Java:无法连接到mySql数据库

我刚刚建立了一个本地mySql数据库。我可以通过命令行和第三方软件（Navicat…）正确连接到它

服务器：

localhost:3306

用户：

root

密码：

密码

数据库名称：

students

然而，当我尝试连接java时，我得到了一个错误

代码：

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

public class Sql {

   public static void main(String[] args) {

    Connection conn = null;

    try {

        Class.forName("com.mysql.jdbc.Driver");

        conn = DriverManager.getConnection("jdbc:mysql://localhost:3306//students?autoReconnect=true&useSSL=false",
                "root", "password");

        Statement sqlState = conn.createStatement();


    } catch (SQLException ex) {

        System.out.println("SQLException" + ex.getMessage());
        System.out.println("SQLException" + ex.getSQLState());

    } catch (ClassNotFoundException e) {
        e.printStackTrace();
    }

   }

}

SQLExceptionCould not create connection to database server. Attempted reconnect 3 times. Giving up.
SQLException08001

conn = DriverManager.getConnection("jdbc:mysql://localhost:3306//students", "root", "password");

输出：

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

public class Sql {

   public static void main(String[] args) {

    Connection conn = null;

    try {

        Class.forName("com.mysql.jdbc.Driver");

        conn = DriverManager.getConnection("jdbc:mysql://localhost:3306//students?autoReconnect=true&useSSL=false",
                "root", "password");

        Statement sqlState = conn.createStatement();


    } catch (SQLException ex) {

        System.out.println("SQLException" + ex.getMessage());
        System.out.println("SQLException" + ex.getSQLState());

    } catch (ClassNotFoundException e) {
        e.printStackTrace();
    }

   }

}

SQLExceptionCould not create connection to database server. Attempted reconnect 3 times. Giving up.
SQLException08001

conn = DriverManager.getConnection("jdbc:mysql://localhost:3306//students", "root", "password");

也尝试过：

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

public class Sql {

   public static void main(String[] args) {

    Connection conn = null;

    try {

        Class.forName("com.mysql.jdbc.Driver");

        conn = DriverManager.getConnection("jdbc:mysql://localhost:3306//students?autoReconnect=true&useSSL=false",
                "root", "password");

        Statement sqlState = conn.createStatement();


    } catch (SQLException ex) {

        System.out.println("SQLException" + ex.getMessage());
        System.out.println("SQLException" + ex.getSQLState());

    } catch (ClassNotFoundException e) {
        e.printStackTrace();
    }

   }

}

SQLExceptionCould not create connection to database server. Attempted reconnect 3 times. Giving up.
SQLException08001

conn = DriverManager.getConnection("jdbc:mysql://localhost:3306//students", "root", "password");

及

其他尝试：

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

public class Sql {

   public static void main(String[] args) {

    Connection conn = null;

    try {

        Class.forName("com.mysql.jdbc.Driver");

        conn = DriverManager.getConnection("jdbc:mysql://localhost:3306//students?autoReconnect=true&useSSL=false",
                "root", "password");

        Statement sqlState = conn.createStatement();


    } catch (SQLException ex) {

        System.out.println("SQLException" + ex.getMessage());
        System.out.println("SQLException" + ex.getSQLState());

    } catch (ClassNotFoundException e) {
        e.printStackTrace();
    }

   }

}

SQLExceptionCould not create connection to database server. Attempted reconnect 3 times. Giving up.
SQLException08001

conn = DriverManager.getConnection("jdbc:mysql://localhost:3306//students", "root", "password");

防火墙已禁用

我通过将.bin.jar放入以下位置来安装Jconnector：

C:\ProgramFiles\Java\jdk1.8.0\U 73\jre\lib\ext

我可以在Eclipse中的JRE下面的左侧看到它，导入没有给出错误

注意事项：

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

public class Sql {

   public static void main(String[] args) {

    Connection conn = null;

    try {

        Class.forName("com.mysql.jdbc.Driver");

        conn = DriverManager.getConnection("jdbc:mysql://localhost:3306//students?autoReconnect=true&useSSL=false",
                "root", "password");

        Statement sqlState = conn.createStatement();


    } catch (SQLException ex) {

        System.out.println("SQLException" + ex.getMessage());
        System.out.println("SQLException" + ex.getSQLState());

    } catch (ClassNotFoundException e) {
        e.printStackTrace();
    }

   }

}

SQLExceptionCould not create connection to database server. Attempted reconnect 3 times. Giving up.
SQLException08001

conn = DriverManager.getConnection("jdbc:mysql://localhost:3306//students", "root", "password");

从终端、工作台或Navicat使用mySQL不会出现错误，任何查询都有效，本地服务器运行正常，凭据正确，用户拥有完全的管理权限

---

有什么建议吗？

此异常可能有4个原因：

用户没有连接到数据库的权限

MySQL服务未运行

不正确的MySQL连接器Jar

数据库URL不正确

---

在连接MySQL数据库之前，请检查上述先决条件。

我最近遇到了类似问题。我的问题是MySQL服务器版本是8.0.19，而flyway使用的是java MySQL库的5.1.40版本

---

一旦我将MySQL库版本更新到8.0.19，我的错误就消失了。

你可以通过MySQL控制台或Workbenchys登录吗？正如我在开头所写的那样。它不应该是

localhost:3306/students

？不确定，请尝试更改mysql连接器jar@Fast蜗牛哈哈，你说得对，是本地主机：3306/学生。我讨厌打字错误，非常感谢，先生，现在一切都正常了。