How do I use iText Phrase class?

By I Wayan Saryada in iText PDF 0 Comment

The com.itextpdf.text.Phrase represent a phrase of text in the Document object. The Phrase object knows how to add spacing between lines of text. So if we add some phrase into the document it will start on a new line when it reaches the right edge of the document. The default leading / line spacing of a Phrase object is 16.

package org.kodejava.itextpdf;

import com.itextpdf.text.Document;
import com.itextpdf.text.DocumentException;
import com.itextpdf.text.Phrase;
import com.itextpdf.text.pdf.PdfWriter;

import java.io.FileNotFoundException;
import java.io.FileOutputStream;

public class PhraseDemo {
    public static void main(String[] args) {
        // Creates an instance of Document.
        Document document = new Document();
        try {
            // Write the pdf document into a file using the PdfWriter
            // and passes the document object and a FileOutputStream.
            PdfWriter.getInstance(document, new FileOutputStream("PhraseDemo.pdf"));
            document.open();

            // Add a some Phrase element into the document.
            document.add(new Phrase("This is the first text "));
            document.add(new Phrase("This is the second text "));
            document.add(new Phrase("This is the third text "));
            document.add(new Phrase("This is the fourth text "));
            document.add(new Phrase("This is the fifth text "));
        } catch (DocumentException | FileNotFoundException e) {
            e.printStackTrace();
        } finally {
            document.close();
        }
    }
}

Maven Dependencies

<dependency>
    <groupId>com.itextpdf</groupId>
    <artifactId>itextpdf</artifactId>
    <version>5.5.13.3</version>
</dependency>

Maven Central

How do I use iText Chunk class?

By I Wayan Saryada in iText PDF 0 Comment

A chunk com.itextpdf.text.Chunk is the smallest significant part that can be added to a document. A chunk is a string with Font information.

A chunk doesn’t add line breaks, a paragraph spacing or any other spacing. The layout parameters of a chunk should be defined in the object to which this chunk is added.

When you run this example the chunk will be written from left to right. But when it reaches the right edge of the document it will start writing another chunk from the left overwriting the previous chunk.

package org.kodejava.itextpdf;

import com.itextpdf.text.*;
import com.itextpdf.text.pdf.PdfWriter;

import java.io.FileNotFoundException;
import java.io.FileOutputStream;

public class ChunkDemo {
    public static void main(String[] args) {
        Document document = new Document();
        try {
            PdfWriter.getInstance(document,
                    new FileOutputStream("ChunkDemo.pdf"));
            document.open();

            // Add some chunks into the document object.
            document.add(new Chunk("The quick brown fox "));
            document.add(new Chunk("jumps over the lazy dog."));
            document.add(new Chunk("The quick brown fox "));
            document.add(new Chunk("jumps over the lazy dog."));
            document.add(new Chunk("The quick brown fox ",
                    FontFactory.getFont(FontFactory.HELVETICA, 20,
                            Font.ITALIC, new BaseColor(0, 128, 0))));
            document.add(new Chunk("jumps over the lazy dog."));
            document.close();
        } catch (DocumentException | FileNotFoundException e) {
            e.printStackTrace();
        } finally {
            document.close();
        }
    }
}

Maven Dependencies

<dependency>
    <groupId>com.itextpdf</groupId>
    <artifactId>itextpdf</artifactId>
    <version>5.5.13.3</version>
</dependency>

Maven Central

How do I use iText Document class?

By I Wayan Saryada in iText PDF 1 Comment

The com.itextpdf.text.Document is the core class of the iText library. This class represents a pdf document. Basically to work with a document we must first create an instance of a Document. After the instance created we open the document by calling the open() method. To add some content into the document we can use the add() method. Finally, after done with the document we must close it by calling the close() method.

If you need to write and flush the document into a file we can use a PdfWriter class. The class constructor accept a Document object and an OutputStream object to do the work.

package org.kodejava.itextpdf;

import com.itextpdf.text.Document;
import com.itextpdf.text.DocumentException;
import com.itextpdf.text.Paragraph;

public class DocumentDemo {
    public static void main(String[] args) {
        // Creates an instance of a Document.
        Document document = new Document();
        try {
            // To work with a Document we must open the document, add
            // some contents and finally close the document.
            document.open();
            document.add(new Paragraph("Hello World!"));
            document.close();
        } catch (DocumentException e) {
            e.printStackTrace();
        }
    }
}

Maven Dependencies

<dependency>
    <groupId>com.itextpdf</groupId>
    <artifactId>itextpdf</artifactId>
    <version>5.5.13.3</version>
</dependency>

Maven Central

How do I create a BasicDataSource object?

By I Wayan Saryada in Apache Commons, Commons DBCP 0 Comment

This example demonstrates how to use the BasicDataSource class of Apache Commons DBCP to create a basic requirements for database connection. The configuration of the data source can be defined using some property method provided by this class. The basic properties are the driver classname, connection url, username and password.

