class MyClass:
    def __init__(self, value):
        self._readonly_value = value
    
    @property
    def readonly_value(self):
        return self._readonly_value

# 使用
obj = MyClass(10)
print(obj.readonly_value)  # 可以读取
obj.readonly_value = 20    # 会抛出AttributeError

const obj = {};
let internalValue = 10;

Object.defineProperty(obj, 'readonlyValue', {
    get: function() {
        return internalValue;
    },
    // 不定义setter使其只读
    enumerable: true,
    configurable: false
});

console.log(obj.readonlyValue); // 10
obj.readonlyValue = 20; // 静默失败或严格模式下报错

public class MyClass {
    private final int readonlyValue;
    
    public MyClass(int value) {
        this.readonlyValue = value;
    }
    
    public int getReadonlyValue() {
        return readonlyValue;
    }
    
    // 不提供setter方法
}

obj._MyClass__readonly_value = 20  # 不推荐，破坏封装

Object.defineProperty(obj, 'readonlyValue', {
    value: 20,
    writable: true
});

Field field = MyClass.class.getDeclaredField("readonlyValue");
field.setAccessible(true);
field.set(obj, 20);