package com.dao;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import com.entity.Student;
import com.util.JDBC;
public class StudentDAO {
static Connection conn=new JDBC().getConn();
static PreparedStatement pstml=null;
static ResultSet rs=null;
public void menu(){
System.out.println("********学生管理系统********");
System.out.println("*1. 查询所有学生信息");
System.out.println("*2. 录入学生信息");
System.out.println("*3. 删除学生信息");
System.out.println("*4. 查询单个学生信息");
System.out.println("*5. 修改学生信息");
System.out.println("*exit. 退出");
System.out.println("*help. 帮助");
System.out.println("****************************");
}
public int addStudent(Student s) throws SQLException{
String sql="insert into student(name,sex,age,tel)" +
"values(?,?,?,?)";
pstml= conn.prepareStatement(sql);
//pstml.setInt(1, s.getId());
pstml.setString(1, s.getName());
pstml.setString(2, s.getSex());
pstml.setInt(3, s.getAge());
pstml.setLong(4, s.getTel());
return pstml.executeUpdate();
}
public int deleteStudent(int id) throws SQLException{
String sql="delete * from student where id=?";
pstml= conn.prepareStatement(sql);
pstml.setInt(1, id);
return pstml.executeUpdate();
}
public int change(Student s) throws SQLException{
String sql="update student set name=?,sex=?,age=?,tel=? where id=?";
pstml= conn.prepareStatement(sql);
pstml.setString(1, s.getName());
pstml.setString(2, s.getSex());
pstml.setInt(3, s.getAge());
pstml.setLong(4, s.getTel());
pstml.setInt(5, s.getId());
return pstml.executeUpdate();
}
public Student studentFindById(int id) throws SQLException{
String sql="select * from student where id=?";
pstml= conn.prepareStatement(sql);
pstml.setInt(1, id);
rs=pstml.executeQuery();
Student s = null;
while(rs.next()){
s=new Student();
s.setId(rs.getInt("id"));
s.setName(rs.getString("name"));
s.setSex(rs.getString("sex"));
s.setAge(rs.getInt("age"));
s.setTel(rs.getLong("tel"));
}
return s;
}
public ArrayList<Student> studentFindAll() throws SQLException{
ArrayList<Student> studentList=new ArrayList<Student>();
String sql="select * from student";
pstml= conn.prepareStatement(sql);
rs=pstml.executeQuery();
while(rs.next()){
Student s=new Student();
s.setId(rs.getInt("id"));
s.setName(rs.getString("name"));
s.setSex(rs.getString("sex"));
s.setAge(rs.getInt("age"));
s.setTel(rs.getLong("tel"));
studentList.add(s);
}
return studentList;
}
public static void close() throws SQLException{
if(conn!=null){
conn.close();
}else if(pstml!=null){
pstml.close();
}else if(rs!=null){
rs.close();
}
}
}
package com.entity;
public class Student {
private int id;
private String name;
private String sex;
private int age;
private long tel;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public Student() {
super();
// TODO Auto-generated constructor stub
}
public Student(int id, String name, String sex, int age, long tel) {
super();
this.id = id;
this.name = name;
this.sex = sex;
this.age = age;
this.tel = tel;
}
public Student( String name, String sex, int age, long tel) {
super();
this.name = name;
this.sex = sex;
this.age = age;
this.tel = tel;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public long getTel() {
return tel;
}
public void setTel(long tel) {
this.tel = tel;
}
public String toString(){
return "Student [id="+getId()+", name="+getName()+", age="+getAge()+", sex="+getSex()+", tel="+getTel()+"]";
}
}
package com.test;
import java.util.List;
import java.util.Scanner;
import com.dao.StudentDAO;
import com.entity.Student;
public class StudentManager {
public static void main(String[] args){
StudentDAO studentDao = new StudentDAO();
studentDao.menu();
Scanner sc = new Scanner(System.in);
while(true){
try {
System.out.print("请输入功能编号：");
String option = sc.nextLine();
switch(option){
case "1":
System.out.println("以下是学生的信息：");
List<Student> arr = studentDao.studentFindAll();
for(int i=0;i<arr.size();i++){
System.out.println(arr.get(i));
}
System.out.println("总计 "+arr.size()+" 个");
