在执行将 Java 对象转换为 JSON 的具体任务之前,我已经测试了下面的示例。
我一直在寻找更好的性能(转换时间应该非常少)。
我的发现例如我提到的第一个链接(记录很少):
ValueData object = new ValueData();
List<ValueItems> information = new ArrayList<ValueItems>();
ValueItems v1 = new ValueItems(String.valueOf(Calendar.getInstance().getTimeInMillis()), "feat1", 1, "data1");
ValueItems v2 = new ValueItems(String.valueOf(Calendar.getInstance().getTimeInMillis()), "feat2", 2, "data2");
ValueItems v3 = new ValueItems(String.valueOf(Calendar.getInstance().getTimeInMillis()), "feat3", 3, "data3");
ValueItems v4 = new ValueItems(String.valueOf(Calendar.getInstance().getTimeInMillis()), "feat4", 4, "data4");
ValueItems v5 = new ValueItems(String.valueOf(Calendar.getInstance().getTimeInMillis()), "feat5", 5, "data5");
ValueItems v6 = new ValueItems(String.valueOf(Calendar.getInstance().getTimeInMillis()), "feat6", 6, "data6");
ValueItems v7 = new ValueItems(String.valueOf(Calendar.getInstance().getTimeInMillis()), "feat7", 7, "data7");
information.add(v1);
information.add(v2);
information.add(v3);
information.add(v4);
information.add(v5);
information.add(v6);
information.add(v7);
object.setInformation(information);
我将使用 Jackson 来转换这个
object
:
long smili = Calendar.getInstance().getTimeInMillis();
ObjectWriter ow = new ObjectMapper().writer().withDefaultPrettyPrinter();
String json = ow.writeValueAsString(object);
long emili = Calendar.getInstance().getTimeInMillis();
System.out.println("taken time using jackson = " + (emili - smili) + " milli seconds");
现在我正在使用
StringBuilder
:
smili = Calendar.getInstance().getTimeInMillis();
StringBuilder sb = new StringBuilder();
sb.append("{\n\"information\" : [\n");
for (ValueItems vi : object.getInformation()) {
sb.append("{\n\"timestamp\" : \""+vi.getTimestamp()+"\",");
sb.append("\"feature\" : \""+vi.getFeature()+"\",");
sb.append("\"ean\" : "+vi.getEan()+",");
sb.append("\"data\" : \""+vi.getData()+"\"\n},");
}
sb.deleteCharAt(sb.length() - 1);
sb.append("]\n}");
emili = Calendar.getInstance().getTimeInMillis();
System.out.println("taken time using StringBuilder = " + (emili - smili) + " milli seconds");
我得到了下面给出的列表的时间
size
7:
taken time using jackson = 534 milli seconds
taken time using StringBuilder = 1 milli seconds
我想转换
information list
大小超过10k的对象,但时间应该会非常少。
StringBuilder
创建 JSON 在这种情况下会有帮助吗?请帮我解决这个问题。
谢谢萨姆 B。
我尝试过 jakson-afterburner:
ObjectMapper mapper = new ObjectMapper();
mapper.registerModule(new AfterburnerModule());
ow = mapper.writer().withDefaultPrettyPrinter();
json = ow.writeValueAsString(object);
我已经测试了列表大小 7、7000、70000 和 700000:
时间是:
7人份:
taken time using jackson = 217 milli seconds
taken time using StringBuilder = 1 milli seconds
taken time using after-burner = 25 milli seconds
7000 人:
taken time using jackson = 310 milli seconds
taken time using StringBuilder = 31 milli seconds
taken time using after-burner = 65 milli seconds
70000:
taken time using jackson = 469 milli seconds
taken time using StringBuilder = 149 milli seconds
taken time using after-burner = 101 milli seconds
700000:
taken time using jackson = 1120 milli seconds
taken time using StringBuilder = 705 milli seconds
taken time using after-burner = 623 milli seconds
当列表大小增加时,加力是高效的。