1. 首先，你需要下载URL（作为文本）：

private static String readUrl(String urlString) throws Exception {
    BufferedReader reader = null;
    try {
        URL url = new URL(urlString);
        reader = new BufferedReader(new InputStreamReader(url.openStream()));
        StringBuffer buffer = new StringBuffer();
        int read;
        char[] chars = new char[1024];
        while ((read = reader.read(chars)) != -1)
            buffer.append(chars, 0, read); 

        return buffer.toString();
    } finally {
        if (reader != null)
            reader.close();
    }
}

1. 然后你需要解析它（这里有一些选项）。

GSON（完整示例）：

static class Item {
    String title;
    String link;
    String description;
}

static class Page {
    String title;
    String link;
    String description;
    String language;
    List<Item> items;
}

public static void main(String[] args) throws Exception {

    String json = readUrl("http://www.javascriptkit.com/"
                          + "dhtmltutors/javascriptkit.json");

    Gson gson = new Gson();        
    Page page = gson.fromJson(json, Page.class);

    System.out.println(page.title);
    for (Item item : page.items)
        System.out.println("    " + item.title);
}

输出：

javascriptkit.com
    Document Text Resizer
    JavaScript Reference- Keyboard/ Mouse Buttons Events
    Dynamically loading an external JavaScript or CSS file

试试json.org上的Java API ：

try {
    JSONObject json = new JSONObject(readUrl("..."));

    String title = (String) json.get("title");
    ...

} catch (JSONException e) {
    e.printStackTrace();
}