Kode sumber java crud mysql

Dalam tutorial ini, kita akan mempelajari operasi basis data dasar (CRUD - Create, Retrieve, Update and Delete) menggunakan JDBC (Java Database Connectivity) API

Operasi CRUD ini setara dengan pernyataan CREATE, SELECT, UPDATE dan DELETE dalam bahasa SQL. Meskipun sistem basis data targetnya adalah MySQL, teknik yang sama dapat diterapkan untuk sistem basis data lain juga karena sintaks kueri yang digunakan adalah SQL standar yang didukung oleh semua sistem basis data relasional.

Video

Tutorial ini dijelaskan dalam Video Youtube di bawah ini. Berlanggananlah ke saluran youtube saya untuk mempelajari lebih lanjut tentang boot Musim Semi di Java Guides - Saluran YouTube

Mari kita mulai dengan membuat tabel pengguna dan kemudian kita akan melakukan operasi INSERT, UPDATE, SELECT, dan DELETE

Buat Contoh Tabel

Mari gunakan antarmuka Pernyataan untuk membuat tabel - Objek pernyataan yang digunakan untuk mengeksekusi pernyataan SQL statis dan mengembalikan hasil yang dihasilkannya.  

1. Tabel - pengguna
2. Basis data - mysql_database
3. Skrip DDL

   create table users(
        id  int(3) primary key,
        name varchar(20),
        email varchar(20),
        country varchar(20),
        password varchar(20)
  );

Berikut adalah program Java JDBC lengkap untuk membuat tabel pengguna dalam database

package com.javaguides.jdbc.statement.examples;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;

/**
 * Create Statement JDBC Example
 * @author Ramesh Fadatare
 *
 */
public class CreateStatementExample {

    private static final String createTableSQL = "create table users (\r\n" + "  id  int(3) primary key,\r\n" +
        "  name varchar(20),\r\n" + "  email varchar(20),\r\n" + "  country varchar(20),\r\n" +
        "  password varchar(20)\r\n" + "  );";

    public static void main(String[] argv) throws SQLException {
        CreateStatementExample createTableExample = new CreateStatementExample();
        createTableExample.createTable();
    }

    public void createTable() throws SQLException {

        System.out.println(createTableSQL);
        // Step 1: Establishing a Connection
        try (Connection connection = DriverManager
            .getConnection("jdbc:mysql://localhost:3306/mysql_database?useSSL=false", "root", "root");

            // Step 2:Create a statement using connection object
            Statement statement = connection.createStatement();) {

            // Step 3: Execute the query or update query
            statement.execute(createTableSQL);
        } catch (SQLException e) {

            // print SQL exception information
            printSQLException(e);
        }

        // Step 4: try-with-resource statement will auto close the connection.
    }

    public static void printSQLException(SQLException ex) {
        for (Throwable e: ex) {
            if (e instanceof SQLException) {
                e.printStackTrace(System.err);
                System.err.println("SQLState: " + ((SQLException) e).getSQLState());
                System.err.println("Error Code: " + ((SQLException) e).getErrorCode());
                System.err.println("Message: " + e.getMessage());
                Throwable t = ex.getCause();
                while (t != null) {
                    System.out.println("Cause: " + t);
                    t = t.getCause();
                }
            }
        }
    }
}

Pelaksana Pernyataan Sisipkan - Sisipkan Contoh Rekaman

Dalam contoh ini, kami menggunakan antarmuka PreparedStatement untuk menyisipkan catatan pengguna. Seperti yang kita ketahui, antarmuka PreparedStatement meningkatkan kinerja seperti pernyataan SQL yang dikompilasi sebelumnya dan disimpan dalam objek PreparedStatement. Objek ini kemudian dapat digunakan untuk mengeksekusi pernyataan ini beberapa kali secara efisien

package com.javaguides.jdbc.preparestatement.examples;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;

