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  • net.sf.json在处理json对象转换为普通java实体对象时的问题和解决方案

    我使用的net.sf.json是json-lib-2.4-jdk15.jar,把json对象转换为普通java实体对象时候有个问题,josn对象转换为java对象之后,json串里面的那几个小数点的值对应的java属性的值取不到。

    json串如下所示:

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

    java实体对象如下:

    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;
        }
    }

    转换代码如下:

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

    Average的值拿不到,所以输出的结果是:0.0,而不是0.28。

    解决方案:

    我放弃了json.lib,用google的Gson能够完美的解决。

    Gson把json串转换成java实体对象的方法如下:

    1.首页导入Gson的jar包,网上可以下载。

    2. 实体类还是使用上面的实体类,转换代码如下所示:

    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,打印结果正确。

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  • 原文地址:https://www.cnblogs.com/longshiyVip/p/5043321.html
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