1.Class
Class是Type接口的實現類
2.AtomicReference
AtomicReference和AtomicInteger非常類似,不同之處就在於AtomicInteger是對整數的封裝,而AtomicReference則對應普通的對象引用。也就是它可以保證你在修改對象引用時的線程安全性
3.ObjectMapper
1)用來讀寫JSON
2)ObjectReader,ObjectWriter的工廠
3)雖然ObjectMapper 暴露了大部分的讀寫方法,但是有部分讀寫是隻在ObjectReader,ObjectWriter中
4)使用例子:
讀文件中的json爲對象
將對象寫入json文件
json是樹結構的讀寫,源碼註釋
final ObjectMapper mapper = new ObjectMapper(); // can use static singleton, inject: just make sure to reuse!
MyValue value = new MyValue();
// ... and configure
File newState = new File("my-stuff.json");
mapper.writeValue(newState, value); // writes JSON serialization of MyValue instance
// or, read
MyValue older = mapper.readValue(new File("my-older-stuff.json"), MyValue.class);
// Or if you prefer JSON Tree representation:
JsonNode root = mapper.readTree(newState);
// and find values by, for example, using a {@link com.fasterxml.jackson.core.JsonPointer} expression:
int age = root.at("/personal/age").getValueAsInt();