I am now want to read a series of JSON data(Nodes data) from local txt file(shown below, NODES.txt
). I use javax.json to do this.
Currently, I have a Node class which contains the attributes:type, id, geometry class(contains type, coordinates), properties class (contains name);
Here is the data I need to retrieve, it contains more than 500 nodes in it, here I just list 3 of them, so I need to use a loop to do it, I am quite new to this, please help !!
The sample JSON data in NODES.txt
[
{
"type" : "Feature",
"id" : 8005583,
"geometry" : {
"type" : "Point",
"coordinates" : [
-123.2288,
48.7578
]
},
"properties" : {
"name" : 1
}
},
{
"type" : "Feature",
"id" : 8005612,
"geometry" : {
"type" : "Point",
"coordinates" : [
-123.2271,
48.7471
]
},
"properties" : {
"name" : 2
}
},
{
"type" : "Feature",
"id" : 8004171,
"geometry" : {
"type" : "Point",
"coordinates" : [
-123.266,
48.7563
]
},
"properties" : {
"name" : 3
}
},
****A Lot In the Between****
{
"type" : "Feature",
"id" : 8004172,
"geometry" : {
"type" : "Point",
"coordinates" : [
-113.226,
45.7563
]
},
"properties" : {
"name" : 526
}
}
]
Answer
Create classes to represent the entries:
Feature.java:
import java.util.Map;
public class Node {
public String type;
public String id;
public Geometry geometry;
public Properties properties;
}
Geometry.java:
import java.util.List;
public class Geometry {
public String type;
public List coordinates;
}
Properties.java:
public class Properties {
public String name;
}
And an application main class to drive the processing.
Main.java:
import com.google.gson.Gson;
import java.io.FileReader;
import java.io.Reader;
public class Main {
public static void main(String[] args) throws Exception {
try (Reader reader = new FileReader("NODES.txt")) {
Gson gson = new Gson();
Node[] features = gson.fromJson(reader, Node[].class);
// work with features
}
}
}
No comments:
Post a Comment