json to java object, java object to json

GSON jar包:http://code.google.com/p/google-gson/

//java object to json
public String toJson(Object obj){
    Gson gson = new Gson();
    return gson.toJson(obj);
}

//json to java object
public Object toObject(String jsonStr, Class c){
    Gson gson = new Gson();
    return gson.fromJson(jsonStr, c);

}

jackson jar 包: http://jackson.codehaus.org/

//java object to json
public String toJson(Object obj){
    ObjectMapper om = new ObjectMapper ();
    return om.writeValueAsString(obj);
}

//json to java object
public Object toObject(String json, Class c){
    ObjectMapper mapper = new ObjectMapper();
    User user = mapper.readValue(json, c);
}