如何使用JDBC连接到MySQL数据库? 假定数据库名称是:testdb
,其中有一个表:employee
,这个表中有4
条记录。
创建数据库表的语句 -
use testdb;
create table if not exists employees (
id int not null,
age int not null,
first varchar (255),
last varchar (255)
);
INSERT INTO Employees VALUES (100, 28, 'Max', 'Su');
INSERT INTO Employees VALUES (101, 25, 'Wei', 'Wang');
INSERT INTO Employees VALUES (102, 30, 'Kida', 'Su');
INSERT INTO Employees VALUES (103, 28, 'Kobe', 'Bryant');
以下示例使用getConnection()
,createStatement()
和executeQuery()
方法连接到数据库并执行查询。
package com.yiibai;
import java.sql.*;
public class JdbcConn {
public static void main(String[] args) {
String JDBC_DRIVER = "com.mysql.jdbc.Driver";
String DB_URL = "jdbc:mysql://localhost/testdb?useSSL=false";
String User = "root";
String Passwd = "123456";
try {
Class.forName(JDBC_DRIVER);
} catch (ClassNotFoundException e) {
System.out.println("Class not found " + e);
}
int total_rows = 0;
try {
Connection con = DriverManager.getConnection(DB_URL, User, Passwd);
Statement stmt = con.createStatement();
ResultSet rs = stmt.executeQuery("SELECT * FROM employees");
while (rs.next()) {
total_rows++;
}
System.out.println("There are " + total_rows + " records in the table");
} catch (SQLException e) {
System.out.println("SQL exception occured" + e);
}
}
}
上述代码示例将产生以下结果(结果可能会有所不同)。
There are 4 records in the table
注:如果JDBC驱动程序安装不正确,将获得
ClassNotfound
异常。
Class not found java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
JDBC Class found
SQL exception occuredjava.sql.SQLException: No suitable driver found for jdbc:mysql://localhost/testdb