几种json lib 将json字符串转换成java对象

//////////net.sf.json//////////

JSONObject sfObject = JSONObject.fromObject(str); 
//String str = jsonObject.toString(); //转json字符串
Model ecs = (Model) JSONObject.toBean(sfObject, Model.class); //json字符串转java对象



//////////google的Gson//////////

//对象转json字符串
Gson gson = new Gson();  
String str = gson.toJson(model);
 
Model model = new Gson().fromJson(str, Model.class); //json字符串转java对象


//////////alibaba的fastjson//////////

JSONObject jsonObject = JSON.parseObject(str);
//String str = jsonObject.toJSONString(); //转json字符串
Model model = JSON.parseObject(s, Model.class); //json字符串转java对象

//json字符串
String str = "{\"Average\":0.29,\"Maximum\":0.32,\"Minimum\":0.25,\"instanceId\":\"i-426auf2hf\",\"timestamp\":1449939900000,\"userId\":\"1467232540347717\"}";


//实体类
public class Model {
    private double Average;
    private double Maximum;
    private double Minimum;
    private String instanceId;
    private long timestamp;
    private String userId;
 
    public double getAverage() {
        return Average;
    }
 
    public void setAverage(double average) {
        Average = average;
    }
 
    public double getMaximum() {
        return Maximum;
    }
 
    public void setMaximum(double maximum) {
        Maximum = maximum;
    }
 
    public double getMinimum() {
        return Minimum;
    }
 
    public void setMinimum(double minimum) {
        Minimum = minimum;
    }
 
    public String getInstanceId() {
        return instanceId;
    }
 
    public void setInstanceId(String instanceId) {
        this.instanceId = instanceId;
    }
 
    public long getTimestamp() {
        return timestamp;
    }
 
    public void setTimestamp(long timestamp) {
        this.timestamp = timestamp;
    }
 
    public String getUserId() {
        return userId;
    }
 
    public void setUserId(String userId) {
        this.userId = userId;
    }
}