地图检索结果的位置点Position( point )问题

// 创建检索位置点对象
var posObj = new plus.maps.Position( new plus.maps.Point(116.404,39.915) );
console.log(JSON.stringify(posObj))
打印出来的
{"point":{"longitude":116.404,"latitude":39.915},"address":"","city":"","name":"","phone":"","postcode":""}
为什么取不到，全是空的？