JSON

一、JSON语法：

　　1.数组：[1,2,3]；//数组里面可以放对象；

　　2.对象：{"key"：value，"key"：value}；//对象里面可以放数组；

二、fastjson解析：

　　1.导包：fastjson.jar；

　　2.解析：

　　（1）序列化：String toJSONString(Object object)；

@WebServlet("/jsonTest")
public class JsonTest extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        User user = new User();
        user.setName("zs");
        user.setAge(12);
        String userStr = JSON.toJSONString(user);
        resp.getWriter().print(userStr);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doGet(req, resp);
    }
}　　

　　（2）反序列化：

　　　　1.普通对象：

　　　　　　1）class<?> JSON.parseObject(String, class<?>.class);

@WebServlet("/jsonTest")
public class JsonTest extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String userStr = "{\"name\":\"zs\",\"age\":13}";
        User user = JSON.parseObject(userStr, User.class);
        System.out.println(user);
    }
}

　　　　　　2）List<Object> JSON.parseArray(String, Object.class)

@WebServlet("/jsonTest")
public class JsonTest extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String usersStr = "[{\"name\":\"zs\",\"age\":12},{\"name\":\"ls\",\"age\":16}]";
        List<User> users = JSON.parseArray(usersStr, User.class);
        for (Iterator<User> iterator = users.iterator(); iterator.hasNext(); ) {
            User user = iterator.next();
            System.out.println(user);
        }
    }
}

　　　　2.Lsit，set集合：

　　　　　　1）将json转换成List：

　　　　　　　　List list = JSON.parseObject(json,new TypeReference<ARRAYLIST>(){});

@WebServlet("/jsonTest")
public class JsonTest extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String usersStr =  "[{\"name\":\"zs\",\"age\":12},{\"name\":\"ls\",\"age\":16}]";
        List<User> users = JSON.parseObject(usersStr, new TypeReference<List<User>>() {});
        for (Iterator<User> iterator = users.iterator(); iterator.hasNext(); ) {
            User user = iterator.next();
            System.out.println(user);
        }
    }
}

　　　　　　2）将json转换成Set：

　　　　　　　　Set set = JSON.parseObject(json,new TypeReference<HASHSET>(){});

@WebServlet("/jsonTest")
public class JsonTest extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String usersStr =  "[{\"name\":\"zs\",\"age\":12},{\"name\":\"ls\",\"age\":16}]";
        Set<User> users = JSON.parseObject(usersStr, new TypeReference<Set<User>>() {});
        for (Iterator<User> iterator = users.iterator(); iterator.hasNext(); ) {
            User user = iterator.next();
            System.out.println(user);
        }
    }
}

三、Gson解析：

　　1.导包：google-gson.jar；

　　2.解析：

　　（1）序列化：

　　　　Gson gson = new Gson();

　　　　String json = gson.toJson(obj);

@WebServlet("/jsonTest")
public class JsonTest extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        User user = new User();
        user.setName("zs");
        user.setAge(12);
        Gson gson = new Gson();
        String userStr = gson.toJson(user);
        resp.getWriter().print(userStr);
    }
}

　　（2）反序列化：

　　　　1）普通对象

　　　　Gson gson = new Gson();

　　　　Book book = gson.fromJson(json, Book.class);

@WebServlet("/jsonTest")
public class JsonTest extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String userStr = "{\"name\":\"zs\",\"age\":13}";
        Gson gson = new Gson();
        User user = gson.fromJson(userStr, User.class);
        System.out.println(user);
    }
}

　　2）Lsit，set集合

　　　　//将json转换成List

　　　　List list = gson.fromJson(json,new TypeToken<List>() {}.getType());

@WebServlet("/jsonTest")
public class JsonTest extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String usersStr =  "[{\"name\":\"zs\",\"age\":12},{\"name\":\"ls\",\"age\":16}]";
        Gson gson = new Gson();
        List list = gson.fromJson(usersStr, new TypeToken<List>() {}.getType());
        for (Iterator iterator = list.iterator(); iterator.hasNext(); ) {
            Object user =  iterator.next();
            System.out.println(user);
        }
    }
}

　　　　//将json转换成Set

　　　　Set set = gson.fromJson(json,new TypeToken<Set>() {}.getType());

@WebServlet("/jsonTest")
public class JsonTest extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String usersStr =  "[{\"name\":\"zs\",\"age\":12},{\"name\":\"ls\",\"age\":16}]";
        Gson gson = new Gson();
        Set set =gson.fromJson(usersStr, new TypeToken<Set>() {}.getType());
        for (Iterator iterator = set.iterator(); iterator.hasNext(); ) {
            Object user =  iterator.next();
            System.out.println(user);
        }
    }
}

三、js序列化/反序列化：

　　1.序列化：JSON.stringify(obj[arr])；//把对象或数组转为String；

　　2.反序列化：JSON.parse(字符串);  //把字符串转换为javascript对象；

　　　　//非标字符串：使用eval("("+字符串+")");

　　3.json字符串：

　　　　1）标准：var str = '{"sid":"001","sname":"张三","sage":17,"ssex":"男"}';

　　　　//JSON.parse(str)；

　　　　2）非标：var str = "{'sid':'001','sname':'张三','sage':17,'ssex':'男'}";

　　　　//eval("("+str+")")；