数据库的增删改查加遍历
一、jar包的导入，和相关类的创建：
二、创建数据库，在其中创建表。
三、功能选择程序，主要引用method类中的方法：package com.cn.database;
import java.sql.SQLException;
import java.util.Scanner;
public class start {
Method m =new Method();
public void reset(){
Scanner in = new Scanner(System.in);
System.out.println("请选择功能：");
System.out.println("1.查询 2.删除3.遍历数据库信息 4.增加 5.改数据");
int i = in.nextInt();
if(i>5||i<1){
System.out.println("您输出的数值超出有效数值，请重新输入！！！！");
}
switch(i){
case 1:
try {
m.find();
} catch (SQLException e) {
e.printStackTrace();
}
break;
case 2:
try {
m.delete();
} catch (SQLException e) {
e.printStackTrace();
}
break;
case 3:
try {
m.ergodic();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
break;
case 4:
try {
m.insert();
} catch (SQLException e) {
e.printStackTrace();
}
break;
case 5:
try {
m.change();
} catch (SQLException e) {
e.printStackTrace();
}
break;
}
}
public static void main(String args[]) throws SQLException, ClassNotFoundException{
start s =new start();
for(int i=0;i<1;i--){
s.reset();
}
}
}4、method类，实现加载驱动和数据库的连接，五个方法分别是数据库的增删改查加遍历（顺序自己对号入座*——*）package com.cn.database;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Scanner;
public class Method {
Connection con ;
PreparedStatement pst=null;
ResultSet rs = null;
String Driver="com.mysql.jdbc.Driver";//创建加载驱动
String Url="jdbc:mysql://localhost:3306/student?useUnicode=true&characterEncoding=utf8";//创建数据库连接
String userName="root";//数据库用户名
String pwd="123456";//数据库密码
//安装时我的数据空权限是可以不用密码访问，所以这两句可写可不写，但是印在危险不多说，我有点怕
Scanner in = new Scanner(System.in);
public void find() throws SQLException{//查找方法
try {
System.out.println("请输入名字：");
String name = in.nextLine();
String sql="select * from studentinfo where stuname=?";//查的sql语句
Class.forName(Driver);加载驱动
con=DriverManager.getConnection(Url,userName,pwd);//加载数据库
pst=con.prepareStatement(sql);
pst.setString(1,name);//从第一行开始匹配 我们要找的内容
rs=pst.executeQuery();//执行sql语句，rs为查找的对象
while (rs.next()) {//对查找的结果遍历
String stuname = rs.getString("stuname");
String stumajor = rs.getString("stumajor");
String stugrade = rs.getString("stugrade");
String studirection = rs.getString("studirection");
System.out.println("______________________________________________");
System.out.println(stuname+" "+stumajor+" "+stugrade+" "+studirection);
System.out.println("______________________________________________");
}
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
rs.close();
pst.close();
con.close();//数据库的三个关闭流，关闭的顺序是从下往上关；
}
}
public void delete()throws SQLException{//删除的方法
ResultSet rs1 = null;
PreparedStatement pst1 = null;
try{
System.out.println("请输入名字：");
String name = in.nextLine();
Class.forName(Driver);
con=DriverManager.getConnection(Url,userName,pwd);
String sql="delete from studentinfo where stuname=?";//删除的sql语句
pst=con.prepareStatement(sql);
pst.setString(1, name);
pst.executeUpdate();
System.out.println("______________________________________________");
System.out.println("恭喜你，删除成功！");
System.out.println("______________________________________________");
pst.close();
con.close();
String sql1="select * from studentinfo ";//遍历数据库
Class.forName(Driver);
con=DriverManager.getConnection(Url,userName,pwd);
pst1=con.prepareStatement(sql1);
rs1=pst1.executeQuery();
System.out.println("删除后的表的信息为：");
System.out.println("______________________________________________");
while (rs1.next()) {
String stuname = rs1.getString("stuname");
String stumajor = rs1.getString("stumajor");
String stugrade = rs1.getString("stugrade");
String studirection = rs1.getString("studirection");
System.out.println(stuname+""+stumajor+""+stugrade+""+studirection);
}
System.out.println("______________________________________________");
}catch(ClassNotFoundException e){
e.printStackTrace();
}finally{
rs1.close();
