Scanner(System.in);
System.out.println("请输入您要删除学生的学号:");
String sid = sc.nextLine();
boolean flag = true;
// j用来获取要删除对象的索引
int j = 0;
for (int i = 0; i < array.size(); i++) {
if (sid.equals(array.get(i).getSid())) {
flag = false;
j = i;
}
}
if(flag){
System.out.println("有内鬼,停止交易!");
}else{
System.out.println("正在删除.........");
array.remove(array.get(j));
}
}
// 修改学生
// 选择修改学生的学号,然后可以修改的对象
public static void modifyStudent(ArrayList<Student> array){
Scanner sc = new Scanner(System.in);
System.out.println("请输入您要修改学生的学号:");
String sid = sc.nextLine();
boolean flag = false;
int j = 0;
for (int i = 0; i < array.size(); i++) {
if (sid.equals(array.get(i).getSid())) {
flag = true;
j = i;
}
}
if(flag){
System.out.println("修改的学号为:");
sid = sc.nextLine();
array.get(j).setSid(sid);
System.out.println("修改的姓名为:");
sid = sc.nextLine();
array.get(j).setName(sid);
System.out.println("修改的年龄为:");
sid = sc.nextLine();
array.get(j).setAge(sid);
System.out.println("修改的地址为:");
sid = sc.nextLine();
array.get(j).setAddress(sid);
System.out.println("修改成功,请进行查看");
}else{
System.out.println("有内鬼,终止交易!");
}
}
// 查看所有学生
// 传入参数是学生数组,进行遍历,不返回
public static void showStudent(ArrayList<Student> array) {
if (array.size() != 0) {
System.out.println("学号\t\t"+"姓名\t\t"+"年龄\t\t"+"地址");
for (int i = 0; i < array.size(); i++) {
System.out.printf("%-8s",array.get(i).getSid());
System.out.printf("%-8s",array.get(i).getName());
System.out.printf("%-8s",array.get(i).getAge());
System.out.printf("%-8s",array.get(i).getAddress());
System.out.println();
}
System.out.println("查看完毕");
}
else{
System.out.println("请先添加学生,再进行查看!");
}
}
}