Java改进：构造方法实例和图析，学生管理系统（含查询所有和单个学生信息，增删改查）
定义学生类，包含学生id，名称，年龄，成绩,在构造方法里对属性进行赋值,定义学生介绍自己的方法，介绍的时候打印自己的信息
package fuXi;
public class jieSao {
public static void main(String[] args) {
student s1 = new student(1, "诗书", 19, 99.8);
student s2 = new student(2, "画唱", 20, 99.9);
student s3 = new student(2, "诗书画唱", 21, 100);
}
}
class student {
private int age;
private double chengJi;
private int ID;
private String name;
public student(int ID, String name, int age, double chengJi) {
System.out.println("大家好!我是" + name + ",今年" + age + "岁,学生编号是" + ID + ","
+ "成绩是" + chengJi + "分，希望与你们共同努力，互相帮助，一起进步，谢谢！");
}
public int getAge() {
return age;
}
public double getChengJi() {
return chengJi;
}
public int getID() {
return ID;
}
public String getName() {
return name;
}
public void setAge(int age) {
this.age = age;
}
public void setChengJi(double chengJi) {
this.chengJi = chengJi;
}
public void setID(int iD) {
ID = iD;
}
public void setName(String name) {
this.name = name;
}
}
登录
package fuXi;
import java.util.Scanner;
public class dengLu {
public static void main(String[] args) {
Scanner s = new Scanner(System.in);
yonghu y = new yonghu();
while (true) {
System.out.println("欢迎来到诗书画唱学生管理系统");
System.out.println("请登录！先点赞!先投币！先收藏！先三连!先关注！");
System.out.println("请输入用户名:");
String uname = s.next();
System.out.println("请输入密码:");
String pwd = s.next();
if (y.getUname().equals(uname) && y.getPwd().equals(pwd)) {
break;
} else {
System.out.println("用户名或密码输入错误,请重新输入！点个赞！点个关注！");
}
}
System.out.println("登录成功!");
}
}
class yonghu {
private String pwd = "1";
private String uname = "1";
public String getPwd() {
return pwd;
}
public String getUname() {
return uname;
}
public void setPwd(String pwd) {
this.pwd = pwd;
}
public void setUname(String uname) {
this.uname = uname;
}
}
学生管理系统（登录成功后有以下选项，1.查询所有学生信息 2，根据用户编号查询学生信息 3.根据用户编号修改学生信息 4.删除学生 5.退出系统)
package fuXi;
import java.util.ArrayList;
import java.util.Scanner;
public class lizi {
public static void main(String[] args) {
Scanner s = new Scanner(System.in);
yonghu y = new yonghu();
while (true) {
System.out.println("欢迎来到诗书画唱学生管理系统");
System.out.println("请登录！先点赞!先投币！先收藏！先三连!先关注！");
System.out.println("请输入用户名:");
String uname = s.next();
System.out.println("请输入密码:");
String pwd = s.next();
if (y.getUname().equals(uname) && y.getPwd().equals(pwd)) {
break;
} else {
System.out.println("用户名或密码输入错误,请重新输入！点个赞！点个关注！");
}
}
System.out.println("登录成功!");
ArrayList<student> arr = new ArrayList<student>();
arr.add(new student(1, "诗名", '男', 95));
arr.add(new student(2, "书名", '男', 92));
arr.add(new student(3, "画名", '男', 90));
arr.add(new student(4, "唱名", '男', 111));
arr.add(new student(5, "帅名", '男', 134));
while (true) {
System.out.println("请选择你要执行的功能1.查询所有学生信息 "
+ " 2，根据用户编号查询学生信息3根据用户编号修改学生信息" + "4.删除学生 5.退出系统");
Scanner s1 = new Scanner(System.in);
int num = s1.nextInt();
if (num == 1) {
System.out.println("执行查询功能");
for (student i : arr) {
System.out.println(i);
}
} else if (num == 2) {
System.out.println("执行查询单个学生信息的功能");
System.out.println("请输入你要查询的学生的编号");
int bianhao = s1.nextInt();
for (int j = 0; j < arr.size(); j++) {
if (bianhao == arr.get(j).bianhao) {
System.out.println(arr.get(j));
}
}
} else if (num == 3) {
System.out.println("执行修改功能");
System.out.println("请输入你要修改的学生的编号");
int bianhao = s1.nextInt();
for (int i = 0; i < arr.size(); i++) {
if (bianhao == arr.get(i).bianhao) {
System.out.println("你要修改的成绩为多少?");
double d = s1.nextDouble();
arr.get(i).ChengJi = d;
}
}
} else if (num == 4) {
System.out.println("执行删除功能");
System.out.println("请输入你要删除的学生的编号");
int bianhao = s1.nextInt();
for (int i = 0; i < arr.size(); i++) {
if (bianhao == arr.get(i).bianhao) {
arr.remove(arr.get(i));
}
}
System.out.println("删除完毕");
}
else if (num == 5) {
System.exit(0);
}
}
}
}
class student {
int bianhao;
double ChengJi;
String name;
char sex;
public student(int bianhao, String name, char sex, double ChengJi) {
this.bianhao = bianhao;
this.name = name;
this.sex = sex;
this.ChengJi = ChengJi;
}
@Override
public String toString() {
return "编号:" + bianhao + ",\t名字:" + name + ",\t性别:" + sex + ",\t成绩:"
+ ChengJi;
}
}
class yonghu {
private String pwd = "1";
private String uname = "1";
public String getPwd() {
return pwd;
}
public String getUname() {
return uname;
}
public void setPwd(String pwd) {
this.pwd = pwd;
}
public void setUname(String uname) {
this.uname = uname;
}
}
