利用fastjson序列化对象

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sherine

最新推荐文章于 2025-05-23 23:45:00 发布

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分类专栏： fastjson 文章标签： fastjson json序列化

本文链接：https://blog.youkuaiyun.com/muyu709287760/article/details/51506576

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本文详细介绍了如何使用Fastjson库进行对象的序列化，包括将普通对象转换为Json String以及如何序列化一个List对象，强调了在序列化List时必须使用List对象而非ArrayList，否则会导致错误。

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fastjson-version: fastjson-1.1.6.jar
author: sherine_zju
Date: 2016/05/26

1.序列化一个普通对象

1.1 对象定义

public class JSONobject {
    Date time;
    int Pid;
    String activity;
    float x;
    float y;
    public Date getTime() {
        return time;
    }
    public void setTime(Date time) {
        this.time = time;
    }
    public int getPid() {
        return Pid;
    }
    public void setPid(int pid) {
        Pid = pid;
    }
    public String getActivity() {
        return activity;
    }
    public void setActivity(String activity) {
        this.activity = activity;
    }
    public float getX() {
        return x;
    }
    public void setX(float x) {
        this.x = x;
    }
    public float getY() {
        return y;
    }
    public void setY(float y) {
        this.y = y;

    public Date transStringToDate(String time){
            Date date = null;
            try  
            {  
                SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");  
                date = sdf.parse(time);  
            }  
            catch (Exception e)  
            {  
                System.out.println(e.getMessage());  
            } 
            return date;
        }
}

1.2 利用fastjson序列化为Json String

public class fastjson {  

    public static void main(String[] args) {  
        // TODO Auto-generated method stub  
        JSONobject ins = new JSONobject();  
        ins.setTime(transStringToDate("2014-6-06 20:12:07"););  
        ins.setPid(1);  

        //序列化  
        String text = JSON.toJSONString(ins);  
        System.out.println(text);      
    //存为json文件
    String file = "e://z_word//csvJson.json";
    FileWriter fwriter = null;
    try {
        fwriter = new FileWriter(file);
        fwriter.write(text);
    } catch (IOException ex) {
        ex.printStackTrace();
    } finally {
    try {
       fwriter.flush();
       fwriter.close();
    } catch (IOException ex) {
       ex.printStackTrace();
      }
    }  
    }  

}

2.序列化一个List对象

List<>对象，List<List<>>对象，List<List<List<>>>都可以序列化，这里的例子是序列化List<List<>>对象。

注意一定要是List对象，ArrayList不可以，会报错。

fastjson.JSONException : create asm serilizer error, class class JSONobject

2.1 JsonObject定义

public class JSONobject {
    Date time;
    int Pid;
    String activity;
    float x;
    float y;
    List<ReadCSV> subpart = new ArrayList();
    private List<List<ReadCSV>> parts = new ArrayList();  


    public List<ReadCSV> getSubpart() {
        return subpart;
    }
    public void setSubpart(List<ReadCSV> subpart) {
        this.subpart = subpart;
    }
    public List<List<ReadCSV>> getParts() {
        return parts;
    }
    public void setParts(List<List<ReadCSV>> parts) {
        this.parts = parts;
    }

    public Date getTime() {
        return time;
    }
    public void setTime(Date time) {
        this.time = time;
    }
    public int getPid() {
        return Pid;
    }
    public void setPid(int pid) {
        Pid = pid;
    }
    public String getActivity() {
        return activity;
    }
    public void setActivity(String activity) {
        this.activity = activity;
    }
    public float getX() {
        return x;
    }
    public void setX(float x) {
        this.x = x;
    }
    public float getY() {
        return y;
    }
    public void setY(float y) {
        this.y = y;
    }      
}

2.2 fastjson序列化List

    //得到聚类结果
    ArrayList<ArrayList<ReadCSV>> cluster=k.getCluster();
    //结果存为json变量
    JSONobject jsoNobject = new JSONobject();
    for(int i=0;i<cluster.size();i++)
    {   
        jsoNobject.getParts().add(cluster.get(i));  
    }   
    String text = JSON.toJSONString(jsoNobject);  
    System.out.println(text);

    //保存为json文件
    String file = "e://z_word//csvJson.json";
    FileWriter fwriter = null;
    try {
        fwriter = new FileWriter(file);
        fwriter.write(text);
    } catch (IOException ex) {
        ex.printStackTrace();
    } finally {
    try {
       fwriter.flush();
       fwriter.close();
    } catch (IOException ex) {
       ex.printStackTrace();
      }
    }