JSONUtil

介绍

JSONUtil是针对JSONObject和JSONArray的静态快捷方法集合，在之前的章节我们已经介绍了一些工具方法，在本章节我们将做一些补充。

使用

1、JSON字符串创建

JSONUtil.toJsonStr可以将任意对象（Bean、Map、集合等）直接转换为JSON字符串。 如果对象是有序的Map等对象，则转换后的JSON字符串也是有序的。

    /**
     * 转换为JSON字符串
     * <p>
     * 被转为JSON的对象
     *
     * @return JSON字符串
     */
    @Test
    void toJsonStrTest() {
        //map
        SortedMap<Object, Object> sortedMap = new TreeMap<Object, Object>() {
            private static final long serialVersionUID = 1L;
            {
                put("attributes", "a");
                put("b", "b");
                put("c", "c");
            }
        };
        //对象
        Student beanString = new Student(1, 1, 1, "张三");

        //集合
        List<Student> list = new ArrayList<>();
        list.add(new Student(1, 1, 1, "张三"));
        list.add(new Student(1, 1, 2, "李四"));
        list.add(new Student(1, 1, 3, "王五"));

        System.out.println("JSONUtil.toJsonStr(beanString) = " + JSONUtil.toJsonStr(beanString));
        System.out.println("JSONUtil.toJsonStr(sortedMap) = " + JSONUtil.toJsonStr(sortedMap));
        System.out.println("JSONUtil.toJsonStr(list) = " + JSONUtil.toJsonStr(list));
    }

结果

JSONUtil.toJsonStr(beanString) = {"gradeId":0,"studentId":1,"termId":1,"classId":1,"name":"张三"}
JSONUtil.toJsonStr(sortedMap) = {"attributes":"a","b":"b","c":"c"}
JSONUtil.toJsonStr(list) = [{"gradeId":0,"studentId":1,"termId":1,"classId":1,"name":"张三"},
{"gradeId":0,"studentId":2,"termId":1,"classId":1,"name":"李四"},
{"gradeId":0,"studentId":3,"termId":1,"classId":1,"name":"王五"}]

如果我们想获得格式化后的JSON，则：

JSONUtil.toJsonPrettyStr(object);

System.out.println("JSONUtil.toJsonPrettyStr(sortedMap) = "
 + JSONUtil.toJsonPrettyStr(sortedMap));

结果

JSONUtil.toJsonPrettyStr(sortedMap) = {
    "attributes": "a",
    "b": "b",
    "c": "c"
}

2、JSON字符串解析

    /**
     * JSON字符串转JSONObject对象
     * <p>
     * JSON字符串
     *
     * @return JSONObject
     */
    @Test
    void Test() {
        String html = "{\"name\":\"Something must have been changed since you leave\"}";
        JSONObject jsonObject = JSONUtil.parseObj(html);
        System.out.println("jsonObject.getStr(\"name\") = " + jsonObject.getStr("name"));
    }

结果

jsonObject.getStr("name") = Something must have been changed since you leave

3、XML字符串转换为JSON

    /**
     * XML字符串转为JSONObject
     *
     *  XML字符串
     * @return JSONObject
     */
    @Test
    void parseFromXmlTest() {
        String s = "<sfzh>123</sfzh><sfz>456</sfz><name>aa</name><gender>1</gender>";
        JSONObject json = JSONUtil.parseFromXml(s);
        System.out.println("json.get(\"sfzh\") = " + json.get("sfzh"));
        System.out.println("json.get(\"name\") = " + json.get("name"));

    }

结果

json.get("sfzh") = 123
json.get("name") = aa

4、JSON转换为XML

    /**
     * 转换为XML字符串
     *
     * @param json JSON
     * @return XML字符串
     */
    @Test
    void toXmlStrTest() {
        final JSONObject put = JSONUtil.createObj()
                .set("aaa", "你好")
                .set("键2", "test");

// <aaa>你好</aaa><键2>test</键2>
        final String s = JSONUtil.toXmlStr(put);
        System.out.println("s = " + s);

    }

结果

s = <aaa>你好</aaa><键2>test</键2>

5、 JSON转Bean

我们先定义两个较为复杂的Bean（包含泛型）

    @Data
    public class ADT {
        private List<String> BookingCode;
    }

    @Data
    public class Price {
        private List<List<ADT>> ADT;
    }

    /**
     * JSON字符串转为实体类对象，转换异常将被抛出
     *
     * @param <T>        Bean类型
     * @param jsonString JSON字符串
     * @param beanClass  实体类对象
     * @return 实体类对象
     * @since 3.1.2
     */
    @Test
    void toBeanTest() {
        String json = "{\"ADT\":[[{\"BookingCode\":[\"N\",\"N\"]}]]}";
        Price price = JSONUtil.toBean(json, Price.class);
        System.out.println("price = " + price);
    }