在 Netbeans 中连接 azure 数据库的 Java 程序我收到错误

Question

I'm getting the following error:

I tried various ways I'm getting an error please see the following error.

run: java.lang.ClassNotFoundException: com.microsoft.sqlserver.jdbc.SQLServerDriver at java.net.URLClassLoader.findClass(URLClassLoader.java:381) at java.lang.ClassLoader.loadClass(ClassLoader.java:424) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:338) at java.lang.ClassLoader.loadClass(ClassLoader.java:357) at java.lang.Class.forName0(Native Method) at java.lang.Class.forName(Class.java:264) at com.sqldbsamples.App.main(App.java:23)

BUILD SUCCESSFUL (total time: 0 seconds)

This is my code: please help me with how to connect my database to azure using java program !!!

public class App {

    public static void main(String[] args) {

        // Connect to database
        String hostName = "testchinnaa.database.windows.net:1433"; // update me
        String dbName = "Test_Gopi"; // update me
        String user = "chinna"; // update me
        String password = "******"; // update me

        String url = String.format("jdbc:sqlserver://testchinnaa.database.windows.net:1433;database=Test_Gopi;user=chinna@testchinna;password=*****;encrypt=true;trustServerCertificate=false;hostNameInCertificate=*.database.windows.net;loginTimeout=30;"
            + "hostNameInCertificate=*.database.windows.net;loginTimeout=30;", hostName, dbName, user, password);
        Connection connection = null;
        try {
            Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
            connection = DriverManager.getConnection(url);
            String schema = connection.getSchema();
            System.out.println("Successful connection - Schema: " + schema);

            System.out.println("Query data example:");
            System.out.println("=========================================");

            // Create and execute a SELECT SQL statement.
            String selectSql = "SELECT TOP 20 pc.Name as CategoryName, p.name as ProductName "
                + "FROM [SalesLT].[ProductCategory] pc "  
                + "JOIN [SalesLT].[Product] p ON pc.productcategoryid = p.productcategoryid";

            try (Statement statement = connection.createStatement();
            ResultSet resultSet = statement.executeQuery(selectSql)) {

                // Print results from select statement
                System.out.println("Top 20 categories:");
                while (resultSet.next())
                {
                    System.out.println(resultSet.getString(1) + " "
                        + resultSet.getString(2));
                }
                connection.close();
            }
        }
        catch (Exception e) {
            e.printStackTrace();
        }
    }
}

Answer 1

Sorry, you have to figure out if you are using MySql or MSSql . You said that you used mysql. However, in your connection string, it is a sqlserver which means it is a MSSql.

Here is the tutorial for accessing database using java:

1. You need to download connector for your database:

   • For MySql: MySQL Connector/J

   • For MSSql: Microsoft JDBC Driver for SQL Server

2. Manually add connector jar file to your classpath. Or you can use Maven dependencies manager to install and configure the Connector/J library in your project.

    <!-- Example for mysql --> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>8.0.18</version> </dependency>

3. Code sample

   • For MSSql:

      try { Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver").newInstance(); connection = DriverManager.getConnection("conntection_string"); String SQL = "SELECT name FROM sysdatabases;"; try (Statement statement = connection.createStatement(); ResultSet resultSet = statement.executeQuery(SQL)) { // Print results from select statement while (resultSet.next()) { System.out.println(resultSet.getString(1)); } connection.close(); } } catch (Exception e) { e.printStackTrace(); }

   • For MySql:

      Connection conn = null; ResultSet rs = null; try { Class.forName("com.mysql.cj.jdbc.Driver"); String connectionUrl = "jdbc:mysql://{server_name}.mysql.database.azure.com:3306?useSSL=true&requireSSL=false&serverTimezone=UTC";; conn = DriverManager.getConnection(connectionUrl, "username_from_portal, like: jack@mysqldemo258", "password"); rs = conn.prepareStatement("show databases").executeQuery(); while(rs.next()){ System.out.println(rs.getString(1)); } } catch (ClassNotFoundException e) { e.printStackTrace(); } catch (SQLException e) { e.printStackTrace(); } finally { try{ if(rs != null) rs.close(); if(conn != null) conn.close(); } catch (SQLException e) { e.printStackTrace(); } }