REST-SparkJava在使用GET时不更新对象JSON

在我获取文本的页面上进行更改后，我遇到了更新对象json的问题。下面是我的代码和响应API

响应API:

[
    { "title": "„Jak wykorzystać media i nowoczesne technologie w edukacji?” – warsztaty dla nauczycieli",
      "url": "http://www.up.krakow.pl/uniwersytet/aktualnosci/1772-jak-wykorzystac-media-i-nowoczesne-technologie-w-edukacji-warsztaty-dla-nauczycieli"
    }
]

public class NewsService implements NewsServiceInterface {
    private Document doc = Jsoup.connect("http://www.up.krakow.pl/uniwersytet/aktualnosci").get();
    private Elements links = doc.select("div.page-header");
    private LinkedHashMap<String, String> store = new LinkedHashMap<>();

    public NewsService() throws IOException {
    }

    @Override
    public List<News> getNews() {
        List<News> newsList = new ArrayList<>();
        for (Element element : links) {
            String title = element.select("a[href]").text(); // get only text
            String url = "http://www.up.krakow.pl" + element.select("a[href]").attr("href"); // get only link
            if (!store.containsKey(title)) {
                store.put(title, url);
            }
        }
        for (Map.Entry<String, String> entry : store.entrySet()) {
            newsList.add(new News(entry.getKey(), entry.getValue()));
        }
        return Lists.reverse(newsList);
    }
}

public class News implements Serializable {
    @Expose
    @SerializedName("id")
    private String id;
    @Expose
    @SerializedName("title")
    private String title;
    @Expose
    @SerializedName("url")
    private String url;
    @Expose
    @SerializedName("counterAllNews")
    private String counterAllNews;

    public News() {
    }

    public News(String title, String url) {
        this.title = title;
        this.url = url;
    }

// getter and setter

}

public class Hello {
    public static void main(String[] args) throws IOException {
        try {
            new NewsController(new NewsService());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

public class JsonUtil {
    public static String toJson(Object object) {
        return new Gson().toJson(object);
    }


    public static ResponseTransformer json() {
        return JsonUtil::toJson;
    }
}

Java服务：

[
    { "title": "„Jak wykorzystać media i nowoczesne technologie w edukacji?” – warsztaty dla nauczycieli",
      "url": "http://www.up.krakow.pl/uniwersytet/aktualnosci/1772-jak-wykorzystac-media-i-nowoczesne-technologie-w-edukacji-warsztaty-dla-nauczycieli"
    }
]

public class NewsService implements NewsServiceInterface {
    private Document doc = Jsoup.connect("http://www.up.krakow.pl/uniwersytet/aktualnosci").get();
    private Elements links = doc.select("div.page-header");
    private LinkedHashMap<String, String> store = new LinkedHashMap<>();

    public NewsService() throws IOException {
    }

    @Override
    public List<News> getNews() {
        List<News> newsList = new ArrayList<>();
        for (Element element : links) {
            String title = element.select("a[href]").text(); // get only text
            String url = "http://www.up.krakow.pl" + element.select("a[href]").attr("href"); // get only link
            if (!store.containsKey(title)) {
                store.put(title, url);
            }
        }
        for (Map.Entry<String, String> entry : store.entrySet()) {
            newsList.add(new News(entry.getKey(), entry.getValue()));
        }
        return Lists.reverse(newsList);
    }
}

public class News implements Serializable {
    @Expose
    @SerializedName("id")
    private String id;
    @Expose
    @SerializedName("title")
    private String title;
    @Expose
    @SerializedName("url")
    private String url;
    @Expose
    @SerializedName("counterAllNews")
    private String counterAllNews;

    public News() {
    }

    public News(String title, String url) {
        this.title = title;
        this.url = url;
    }

// getter and setter

}

public class Hello {
    public static void main(String[] args) throws IOException {
        try {
            new NewsController(new NewsService());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

public class JsonUtil {
    public static String toJson(Object object) {
        return new Gson().toJson(object);
    }


    public static ResponseTransformer json() {
        return JsonUtil::toJson;
    }
}

JavaPOJO:

[
    { "title": "„Jak wykorzystać media i nowoczesne technologie w edukacji?” – warsztaty dla nauczycieli",
      "url": "http://www.up.krakow.pl/uniwersytet/aktualnosci/1772-jak-wykorzystac-media-i-nowoczesne-technologie-w-edukacji-warsztaty-dla-nauczycieli"
    }
]

public class NewsService implements NewsServiceInterface {
    private Document doc = Jsoup.connect("http://www.up.krakow.pl/uniwersytet/aktualnosci").get();
    private Elements links = doc.select("div.page-header");
    private LinkedHashMap<String, String> store = new LinkedHashMap<>();

    public NewsService() throws IOException {
    }

    @Override
    public List<News> getNews() {
        List<News> newsList = new ArrayList<>();
        for (Element element : links) {
            String title = element.select("a[href]").text(); // get only text
            String url = "http://www.up.krakow.pl" + element.select("a[href]").attr("href"); // get only link
            if (!store.containsKey(title)) {
                store.put(title, url);
            }
        }
        for (Map.Entry<String, String> entry : store.entrySet()) {
            newsList.add(new News(entry.getKey(), entry.getValue()));
        }
        return Lists.reverse(newsList);
    }
}

public class News implements Serializable {
    @Expose
    @SerializedName("id")
    private String id;
    @Expose
    @SerializedName("title")
    private String title;
    @Expose
    @SerializedName("url")
    private String url;
    @Expose
    @SerializedName("counterAllNews")
    private String counterAllNews;

    public News() {
    }

    public News(String title, String url) {
        this.title = title;
        this.url = url;
    }