break;
case "2":
while(true){
//假设学生年龄在0~80之间
System.out.println("请输入学生信息【name#sex#age#tel】或者输入【break】返回上一级目录");
String stuStr = sc.nextLine();
if(stuStr.equals("break")){
break;
}
String[] stuArr = stuStr.split("#");
String name = stuArr[0];
String sex = stuArr[1];
int age = Integer.parseInt(stuArr[2]);
Long tel=Long.parseLong(stuArr[3]);
Student s=new Student(name,sex,age,tel);
if(
name==null||name.equals("")||
sex==null||sex.equals("")||
(((sex.equals("男")||sex.equals("女"))==false)||
age<=0||age>=80||
((tel>=10000000&&tel<100000000)||( tel>=10000000000l && tel<100000000000l))==false)
)
{
System.out.println("信息格式错误！注意：\n" +
"1、学生姓名，性别，年龄，电话号码不能为空\n" +
"2、性别只能为男和女\n" +
"3、年龄在0~80之间\n" +
"4、" +
"5、tel为电话号码或者手机号码，必须是8位或者11位数字");
continue;
}else{
int i=studentDao.addStudent(s);
if(i>0){
System.out.println("添加成功！");
}else{
System.out.println("系统异常，信息添加失败！");
}
}
}
break;
case "3":
while(true){
System.out.println("请输入要删除学生的学号或者输入【break】返回上一级目录");
String idStr = sc.nextLine();
if(idStr.equals("break")){
break;//跳出当前循环，返回主菜单
}
int id = Integer.parseInt(idStr);
Student oldStu = studentDao.studentFindById(id);
if(oldStu == null){
System.out.println("您要删除的学生不存在！");
continue;
}
int i=studentDao.deleteStudent(id);
if(i>0){
System.out.println("添加成功！");
}else{
System.out.println("系统异常，信息添加失败！");
}
}
break;
case "4":
while(true){
System.out.println("请输入学号或者输入【break】返回上一级目录");
String idStr = sc.nextLine();
if(idStr.equals("break")){
break;
}
//1001#terry#12
int id = Integer.parseInt(idStr);
Student stu = studentDao.studentFindById(id);
System.out.println(stu==null?"sorry,not found!":stu);
}
break;
case "5"://修改
while(true){
System.out.println("请输入要修改学生的学号或者输入【break】返回上一级目录");
String idStr = sc.nextLine();
if(idStr.equals("break")){
break;//跳出当前循环，返回主菜单
}
int id = Integer.parseInt(idStr);
Student oldStu = studentDao.studentFindById(id);
if(oldStu == null){
System.out.println("您要修改的学生不存在！");
continue;
}
System.out.println("原有信息为："+oldStu);
System.out.println("请输入学生信息【name#sex#age#tel】");
String stuStr = sc.nextLine();
if(stuStr.equals("break")){
break;
}
String[] stuArr = stuStr.split("#");
int stuId=id;
String name = stuArr[0];
String sex = stuArr[1];
int age = Integer.parseInt(stuArr[2]);
Long tel=Long.parseLong(stuArr[3]);
Student s=new Student(stuId,name,sex,age,tel);
if(
name==null||name.equals("")||
sex==null||sex.equals("")||
(((sex.equals("男")||sex.equals("女"))==false)||
age<=0||age>=80||
((tel>=10000000&&tel<100000000)||( tel>=10000000000l && tel<100000000000l))==false)
)
{
System.out.println("信息格式错误！注意：\n" +
"1、学生姓名，性别，年龄，电话号码不能为空\n" +
"2、性别只能为男和女\n" +
"3、年龄在0~80之间\n" +
"4、" +
"5、tel为电话号码或者手机号码，必须是8位或者11位数字");
continue;
}else{
int i=studentDao.change(s);
if(i>0){
System.out.println("修改成功！");
}else{
System.out.println("系统异常，信息添加失败！");
}
}
}
break;
case "exit":
System.out.println("bye bye,欢迎再次使用！");
System.exit(0);
case "help":
studentDao.menu();
break;
default:
System.out.println("不合法输入！");
}
} catch (Exception e) {
System.out.println("输入出错！");
e.printStackTrace();
continue;
}
}
}
}
package com.util;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class JDBC {
private final String DRIVER="com.mysql.jdbc.Driver";
private final String URL="jdbc:mysql://localhost:3306/test";
String username = "root" ;
String password = "root" ;
Connection conn=null;
public Connection getConn(){
try{
Class.forName(DRIVER);
conn =DriverManager.getConnection(URL,username,password) ;
}catch(SQLException se){
System.out.println("数据库连接失败！");
se.printStackTrace() ;
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
return conn;
}
}
1、switch可以使用穿透，就是多个选项同一个效果。
switch(c){
case 1:
case 2:
System.out.println("nihao");
break;
default:
System.out.println("byby");
}
2、接收到的数据类型是否对应类型可以不必使用Scanner的hasNextInt（），而使用try、catch异常处理判断类型接受的是否正确，因为错误的类型会抛出异常。
3、在实现多个同级模块的功能后返回初始的选择可以使用while循环镶嵌switch达到，返回的话只需要在需要的位置跳出switch循环就好了。
4、学会使用三目运算符简化代码。
时间： 2024-11-15 07:14:23