package com.jdbc.demo2;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import org.junit.Test;
/**
* JDBC的CRUD的操作
* @author lyt
*
*/
public class JDBCDemo2 {
@Test
/**
* 查询单条记录
*/
public void demo5() {
Connection conn = null;
Statement stmt = null;
ResultSet rs = null;
try {
//注册驱动
Class.forName("com.mysql.jdbc.Driver");
//获得连接
conn = DriverManager.getConnection("jdbc:mysql:///test", "root", "oracle");
//创建SQL语句对象
stmt = conn.createStatement();
//编写SQL
String sql = "select * from user";
//执行SQL语句
rs = stmt.executeQuery(sql);
if(rs.next()) {
System.out.println(rs.getInt("id")+" "+rs.getString("username")+" "+rs.getString("password"));
}
}catch(Exception e) {
e.printStackTrace();
}finally {
if(conn!=null) {
try {
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
conn = null;
}
if(stmt!=null) {
try {
stmt.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
stmt = null;
}
if(rs!=null) {
try {
rs.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
conn = null;
}
}
}
@Test
/**
* 查询多条记录
*/
public void demo4() {
Connection conn = null;
Statement stmt = null;
ResultSet rs = null;
try {
//注册驱动
Class.forName("com.mysql.jdbc.Driver");
//获得连接
conn = DriverManager.getConnection("jdbc:mysql:///test", "root", "oracle");
//创建SQL语句对象
stmt = conn.createStatement();
//编写SQL
String sql = "select * from user";
//执行SQL语句
rs = stmt.executeQuery(sql);
while(rs.next()) {
System.out.println(rs.getInt("id")+" "+rs.getString("username")+" "+rs.getString("password"));
}
}catch(Exception e) {
e.printStackTrace();
}finally {
if(conn!=null) {
try {
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
conn = null;
}
if(stmt!=null) {
try {
stmt.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
stmt = null;
}
if(rs!=null) {
try {
rs.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
conn = null;
}
}
}
@Test
/**
* 删除操作的代码实现
*/
public void demo3() {
Connection conn = null;
Statement stmt = null;
try {
//注册驱动
Class.forName("com.mysql.jdbc.Driver");
//获得连接
conn = DriverManager.getConnection("jdbc:mysql:///test","root","oracle");
//创建SQL语句对象
stmt = conn.createStatement();
//编写SQL语句
String sql = "delete from user where id=6";
//执行SQL语句
int num = stmt.executeUpdate(sql);
if(num>0) {
System.out.println("ID为6的用户删除成功");
}
}catch(Exception e){
e.printStackTrace();
}finally {
if(conn!= null) {
try {
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if(stmt!= null) {
try {
stmt.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
@Test
/**
* 修改操作代码实现
*/
public void demo2() {
Connection conn= null;
Statement stmt =null;
try {
//注册驱动
Class.forName("com.mysql.jdbc.Driver");
//获得连接
conn = DriverManager.getConnection("jdbc:mysql:///test", "root", "oracle");
//执行操作
//创建执行SQL语句的对象
stmt = conn.createStatement();
//编写SQL语句
String sql = "update user set password=‘abc‘ where id=4";
//执行SQL
int num = stmt.executeUpdate(sql);
if(num>0) {
System.out.println("修改密码成功！！");
}
}catch(Exception e) {
e.printStackTrace();
}finally {
if(conn!=null) {
try {
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
conn =null;
}
if(stmt!=null) {
try {
stmt.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
conn =null;
}
}
}
@Test
/**
* 保存操作的代码实现
*/
public void demo1() {
Connection conn = null;
Statement stmt = null;
try {
//注册驱动；
Class.forName("com.mysql.jdbc.Driver");
//获得连接
conn = DriverManager.getConnection("jdbc:mysql:///test", "root", "oracle");
//创建执行SQL语句对象
stmt = conn.createStatement();
//编写SQL语句
String sql = "insert into user values(null,‘eee‘,‘123‘,‘小米‘,21)";
//执行SQL
int num = stmt.executeUpdate(sql);
if(num>0) {
System.out.println("保存用户成功！！");
}
}catch(Exception e) {
e.printStackTrace();
}finally {
//资源释放
if(stmt!=null) {
try {
stmt.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
stmt = null;
}
if(conn!=null) {
try {
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
conn = null;
}
}
}
}
配置文件如上图
原文地址：https://www.cnblogs.com/lytuser/p/12227226.html
时间： 2024-10-10 06:09:41