// getter and setter

}

public class Hello {
    public static void main(String[] args) throws IOException {
        try {
            new NewsController(new NewsService());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

public class JsonUtil {
    public static String toJson(Object object) {
        return new Gson().toJson(object);
    }


    public static ResponseTransformer json() {
        return JsonUtil::toJson;
    }
}

Javamain:

[
    { "title": "„Jak wykorzystać media i nowoczesne technologie w edukacji?” – warsztaty dla nauczycieli",
      "url": "http://www.up.krakow.pl/uniwersytet/aktualnosci/1772-jak-wykorzystac-media-i-nowoczesne-technologie-w-edukacji-warsztaty-dla-nauczycieli"
    }
]

public class NewsService implements NewsServiceInterface {
    private Document doc = Jsoup.connect("http://www.up.krakow.pl/uniwersytet/aktualnosci").get();
    private Elements links = doc.select("div.page-header");
    private LinkedHashMap<String, String> store = new LinkedHashMap<>();

    public NewsService() throws IOException {
    }

    @Override
    public List<News> getNews() {
        List<News> newsList = new ArrayList<>();
        for (Element element : links) {
            String title = element.select("a[href]").text(); // get only text
            String url = "http://www.up.krakow.pl" + element.select("a[href]").attr("href"); // get only link
            if (!store.containsKey(title)) {
                store.put(title, url);
            }
        }
        for (Map.Entry<String, String> entry : store.entrySet()) {
            newsList.add(new News(entry.getKey(), entry.getValue()));
        }
        return Lists.reverse(newsList);
    }
}

public class News implements Serializable {
    @Expose
    @SerializedName("id")
    private String id;
    @Expose
    @SerializedName("title")
    private String title;
    @Expose
    @SerializedName("url")
    private String url;
    @Expose
    @SerializedName("counterAllNews")
    private String counterAllNews;

    public News() {
    }

    public News(String title, String url) {
        this.title = title;
        this.url = url;
    }

// getter and setter

}

public class Hello {
    public static void main(String[] args) throws IOException {
        try {
            new NewsController(new NewsService());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

public class JsonUtil {
    public static String toJson(Object object) {
        return new Gson().toJson(object);
    }


    public static ResponseTransformer json() {
        return JsonUtil::toJson;
    }
}

JavaJSON:

[
    { "title": "„Jak wykorzystać media i nowoczesne technologie w edukacji?” – warsztaty dla nauczycieli",
      "url": "http://www.up.krakow.pl/uniwersytet/aktualnosci/1772-jak-wykorzystac-media-i-nowoczesne-technologie-w-edukacji-warsztaty-dla-nauczycieli"
    }
]

public class NewsService implements NewsServiceInterface {
    private Document doc = Jsoup.connect("http://www.up.krakow.pl/uniwersytet/aktualnosci").get();
    private Elements links = doc.select("div.page-header");
    private LinkedHashMap<String, String> store = new LinkedHashMap<>();

    public NewsService() throws IOException {
    }

    @Override
    public List<News> getNews() {
        List<News> newsList = new ArrayList<>();
        for (Element element : links) {
            String title = element.select("a[href]").text(); // get only text
            String url = "http://www.up.krakow.pl" + element.select("a[href]").attr("href"); // get only link
            if (!store.containsKey(title)) {
                store.put(title, url);
            }
        }
        for (Map.Entry<String, String> entry : store.entrySet()) {
            newsList.add(new News(entry.getKey(), entry.getValue()));
        }
        return Lists.reverse(newsList);
    }
}

public class News implements Serializable {
    @Expose
    @SerializedName("id")
    private String id;
    @Expose
    @SerializedName("title")
    private String title;
    @Expose
    @SerializedName("url")
    private String url;
    @Expose
    @SerializedName("counterAllNews")
    private String counterAllNews;

    public News() {
    }

    public News(String title, String url) {
        this.title = title;
        this.url = url;
    }

// getter and setter

}

public class Hello {
    public static void main(String[] args) throws IOException {
        try {
            new NewsController(new NewsService());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

public class JsonUtil {
    public static String toJson(Object object) {
        return new Gson().toJson(object);
    }


    public static ResponseTransformer json() {
        return JsonUtil::toJson;
    }
}

