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Class.forName("com.mysql.cj.jdbc.Driver");
此处地址获取如图位置:
+ 右键点击Driver
URL:jdbc:mysql://ip:端口号/数据库名?时区(serverTimezone=Asia/Shanghai)
User:root
password:root
方式一:本地数据库连接直接使用localhost作为ip
Connection conn= DriverManager.getConnection("jdbc:mysql://localhost:3306/test3?serverTimezone=Asia/Shanghai", "root", "521521");
方式二:利用ip远程操纵数据库,连接其他电脑需要ip,user,password,所连电脑关闭防火墙。
flush privileges
刷新数据库测试连接是否成功:
System.out.println(conn2.isClosed()==false? "连接成功":"连接失败");
String sql2="delete from student where sname='回'";
//基本增删改查语句
/* String sql="insert into student values('1','回','男','1997-04-22','950')"; //增
String sql1="update student set sname='回' where sno='950'"; //改
String sql2="delete from student where sname='嘿嘿'"; //删
String sql3="select * from student"; //查
*/
Statement st=conn2.createStatement();
int i=st.executeUpdate(sql2);
System.out.println(i);
//查询需要使用ResultSet 接收返回结果集
/*ResultSet rs=st.executeQuery(sql3);
while(rs.next())
{
String sno=rs.getString(1);
String sname=rs.getString(2);
String ssex=rs.getString(3);
Date sbirthday=rs.getDate(4);
String sclass=rs.getString(5);
System.out.println(sno+"\t"+sname+"\t"+ssex+"\t"+sbirthday+"\t"+sclass);
}
*/
// rs.close();
st.close();
conn2.close();
数据库连接完成!常用sql查询语句移步
常用查询语句
package com.zhiyou.jdbcTest; import java.sql.Connection; import java.sql.Date; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.SQLException; import java.sql.Timestamp; public class PreperTest { public static void main(String[] args) { try { Connection conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/test3?serverTimezone=Asia/Shanghai", "root", "521521"); String sql="insert into student values(?,?,?,?,?)"; //?占位 PreparedStatement ps=conn.prepareStatement(sql); ps.setString(1, "20"); //向所占位置添加数据 ps.setString(2, "哈哈哈"); ps.setString(3, "男"); //输入时间格式3种: //1.可获取时分秒 Timestamp ts=new Timestamp(new java.util.Date().getTime()); ps.setObject(4, ts); //2.直接输入,必须用-连接 //ps.setDate(4,Date.valueOf("2019-04-22")); //3.字符串类型输入 //ps.setString(4, "2019.04.22"); ps.setString(5, "95320"); int i=ps.executeUpdate(); //返回修改记录条数 System.out.println(i); ps.close(); conn.close(); } catch (SQLException e) { e.printStackTrace(); } } }
package com.zhiyou.jdbcTest; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; public class MysqlTool { //定义数据库参数 private static String URL="jdbc:mysql://localhost:3306/test3?serverTimezone=Asia/Shanghai"; private static String USER="root"; private static String PASSWORD="521521"; //创建连接对象,载体,结果集对象 private static Connection conn=null; private static PreparedStatement ps=null; private static ResultSet rs=null; //创建连接对象,可以直接在实例化前加载,使用静态方法 static{ try { conn=DriverManager.getConnection(URL, USER, PASSWORD); System.out.println(conn.isClosed()==false? "数据库连接成功...":"数据库连接失败..."); } catch (SQLException e) { e.printStackTrace(); } } /** * 增删改方法update * @param sql 需要执行的sql语句 * @param objects 封装了数据的数组,需要和sql语句中的占位符一一对应 * @return 返回影响条数,反之为0 */ public int update(String sql,Object[] objects){ int a=0; try { //创建sql载体 ps=conn.prepareStatement(sql); //给占位符赋值 for(int i=0;i<objects.length;i++){ ps.setObject(i+1, objects[i]); } //操作SQL语句 a=ps.executeUpdate(); } catch (SQLException e) { e.printStackTrace(); } return a; } /** * * @param sql 需要执行的sql语句 * @param objects 封装了数据的数组,需要和sql语句中的占位符一一对应 * @return 封装了数据的结果集,失败返回null */ public ResultSet query(String sql,Object[] objects){ try { ps=conn.prepareStatement(sql); //给占位符赋值 for(int i=0;i<objects.length;i++){ ps.setObject(i+1, objects[i]); } rs=ps.executeQuery(); } catch (SQLException e) { e.printStackTrace(); } return rs; } public void close(){ //关闭数据库 try { if(rs!=null){ rs.close(); } if(ps!=null){ ps.close(); } if(conn!=null) { conn.close(); System.out.println("数据库已关闭...."); } } catch (SQLException e) { e.printStackTrace(); } } }
package com.zhiyou.jdbcTest; import java.sql.Date; import java.sql.ResultSet; import java.sql.SQLException; public class MysqlTest { public static void main(String[] args) { MysqlTool mt=new MysqlTool(); String sql="insert into student values(?,?,?,?,?)"; Object[] objects={"2","嘿嘿","男","1995.02.03","5645"}; /*String sql1="update student set sname='hhh' where sno=?"; String sql3 = "delete from student where sno=?"; Object[] objects1={2};*/ int i=mt.update(sql, objects); System.out.println("成功操作"+i+"条数据..."); String sql4="select * from student LIMIT 1,2"; Object[] objects2={}; ResultSet rs=mt.query(sql4, objects2); try { while(rs.next()){ Date date = rs.getDate("sbirthday"); int sid = rs.getInt("sno"); String sname = rs.getString("sname"); System.out.println(sid+"\t"+sname+"\t"+date); } } catch (SQLException e) { e.printStackTrace(); } mt.close(); } }
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