【初学者适用】Java学生信息管理简单增删改查

package JavaWebDemo.java.student; import java.util.ArrayList; import java.util.List; import java.util.Scanner; public class StudentManager { static List<Student> list=new ArrayList<>(); StudentDao dao=new StudentDao(); /** //main函数是JavaSE入口函数 public static void main(String[] args) { //sysout.out 输出信息必须要有的 //System.out.println("Hello Word"); //简单的获取到student累的对象 //Student 变量类型 //student 学生的对象 // = 是赋值语法创建了2个对象 //new Student()构造函数 Student student=new Student(); System.out.println("请输入学生的年龄： "); Scanner sc=new Scanner(System.in);//获取的是一个输入流的对象 int age=sc.nextInt(); student.setAge(age); //student.setSex("男"); System.out.println("学生student的年龄"+student.getAge()+"岁~"); //System.out.println("学生student的性别是"+student.getSex()+"生"); } **/ public static void main(String[] args) { //在static修士的方法A中调用非static修士的方法B //1.先获取方法B所在类的对象（实例），在通过对象调方法B //2.直接在方法B中添加static关键字 StudentManager manager=new StudentManager(); manager.studentMain(); //studentMain(); } /** 每个方法只做一件事 **/ public void studentMain(){ System.out.println("欢迎登陆学生管理界面"); System.out.println("请根据编号进行选择要进行的操作"); System.out.println("1:查询学生信息"); System.out.println("2:新增学生信息"); System.out.println("3:修改学生信息"); System.out.println("4:删除学生信息"); System.out.println("请输入:"); boolean flag=true; Scanner sc=new Scanner(System.in); StudentManager student=new StudentManager(); while(flag){ int actionIndex=sc.nextInt(); switch(actionIndex){ case 1: System.out.println("查询结果:"); //查询的时候从list查询 /** Iterator<String> iterator=list.iterator(); int i=0; while(iterator.hasNext()){ String str=iterator.next(); i++; System.out.println(str); } **/ student.query(); break; case 2: System.out.println("新增"); //System.out.println("请输入要新增学生的信息："); //新增就是向全局变量list添加元素 //String in=sc.next(); /** list.add(0,"1001,王明,21,男, 1班"); list.add(1,"1002,丽丽,20,女, 1班"); list.add(2,"1003,小华,20,女, 2班"); list.add(3,"1004,小刚,22,男, 2班"); **/ //list.add(in); //System.out.println("新增结果："); student.insert(); break; case 3: System.out.println("修改"); student.update(); break; case 4: System.out.println("删除"); // String queryNo=sc.next(); student.delete(); break; } } } public void insert(){ Scanner scanner=new Scanner(System.in); System.out.println("请输入要新增学生的信息："); System.out.println("请输入学生学号:"); String stuNo=scanner.next(); System.out.println("请输入学生姓名:"); String stuName=scanner.next(); System.out.println("请输入学生班级:"); int classId=scanner.nextInt(); int id=1; Student stu=new Student(stuNo, stuName, classId); // stu.setStuNo(stuNo);//变量命名的一致性（连续性） // stu.setStuName(stuName); //stu.setClassId(classId); // list.add(stu); int result=dao.insert(stu); if(result>0){ System.out.println("新增成功"); } else{ System.out.println("操作失败"); } List<Student> studentlist=new ArrayList<>(); System.out.println("学号 学生姓名 所在班级ID"); studentlist= dao.query(""); for (Student student : studentlist) { System.out.println("学号："+student.getStuNo()+" 姓名："+student.getStuName() +" 年龄："+student.getAge()+" 性别："+student.getSex()+" 班级ID："+student.getClassId()); } //// //list是要遍历的集合，Student是集合中的类型，s是保存遍历元素的临时变量 // for(Student s:list){ //foreach // System.out.println(s.getStuNo()+" " // +s.getStuName()+" "+s.getClassId()); // // } StudentManager manager=new StudentManager(); manager.studentMain(); } public void query(){ System.out.println("是否待条件查询（Y:待条件查询，N:全部查询）:"); Scanner sc=new Scanner(System.in); String flag=sc.next(); List<Student> studentlist=new ArrayList<>(); if("Y".equals(flag)){ //进行模糊查询 System.out.println("请输入学生的学号:"); String queryData=sc.next(); studentlist=dao.query(queryData); }else{ studentlist=dao.query(""); } for (Student student : studentlist) { System.out.println("学号："+student.getStuNo()+" 姓名："+student.getStuName() +" 年龄："+student.getAge()+" 性别："+student.getSex()+" 班级ID："+student.getClassId()); } System.out.println("查询成功"); StudentManager manager = new StudentManager(); manager.studentMain(); } public void update(){ System.out.println("请输入要修改学生学号："); Scanner sc=new Scanner(System.in); String stuNo=sc.next(); List<Student> studentlist=new ArrayList<>(); studentlist=dao.query(stuNo); for (Student student : studentlist) { System.out.println("学号："+student.getStuNo()+" 姓名："+student.getStuName() +" 年龄："+student.getAge()+" 性别："+student.getSex()+" 班级ID："+student.getClassId()); } // String queryNo=sc.next(); // Student student =null; // for(Student s:list){ // if(queryNo.equals(s.getStuNo())){ // student=s; // // break; // } // if(student!=null){ // System.out.println("学号 学生姓名 所在班级ID"); // System.out.println(student.getStuNo()+" " // +student.getStuName()+" "+student.getClassId()); // System.out.println("请输入想要修改学生学号:"); // String stuNo=sc.next(); System.out.println("请输入想要修改学生姓名:"); String stuName=sc.next(); System.out.println("请输入想要修改学生班级:"); int classId=sc.nextInt(); int id =1; Student stu=new Student(stuNo,stuName, classId); StudentDao dao=new StudentDao(); int result= dao.update(stu); if(result>0){ System.out.println("修改成功"); studentlist=dao.query(""); for (Student student : studentlist) { System.out.println("学号："+student.getStuNo()+" 姓名："+student.getStuName() +" 年龄："+student.getAge()+" 性别："+student.getSex()+" 班级ID："+student.getClassId()); } } else{ System.out.println("操作失败"); } // // int count=-1; // for(Student s1:list){ // count++; // if(queryNo.equals(s1.getStuNo())){ // s1=stu; // list.set(count, stu); // System.out.println(s1.getStuNo()+" " // +s1.getStuName()+" "+s1.getClassId()); // // break; // } // } StudentManager manager=new StudentManager(); manager.studentMain(); } //} //} public void delete(){ System.out.println("请输入要删除的学生学号："); Scanner sc=new Scanner(System.in); List<Student> studentlist=new ArrayList<>(); String queryNo=sc.next(); String stuNo=queryNo; StudentDao dao=new StudentDao(); int result= dao.delete(stuNo); if(result>0){ System.out.println("删除成功"); studentlist=dao.query