一、java实现关系型数据库操作
1、java操作mysql增删改查
1、帮助类
package com.gr.DBHerpel;
import java.sql.*; //导包
/**
* ClassName: DBHerpel
* @Description: TODO 数据库辅助类
* @author 情绪i
*/
public class DBHerpel {
private static Connection Conn; // 数据库连接对象
// 数据库连接地址
private static String URL = "jdbc:mysql://localhost:3306/myschool?characterEncoding=utf8&useSSL=true";
// 数据库的用户名
private static String UserName = "root";
// 数据库的密码
private static String Password = "1234";
/**
* * @Description: TODO 获取访问数据库的Connection对象
* @param @return
* @return Connection 连接数据的对象
* @author 情绪i
*/
public static Connection getConnection() {
try {
Class.forName("com.mysql.jdbc.Driver"); // 加载驱动
System.out.println("加载驱动成功!!!");
} catch (ClassNotFoundException e) {
// TODO: handle exception
e.printStackTrace();
}
try {
//通过DriverManager类的getConenction方法指定三个参数,连接数据库
Conn = DriverManager.getConnection(URL, UserName, Password);
System.out.println("连接数据库成功!!!");
//返回连接对象
return Conn;
} catch (SQLException e) {
// TODO: handle exception
e.printStackTrace();
return null;
}
}
}
2、增删改查
package com.gr.visitServer;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.Statement;
import com.gr.DBHerpel.DBHerpel;
public class VisitMySql {
// 连接对象
private Connection conn;
// 传递sql语句
private Statement stt;
// 结果集
private ResultSet set;
// 1、查询
public void Select() {
try {
// 获取连接
conn = DBHerpel.getConnection();
if (conn == null)
return;
// 定义sql语句
String Sql = "select * from login";
// 执行sql语句
stt = conn.createStatement();
// 返回结果集
set = stt.executeQuery(Sql);
// 获取数据
while (set.next()) {
System.out.println("用户名:" + set.getString(1) + " 密码:"
+ set.getString(2));
}
} catch (Exception e) {
e.printStackTrace();
} finally {
// 释放资源
try {
set.close();
conn.close();
} catch (Exception e2) {
// TODO: handle exception
}
}
}
//2、增
// 使用Statement接口的executeUpdate()方法向数据库添加数据
public void Add(){
try {
//获取连接
conn = DBHerpel.getConnection();
if(conn==null)
return;
//获取用户输入的账号和密码
Scanner input = new Scanner(System.in);
System.out.print("请输入用户名:");
int user = input.nextInt();
System.out.print("请输入密码:");
String pwd = input.next();
//定义sql语句
String sql = "insert into login values("+user+" , '"+pwd+"');";
//获取Statement对象
stt = conn.createStatement();
//执行sql语句
stt.executeUpdate(sql);
} catch (Exception e) {
e.printStackTrace();
}finally{
//释放资源
try {
conn.close();
} catch (Exception e2) {}
}
}
//3、删
//使用Statement接口的executeUpdate()方法实现从数据库删除数据
public void Delete(){
try {
//获取连接
conn = DBHerpel.getConnection();
if(conn==null)
return;
//提示用户输入要删除的用户
System.out.print("请输入删除的用户:");
Scanner input = new Scanner(System.in);
int user = input.nextInt();
//定义sql语句
String deleteSql = "DELETE FROM login WHERE user="+user+";";
//获取Statement对象
stt = conn.createStatement();
//执行sql语句
stt.executeUpdate(deleteSql);
} catch (Exception e) {
e.printStackTrace();
}finally{
//释放资源
try {
conn.close();
} catch (Exception e2) {}
}
}
//4、改
//使用PreparedStatement接口中的executeUpdate()方法实现修改数据
public void Update(){
try {
//获取连接
conn = DBHerpel.getConnection();
if(conn==null)
return;
//用户输入要修改的账户
System.out.print("请输入用户名:");
Scanner input = new Scanner(System.in);
int user = input.nextInt(); //提示用户输入新的密码
System.out.print("请输入新的密码:");
String NewPwd = input.next();
//定义Sql语句
String UpdateSql = "UPDATE login SET pwd = '"+NewPwd+"' WHERE user = "+user+";";
