net.sf.json在處理json對象轉換為普通java實體對象時的問題和解決方案

我使用的net.sf.json是json-lib-2.4-jdk15.jar,把json對象轉換為普通java實體對象時候有個問題，josn對象轉換為java對象之后，json串里面的那幾個小數點的值對應的java屬性的值取不到。

json串如下所示:

{"Average":0.28,"Maximum":0.32,"Minimum":0.2,"instanceId":"i-426auf2hf","timestamp":1449938400000,"userId":"1467232540347717"}

java實體對象如下:

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;
    }
}

轉換代碼如下:

JSONObject sfObject = JSONObject.fromObject(str);
// 轉換方法
Model ecs = (Model) JSONObject.toBean(sfObject, Model.class);
System.out.println(ecs.getAverage());

Average的值拿不到，所以輸出的結果是:0.0,而不是0.28。

解決方案:

我放棄了json.lib,用google的Gson能夠完美的解決。

Gson把json串轉換成java實體對象的方法如下：

1.首頁導入Gson的jar包，網上可以下載。

2. 實體類還是使用上面的實體類，轉換代碼如下所示:

String str = "{\"Average\":0.29,\"Maximum\":0.32,\"Minimum\":0.25,\"instanceId\":\"i-426auf2hf\",\"timestamp\":1449939900000,\"userId\":\"1467232540347717\"}";
Model model = new Gson().fromJson(str, Model.class);
System.out.println(model.getAverage());

使用Gson之后，打印結果正確。