经过了几天的学习后，我觉得如果仅仅使用文件来保存数据，不仅十分繁琐而且数据也不安全，如果文件丢失或者出现异常，那么将无法挽回。这时候使用数据库MySQL来保存则更好。
学生类：
package Student;
public class Student {
private String Name;
private int StNo;
private int StAge;
private String Sex;
public void SetStudent(String name,int StNo,int StAge,String sex){
this.Name = name;
this.StNo = StNo;
this.StAge = StAge;
this.Sex = sex;
}
public void print(){
System.out.println("学号："+this.StNo+" "+"姓名："+this.Name+" "+"年龄："+this.StAge);
}
public int GetNO()
{
return this.StNo;
}
public String GetName(){
return this.Name;
}
public int GetAge(){
return this.StAge;
}
public String GetSex(){
return this.Sex;
}
}
数据库类：
package Student;
import java.sql.*;
import java.util.Scanner;
public class StuSql {
public boolean idIsUsed(Connection con, int id){
Statement stat = null;
try {
stat = con.createStatement();
} catch (SQLException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
ResultSet result = null;
try {
result = stat.executeQuery("select * from test");
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
while (result.next())
{
if(id == result.getInt("id")){
return true;
}
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return false;
}
public Connection getconnection(){
try {
Class.forName("com.mysql.jdbc.Driver");
System.out.println("成功加载MySql驱动器");
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
System.out.println("找不到MySql驱动器");
e.printStackTrace();
}
String url="jdbc:mysql://localhost:3306/hello"; //JDBC的URL,hello为数据库名字
// MySQL配置时的用户名
String user = "root";
// MySQL配置时的密码
String password = "123456";
//调用DriverManager对象的getConnection()方法，获得一个Connection对象
Connection con = null;
try {
con = DriverManager.getConnection(url,user,password);
System.out.println("成功连接到数据库");
}catch (SQLException e) {
e.printStackTrace();
}
return con;
}
public void insertStuSql(Connection con){
Student st = new Student();
System.out.println("请输入学号姓名年龄和性别:");
@SuppressWarnings("resource")
Scanner sc = new Scanner(System.in);
int StNo = sc.nextInt();
String name = sc.next();
int StAge = sc.nextInt();
String sex = sc.next();
st.SetStudent(name, StNo, StAge, sex);
if (!idIsUsed(con, StNo) && StNo > 0) {
java.sql.PreparedStatement stat = null;
try {
stat = con.prepareStatement("insert into test values(?, ?, ?, ?)");
} catch (SQLException e4) {
// TODO Auto-generated catch block
e4.printStackTrace();
}
try {
stat.setInt(1, st.GetNO());
} catch (SQLException e3) {
e3.printStackTrace();
}
try {
stat.setString(2, st.GetName());
} catch (SQLException e2) {
e2.printStackTrace();
}
try {
stat.setInt(3, st.GetAge());
} catch (SQLException e1) {
e1.printStackTrace();
}
try {
stat.setString(4, st.GetSex());
} catch (SQLException e) {
e.printStackTrace();
}
try {
stat.execute();
} catch (SQLException e) {
e.printStackTrace();
}
}
else{
System.out.println("无法添加，id已使用!");
}
}
public void reviseStuSql(Connection con,int StuNo)
{
if (idIsUsed(con, StuNo) && StuNo > 0) {
Statement stat = null;
try {
stat = con.createStatement();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
String sql = "delete from test where id=" + StuNo;
try {
stat.executeUpdate(sql);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
else{
System.out.println("无法删除，用户不存在!");
}
}
public void updateStuSql(Connection con,int StuNo){
if (idIsUsed(con, StuNo) && StuNo > 0) {
@SuppressWarnings("resource")
Scanner sc = new Scanner(System.in);
System.out.println("请输入更新后的名字年龄性别:");
String name = sc.next();
int age = sc.nextInt();
String sex = sc.next();
String sql = "update test set name='" + name + "',age='"+age+"',sex='"+sex+"' where id='"
+ StuNo + "'";
PreparedStatement pstmt = null;
try {
pstmt = (PreparedStatement) con.prepareStatement(sql);
int i = pstmt.executeUpdate();
System.out.println("resutl: " + i);
if (i < 1) {
System.out.println("用户不存在!");
}
pstmt.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
else {
System.out.println("无法更新，用户不存在!");
}
}
public void selectStuSql(Connection con){
Statement stat = null;
try {
stat = con.createStatement();
} catch (SQLException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
ResultSet result = null;
try {
result = stat.executeQuery("select * from test");
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
System.out.println("当前数据如下:");
while (result.next())
{
System.out.println(result.getInt("id") + " " + result.getString("name") + " " + result.getInt("age")+" " + result.getString("sex"));
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
展示类：
package Student;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Scanner;
public class StList {
public void Show(){
@SuppressWarnings("resource")
Scanner scanner = new Scanner(System.in);
StuSql sql = new StuSql();
Connection con = sql.getconnection();
int value;
while(true){
System.out.println("学生管理系统");
System.out.println("请输入相应的数字选择功能方式：");
System.out.println("1:增加\t2:删除\t3:修改\t4:查看\t5:退出");
value = scanner.nextInt();
switch (value) {
case 1:
sql.insertStuSql(con);
break;
case 2:
System.out.println("请输入要删除的学号:");
int index = scanner.nextInt();
sql.reviseStuSql(con, index);
break;
case 3:
System.out.println("请输入要修改的学号!");
int inde = scanner.nextInt();
sql.updateStuSql(con, inde);
break;
case 4:
sql.selectStuSql(con);
break;
case 5:
System.out.println("程序已退出!");
try {
con.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return;
default:
System.out.println("您的输入有误!");
break;
}
}
}
public static void main(String[] args){
StList list = new StList();
list.Show();
}
}
