JDBC 连接失败：java.sql.SQLException：通信链接失败：握手错误

Question

我是 JDBC 的新手。我在尝试将我的 java 程序与 Mysql 数据库连接时遇到了一个 SQLException。

请在下面找到运行时错误的详细信息：

Exception in thread "main" java.sql.SQLException: Communication link failure: Bad handshake
    at com.mysql.jdbc.MysqlIO.init(Unknown Source)
    at com.mysql.jdbc.Connection.connectionInit(Unknown Source)
    at com.mysql.jdbc.jdbc2.Connection.connectionInit(Unknown Source)
    at com.mysql.jdbc.Driver.connect(Unknown Source)
    at java.sql.DriverManager.getConnection(DriverManager.java:664)
    at java.sql.DriverManager.getConnection(DriverManager.java:247)
    at databaseexample.DatabaseExample.connect(DatabaseExample.java:40)
    at databaseexample.DatabaseExample.main(DatabaseExample.java:26)
/home/sreejith/.cache/netbeans/8.2/executor-snippets/run.xml:53: Java returned: 1

Program Details :
package databaseexample;
import java.sql.*

;

public class DatabaseExample {

    static boolean flag = false;
    static String DBURL = "jdbc:mysql://localhost:3306/testdb";


    static String  CHECK_SQL_QUERY = "SELECT 1";
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) throws SQLException, ClassNotFoundException {
        // TODO code application logic here
        Class.forName("com.mysql.jdbc.Driver");
        flag =  connect();
        if(flag == true)
        {
            System.out.println("Connnected !");
        } else
        {
            System.out.println("not connected.");
        }



    }

    public static boolean connect() throws SQLException {
        Connection conn = DriverManager.getConnection(DBURL,"root","root");

        return true;
    }

}

我尝试 telnet 3306 端口，结果如下：

sreejith@desktop:~$ telnet localhost 3306
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
[
5.7.19-0ubuntu0.16.04.1*4` `iw2)Ml,L*
                                         Lmysql_native_password

!#08S01Got packets out of orderConnection closed by foreign host.

顺便说一句，我在 ubuntu 16.04 上运行。 在此先感谢:)

Answer 1

试试这个方法：

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

public class Connection
{
    private static java.sql.Connection connection;

    public Connection(String serverAddress, String database, String user, String pass) throws ClassNotFoundException, SQLException
    {
        Class.forName("com.mysql.jdbc.Driver");
        String url = "jdbc:mysql://" + serverAddress + ":3306/" + database;
        connection = DriverManager.getConnection(url, user, pass);
    }

    public java.sql.Connection getConnection()
    {
        return connection;
    }
}