Java优学网构造方法入门解析：从零掌握Java对象初始化技巧

public class Student {

// 这是一个构造方法
public Student() {
    // 初始化代码
}

}

public class User {

private String username;
private String email;
private int age;

// 基本构造方法
public User(String username) {
    this.username = username;
}

// 完整信息构造方法
public User(String username, String email, int age) {
    this.username = username;
    this.email = email;
    this.age = age;
}

}

public class DatabaseConfig {

private String url;
private String username;
private String password;
private int maxConnections = 10;
private int timeout = 30;

public DatabaseConfig(String url, String username, String password) {
    this.url = url;
    this.username = username;
    this.password = password;
}

// 全参数构造方法供特殊场景使用
public DatabaseConfig(String url, String username, String password, 
                     int maxConnections, int timeout) {
    this(url, username, password);
    this.maxConnections = maxConnections;
    this.timeout = timeout;
}

}