没有合适的驱动程序找到jdbc mysql？ [英] No suitable driver found for jdbc mysql?

问题描述

我正在尝试编写一个连接到eclipse中的MySQL数据库的程序，但是我收到错误java.sql.SQLException：找不到合适的驱动程序。
$ b

java代码是：

  import java.sql。 *; 
 
 public class FirstExample {
 
 // static final String S_JDBC_DRIVER =com.mysql.jdbc.Driver; 
 static final String S_DB_URL =jdbc：mysql：// localhost：3306 / emp; 
 static final String S_USER =root; 
 static final String S_PASS =root; 
 
 public static void main（String [] args）{
 
 try {
 
 System.out.println（Connecting to database ... ）; 
 //Class.forName(S_JDBC_DRIVER）; 
连接连接= DriverManager.getConnection（S_DB_URL，
 S_USER，S_PASS）; 
 
 System.out.println（创建语句...）; 
语句语句= connection.createStatement（）; 
 String sql =SELECT * FROM Employee; 
 ResultSet resultSet = statement.executeQuery（sql）; 
 
 while（resultSet.next（））{
 
 int iId = resultSet.getInt（id）; 
 int iAge = resultSet.getInt（age）; 
 String sFirst = resultSet.getString（fname）; 
 String sLast = resultSet.getString（lname）; 
 
 System.out.print（ID：+ iId）; 
 System.out.print（\tAge：+ iAge）; 
 System.out.print（\tFirst：+ sFirst）; 
 System.out.println（\tLast：+ sLast）; 
} 
 
 resultSet.close（）; 
 statement.close（）; 
 connection.close（）; 
} catch（SQLException se）{
 
 for（Throwable t：se）{
 t.printStackTrace（）; 
} 
} 
 System.out.println（再见！）; 
} 
  

}

控制台选项卡中的输出是：

 连接到数据库... 
 java.sql.SQLException：没有合适驱动程序找到jdbc：mysql：// localhost：3306 / emp 
在java.sql.DriverManager.getConnection（未知源）
在java.sql.DriverManager.getConnection（未知来源）
在FirstExample.main（FirstExample.java:21）
再见！ 
  

我使用了MySQL Connector / J。它在MySQL安装目录中解压缩，并将jar文件添加到CLASSPATH。

还请参考此图像。有一个 ！在项目根目录下 image01

我收到错误，如下图所示： image02 当我包含2个注释的语句：

  static final String S_JDBC_DRIVER =com。 mysql.jdbc.Driver; 
 Class.forName（S_JDBC_DRIVER）; 
  

解决方案

除了最简单的应用程序之外， CLASSPATH 环境变量使用不。通常，库包含在jar的清单中的 Class-Path 条目中，或 -cp 选项的命令行。

在这种情况下，您需要将MySQL JDBC驱动程序添加到Eclipse项目的构建路径。

I am trying to write a program to connect to a MySQL database in eclipse, but I get the error "java.sql.SQLException: No suitable driver found".

The java code is:

import java.sql.*;

public class FirstExample {

//static final String S_JDBC_DRIVER = "com.mysql.jdbc.Driver";  
static final String S_DB_URL = "jdbc:mysql://localhost:3306/emp";
static final String S_USER = "root";
static final String S_PASS = "root";

public static void main(String[] args) {

    try {

        System.out.println("Connecting to database...");
        //Class.forName(S_JDBC_DRIVER);
        Connection connection = DriverManager.getConnection(S_DB_URL,
                S_USER, S_PASS);

        System.out.println("Creating statement...");
        Statement statement = connection.createStatement();
        String sql = "SELECT * FROM Employee";
        ResultSet resultSet = statement.executeQuery(sql);

        while (resultSet.next()) {

            int iId = resultSet.getInt("id");
            int iAge = resultSet.getInt("age");
            String sFirst = resultSet.getString("fname");
            String sLast = resultSet.getString("lname");

            System.out.print("ID: " + iId);
            System.out.print("\tAge: " + iAge);
            System.out.print("\tFirst: " + sFirst);
            System.out.println("\tLast: " + sLast);
        }

        resultSet.close();
        statement.close();
        connection.close();
    } catch (SQLException se) {

        for (Throwable t : se) {
            t.printStackTrace();
        }
    } 
    System.out.println("Goodbye!");
}

}

The output in the console tab is:

Connecting to database...
java.sql.SQLException: No suitable driver found for jdbc:mysql://localhost:3306/emp
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at FirstExample.main(FirstExample.java:21)
Goodbye!

I have used the MySQL Connector/J. It is unzipped in the MySQL installation directory and the jar file is added to the CLASSPATH.

Also refer to this image. There is an ! mark at the project root.image01

I get the error as in the next image: image02 when I include the 2 commented statements:

static final String S_JDBC_DRIVER = "com.mysql.jdbc.Driver";
Class.forName(S_JDBC_DRIVER);

解决方案

For all but the most trivial applications the CLASSPATH environment variable is NOT used. Normally the libraries are include in the Class-Path entry in the manifest of the jar, or in the -cp option of the java commandline.

In this case you need to add the MySQL JDBC driver to the buildpath of your Eclipse project.

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