fastjson常用方法实例

Map转JSON字符串

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/**
 * 将Map转Json字符串
 */
@Test
public void test1() {
    Map<String, Object> map = new HashMap<String, Object>();
    map.put("key1", "One");
    map.put("key2", "Two");
    String mapJson = JSON.toJSONString(map);
    System.out.println(mapJson);//输出：{"key1":"One","key2":"Two"}
}

POJO List转JSON字符串

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/**
 * 将Java Bean List转Json字符串
 */
@Test
public void test6() {
    Person person1 = new Person();
    person1.setName("张三");
    person1.setAge(28);
    person1.setBirthday(new Date());
 
    Person person2 = new Person();
    person2.setName("李四");
    person2.setAge(25);
    person2.setBirthday(new Date());
 
    List<Person> persons = new ArrayList<Person>();
    persons.add(person1);
    persons.add(person2);
 
    String object = JSON.toJSONString(persons);
    System.out.println(object);
    /**输出如下：
     * [{"age":28,"birthday":1530511546991,"name":"张三"},    
        {"age":25,"birthday":1530511546991,"name":"李四"}]
     */
}

JSON字符串转JsonObject

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/**
 * 将Json字符串转为JsonObject对象
 * 取值不存在时，返回null,使用Gson会抛异常
 */
@Test
public void test2() {
    String jsonStr = "{\"key1\":\"One\",\"key2\":\"110\"}";
    JSONObject jsonObject = JSONObject.parseObject(jsonStr);
    System.out.println(jsonObject.getString("key1"));//输出one
    System.out.println(jsonObject.getInteger("key2"));//输出110
    System.out.println(jsonObject.getString("key3"));//输出null
}

JsonObject转Json字符串

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/**
 * 将JsonObject对象转为Json字符串
 * 取值不存在时，返回null,使用Gson会抛异常
 */
@Test
public void test3() {
    String jsonStr = "{\"key1\":\"One\",\"key2\":\"110\"}";
    JSONObject jsonObject = JSONObject.parseObject(jsonStr);
    System.out.println(jsonObject.getString("key1"));//输出：one
    System.out.println(jsonObject.getInteger("key2"));//输出：110
    System.out.println(jsonObject.getString("key3"));//输出：null
    String parserJsonStr = JSONObject.toJSONString(jsonObject);
    System.out.println(parserJsonStr);//输出：{"key1":"One","key2":"110"}
}

JsonArray添加JsonObject

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/**
 * 将JsonObject添加到JsonArray
 */
@Test
public void test4() {
    JSONObject jsonObject1 = new JSONObject();
    jsonObject1.put("name", "张三");
    jsonObject1.put("age", 25);
 
    JSONObject jsonObject2 = new JSONObject();
    jsonObject2.put("name", "李四");
    jsonObject2.put("age", 28);
 
    JSONArray jsonArray = new JSONArray();
    jsonArray.add(jsonObject1);
    jsonArray.add(jsonObject2);
 
    String jsonArrStr = JSONArray.toJSONString(jsonArray);
    System.out.println(jsonArrStr);//输出：[{"name":"张三","age":25},{"name":"李四","age":28}]
}

Json数组字符串转JsonArray

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/**
 * 将Json数组字符串转JsonArray
 */
@Test
public void test5() {
    String jsonArrStr = "[{\"name\":\"张三\",\"age\":25},{\"name\":\"李四\",\"age\":28}]";
    JSONArray jsonArray = JSONArray.parseArray(jsonArrStr);
    for (Object object : jsonArray) {
        JSONObject jsonObject = (JSONObject) object;
        System.out.println(jsonObject.getString("name"));
        System.out.println(jsonObject.getString("age"));
        System.out.println("--------------");
    }
}

POJO转Json字符串

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/**
 * 将Java Bean 转Json字符串
 */
@Test
public void test7_2() {
    Person person1 = new Person();
    person1.setName("张三");
    person1.setAge(26);
    person1.setBirthday(new Date());
 
    /**两种方式都行
     * 因为JSONObject继承了JSON*/
    String object = JSONObject.toJSONString(person1);
    /*String object = JSON.toJSONString(person1);*/
 
