Java里面的switch语句怎样优化

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Java里面的switch语句怎样优化

发布时间:2024-10-01 14:42

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在Java中，switch语句可以通过以下方法进行优化：

使用枚举代替switch语句：如果你的switch语句是基于某个枚举类型的值，那么可以直接使用枚举的ordinal()方法或者name()方法来替代switch语句。这样可以提高代码的可读性和可维护性。

public enum Color {     RED, GREEN, BLUE; }  Color color = Color.RED;  // 使用ordinal()方法 int index = color.ordinal(); switch (index) {     case 0:         // Do something for red         break;     case 1:         // Do something for green         break;     case 2:         // Do something for blue         break; }  // 使用name()方法 String colorName = color.name(); switch (colorName) {     case "RED":         // Do something for red         break;     case "GREEN":         // Do something for green         break;     case "BLUE":         // Do something for blue         break; }

使用HashMap代替switch语句：如果你的switch语句是基于某个对象的属性值，那么可以考虑使用HashMap来存储属性值和对应的操作。这样可以提高代码的可扩展性和性能。

public class Operation {     public static void add(int a, int b) {         // Do something for addition     }      public static void subtract(int a, int b) {         // Do something for subtraction     }      public static void multiply(int a, int b) {         // Do something for multiplication     }      public static void divide(int a, int b) {         // Do something for division     } }  String operation = "add"; int a = 1; int b = 2;  Map<String, Runnable> operations = new HashMap<>(); operations.put("add", () -> Operation.add(a, b)); operations.put("subtract", () -> Operation.subtract(a, b)); operations.put("multiply", () -> Operation.multiply(a, b)); operations.put("divide", () -> Operation.divide(a, b));  if (operations.containsKey(operation)) {     operations.get(operation).run(); } else {     // Do something for invalid operation }

使用多态代替switch语句：如果你的switch语句是基于某个对象的类型，那么可以考虑使用多态来替代switch语句。这样可以提高代码的可扩展性和可维护性。

public abstract class Shape {     public abstract double getArea(); }  public class Circle extends Shape {     private double radius;      public Circle(double radius) {         this.radius = radius;     }      @Override     public double getArea() {         return Math.PI * radius * radius;     } }  public class Rectangle extends Shape {     private double width;     private double height;      public Rectangle(double width, double height) {         this.width = width;         this.height = height;     }      @Override     public double getArea() {         return width * height;     } }  Shape shape = new Circle(5); System.out.println("Area: " + shape.getArea());