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ClassNotFoundException java_Java_Mysql_Classnotfoundexception - Fatal编程技术网

ClassNotFoundException java

ClassNotFoundException java,java,mysql,classnotfoundexception,Java,Mysql,Classnotfoundexception,我对班级没有发现异常表示怀疑。我已经在我的文件中添加了所有的罐子,但我似乎无法使它工作。我已经在我的项目中添加了mysql-connector.jar。有人知道如何纠正吗 try { String driverName = "com.mysql.jdbc.Driver"; Class.forName(driverName); String serverName = "localhost"; String mydatabase = "UFRJSocial";

我对班级没有发现异常表示怀疑。我已经在我的文件中添加了所有的罐子,但我似乎无法使它工作。我已经在我的项目中添加了mysql-connector.jar。有人知道如何纠正吗

try {
    String driverName = "com.mysql.jdbc.Driver";
    Class.forName(driverName);

    String serverName = "localhost";
    String mydatabase = "UFRJSocial";
    String url = "jdbc:mysql://" + serverName + "/" + mydatabase;
    String username = "root";
    String password = "";

    connection = DriverManager.getConnection(url, username, password);

    if (connection != null) {
        status = ("STATUS--->Connected!");
    } else {
        status = ("STATUS--->The connection failed");
    }

    return connection;

} catch (ClassNotFoundException e) {
    System.out.println("The specified driver was nor found");
    //THIS IS THE LINE THAT MY CONSOLE IS SHOWING
    return null;
} catch (SQLException e) {
    System.out.println("it was not possible to connect to the database.");
    return null;
}

请查看此代码:

enter code
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import app.dao.connector.DatabaseManager;

public class MySQLDatabaseManager implements DatabaseManager{
@Override
public Connection getConnection() {
    final String USER_NAME  ="root";
    final String PASSWORD = "1234";
    final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
    final String JDBC_URL = "jdbc:mysql://localhost:3306/inventory system";

    Connection conn = null;

    try{
        Class.forName(JDBC_DRIVER);
        conn = DriverManager.getConnection(JDBC_URL, USER_NAME, PASSWORD);
    }catch(ClassNotFoundException e){
        e.printStackTrace();
    }catch(SQLException e){
        e.printStackTrace();
    }
    return conn;
    }

如您所见,我试图在try-and-catch块之外声明所有变量。在声明JDBC_URL时,请指定您的数据库。

我已设法使其正常工作。Web INF文件夹中缺少mysql.jar文件

你是如何运行你的程序的?您的类路径设置为什么?您可能想检查一下如何使用Java连接到MySQL数据库。我正在Eclipse jee上用Tomcat7运行它。这段代码不是我的,所以我实际上还找不到我的类路径设置为什么。我将在这里搜索错误的类路径,这就是我所能说的,我如何才能使它正确?这样你就可以标记出答案,是吗?您可以自己添加一个答案并检查它。