Java 读取 Json格式的 内容

一、Json 报文格式如下：

二、获取 Json 报文中字段的内容

 1 import java.io.IOException;
 2 import com.fasterxml.jackson.core.JsonProcessingException;
 3 import com.fasterxml.jackson.databind.JsonNode;
 4 import com.fasterxml.jackson.databind.ObjectMapper;
 5
 6 public class ReadJsonValue_1_00_001 {
 7
 8     public static void main(String args[]) {
 9
10         String test = "{\n" +
11             "  \"results\":\n" +
12             "  [\n" +
13             "    {\n" +
14             "      \"objectID\":\"357\",\n" +
15             "      \"geoPoints\":\n" +
16             "      [\n" +
17             "        {\n" +
18             "          \"x\":504604.59802246094,\n" +
19             "          \"y\":305569.9150390625\n" +
20             "        }\n" +
21             "      ]\n" +
22             "    },\n" +
23             "    {\n" +
24             "      \"objectID\":\"358\",\n" +
25             "      \"geoPoints\":\n" +
26             "      [\n" +
27             "        {\n" +
28             "          \"x\":504602.2680053711,\n" +
29             "          \"y\":305554.43603515625\n" +
30             "        }\n" +
31             "      ]\n" +
32             "    }\n" +
33             "  ]\n" +
34             "}\n";
35
36         System.out.println( test );
37
38         ObjectMapper mapper = new ObjectMapper();
39         JsonNode node = null;
40         try {
41             node = mapper.readTree( test );
42         } catch (JsonProcessingException e) {
43             e.printStackTrace();
44         } catch (IOException e) {
45             e.printStackTrace();
46         }
47
48         //将Json串以树状结构读入内存
49         JsonNode results = node.get("results");//得到results这个节点下的信息
50         System.out.println( "results.size() = " + results.size() );
51
52         for(int i = 0; i < results.size(); i++ ) //遍历results下的信息，size()函数可以得节点所包含的的信息的个数，类似于数组的长度
53         {
54             System.out.println( results.get(i).get("objectID").textValue() ); //读取节点下的某个子节点的值
55
56             JsonNode geoNumber = results.get(i).get("geoPoints");
57             System.out.println( "geoNumber() = " + geoNumber.size() );
58             for(int j = 0; j < geoNumber.size(); j++ )   //循环遍历子节点下的信息
59             {
60                 System.out.println(geoNumber.get(j).get("x").doubleValue()+"--"+geoNumber.get(j).get("y").doubleValue());
61             }
62         }
63     }
64
65 }

三、读取结果为

原文地址：https://www.cnblogs.com/dgm2088/p/10000380.html