    System.out.println(object);
    /**输出如下：
     * {"age":26,"birthday":1530511790302,"name":"张三"}
     */
}

POJO转JsonObject

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/**
 * 将Java Bean 转Json 对象
 */
@Test
public void test8() {
    Person person1 = new Person();
    person1.setName("张三");
    person1.setAge(28);
    person1.setBirthday(new Date());
 
    /**方式一*/
    String jsonStr = JSONObject.toJSONString(person1);
    JSONObject jsonObject = JSONObject.parseObject(jsonStr);
    System.out.println(jsonObject.get("name"));//输出：张三
 
    /**方式二*/
    JSONObject jsonObject1 = (JSONObject)JSONObject.toJSON(person1);
    System.out.println(jsonObject1.get("age"));//输出：28
}

POJO List转JsonArray

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/**
 * 将Java Bean List 转Json 数组
 */
@Test
public void test9() {
    Person person1 = new Person();
    person1.setName("张三");
    person1.setAge(28);
    person1.setBirthday(new Date());
 
    Person person2 = new Person();
    person2.setName("李四");
    person2.setAge(25);
    person2.setBirthday(new Date());
 
    List<Person> persons = new ArrayList<Person>();
    persons.add(person1);
    persons.add(person2);
 
    /**方式1*/
    String jsonArrStr = JSONArray.toJSONString(persons);
    JSONArray jsonArray = JSONArray.parseArray(jsonArrStr);
    JSONObject jsonObject1 = (JSONObject)jsonArray.get(0);
    System.out.println(jsonObject1.get("name"));//输出：张三
 
    /**方式2*/
    JSONArray jsonArray1 = (JSONArray)JSONArray.toJSON(persons);
    JSONObject jsonObject2 = (JSONObject)jsonArray1.get(1);
    System.out.println(jsonObject2.get("name"));//输出：李四
}

JSON字符串转 Map 与 POJO

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@Test
    public void test1() {
        String content = "{\"PARENT_ID\":1,\"NAME\":\"国家级正职\",\"CODE\":\"101\",\"LEVEL_NUM\":2,\"ID\":2}";
        Map map = JSONObject.parseObject(content, Map.class);//json 对象转 map
        System.out.println(map);
        //输出：{CODE=101, LEVEL_NUM=2, ID=2, PARENT_ID=1, NAME=国家级正职}
    }
/**
 * 将Json 对象 转 Java Bean
 */
@Test
public void test10() {
    Person person1 = new Person();
    person1.setName("张三");
    person1.setAge(28);
    person1.setBirthday(new Date());
 
    String jsonPOJOStr = JSON.toJSONString(person1);
    Person person = JSONObject.parseObject(jsonPOJOStr, Person.class);
    System.out.println(person);
    /**
     * 输出：Person{age=28, name='张三', birthday=Mon Jul 02 14:27:53 CST 2018}
     */
}

字符串Json数组转List

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@Test
    public void test2() {
        String content = "[{\"PARENT_ID\":1,\"NAME\":\"国家级正职 
        \",\"CODE\":\"101\",\"LEVEL_NUM\":2,\"ID\":2},
        {\"PARENT_ID\":1,\"NAME\":\"国家级副职
        \",\"CODE\":\"102\",\"LEVEL_NUM\":2,\"ID\":3}]";
        //parseArray(String text, Class<T> clazz)：clazz 指定 list 中的元素类型
        List<Map> mapList = JSONArray.parseArray(content, Map.class);
        //json 转 List<Map>
        System.out.println(mapList);
    }
 /**
 * 将Json 数组 转 Java List
 */
@Test
public void test11() {
    String jsonArrPOJOStr = "[{\"birthday\":1530512954968,\"name\":\"张三
        \",\"age\":28}," +
    "{\"birthday\":1530512954968,\"name\":\"李四\",\"age\":25}]";
    List<Person> personList = JSONArray.parseArray(jsonArrPOJOStr, Person.class);
    for (Person person : personList) {
        System.out.println(person);
    }
    /**
     * 输出：
     * Person{age=28, name='张三', birthday=Mon Jul 02 14:29:14 CST 2018}
     * Person{age=25, name='李四', birthday=Mon Jul 02 14:29:14 CST 2018}
     */
}