After the datasource ready we can obtain a connection by calling the getConnection() method of the datasource. This method might throw an SQLException when error occurs.

package org.kodejava.commons.dbcp;

import org.apache.commons.dbcp2.BasicDataSource;

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

public class BasicDataSourceExample {
    public static void main(String[] args) {
        // Creates a BasicDataSource and defines its properties
        // including the driver class name, JDBC url, username
        // and password.
        try (BasicDataSource dataSource = new BasicDataSource()) {
            dataSource.setUrl("jdbc:mysql://localhost/kodejava");
            dataSource.setUsername("kodejava");
            dataSource.setPassword("s3cr*t");

            // Get a connection from the data source and do a
            // database query with the obtained connection.
            try (Connection conn = dataSource.getConnection();
                 PreparedStatement stmt = conn.prepareStatement("SELECT * FROM author")) {
                ResultSet rs = stmt.executeQuery();
                while (rs.next()) {
                    System.out.println("Author name: " + rs.getString("author_name"));
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

We can simplify the code above so that we don’t have to close the PreparedStatement and Connection manually like we did in the finally block in the code snippet. We can use try-with-resources to automatically close resources. An example can be seen in the following example: How to automatically close resources in JDBC?.

Maven Dependencies

<dependencies>
    <dependency>
        <groupId>org.apache.commons</groupId>
        <artifactId>commons-dbcp2</artifactId>
        <version>2.10.0</version>
    </dependency>
    <dependency>
        <groupId>com.mysql</groupId>
        <artifactId>mysql-connector-j</artifactId>
        <version>8.1.0</version>
    </dependency>
</dependencies>

Maven Central Maven Central

How do I create a database connection pool?

By I Wayan Saryada in Apache Commons, Commons DBCP 5 Comments

This example shows you how to create a connection pool implementation using the Apache Commons DBCP library.

package org.kodejava.commons.dbcp;

import org.apache.commons.dbcp2.*;
import org.apache.commons.pool2.impl.GenericObjectPool;
import org.apache.commons.pool2.impl.GenericObjectPoolConfig;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

public class ConnectionPoolExample {
    private static final String URL = "jdbc:mysql://localhost/kodejava";
    private static final String USERNAME = "kodejava";
    private static final String PASSWORD = "s3cr*t";

    private GenericObjectPool<PoolableConnection> connectionPool = null;

    public static void main(String[] args) throws Exception {
        ConnectionPoolExample demo = new ConnectionPoolExample();
        DataSource dataSource = demo.setUp();
        demo.printStatus();

        try (Connection conn = dataSource.getConnection();
             PreparedStatement stmt = conn.prepareStatement("SELECT * FROM author")) {
            demo.printStatus();

            ResultSet rs = stmt.executeQuery();
            while (rs.next()) {
                System.out.println("Author name: " + rs.getString("author_name"));
            }
        }

        demo.printStatus();
    }

    public DataSource setUp() {
        // Creates a connection factory object, which will be used by
        // the pool to create the connection object. We pass the
        // JDBC url info, username and password.
        ConnectionFactory cf = new DriverManagerConnectionFactory(
                ConnectionPoolExample.URL,
                ConnectionPoolExample.USERNAME,
                ConnectionPoolExample.PASSWORD);

        // Creates a PoolableConnectionFactory that will wrap the
        // connection object created by the ConnectionFactory to add
        // object pooling functionality.
        PoolableConnectionFactory pcf = new PoolableConnectionFactory(cf, null);
        pcf.setValidationQuery("SELECT 1");

        // Creates an instance of GenericObjectPool that holds our
        // pool of connection objects.
        GenericObjectPoolConfig<PoolableConnection> config = new GenericObjectPoolConfig<>();
        config.setTestOnBorrow(true);
        config.setMaxTotal(10);
        connectionPool = new GenericObjectPool<>(pcf, config);
        pcf.setPool(connectionPool);

        return new PoolingDataSource<>(connectionPool);
    }

    private GenericObjectPool<PoolableConnection> getConnectionPool() {
        return connectionPool;
    }

    /**
     * Prints connection pool status.
     */
    private void printStatus() {
        System.out.println("Max   : " + getConnectionPool().getNumActive() + "; " +
                "Active: " + getConnectionPool().getNumActive() + "; " +
                "Idle  : " + getConnectionPool().getNumIdle());
    }
}

The code shows the following status as output example:

Max   : 0; Active: 0; Idle  : 0
Max   : 1; Active: 1; Idle  : 0
Author name: Raoul-Gabriel Urma
Author name: Mario Fusco
Author name: Alan Mycroft
Max   : 0; Active: 0; Idle  : 1

Maven Dependencies

<dependencies>
    <dependency>
        <groupId>org.apache.commons</groupId>
        <artifactId>commons-dbcp2</artifactId>
        <version>2.10.0</version>
    </dependency>
    <dependency>
        <groupId>com.mysql</groupId>
        <artifactId>mysql-connector-j</artifactId>
        <version>8.1.0</version>
    </dependency>
</dependencies>

Maven Central Maven Central