JDBC(Java Data Base Connectivity)Java数据库连接技术
使用maven依赖:
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.16</version>
</dependency>
jar包百度网盘:
复制这段内容后打开百度网盘App,操作更方便哦。 链接:https://pan.baidu.com/s/1F2uvbRU7TJ8jE6fnRBkkbw 提取码:j261
连接数据库
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class classmysql {
public static void main(String[] args) {
try {
Class.forName("com.mysql.jdbc.Driver");
String url="jdbc:mysql://localhost:3306/库名";
String username="root";
String password="密码";
Connection connection=DriverManager.getConnection(url,username,password);
if (connection!=null){
System.out.println("数据库连接成功");
}else {
System.out.println("数据库连接失败");
}
} catch (ClassNotFoundException e) {
e.printStackTrace();
}catch (SQLException e){
e.printStackTrace();
}
}
}
类:
Connection类:建立连接
DriverManager类:加载数据库驱动
接口:
Statement:执行SQL语句(不安全)
建议使用statement的子类:PreparedStatement:可以使用占位符?来防止SQL注入
ResultSet:返回查询结果集
操作数据库:
使用Statement
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.Statement;
public class caozuojdbcshuju extends caozuojdbc {
public static void main(String[] args) {
try {
Class.forName("com.mysql.cj.jdbc.Driver");
String url="jdbc:mysql://localhost:3306/库名";
String user="root";
String password="密码";
Connection connection=DriverManager.getConnection(url,user,password);
String sql="insert into user_names(ppp,dname,loc) values(10,'张三','男')";//插入
sql2="update user_names set dname='李四'";//修改
sql3="delete from user_names ";//删除整个表
Statement statement=connection.createStatement();
int result=statement.executeUpdate(sql);
System.out.println(result);
/*
查询语句:sql="select * from user_names";
Statement statement=connection.createStatement();
ResultSet resultset=Statement.executeQuery(sql);
while(resultset.next()){
int ppp=resultset.getint(ppp);
String dname=resultset.getString(dname);
String loc=resultset.getString(loc);
System.out.println(ppp+dname+loc);
}
*/
} catch (ClassNotFoundException e) {
e.printStackTrace();
}catch (Exception e){
e.printStackTrace();
}
}
}
使用PreparedStatement
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.Statement;
public class caozuojdbcshuju extends caozuojdbc {
public static void main(String[] args) {
try {
Class.forName("com.mysql.cj.jdbc.Driver");
String url="jdbc:mysql://localhost:3306/lll";
String user="root";
String password="密码";
Connection connection=DriverManager.getConnection(url,user,password);
String sql="insert into user_names(ppp,dname,loc) values(5,'张三','男')";
PreparedStatement preparedStatement=connection.prepareStatement(sql);
int result=preparedStatement.executeUpdate(sql);
System.out.println(result);
} catch (ClassNotFoundException e) {
e.printStackTrace();
}catch (Exception e){
e.printStackTrace();
}
}
}