Java

Json

略

fastjson

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public class FastjsonTest {

    // 将User对象转换成json
    @Test
    public void test1() {
        User user = new User();
        user.setAge(20);
        user.setBirthday(new Date());
        user.setId(1);
        user.setName("tom");


        // 转换成json
        String json = JSONObject.toJSONString(user);
        System.out.println(json);
        User user1 = JSON.parseObject(json, User.class);
        System.out.println(user1.getName());
        // {"age":20,"birthday":1479455891302,"id":1,"name":"tom"}
    }

    // 将List<User>转换成json
    @Test
    public void test2() {
        User u1 = new User();
        u1.setAge(20);
        u1.setBirthday(new Date());
        u1.setId(1);
        u1.setName("tom");

        User u2 = new User();
        u2.setAge(20);
        u2.setBirthday(new Date());
        u2.setId(1);
        u2.setName("fox");
        List<User> users = new ArrayList<User>();
        users.add(u1);
        users.add(u2);

        String json = JSONArray.toJSONString(users);
        System.out.println(json);

        List<User> users1 = JSON.parseArray(json, User.class);
        System.out.println(users1.get(0).getName());
    }
}

jackson

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public class JacksonTest {

    // 将Product转换成json
    @Test
    public void test1() throws JsonGenerationException, JsonMappingException, IOException {
        Product p = new Product();
        p.setId(1);
        p.setName("电视机");
        p.setPrice(2000);
        p.setReleaseDate(new Date());

        ObjectMapper mapper = new ObjectMapper();
        mapper.setDateFormat(new SimpleDateFormat("yyyy-MM-dd")); // 设置日期格式化器
        String json = mapper.writeValueAsString(p);
        System.out.println(json);
        Product p1 = mapper.readValue(json, Product.class);
        System.out.println(p1.getName());
    }

    // 将List<Product>转换成json
    @Test
    public void test2() throws JsonGenerationException, JsonMappingException, IOException {
        Product p1 = new Product();
        p1.setId(1);
        p1.setName("电视机");
        p1.setPrice(2000);

        Product p2 = new Product();
        p2.setId(2);
        p2.setName("电冰箱");
        p2.setPrice(3000);

        List<Product> ps = new ArrayList<Product>();
        ps.add(p1);
        ps.add(p2);

        ObjectMapper mapper = new ObjectMapper();

        // 处理过滤属性
        FilterProvider fp = new SimpleFilterProvider().addFilter("productFilter",
                SimpleBeanPropertyFilter.filterOutAllExcept("id", "name")); //只包含id与name

        //FilterProvider fp = new SimpleFilterProvider().addFilter("productFilter",
                //SimpleBeanPropertyFilter.serializeAllExcept("id", "name")); //不包含id与name

        mapper.setFilters(fp);

        String json = mapper.writeValueAsString(ps);
        System.out.println(json);
        JavaType javaType = getCollectionType(ArrayList.class, Product.class);
        List<Product> ps1 = (List<Product>) mapper.readValue(json, javaType);
        System.out.println(ps1.get(0).getName());
    }


     public static JavaType getCollectionType(Class<?> collectionClass, Class<?>... elementClasses) {
         ObjectMapper mapper = new ObjectMapper();
         return mapper.getTypeFactory().constructParametricType(collectionClass, elementClasses);
     }
}