---

问题在哪里？如果我重新启动jetty服务器，JSON将更新。否则不会。

如果我理解正确，您在重复呼叫服务时总是得到相同的结果？您希望得到不断变化的条目，因为您获取它们的原始源发生了变化

这是因为当

新闻服务

实例化时，您只能从www.up.krakow.pl/uniwersytet/aktualnoci读取一次该信息。这在您的主要方法中只执行一次：

new NewsController(new NewsService());

更改

新闻服务

实现，以便在每次获取时重新提取新闻数据：

public class NewsService implements NewsServiceInterface {
    private LinkedHashMap<String, String> store = new LinkedHashMap<>();

    public NewsService() throws IOException {
    }

    @Override
    public List<News> getNews() {
        Document doc = Jsoup.connect("http://www.up.krakow.pl/uniwersytet/aktualnosci").get();
        Elements links = doc.select("div.page-header");
        List<News> newsList = new ArrayList<>();
        for (Element element : links) {
            String title = element.select("a[href]").text(); // get only text
            String url = "http://www.up.krakow.pl" + element.select("a[href]").attr("href"); // get only link
            if (!store.containsKey(title)) {
                store.put(title, url);
            }
        }
        for (Map.Entry<String, String> entry : store.entrySet()) {
            newsList.add(new News(entry.getKey(), entry.getValue()));
        }
        return Lists.reverse(newsList);
    }
}

公共类NewsService实现NewsServiceInterface{
私有LinkedHashMap存储=新建LinkedHashMap（）；
公共新闻服务（）引发IOException{
}
@凌驾
公共列表getNews（）{
Document doc=Jsoup.connect（“http://www.up.krakow.pl/uniwersytet/aktualnosci）.get（）；
元素链接=文件选择（“div.page-header”）；
List newsList=newarraylist（）；
用于（元素：链接）{
String title=element.select（“a[href]”）.text（）；//仅获取文本
字符串url=”http://www.up.krakow.pl“+element.select（“a[href]”）.attr（“href”）；//仅获取链接
如果（！store.containsKey（标题））{
store.put（标题、url）；
}
}
对于（Map.Entry:store.entrySet（））{
添加（新新闻（entry.getKey（），entry.getValue（））；
}
返回列表。反向（新闻列表）；
}
}

---

这只是一个修复程序，用于获得始终相同的值。根据调用服务的频率，这可能会导致对正在查询的后端服务器的大量请求。在这种情况下，您应该添加某种缓存，例如，当最后一个数据太旧时，它只从后面获取新数据。但那是另一回事。

如果我没有弄错的话，您在反复呼叫服务时总是得到相同的结果？您希望得到不断变化的条目，因为您获取它们的原始源发生了变化

这是因为当

新闻服务

实例化时，您只能从www.up.krakow.pl/uniwersytet/aktualnoci读取一次该信息。这在您的主要方法中只执行一次：

new NewsController(new NewsService());

更改

新闻服务

实现，以便在每次获取时重新提取新闻数据：

public class NewsService implements NewsServiceInterface {
    private LinkedHashMap<String, String> store = new LinkedHashMap<>();

    public NewsService() throws IOException {
    }

    @Override
    public List<News> getNews() {
        Document doc = Jsoup.connect("http://www.up.krakow.pl/uniwersytet/aktualnosci").get();
        Elements links = doc.select("div.page-header");
        List<News> newsList = new ArrayList<>();
        for (Element element : links) {
            String title = element.select("a[href]").text(); // get only text
            String url = "http://www.up.krakow.pl" + element.select("a[href]").attr("href"); // get only link
            if (!store.containsKey(title)) {
                store.put(title, url);
            }
        }
        for (Map.Entry<String, String> entry : store.entrySet()) {
            newsList.add(new News(entry.getKey(), entry.getValue()));
        }
        return Lists.reverse(newsList);
    }
}

公共类NewsService实现NewsServiceInterface{
私有LinkedHashMap存储=新建LinkedHashMap（）；
公共新闻服务（）引发IOException{
}
@凌驾
公共列表getNews（）{
Document doc=Jsoup.connect（“http://www.up.krakow.pl/uniwersytet/aktualnosci）.get（）；
元素链接=文件选择（“div.page-header”）；
List newsList=newarraylist（）；
用于（元素：链接）{
String title=element.select（“a[href]”）.text（）；//仅获取文本
字符串url=”http://www.up.krakow.pl“+element.select（“a[href]”）.attr（“href”）；//仅获取链接
如果（！store.containsKey（标题））{
store.put（标题、url）；
}
}
对于（Map.Entry:store.entrySet（））{
添加（新新闻（entry.getKey（），entry.getValue（））；
}
返回列表。反向（新闻列表）；
}
}

---

这只是一个修复程序，用于获得始终相同的值。根据调用服务的频率，这可能会导致对正在查询的后端服务器的大量请求。在这种情况下，您应该添加某种缓存，例如，当最后一个数据太旧时，它只从后面获取新数据。但那是另一回事。

谢谢你的回答。你说得对。我更改了代码，我会通知您结果谢谢您的回答。你说得对。我更改了代码，我将通知结果