Java Technology Stack Practical Guide: Java development skills from entry-level to proficient, specific code examples are required
Introduction:
With the rapid development of the software industry, Java has become one of the most popular programming languages. Its extremely flexible features and rich third-party libraries make it a top choice among developers. However, to become a qualified Java developer, we need to master a wide range of Java technology stacks. This article will provide a practical guide to the Java technology stack, taking you from entry to mastery to explore the essence of Java development.
1. Basic knowledge of Java
When starting Java development, the first thing you must master is the basic knowledge of Java. This includes Java syntax, object-oriented programming, exception handling, collection frameworks, etc. The following is some sample code for Java basics:
Example 1: Definition and use of Java classes
public class HelloWorld { public static void main(String[] args) { System.out.println("Hello, World!"); } }
Example 2: Java exception handling
try { // 可能抛出异常的代码 } catch (Exception e) { // 处理异常的代码 } finally { // 无论是否抛出异常都会执行的代码 }
Example 3: Java collections The use of framework
List<String> list = new ArrayList<>(); list.add("Java"); list.add("Python"); list.add("Ruby"); for (String language : list) { System.out.println(language); }
2. Web development technology
Web development is the most common and important part of Java development. Mastering web development technology will help us build powerful web applications. This includes Java EE, Spring Framework, Servlets, JSP, etc. The following is some sample code for Web development technology:
Example 4: Use of Servlet
@WebServlet("/hello") public class HelloServlet extends HttpServlet { protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.getWriter().println("Hello, Servlet!"); } }
Example 5: Use of Spring framework
@Service public class UserService { @Autowired private UserRepository userRepository; public User getUserById(int id) { return userRepository.findById(id); } }
Example 6: Use of JSP page
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>Hello JSP</title> </head> <body> <% String name = "Java"; out.println("Hello, " + name); %> </body> </html>
3. Database operation
In Java development, database operation is an essential part. We need to learn to use the database to perform operations such as additions, deletions, modifications, and searches. Commonly used database operation technologies include JDBC, MyBatis, Hibernate, etc. The following is some sample code for database operations:
Example 7: The use of JDBC
Class.forName("com.mysql.cj.jdbc.Driver"); Connection connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "password"); Statement statement = connection.createStatement(); String sql = "SELECT * FROM users"; ResultSet resultSet = statement.executeQuery(sql); while (resultSet.next()) { int id = resultSet.getInt("id"); String name = resultSet.getString("name"); String email = resultSet.getString("email"); System.out.println("id: " + id + ", name: " + name + ", email: " + email); } resultSet.close(); statement.close(); connection.close();
Example 8: The use of MyBatis
@Mapper public interface UserMapper { @Select("SELECT * FROM users WHERE id = #{id}") User getUserById(int id); }
Example 9: The use of Hibernate
@Entity @Table(name = "users") public class User { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private int id; private String name; private String email; // 省略getter和setter方法 }
Conclusion:
Through the sample code in this article, I hope it can help readers better master the practice of Java technology stack. Of course, this is just the tip of the iceberg when it comes to Java development, and there are many other technologies and tools to master. Only through continuous learning and practice can you continue to deepen and grow in the field of Java development. I wish readers better success in their Java development journey!
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