FastJson

json格式:
  格式1:value可以为任意值
   {"key":value,"key1":value1}
  格式2:e可以为任意值
   [e1,e2]

 jsonlib工具类,可以使对象转换成json数据
  1.导入jar包
  2.使用api
   JSONArray.fromObject(对象)  数组和list 
   JSONObject.fromObject(对象) bean和map 

 

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.junit.Test;
import com.pojo.Province;
import net.sf.json.JSONArray;
import net.sf.json.JSONObject;

public class Demo {
    
    @Test
    //数组
    public void f1(){
        String[] arr={"aaa","bb","cc"};
        JSONArray json = JSONArray.fromObject(arr);
        System.out.println(json);
    }
    
    @Test
    //list
    public void f2(){
        List<String> list=new ArrayList<>();
        list.add("11");
        list.add("22");
        list.add("33");
        JSONArray json = JSONArray.fromObject(list);
        System.out.println(json);
    }
    
    @Test
    //bean
    public void f3(){
        Province pro = new Province();
        pro.setName("北京");
        pro.setProvinceid(1);
        
        JSONObject json = JSONObject.fromObject(pro);
        
        System.out.println(json);
    }
    
    @Test
    //map
    public void f4(){
        Map<String, Object> map=new HashMap<>();
        map.put("username", "tom");
        map.put("age", 18);
        JSONObject json = JSONObject.fromObject(map);
        
        System.out.println(json);
    }
    
    @Test
    //bean
    public void f5(){
        List<Province> list=new ArrayList<>();
        list.add(new Province(1,"bj"));
        list.add(new Province(2,"tj"));
        list.add(new Province(3,"nj"));
        list.add(new Province(4,"dj"));

        JSONArray json = JSONArray.fromObject(list);
        
        System.out.println(json);
    }
    
}

 

通过输入流，来解析Json对象

@Test
    public void parseJsonFromFile(){
        final String filePath  = "C:/Users/DELL/Desktop/APP/demo";
        final String fileName = "ErrorExample.info";
        InputStream in = null;
        ValidateFileResponse validateFileResponse = new ValidateFileResponse();

        try {
            in = new FileInputStream(filePath + "/" + fileName);
            validateFileResponse = JSONObject.parseObject(in, ValidateFileResponse.class);
            log.info("name:{} version:{} author:{} ",validateFileResponse.getName(),validateFileResponse.getVersion(),validateFileResponse.getAuthor());
        }catch (FileNotFoundException e){
            e.printStackTrace();
        } catch (IOException e) {
            //文件解析失败
            e.printStackTrace();
        }catch (JSONException e){
            //文件解析失败
            e.printStackTrace();
            log.error("{} json format error",fileName);
        }finally {
            if(in != null){
                try {
                    in.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }