Question

我是D3新手。当我正在努力的时候，我得到了一个要求，我必须建立一个像这样的json -

 {
  "nodes":[
      {"name":"0","group":1},
      {"name":"1","group":1},
      {"name":"2","group":10},
      {"name":"3","group":1},
      {"name":"4","group":1}    
 ],
  "links":[
      {"source":1,"target":0},
      {"source":2,"target":0},
      {"source":3,"target":0},
      {"source":3,"target":2},
      {"source":2,"target":4},
      {"source":1,"target":4}
 ]
}

我所做的就是这样 -

"allCalls":[{"Name":"Voice","Data":"40"},
        {"Name":"SMS","Data":"30"},
        {"Name":"MMS","Data":"5"},
        {"Name":"GPRS","Data":"20"},
        {"Name":"Others","Data":"5"}],
   "allCallsRatio":5}

这是servlet

 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    String start = request.getParameter("source");
    String end = request.getParameter("count");

    if (start == null && end == null) {
        PrintWriter out = response.getWriter();
        response.setContentType("text/html");
        ArrayList<IndCallType> ratios = new ArrayList<IndCallType>();
        ratios.add(new IndCallType("Voice", "40"));
        ratios.add(new IndCallType("SMS", "30"));
        ratios.add(new IndCallType("MMS", "5"));
        ratios.add(new IndCallType("GPRS", "20"));
        ratios.add(new IndCallType("Others", "5"));
        Gson gson = new Gson();
        JsonArray arrayObj = new JsonArray();
        for (int i = 0; i < ratios.size(); i++) {
            IndCallType count = ratios.get(i);
            JsonElement linObj = gson.toJsonTree(count);
            arrayObj.add(linObj);
        }

        JsonObject myObj = new JsonObject();
        myObj.addProperty("success", true);
        myObj.add("allCalls", arrayObj);
        myObj.addProperty("allCallsRatio", ratios.size());

        System.out.println(myObj.toString());

我给了servlet的主要部分，我在这里建立了JSON。但它不是我想要的......任何人都可以帮助我......

Answer 1

我知道你需要一些东西来序列化你发布的第一个 JSON。最简单的方法是构建相应的POJO，然后使用Gson序列化它们。你可以忘记所有Json * .java的东西。 Gson将为您完成所有工作。

这是一个示例，您可以直接复制并运行到显示该想法的IDE中。您可以轻松地将其调整为您的代码。

package stackoverflow.questions;

import java.util.*;

import com.google.gson.Gson;

public class Q20162819 {

   public static class Node {
      String name;
      Integer group;

      public Node(String name, Integer group) {
         this.name = name;
         this.group = group;
      }

   }

   public static class Link {
      Integer source;
      Integer target;

      public Link(Integer source, Integer target) {
         this.source = source;
         this.target = target;
      }
   }

   public static class Data {
      List<Node> nodes = new ArrayList<>(); // java7
      List<Link> links = new ArrayList<>(); // java7
   }

   /**
    * @param args
    */
   public static void main(String[] args) {
      Data d = new Data();
      d.links.add(new Link(0, 1));
      d.links.add(new Link(2, 10));
      d.links.add(new Link(1, 20));

      d.nodes.add(new Node("1", 1));
      d.nodes.add(new Node("1", 2));
      d.nodes.add(new Node("3", 5));

      Gson g = new Gson();

      System.out.println(g.toJson(d));

   }

}

这是结果（我使用external tool格式化了它。）

{
    "nodes": [
        {
            "name": "1", 
            "group": 1
        }, 
        {
            "name": "1", 
            "group": 2
        }, 
        {
            "name": "3", 
            "group": 5
        }
    ], 
    "links": [
        {
            "source": 0, 
            "target": 1
        }, 
        {
            "source": 2, 
            "target": 10
        }, 
        {
            "source": 1, 
            "target": 20
        }
    ]
}

制作网络结构json

1 个答案: