JSON字符串

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json和xml比较

json字符串表示的是键值对字符串，和xml有很多相似之处
xml例子

<?xml version="1.0" encoding="utf-8"?>
<country>
    <name>中国</name>
    <province>
        <name>黑龙江</name>
        <cities>
            <city>哈尔滨</city>
            <city>大庆</city>
        </cities>
    </province>
    <province>
        <name>广东</name>
        <cities>
            <city>广州</city>
            <city>深圳</city>
            <city>珠海</city>
        </cities>
    </province>
    <province>
        <name>台湾</name>
        <cities>
            <city>台北</city>
            <city>高雄</city>
        </cities>
    </province>
    <province>
        <name>新疆</name>
        <cities>
            <city>乌鲁木齐</city>
        </cities>
    </province>
</country>

json例子

{
    "name": "中国",
    "province": [{
        "name": "黑龙江",
        "cities": {
            "city": ["哈尔滨", "大庆"]
        }
    }, {
        "name": "广东",
        "cities": {
            "city": ["广州", "深圳", "珠海"]
        }
    }, {
        "name": "台湾",
        "cities": {
            "city": ["台北", "高雄"]
        }
    }, {
        "name": "新疆",
        "cities": {
            "city": ["乌鲁木齐"]
        }
    }]
}

java

使用json-lib-2.1-jdk15.jar包

/**
* 将普通对象转换成JSON数据
*
* @return String
*/
public static String objectToJson(Object object) {
JSONObject jsonObject = JSONObject.fromObject(object);
return jsonObject.toString();
}

/**
* 将JSON数据转换成类对象
*
* @return Object
*/
@SuppressWarnings("unchecked")
public static Object jsonToObject(String jsonString, Class beanClass) {
JSONObject jsonObject = JSONObject.fromObject(jsonString);
Object object = JSONObject.toBean(jsonObject, beanClass);

return object;
}

/**
* 将List对象转换成JSON数据
*
* @return String
*/
@SuppressWarnings("unchecked")
public static String objectListToJson(List list) {
JSONArray object = JSONArray.fromObject(list);
return object.toString();
}
/**
* 将JSON数据转换成List对象
*
* @return List
*/
@SuppressWarnings({ "unchecked" })
public static List jsonToObjectList(String jsonString, Class entityClass) {
JSONArray jsonArray = JSONArray.fromObject(jsonString);
List objectList = new ArrayList();
for (Iterator iter = jsonArray.iterator(); iter.hasNext();) {
JSONObject jsonObject = (JSONObject) iter.next();
objectList.add(JSONObject.toBean(jsonObject, entityClass));
}
return objectList;
}
/**
*
* 将JSON数据转换成List对象，转换有日期格式的
* @return List
* 结果集
* @param jsonString
* json字符串
* @param entityClass
* 转对象
* @param dataFormats
* 日期格式数组
* @author wr
*/
@SuppressWarnings({ "unchecked" })
public static List jsonToObjectList(String jsonString, Class entityClass,String[] dataFormats) {
JSONArray jsonArray = JSONArray.fromObject(jsonString);
List objectList = new ArrayList();
for (Iterator iter = jsonArray.iterator(); iter.hasNext();) {
JSONObject jsonObject = (JSONObject) iter.next();
JSONUtils.getMorpherRegistry().registerMorpher(new DateMorpher(dataFormats));
objectList.add(JSONObject.toBean(jsonObject, entityClass));
}
return objectList;
}

/**
*
* @Title: jsonToMaps
* @Description: json 字符串转map
* @param jsonStr
* @return
* @author wr
* @since 2016-10-26上午11:00:07
*/
@SuppressWarnings({ "unchecked" })
public static List<Map> jsonToMaps(String jsonStr){
JSONArray jsonArray = JSONArray.fromObject(jsonStr);
List objectList = new ArrayList();
Map map = null;
for (Iterator iter = jsonArray.iterator(); iter.hasNext();) {
map = new HashMap();
JSONObject jsonObject = (JSONObject) iter.next();
for (Iterator iters = jsonObject.keys(); iters.hasNext();) {
String key = (String) iters.next();
map.put(key, jsonObject.get(key));
}
objectList.add(map);
}
return objectList;
}
/**
* json 转成对应的map
* @param jsonString
* @return
*/
@SuppressWarnings({ "unchecked" })
public static Map jsonToMap(String jsonString) {
JSONObject jsonObject = JSONObject.fromObject(jsonString);
Map map = null;
map = new HashMap();
for (Iterator iters = jsonObject.keys(); iters.hasNext();) {
String key = (String) iters.next();
map.put(key, jsonObject.get(key));
}
return map;
}
/**
*
* @Title: parseToMap
* @Description:
* <font color="red">json字符串转map集合</font><br/>
* @param jsonStr
* @return List<Map<String, Object>>
* @author wr
* @since 2015-1-7, 下午02:27:32
*/
@SuppressWarnings("unchecked")
public static List<Map<String, Object>> parseToMap(String jsonStr) {
JSONArray jsonArray = JSONArray.fromObject(jsonStr);
List<Map<String,Object>> mapListJson = (List)jsonArray;
return mapListJson;
}

/**
* 检查JSON对象中是否包含某一键值
*
* @param jsonString
* JSON对象
* @param key
* 键值名称
* @return boolean
*/
public static boolean jsonContainsKey(String jsonString, String keyName) {
JSONObject jsonObject = JSONObject.fromObject(jsonString);
return jsonObject.containsKey(keyName);
}

var obj = {a: 'Hello', b: 'World'}; //这是一个对象，注意键名也是可以使用引号包裹的
var json = '{"a": "Hello", "b": "World"}'; //这是一个 JSON 字符串，本质是一个字符串
// 对象转换成json字符串
var json = JSON.stringify({a: 'Hello', b: 'World'}); //结果是 '{"a": "Hello", "b": "World"}'
// json字符串转换成对象
var obj = JSON.parse('{"a": "Hello", "b": "World"}'); //结果是 {a: 'Hello', b: 'World'}

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