Jackson的读取和生成

// JSON转换成对象
ObjectMapper mapper = new ObjectMapper();
AccessToken token = mapper.readValue(result, AccessToken.class);

//不创建对象，直接读取：
Map map = mapper.readValue(result, Map.class)


//对象转JSON
ObjectMapper mapper = new ObjectMapper();
String json = mapper.writeAsString(new AccessToken())

// 导入依赖
compile group: 'com.fasterxml.jackson.core', name: 'jackson-core', version: '2.9.1'
compile group: 'com.fasterxml.jackson.core', name: 'jackson-databind', version: '2.9.1'
compile group: 'com.fasterxml.jackson.core', name: 'jackson-annotations', version: '2.9.1'