Java中的record使用详解

public record ClassName(Type fieldName1, Type fieldName2, ...) {
    // 可选：可以添加额外的方法或逻辑
}

public record Point(int x, int y) {
}

public final class Point {
    private final int x;
    private final int y;
    // 全参构造器
    public Point(int x, int y) {
        this.x = x;
        this.y = y;
    }
    // Getter 方法
    public int x() { return x; }
    public int y() { return y; }
    // 自动覆盖 equals 和 hashCode
    @Override
    public boolean equals(Object obj) {
        if (!(obj instanceof Point)) return false;
        Point other = (Point) obj;
        return this.x == other.x && this.y == other.y;
    }
    @Override
    public int hashCode() {
        return Objects.hash(x, y);
    }
    // 自动覆盖 toString
    @Override
    public String toString() {
        return "Point[x=" + x + ", y=" + y + "]";
    }
}

public record Point(int x, int y) {}
Point p = new Point(1, 2);
// p.x = 3; // 编译错误：x 是 final 的，不能修改

Point p1 = new Point(1, 2);
Point p2 = new Point(1, 2);
System.out.println(p1.equals(p2)); // 输出 true
System.out.println(p1.hashCode()); // 输出基于字段值的哈希码
System.out.println(p1);           // 输出 Point[x=1, y=2]

public record User(String name, int age) {}
User user = new User("Alice", 25);
System.out.println(user.name()); // 输出 Alice

@ConfigurationProperties(prefix = "app")
public record AppProperties(String name, int port) {}

public record BookDto(String title, String author, double price) {}

public record Point(int x, int y) {
    public double distanceFromOrigin() {
        return Math.sqrt(x * x + y * y);
    }
}
Point p = new Point(3, 4);
System.out.println(p.distanceFromOrigin()); // 输出 5.0

public record Point(int x, int y) {
    public Point {
        if (x < 0 || y < 0) {
            throw new IllegalArgumentException("Coordinates cannot be negative");
        }
    }
}
// Point p = new Point(-1, 2); // 抛出异常

public final class Point extends java.lang.Record {
    private final int x;
    private final int y;
    // 自动生成构造方法、getters、toString、equals、hashCode 等
}

public record Point(int x, int y) implements Serializable {}