Jackson JSON Processor

Jackson提供接口，可以再json和bean之间互相转换

1. 一个例子

public class JsonToJavaBean {
    public static void main(String[] args) {
        String str="{"student":[{"name":"leilei","age":23},{"name":"leilei02","age":23}]}";
        Student stu = null;
        List<Student> list = null;
        try {
            ObjectMapper objectMapper=new ObjectMapper();
            StudentList studentList=objectMapper.readValue(str, StudentList.class);
             
            list=studentList.getStudent();
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } 
        for(Student s:list){
            System.out.println(s.getName()+"   "+s.getAge());
        }
    }
}

2. 第二个例子

public static void main(String[] args) {
        ArrayList<Student> list=new ArrayList<Student>();
        Student s1=new Student();
        s1.setName("leilei");
        s1.setAge(23);
        Student s2=new Student();
        s2.setName("leilei02");
        s2.setAge(23);
        list.add(s1);
        list.add(s2);
         
        StringWriter str=new StringWriter();
         
        ObjectMapper objectMapper=new ObjectMapper();
        try {
            objectMapper.writeValue(str, list);
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }   
        System.out.println(str);
    }

我见到的用法

public Session fromJson(String json) throws JsonParseException, JsonMappingException, IOException {
        return new ObjectMapper().readValue(json, Session.class);
    }

总结

1. json在java里是以string的形式存在的

2. 转换需要的信息是原始的json数据和转换标准bean的定义

3. 可以转换array和单个object