pst.close();
con.close();
}
}
public void change()throws SQLException{//改的方法
ResultSet rs1=null;
try{
System.out.println("请输入名字：");
String name = in.nextLine();
System.out.println("请输入修改的内容：");
String sql="update studentinfo SET stuname = ? ,stumajor =?, stugrade = ?,studirection = ? where stuname = ?";//改的sql语句
con=DriverManager.getConnection(Url,userName,pwd);
pst=con.prepareStatement(sql);
System.out.println("name:");
String name1 = in.next();
System.out.println("major:");
String major = in.next();
System.out.println("grade:");
String grade = in.next();
System.out.println("direction:");
String direction = in.next();//输入流，输入要插入的信息
pst.setString(1, name1);
pst.setString(2, major);
pst.setString(3,grade);
pst.setString(4, direction);
pst.setString(5, name);
pst.executeUpdate();
System.out.println("您更改后的信息为："+name1+" "+major+" "+grade+" "+direction);
con.close();
System.out.println("______________________________________________");
System.out.println("更改后表的信息为：");
System.out.println("______________________________________________");
String sql1="select * from studentinfo";
con=DriverManager.getConnection(Url,userName,pwd);
pst=con.prepareStatement(sql1);
rs1=pst.executeQuery();
while(rs1.next()){
String stuname = rs1.getString("stuname");
String stumajor = rs1.getString("stumajor");
String stugrade = rs1.getString("stugrade");
String studirection = rs1.getString("studirection");
System.out.println(stuname+" "+stumajor+" "+stugrade+" "+studirection);
}
System.out.println("______________________________________________");
}finally{
rs1.close();
pst.close();
con.close();
}
}
public void insert()throws SQLException{//插入的方法
ResultSet rs1 = null;
try{
System.out.println("请输入你要插入人的信息：");
String sql="insert into studentinfo values(?,?,?,?)";//插入的sql语句
Class.forName(Driver);
con=DriverManager.getConnection(Url,userName,pwd);
pst=con.prepareStatement(sql);
System.out.println("name:");
String name = in.next();
System.out.println("major:");
String major = in.next();
System.out.println("grade:");
String grade = in.next();
System.out.println("direction:");
String direction = in.next();
pst.setString(1, name);
pst.setString(2, major);
pst.setString(3,grade);
pst.setString(4, direction);
pst.executeUpdate();
System.out.println("______________________________________________");
System.out.println("你插入的信息为：");
System.out.println(name+" "+major+" "+grade+" "+direction);
System.out.println("______________________________________________");
String sql2="select * from studentinfo ";
pst=con.prepareStatement(sql2);
rs1=pst.executeQuery();
while (rs1.next()) {
String stuname = rs1.getString("stuname");
String stumajor = rs1.getString("stumajor");
String stugrade = rs1.getString("stugrade");
String studirection = rs1.getString("studirection");
System.out.println(stuname+" "+stumajor+" "+stugrade+" "+studirection);
}
}catch(ClassNotFoundException e){
e.printStackTrace();
}finally{
rs1.close();
pst.close();
con.close();
}
}
public void ergodic()throws SQLException, ClassNotFoundException{//数据库的遍历
String sql="select * from studentinfo ";
Class.forName(Driver);
con=DriverManager.getConnection(Url,userName,pwd);
pst=con.prepareStatement(sql);
rs=pst.executeQuery();
System.out.println("现在的表单内容有：");
System.out.println("______________________________________________");
while(rs.next()){
String stuname = rs.getString("stuname");
String stumajor = rs.getString("stumajor");
String stugrade = rs.getString("stugrade");
String studirection = rs.getString("studirection");
System.out.println(stuname+" "+stumajor+" "+stugrade+" "+studirection);
}
System.out.println("______________________________________________");
rs.close();
pst.close();
con.close();
}
}
第一次写数据库的程序，作为刚学了三天的数据库的小白，可能有很多错误，希望大能多多指教！！！！！1