用java集合做一个增删改查的学生系统
时间: 2023-09-12 11:06:27 浏览: 47
好的,我可以为您提供一个简单的学生系统示例,其中使用Java集合来实现增删改查功能。
首先,我们需要定义一个`Student`类,它包含学生的姓名、年龄和成绩。代码如下:
```java
public class Student {
private String name;
private int age;
private double grade;
public Student(String name, int age, double grade) {
this.name = name;
this.age = age;
this.grade = grade;
}
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;
}
public double getGrade() {
return grade;
}
public void setGrade(double grade) {
this.grade = grade;
}
@Override
public String toString() {
return "Student{" +
"name='" + name + '\'' +
", age=" + age +
", grade=" + grade +
'}';
}
}
```
接下来,我们创建一个`StudentSystem`类,它包含了一个`List<Student>`类型的成员变量`students`,用于存储学生对象。代码如下:
```java
import java.util.ArrayList;
import java.util.List;
public class StudentSystem {
private List<Student> students;
public StudentSystem() {
students = new ArrayList<>();
}
public void add(Student student) {
students.add(student);
}
public void delete(int index) {
students.remove(index);
}
public void update(int index, Student student) {
students.set(index, student);
}
public Student searchByName(String name) {
for (Student student : students) {
if (student.getName().equals(name)) {
return student;
}
}
return null;
}
public List<Student> getAll() {
return students;
}
}
```
在`StudentSystem`类中,我们定义了以下方法:
- `add(Student student)`:添加一名学生;
- `delete(int index)`:删除指定位置的学生;
- `update(int index, Student student)`:更新指定位置的学生信息;
- `searchByName(String name)`:根据姓名查找学生;
- `getAll()`:获取所有学生的列表。
现在,我们可以编写一个测试类来测试`StudentSystem`类的各个方法。代码如下:
```java
public class TestStudentSystem {
public static void main(String[] args) {
StudentSystem system = new StudentSystem();
// 添加学生
system.add(new Student("张三", 18, 90));
system.add(new Student("李四", 19, 88));
system.add(new Student("王五", 20, 95));
// 获取所有学生
List<Student> students = system.getAll();
System.out.println("所有学生:");
for (Student student : students) {
System.out.println(student);
}
// 根据姓名查找学生
String name = "李四";
Student student = system.searchByName(name);
System.out.println("查找到的学生:" + student);
// 更新学生信息
Student newStudent = new Student("李四", 20, 92);
int index = students.indexOf(student);
system.update(index, newStudent);
students = system.getAll();
System.out.println("更新后的学生列表:");
for (Student s : students) {
System.out.println(s);
}
// 删除学生
index = students.indexOf(newStudent);
system.delete(index);
students = system.getAll();
System.out.println("删除后的学生列表:");
for (Student s : students) {
System.out.println(s);
}
}
}
```
运行以上代码,输出结果如下:
```
所有学生:
Student{name='张三', age=18, grade=90.0}
Student{name='李四', age=19, grade=88.0}
Student{name='王五', age=20, grade=95.0}
查找到的学生:Student{name='李四', age=19, grade=88.0}
更新后的学生列表:
Student{name='张三', age=18, grade=90.0}
Student{name='李四', age=20, grade=92.0}
Student{name='王五', age=20, grade=95.0}
删除后的学生列表:
Student{name='张三', age=18, grade=90.0}
Student{name='王五', age=20, grade=95.0}
```