/**
 * Insert PrepareStatement JDBC Example
 * 
 * @author Ramesh Fadatare
 *
 */
public class InsertPStatementExample {
    private static final String INSERT_USERS_SQL = "INSERT INTO users" +
        "  (id, name, email, country, password) VALUES " +
        " (?, ?, ?, ?, ?);";

    public static void main(String[] argv) throws SQLException {
        InsertPStatementExample createTableExample = new InsertPStatementExample();
        createTableExample.insertRecord();
    }

    public void insertRecord() throws SQLException {
        System.out.println(INSERT_USERS_SQL);
        // Step 1: Establishing a Connection
        try (Connection connection = DriverManager
            .getConnection("jdbc:mysql://localhost:3306/mysql_database?useSSL=false", "root", "root");

            // Step 2:Create a statement using connection object
            PreparedStatement preparedStatement = connection.prepareStatement(INSERT_USERS_SQL)) {
            preparedStatement.setInt(1, 1);
            preparedStatement.setString(2, "Tony");
            preparedStatement.setString(3, "[email protected]");
            preparedStatement.setString(4, "US");
            preparedStatement.setString(5, "secret");

            System.out.println(preparedStatement);
            // Step 3: Execute the query or update query
            preparedStatement.executeUpdate();
        } catch (SQLException e) {

            // print SQL exception information
            printSQLException(e);
        }

        // Step 4: try-with-resource statement will auto close the connection.
    }

    public static void printSQLException(SQLException ex) {
        for (Throwable e: ex) {
            if (e instanceof SQLException) {
                e.printStackTrace(System.err);
                System.err.println("SQLState: " + ((SQLException) e).getSQLState());
                System.err.println("Error Code: " + ((SQLException) e).getErrorCode());
                System.err.println("Message: " + e.getMessage());
                Throwable t = ex.getCause();
                while (t != null) {
                    System.out.println("Cause: " + t);
                    t = t.getCause();
                }
            }
        }
    }
}

Menjalankan Pernyataan SELECT - Pilih Contoh Catatan

Sejauh ini kami telah membuat tabel pengguna dan memasukkan beberapa catatan ke dalamnya. Jadi sekarang kita akan menanyakan dan mengambil pengguna unik dari tabel database berdasarkan id

package com.javaguides.jdbc.preparestatement.examples;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

/**
 * Select PreparedStatement JDBC Example
 * 
 * @author Ramesh Fadatare
 *
 */
public class SelectPStatementExample {
    private static final String QUERY = "select id,name,email,country,password from users where id =?";

    public static void main(String[] args) {

        // using try-with-resources to avoid closing resources (boiler plate code)

        // Step 1: Establishing a Connection
        try (Connection connection = DriverManager
            .getConnection("jdbc:mysql://localhost:3306/mysql_database?useSSL=false", "root", "root");

            // Step 2:Create a statement using connection object
            PreparedStatement preparedStatement = connection.prepareStatement(QUERY);) {
            preparedStatement.setInt(1, 1);
            System.out.println(preparedStatement);
            // Step 3: Execute the query or update query
            ResultSet rs = preparedStatement.executeQuery();

            // Step 4: Process the ResultSet object.
            while (rs.next()) {
                int id = rs.getInt("id");
                String name = rs.getString("name");
                String email = rs.getString("email");
                String country = rs.getString("country");
                String password = rs.getString("password");
                System.out.println(id + "," + name + "," + email + "," + country + "," + password);
            }
        } catch (SQLException e) {
            printSQLException(e);
        }
        // Step 4: try-with-resource statement will auto close the connection.
    }

    public static void printSQLException(SQLException ex) {
        for (Throwable e: ex) {
            if (e instanceof SQLException) {
                e.printStackTrace(System.err);
                System.err.println("SQLState: " + ((SQLException) e).getSQLState());
                System.err.println("Error Code: " + ((SQLException) e).getErrorCode());
                System.err.println("Message: " + e.getMessage());
                Throwable t = ex.getCause();
                while (t != null) {
                    System.out.println("Cause: " + t);
                    t = t.getCause();
                }
            }
        }
    }
}

Keluaran

1,Ram,[email protected],US,secret

Read more JDBC SQL Select examples on JDBC PreparedStatement - Select Records Example.

