用java写一个json文件
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Write a json file in java
提问by RuuddR
I want to write a json file in java, but it doesn't work, I get this warning: I want to know how to do this, because I am going to convert a cfg file that is tabbed to json.
我想用java编写一个json文件，但它不起作用，我收到这个警告：我想知道如何做到这一点，因为我要将一个标签式的cfg文件转换为json。
Type safety: The method add(Object) belongs to the raw type ArrayList. References to generic type ArrayList<E> should be parameterized
and I have this code:
我有这个代码：
package json;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
public class JsonWriter {
public static void main(String[] args) {
JSONObject countryObj = new JSONObject();
countryObj.put("Name", "India");
countryObj.put("Population", new Integer(1000000));
JSONArray listOfStates = new JSONArray();
listOfStates.add("Madhya Pradesh");
listOfStates.add("Maharastra");
listOfStates.add("Rajasthan");
countryObj.put("States", listOfStates);
try {
// Writing to a file
File file=new File("JsonFile.json");
file.createNewFile();
FileWriter fileWriter = new FileWriter(file);
System.out.println("Writing JSON object to file");
System.out.println("-----------------------");
System.out.print(countryObj);
fileWriter.write(countryObj.toJSONString());
fileWriter.flush();
fileWriter.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
采纳答案by MichaelCleverly
I would suggest that you just make a simple ArrayList with your objects, and then serialize them into JSON with a serializer (Using the Hymansoin library in the example below). It would look something like this:
我建议您只使用对象创建一个简单的 ArrayList，然后使用序列化程序将它们序列化为 JSON（在下面的示例中使用 Hymansoin 库）。它看起来像这样：
First, define your model in a class (Made without incapsulations for readability):
首先，在一个类中定义你的模型（为了可读性，没有封装）：
public class Country{
public String name;
public Integer population;
public List<String> states;
}
Then you can go ahead and create it, and populate the list:
然后你可以继续创建它，并填充列表：
import java.io.File;
import java.io.IOException;
import org.codehaus.Hymanson.JsonGenerationException;
import org.codehaus.Hymanson.map.JsonMappingException;
import org.codehaus.Hymanson.map.ObjectMapper;
public class JsonWriter {
public static void main(String[] args) {
Country countryObj = new Country();
countryObj.name = "India";
countryObj.population = 1000000;
List<String> listOfStates = new ArrayList<String>();
listOfStates.add("Madhya Pradesh");
listOfStates.add("Maharastra");
listOfStates.add("Rajasthan");
countryObj.states = listOfStates ;
ObjectMapper mapper = new ObjectMapper();
try {
// Writing to a file
mapper.writeValue(new File("c:\country.json"), countryObj );
} catch (IOException e) {
e.printStackTrace();
}
}
}
