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《探索Java API:实验报告》
2023-06-16 17:06:44 深夜i     --     --
Java API

近年来,Java语言在软件开发领域得到了广泛的应用。随着Java API的发展,开发者们可以更加方便地完成常用的编程任务。在这篇实验报告中,我们将研究Java API,并使用几个具体的案例来展示API的用法。

案例1:使用Java API读取CSV文件

我们首先需要下载一个Java API库,如OpenCSV。使用以下代码可以读取CSV文件:


import java.io.FileReader;

import java.io.IOException;

import com.opencsv.CSVReader;

public class ReadCSV {

  public static void main(String[] args) {

    try(CSVReader reader = new CSVReader(new FileReader("data.csv"))){

      String[] line;

      while((line = reader.readNext()) != null){

        System.out.println(line[0] + " | " + line[1] + " | " + line[2]);

      }

    } catch (IOException e) {

      e.printStackTrace();

    }

  }

}

案例2:使用Java API发送邮件

使用Java Mail API,我们可以很容易地发送邮件。以下是发送邮件的示例代码:


import java.util.Properties;

import javax.mail.*;

import javax.mail.internet.*;

public class SendEmail {

  public static void main(String[] args) {

    final String username = "yourEmail@gmail.com";

    final String password = "yourEmailPassword";

    String recipientEmail = "recipientEmail@domain.com";

    String subject = "Subject of Email";

    String body = "Body of Email";

    

    Properties prop = new Properties();

    prop.put("mail.smtp.host", "smtp.gmail.com");

    prop.put("mail.smtp.port", "587");

    prop.put("mail.smtp.auth", "true");

    prop.put("mail.smtp.starttls.enable", "true");

    

    Session session = Session.getInstance(prop,

      new Authenticator() {

        @Override

        protected PasswordAuthentication getPasswordAuthentication() {

          return new PasswordAuthentication(username, password);

        }

      });

      

    try {

      Message message = new MimeMessage(session);

      message.setFrom(new InternetAddress(username));

      message.setRecipients(Message.RecipientType.TO,InternetAddress.parse(recipientEmail));

      message.setSubject(subject);

      message.setText(body);

      Transport.send(message);

      System.out.println("Email sent successfully.");

    } catch (MessagingException e) {

      e.printStackTrace();

    }

  }

}

案例3:使用Java API处理XML文件

使用Java自带的javax.xml包,我们可以轻松地读取和处理XML文件。以下是读取XML文件的代码:


import java.io.File;

import javax.xml.parsers.DocumentBuilder;

import javax.xml.parsers.DocumentBuilderFactory;

import org.w3c.dom.Document;

import org.w3c.dom.Element;

import org.w3c.dom.NodeList;

public class ReadXML {

  public static void main(String[] args) {

    try {

      File inputFile = new File("data.xml");

      DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();

      DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();

      Document doc = dBuilder.parse(inputFile);

      doc.getDocumentElement().normalize();

      System.out.println("Root element :" + doc.getDocumentElement().getNodeName());

      NodeList nList = doc.getElementsByTagName("student");

      System.out.println("-----------------------");

      for (int temp = 0; temp < nList.getLength(); temp++) {

        Node nNode = nList.item(temp);

        System.out.println("\nCurrent Element :" + nNode.getNodeName());

        if (nNode.getNodeType() == Node.ELEMENT_NODE) {

          Element eElement = (Element) nNode;

          System.out.println("Student id : "

          + eElement.getAttribute("id"));

          System.out.println("First Name : "

          + eElement.getElementsByTagName("firstname")

          .item(0)

          .getTextContent());

          System.out.println("Last Name : "

          + eElement.getElementsByTagName("lastname")

          .item(0)

          .getTextContent());

          System.out.println("Age : "

          + eElement.getElementsByTagName("age")

          .item(0)

          .getTextContent());

        }

      }

    } catch (Exception e) {

      e.printStackTrace();

    }

  }

}

通过这些案例,我们可以看出Java API的强大之处。Java API提供了一系列方便易用的类和方法,使得编程变得更加简单高效。

、案例、OpenCSV、Java Mail API、XML文件。

  
  

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