Jackson 教程示例

Json常用的类库如下

Jackson：​​​​http://jackson.codehaus.org/​​​​

JSON-lib：​​​​http://json-lib.sourceforge.net/​​​​

Gson：​​​​http://code.google.com/p/google-gson/​​​​

Jackson可以轻松的将Java对象转换成json对象和xml文档，同样也可以将json、xml转换成Java对象。不仅限于对java对象，对于Map、List、Array同样有效。​

一、准备工作

1、 下载依赖库jar包

Jackson的jar官方下载地址：​​​​http://wiki.fasterxml.com/JacksonDownload​​​​

然后在工程中导入这个jar包即可开始工作

官方示例：​​​​http://wiki.fasterxml.com/JacksonInFiveMinutes​​​​

如果你需要转换xml，那么还需要stax2-api.jar

​注​：以下我的所有示例中省略getter和setter方法，请自行添加

示例1：一个简单的Json和JavaBean之间的转换

/**
     * JavaBean/Map/List/Array互相转换JSON
     */
    public static void main(String[] args) {
        ObjectMapper objectMapper = new ObjectMapper();
        User user = new User();
        user.setAddress("中国河南省");
        user.setEmail("[e-mail]");
        user.setId(1);
        user.setName("X-rapido");
        user.setBirthday(new Birthday("2015-08-06"));

        List<String> list = new ArrayList<String>();
        list.add("a");
        list.add("b");
        list.add("c");

        Map<String, Object> map = new HashMap<String, Object>();
        map.put("a", "1");
        map.put("b", "2");
        map.put("c", "3");
        map.put("list", list);

        String []sz = {"a","b","c"};

        try {
            System.out.println(objectMapper.writeValueAsString(user));
            System.out.println(objectMapper.writeValueAsString(list));
            System.out.println(objectMapper.writeValueAsString(map));
            System.out.println(objectMapper.writeValueAsString(sz));

            String s = "{\"name\":\"X-rapido\"}";
            // Json转换JavaBean
            User a = objectMapper.readValue(s, User.class);
            System.out.println(a.getName());

            // JavaBean转换Json
            System.out.println(objectMapper.writeValueAsString(a));

        } catch (IOException e) {
            e.printStackTrace();
        }
    }
输出打印：
{"id":1,"name":"X-rapido","email":"[e-mail]","address":"中国河南省","birthday":{"birthday":"2015-08-06"}}
["a","b","c"]
{"b":"2","c":"3","a":"1","list":["a","b","c"]}
["a","b","c"]
X-rapido
{"id":0,"name":"X-rapido","email":null,"address":null,"birthday":null}

对于如何与xml进行交互和JsonGenerator类的用法还有各个write、writeObject方法