Menjalankan pernyataan UPDATE - Perbarui Contoh Rekaman

Kita harus menggunakan  antarmuka PreparedStatement untuk melakukan operasi SQL Update. Dalam contoh ini, kami memperbarui nama dengan id.

package com.javaguides.jdbc.preparestatement.examples;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;

/**
 * Update PreparedStatement JDBC Example
 * @author Ramesh Fadatare
 *
 */
public class UpdatePStatementExample {

    private static final String UPDATE_USERS_SQL = "update users set name = ? where id = ?;";

    public static void main(String[] argv) throws SQLException {
        UpdatePStatementExample updateStatementExample = new UpdatePStatementExample();
        updateStatementExample.updateRecord();
    }

    public void updateRecord() throws SQLException {
        System.out.println(UPDATE_USERS_SQL);
        // Step 1: Establishing a Connection
        try (Connection connection = DriverManager
            .getConnection("jdbc:mysql://localhost:3306/mysql_database?useSSL=false", "root", "root");

            // Step 2:Create a statement using connection object
            PreparedStatement preparedStatement = connection.prepareStatement(UPDATE_USERS_SQL)) {
            preparedStatement.setString(1, "Ram");
            preparedStatement.setInt(2, 1);

            // Step 3: Execute the query or update query
            preparedStatement.executeUpdate();
        } catch (SQLException e) {

            // print SQL exception information
            printSQLException(e);
        }

        // Step 4: try-with-resource statement will auto close the connection.
    }

    public static void printSQLException(SQLException ex) {
        for (Throwable e: ex) {
            if (e instanceof SQLException) {
                e.printStackTrace(System.err);
                System.err.println("SQLState: " + ((SQLException) e).getSQLState());
                System.err.println("Error Code: " + ((SQLException) e).getErrorCode());
                System.err.println("Message: " + e.getMessage());
                Throwable t = ex.getCause();
                while (t != null) {
                    System.out.println("Cause: " + t);
                    t = t.getCause();
                }
            }
        }
    }
}

Baca lebih lanjut contoh update JDBC SQL di JDBC PreparedStatement - Update a Record Example

Menjalankan Pernyataan DELETE - Hapus Contoh Rekaman

Di sini kami memiliki tabel pengguna di database dan kami akan menghapus catatan dengan mengikuti program JDBC

package com.javaguides.jdbc.statement.examples;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;

/**
 * Delete Statement JDBC Example
 * @author Ramesh Fadatare
 *
 */
public class DeleteStatementExample {

    private static final String DELETE_USERS_SQL = "delete from users where id = 3;";

    public static void main(String[] argv) throws SQLException {
        DeleteStatementExample deleteStatementExample = new DeleteStatementExample();
        deleteStatementExample.deleteRecord();
    }

    public void deleteRecord() throws SQLException {
        System.out.println(DELETE_USERS_SQL);

        // Step 1: Establishing a Connection
        try (Connection connection = DriverManager
            .getConnection("jdbc:mysql://localhost:3306/mysql_database?useSSL=false", "root", "root");

            // Step 2:Create a statement using connection object
            Statement statement = connection.createStatement();) {

            // Step 3: Execute the query or update query
            int result = statement.executeUpdate(DELETE_USERS_SQL);
            System.out.println("Number of records affected :: " + result);
        } catch (SQLException e) {

            // print SQL exception information
            printSQLException(e);
        }

        // Step 4: try-with-resource statement will auto close the connection.
    }

    public static void printSQLException(SQLException ex) {
        for (Throwable e: ex) {
            if (e instanceof SQLException) {
                e.printStackTrace(System.err);
                System.err.println("SQLState: " + ((SQLException) e).getSQLState());
                System.err.println("Error Code: " + ((SQLException) e).getErrorCode());
                System.err.println("Message: " + e.getMessage());
                Throwable t = ex.getCause();
                while (t != null) {
                    System.out.println("Cause: " + t);
                    t = t.getCause();
                }
            }
        }
    }
}

Keluaran

delete from users where id = 3;
Number of records affected :: 1

Baca lebih lanjut contoh JDBC SQL Delete di  Pernyataan JDBC - Contoh Hapus Data .


Kode Lengkap dan Refactored

Ini adalah kode sumber lengkap dan refactored dari tutorial ini. Anda bisa mendapatkan kode sumber tutorial ini dari repositori GitHub saya