我正在创建一个用于创建 MySQL 数据库和表的 Java 程序。我是相当新的，所以我边走边学。我能够创建数据库，然后继续创建表。当我运行我的程序时，我得到了这个异常错误
java.sql.SQLException: No database selected
我明白我遇到的错误，但我不知道当我已经将我的 URL 设置到我的根目录时我可以选择数据库。
String url = "jdbc:mysql://localhost:3306/";
下面是我的代码，欢迎任何反馈，谢谢。
import java.sql.Connection;
import java.sql.Statement;
import java.sql.DriverManager;
import java.sql.SQLException;
public class MysqlSetUp{
private static final String EMPLOYEE_TABLE = "create table MyEmployees3 ( "
+ " id INT PRIMARY KEY, firstName VARCHAR(20), lastName VARCHAR(20), "
+ " title VARCHAR(20), salary INT )";
public static Connection getConnection() throws Exception {
String driver = "org.gjt.mm.mysql.Driver";
String url = "jdbc:mysql://localhost:3306/";
String username = "root";
String password = "";
Class.forName(driver);
Connection conn = DriverManager.getConnection(url, username, password);
return conn;
}
public static void main(String args[]) {
Connection conn = null;
Statement stmt = null;
try {
conn = getConnection();
stmt = conn.createStatement();
stmt.executeUpdate("CREATE DATABASE Employess");
stmt.executeUpdate(EMPLOYEE_TABLE);
stmt.executeUpdate("insert into MyEmployees3(id, firstName) values(100, 'A')");
stmt.executeUpdate("insert into MyEmployees3(id, firstName) values(200, 'B')");
System.out.println("CreateEmployeeTableMySQL: main(): table created.");
} catch (ClassNotFoundException e) {
System.out.println("error: failed to load MySQL driver.");
e.printStackTrace();
} catch (SQLException e) {
System.out.println("error: failed to create a connection object.");
e.printStackTrace();
} catch (Exception e) {
System.out.println("other error:");
e.printStackTrace();
} finally {
try {
stmt.close();
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
最佳答案
创建后您需要USE Employess。
...
stmt = conn.createStatement();
stmt.executeUpdate("CREATE DATABASE Employess");
stmt.executeUpdate("USE Employess");
stmt.executeUpdate(EMPLOYEE_TABLE);
...
关于Java:在同一个类中创建Mysql数据库和表，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/48915735/