FASTJSON?2.0是FASTJSON项目的重要升级，目标是为下一个十年提供一个高性能的JSON库，同一套API支持JSON/JSONB两种协议，JSONPath是一等公民，支持全量解析和部分解析，支持Java服务端、客户端Android、大数据场景。
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FASJTONS2代码 https://github.com/alibaba/fastjson2/releases/tag/2.0.1
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JSONB格式文档 https://github.com/alibaba/fastjson2/wiki/jsonb_format_cn
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FASTJSON 2性能有了很大提升，具体性能数据看这里 https://github.com/alibaba/fastjson2/wiki/fastjson_benchmark
maven依赖：
<dependency>
?<groupId>com.alibaba.fastjson2</groupId>
?<artifactId>fastjson2</artifactId>
?<version>2.0.1</version>
</dependency
public class FastJsonTest {
public static void main(String[] args) {
/**
* Json类
* */
//将字符串解析成JsonObject对象
//String s="{\"name\":'张三',\"age\":20,\"address\":'太原'}";
String s = "{name:'张三',age:20,address:'太原'}";
JSONObject object = JSON.parseObject(s);
Integer age = object.getInteger("age"); //获取age的value值 20
Object o = object.get("name"); //根据key获取对应的值 张三，返回值integer
int i = object.getIntValue("age"); //根据key获取age的值 20，返回值int
Object name = object.getObject("name", String.class); //根据指定key和value类型找到对应值 张三
// System.out.println(name);
// System.out.println(i);
//将JsonObject对象转换为Java对象
Student student3 = JSON.toJavaObject(object, Student.class);
System.out.println(student3); //Student(name=张三, age=20, address=太原)
String s1 = "[{'name':'张三','age':20,'address':'太原'},{'name':'李四','age':40,'address':'新疆'}]";
//将字符串解析成数组
List<Object> list = JSON.parseArray(s1, Student.class);
System.out.println(list); //[Student(name=张三, age=20, address=太原), Student(name=李四, age=40, address=新疆)]
//将字符串解析成JsonArray对象
String ss = "[{name:'张三',age:20,address:'太原'}]";
JSONArray array = JSON.parseArray(ss);
System.out.println(array.getString(0)); //[{"name":"张三","age":20,"address":"太原"},{"name":"李四","age":40,"address":"新疆"}]
//将字符串解析成Java对象
String s2 = "{\"name\":'张三',\"age\":20,\"address\":'太原'}";
Student student = JSON.parseObject(s2, Student.class);
System.out.println(student);
//将Java对象转换成字符串
String s3 = JSON.toJSONString(student);
System.out.println(s3); //{"address":"太原","age":20,"name":"张三"}
//将Java对象输出成byte[]
byte[] bytes = JSON.toJSONBytes(student);
System.out.println(Arrays.toString(bytes)); //[123, 34, 97, 100, 100, 114, 101, 115, 115](数组过长取了一部分)
//将byte[]装换为Java对象
Student student1 = JSON.parseObject(bytes, Student.class);
System.out.println(student1); //Student(name=张三, age=20, address=太原)
/**
* JsonB
* */
//将Java对象解析成jsonb格式的byte []
byte[] bytes1 = JSONB.toBytes(student);
System.out.println(Arrays.toString(bytes1)); //[-90, 80, 97, 100, 100, 114, 101, 115, 115, 122, 6, -27, -92](数组元素只取了一部分)
//将jsonb格式的byte [] 解析成Java对象
Student student2 = JSONB.parseObject(bytes1, Student.class);
System.out.println(student2); //Student(name=张三, age=20, address=太原)
/**
* JsonPath
* */
//构建JSONPath
//使用JSONPath读取部分数据
String sss = "{\"name\":'小明'}";
JSONPath of = JSONPath.of("$name");
System.out.println(of); //$name
JSONReader reader = JSONReader.of(sss);
Object o1 = of.extract(reader);
System.out.println(o1); //小明
}
}
注意：上面String字符串格式是统一的，不能随遍写，尤其是引号?
