用Java写一个json文件 [英] Write a json file in java
问题描述
我想用Java编写一个json文件,但是它不起作用,我收到此警告: 我想知道如何执行此操作,因为我将要转换为tab格式的cfg文件.
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.
Type safety: The method add(Object) belongs to the raw type ArrayList. References to generic type ArrayList<E> should be parameterized
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();
}
}
}
推荐答案
我建议您只使用对象创建一个简单的ArrayList,然后使用序列化器将它们序列化为JSON(在下面的示例中使用Jacksoin库) .看起来像这样:
I would suggest that you just make a simple ArrayList with your objects, and then serialize them into JSON with a serializer (Using the Jacksoin library in the example below). It would look something like this:
首先,在一个类中定义模型(为了便于阅读,不进行封装)
First, define your model in a class (Made without incapsulations for readability):
public class Country{
public String name;
public Integer population;
public List<String> states;
}
然后您可以继续创建它,并填充列表:
Then you can go ahead and create it, and populate the list:
import java.io.File;
import java.io.IOException;
import org.codehaus.jackson.JsonGenerationException;
import org.codehaus.jackson.map.JsonMappingException;
import org.codehaus.jackson.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();
}
}
}
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