//创建Statement对象
PreparedStatement ps = conn.prepareStatement(UpdateSql);
//执行sql语句
ps.executeUpdate();
} catch (SQLException e) {
e.printStackTrace();
}finally{
//释放资源
try {
conn.close();
} catch (Exception e2) {}
}
}
}
3、测试
package com.gr.Test;
import com.gr.visitServer.VisitMySql;
public class Test {
public static void main(String[] args)
//实例化对象
VisitMySql vs = new VisitMySql();
//调用查询方法
vs.Select();
}
}
2、java操作oracle增删改查
1、帮助类
package oracle;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
/**
* @description: Oracle连接工具类
*/
public class DBUtil {
//数据库连接地址
private static String url="jdbc:oracle:thin:@localhost:1521:orcl";
//用户名
private static String username= "system";
//密码
private static String password ="ZZZ111";
//驱动名称
private static String jdbcName = "oracle.jdbc.OracleDriver";
/*获取数据库连接 */
public static Connection getCon(){
try {
Class.forName(jdbcName);
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
Connection con = null;
try {
con = DriverManager.getConnection(url,username,password);
} catch (SQLException e) {
e.printStackTrace();
}
return con;
}
/*关闭数据库连接*/
public static void closeCon(Connection con) throws SQLException {
if (con != null)
con.close();
}
public static void main(String[] args){
try {
getCon();
System.out.println("数据库连接成功");
} catch (Exception e) {
e.printStackTrace();
System.out.println("数据库连接失败");
}
}
}
2、增删改查
package oracle;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
public class OracleDemo {
//连接对象
Connection connection=null;
//创建预编译对象
PreparedStatement ps=null;
//创建结果集
ResultSet rs = null;
/*插入*/
public int insert(){
int result = 0;
connection = DBUtil.getCon();
String sql = "insert into student values(?,?,?)";
try {
ps = connection.prepareStatement(sql);
ps.setInt(1,2);
ps.setString(2,"老王");
ps.setString(3,"女");
result = ps.executeUpdate();
} catch (SQLException e) {
e.printStackTrace();
}finally {
DBUtil.closeCon(connection);
}
return result;
}
/*查询*/
public void select(){
connection = DBUtil.getCon();
String sql = "select id,name,gender from student";
try {
ps = connection.prepareStatement(sql);
rs = ps.executeQuery();
while (rs.next()){
int id = rs.getInt(1);
String name = rs.getString(2);
String gender = rs.getString(3);
System.out.println("ID:"+id + " NAME:"+name+" GENDER:"+gender);
}
} catch (SQLException e) {
e.printStackTrace();
}finally {
DBUtil.closeCon(connection);
}
}
/*修改*/
public int update(){
connection = DBUtil.getCon();
String sql = "update student set name = ?,gender = ? where id = ?";
int result = 0;
try {
ps = connection.prepareStatement(sql);
ps.setString(1,"老张");
ps.setString(2,"男");
ps.setInt(3,2);
result = ps.executeUpdate();
} catch (SQLException e) {
e.printStackTrace();
}finally {
DBUtil.closeCon(connection);
}
return result;
}
/*删除 */
public int delete(){
int result = 0;
connection = DBUtil.getCon();
String sql = "delete from student where id = ?";
try {
ps = connection.prepareStatement(sql);
ps.setInt(1,1);
result = ps.executeUpdate();
} catch (SQLException e) {
e.printStackTrace();
}finally {
DBUtil.closeCon(connection);
}
return result;
}
public static void main(String[] args){
OracleDemo od = new OracleDemo();
/*int add = od.add();
System.out.println(add);*/
od.select();
// System.out.println(od.delete());
}
}