找不到适合 jdbc mysql 的驱动程序? [英] No suitable driver found for jdbc mysql?

问题描述

我正在尝试编写一个程序以在 Eclipse 中连接到 MySQL 数据库，但出现错误java.sql.SQLException:找不到合适的驱动程序".

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".

java代码为:

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("	Age: " + iAge);
            System.out.print("	First: " + sFirst);
            System.out.println("	Last: " + sLast);
        }

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

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

}

控制台选项卡中的输出为:

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!

我使用了 MySQL Connector/J.解压到MySQL安装目录下，将jar文件添加到CLASSPATH中.

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

另请参阅此图片.有一个 ！在项目根目录处标记.image01

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

我收到如下图所示的错误:image02 当我包括了 2 条评论语句:

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);

推荐答案

CLASSPATH 环境变量不用于除最琐碎的应用程序之外的所有应用程序.通常，这些库包含在 jar 清单的 Class-Path 条目中，或包含在 java 命令行的 -cp 选项中.

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.

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

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

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