如何初始化我的单例对象

发布于 2024-12-04 05:59:38 字数 514 浏览 1 评论 0原文

public class FooClient {

    private Foo foo;
    private final static String key = "<api-key>";

    private static FooClient client = new FooClient();

    private FooClient() {
        foo = new Foo(key);
    }

    public static FooClient getFooClient() {
        return client;
    }
}

以上述方式初始化client可以吗？
我应该声明 private Foo foo;作为静态，我猜情况并非如此。
如果我必须支持不同键的不同单例，我是否应该修改 getFooClient(String key) 来获取键并缓存它，以便我可以返回特定于键的单例 FooClient。

原文

public class FooClient {

    private Foo foo;
    private final static String key = "<api-key>";

    private static FooClient client = new FooClient();

    private FooClient() {
        foo = new Foo(key);
    }

    public static FooClient getFooClient() {
        return client;
    }
}

Is it ok to initialize client in the above fashion.
Should I declare private Foo foo; as static, I am guessing its not the case.
If I have to support different singletons for different keys, should I modify getFooClient(String key) to take in a key and cache it, so that I can return singleton FooClients which are key specific.

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涙—继续流 2024-12-11 05:59:39

通常你声明

private static final FooClient client = new FooClient();

这是传统的单例实现。有关其他实施选项，请参阅维基百科页面。

我不会将 Foo foo 声明为 static。

如果您的单例可以根据键返回不同的实例，那么最好在 getFooClient() 方法中传递键值。

Usually you declare

private static final FooClient client = new FooClient();

This is the traditional Singleton implementation. See wikipedia page for other implementation options.

I would not declare Foo foo as static.

If your singleton can return different instances based on the key, then it's a good idea to pass the key value in the getFooClient() method.

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夜未央樱花落 2024-12-11 05:59:39

如果你有不止一个东西，它就不是单例。

在这两种情况下我都会使用enum。

对于只有一个的情况。

enum FooClient {
    INSTANCE;

    private final Foo foo = new Foo("<api-key>");
}

对于有多个的情况。

enum FooClient {
    INSTANCE1("<api-key>"), INSTANCE2("<api-key2>");

    private final Foo foo;
    FooClient(String apiKey) {
        foo = new Foo(apiKey);
    }
}

If you have more than one of something, its not a singleton.

I would use enum in both cases.

For the case where this is just one.

enum FooClient {
    INSTANCE;

    private final Foo foo = new Foo("<api-key>");
}

for the case where there is more than one.

enum FooClient {
    INSTANCE1("<api-key>"), INSTANCE2("<api-key2>");

    private final Foo foo;
    FooClient(String apiKey) {
        foo = new Foo(apiKey);
    }
}

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