java.sql.SQLException:未找到合适的驱动程序

我尝试使用下面的DbQuery.java类执行简单查询，该类使用DbConnector从DriverManager获取连接

注意：

我已经将“mysql-connector-java-5.1.25-bin.jar”包含在我的 类路径via:export CLASSPATH=$CLASSPATH:/home/me/ocpjp/chapter-10/mysql-connector-java-5.1.25/mysql-connector-java-5.1.25-bin.jar

我可以通过“mysql-uroot-ptcial”连接到mysql “地址簿”，如果有关系的话

也尝试过使用'-cp'运行 争论没有结果

我可以让我的#3 DbConnect.java类说“数据库连接已建立”

另外#4DbQueryWorking.java没有问题，并提供了预期的输出

你能帮我理解这里的问题吗

1） DbConnector.java

package com.me.ocpjp.chapter10;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

public class DbConnector{
public static Connection connectToDb() throws SQLException{
String url = "jdbc:mysql//localhost:3306/";
String db = "addressBook";
String username = "root";
String password = "tcial";
return DriverManager.getConnection(url+db, username, password);
}

}

2） DbQuery.java

package com.me.ocpjp.chapter10;

import java.sql.Connection  ;
import java.sql.Statement  ;
import java.sql.ResultSet  ;
import java.sql.SQLException  ;
import com.me.ocpjp.chapter10.DbConnector;

public class DbQuery{
public static void main(String[] args){
try(Connection connection = DbConnector.connectToDb();
        Statement statement = connection.createStatement();
        ResultSet resultSet = statement.executeQuery("select * from contact")){
System.out.println("ID \tfName \tlName \temail \t\tphoneNo");
while(resultSet.next()){
System.out.println(resultSet.getInt("id") + "\t"
+ resultSet.getString("firstName") + "\t"
+ resultSet.getString("lastName") + "\t"
+ resultSet.getString("email") + "\t"
+ resultSet.getString("phoneNo") );
}

}catch(SQLException sqle){
sqle.printStackTrace();
System.exit(-1);
}

}
}

3） DbConnect.java

package com.me.ocpjp.chapter10;

import java.sql.Connection;
import java.sql.DriverManager;



public class DbConnect{
public static void main(String[] args){

String url = "jdbc:mysql://localhost:3306/";
String database = "addressBook";
String userName = "root";
String password = "tcial";

try(Connection connection = DriverManager.getConnection(url+database, userName, password)){
System.out.println("Database connection established");
}catch(Exception e){
System.out.println("Database connectioni NOT  established");
e.printStackTrace();
}

}

}

4） DbQueryWorking.java

package com.me.ocpjp.chapter10;

import java.sql.Connection  ;
import java.sql.Statement  ;
import java.sql.ResultSet  ;
import java.sql.SQLException  ;
import java.sql.DriverManager;

public class DbQuery{
public static void main(String[] args){
String url = "jdbc:mysql://localhost:3306/";
String database = "addressBook";
String userName = "root";
String password = "tcial";
try(Connection connection = DriverManager.getConnection(url + database, userName, password);
        Statement statement = connection.createStatement();
        ResultSet resultSet = statement.executeQuery("select * from contact")){
System.out.println("ID \tfName \tlName \temail \t\tphoneNo");
while(resultSet.next()){
System.out.println(resultSet.getInt("id") + "\t"
+ resultSet.getString("firstName") + "\t"
+ resultSet.getString("lastName") + "\t"
+ resultSet.getString("email") + "\t"
+ resultSet.getString("phoneNo") );
}

}catch(SQLException sqle){
sqle.printStackTrace();
System.exit(-1);
}

}
}

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您的URL错误，其中缺少冒号，应该是：

String url = "jdbc:mysql://localhost:3306/";

---

看起来

DbConnector.java

中的URL是错误的。缺少一个冒号。url必须是：

jdbc:mysql://localhost:3306/

而不是

jdbc:mysql//localhost:3306/

---

你能发布完整的堆栈跟踪吗？我想我们不再需要了。谢谢