JSON入门学习第三节

public class JsonUtil {

/** 页面传至后台时，json数据在request的参数名称 */
public final static String JSON_ATTRIBUTE = "json";
public final static String JSON_ATTRIBUTE1 = "json1";
public final static String JSON_ATTRIBUTE2 = "json2";
public final static String JSON_ATTRIBUTE3 = "json3";
public final static String JSON_ATTRIBUTE4 = "json4";

/**
* 从一个JSON 对象字符格式中得到一个java对象，形如： {"id" : idValue, "name" : nameValue,
* "aBean" : {"aBeanId" : aBeanIdValue, ...}}
*
* @param object
* @param clazz
* @return
*/
public static Object getDTO(String jsonString, Class clazz) {
JSONObject jsonObject = null;
try {
setDataFormat2JAVA();
jsonObject = JSONObject.fromObject(jsonString);
} catch (Exception e) {
e.printStackTrace();
}
return JSONObject.toBean(jsonObject, clazz);
}

/**
* 从一个JSON 对象字符格式中得到一个java对象，其中beansList是一类的集合，形如： {"id" : idValue, "name" :
* nameValue, "aBean" : {"aBeanId" : aBeanIdValue, ...}, beansList:[{}, {},
* ...]}
*
* @param jsonString
* @param clazz
* @param map
*            集合属性的类型 (key : 集合属性名, value : 集合属性类型class) eg: ("beansList" :
*            Bean.class)
* @return
*/
public static Object getDTO(String jsonString, Class clazz, Map map) {
JSONObject jsonObject = null;
try {
setDataFormat2JAVA();
jsonObject = JSONObject.fromObject(jsonString);
} catch (Exception e) {
e.printStackTrace();
}
return JSONObject.toBean(jsonObject, clazz, map);
}

/**
* 从一个JSON数组得到一个java对象数组，形如： [{"id" : idValue, "name" : nameValue}, {"id" :
* idValue, "name" : nameValue}, ...]
*
* @param object
* @param clazz
* @return
*/
public static Object[] getDTOArray(String jsonString, Class clazz) {
setDataFormat2JAVA();
JSONArray array = JSONArray.fromObject(jsonString);
Object[] obj = new Object[array.size()];
for (int i = 0; i < array.size(); i++) {
JSONObject jsonObject = array.getJSONObject(i);
obj[i] = JSONObject.toBean(jsonObject, clazz);
}
return obj;
}

/**
* 从一个JSON数组得到一个java对象数组，形如： [{"id" : idValue, "name" : nameValue}, {"id" :
* idValue, "name" : nameValue}, ...]
*
* @param object
* @param clazz
* @param map
* @return
*/
public static Object[] getDTOArray(String jsonString, Class clazz, Map map) {
setDataFormat2JAVA();
JSONArray array = JSONArray.fromObject(jsonString);
Object[] obj = new Object[array.size()];
for (int i = 0; i < array.size(); i++) {
JSONObject jsonObject = array.getJSONObject(i);
obj[i] = JSONObject.toBean(jsonObject, clazz, map);
}
return obj;
}

/**
* 从一个JSON数组得到一个java对象集合
*
* @param object
* @param clazz
* @return
*/
public static List getDTOList(String jsonString, Class clazz) {
setDataFormat2JAVA();
JSONArray array = JSONArray.fromObject(jsonString);
List list = new ArrayList();
for (Iterator iter = array.iterator(); iter.hasNext();) {
JSONObject jsonObject = (JSONObject) iter.next();
list.add(JSONObject.toBean(jsonObject, clazz));
}
return list;
}

/**
* 从一个JSON数组得到一个java对象集合，其中对象中包含有集合属性
*
* @param object
* @param clazz
* @param map
*            集合属性的类型
* @return
*/
public static List getDTOList(String jsonString, Class clazz, Map map) {
setDataFormat2JAVA();
JSONArray array = JSONArray.fromObject(jsonString);
List list = new ArrayList();
for (Iterator iter = array.iterator(); iter.hasNext();) {
JSONObject jsonObject = (JSONObject) iter.next();
list.add(JSONObject.toBean(jsonObject, clazz, map));
}
return list;
}

/**
* 从json HASH表达式中获取一个map，该map支持嵌套功能 形如：{"id" : "johncon" , "name" : "小强" }
* 注意commons
* -collections版本，必须包含org.apache.commons.collections.map.MultiKeyMap
*
* @param object
* @return
*/
public static Map getMapFromJson(String jsonString) {
setDataFormat2JAVA();
JSONObject jsonObject = JSONObject.fromObject(jsonString);
Map map = new HashMap();
for (Iterator iter = jsonObject.keys(); iter.hasNext();) {
String key = (String) iter.next();
map.put(key, jsonObject.get(key));
}
return map;
}

/**
* 从json数组中得到相应java数组 json形如：["123" , "456" ]
*
* @param jsonString
* @return
*/
public static Object[] getObjectArrayFromJson(String jsonString) {
JSONArray jsonArray = JSONArray.fromObject(jsonString);
return jsonArray.toArray();
}

/**
* 把数据对象转换成json字符串 DTO对象形如：{"id" : idValue, "name" : nameValue, ...}
* 数组对象形如：[{}, {}, {}, ...] map对象形如：{key1 : {"id" : idValue, "name" :
* nameValue, ...}, key2 : {}, ...}
*
* @param object
* @return
*/
public static String getJSONString(Object object) throws Exception {
String jsonString = null;
// 日期值处理器

JsonConfig jsonConfig = new JsonConfig();
jsonConfig.registerJsonValueProcessor(java.util.Date.class,
new JsonDateValueProcessor());
if (object != null) {
if (object instanceof Collection || object instanceof Object[]) {
jsonString = JSONArray.fromObject(object, jsonConfig)
.toString();
} else {
jsonString = JSONObject.fromObject(object, jsonConfig)
.toString();
}
}
return jsonString == null ? "{}" : jsonString;
}

private static void setDataFormat2JAVA() {
// 设定日期转换格式

JSONUtils.getMorpherRegistry().registerMorpher(
new DateMorpher(new String[] { "yyyy-MM-dd",
"yyyy-MM-dd HH:mm:ss" }));
}

public static void main(String[] arg) throws Exception {
String s = "{status : 'success'}";
System.out.println(" object : " + JsonUtil.getJSONString(s));
}
}

import java.text.SimpleDateFormat;
import java.util.Date;
import net.sf.json.JsonConfig;
import net.sf.json.processors.JsonValueProcessor;

/*
* @author johncon
* 创建日期 2008-9-10
* json日期值处理器
*/
public class JsonDateValueProcessor implements JsonValueProcessor {

private String format = "yyyy-MM-dd HH:mm:ss";

public JsonDateValueProcessor() {

}

public JsonDateValueProcessor(String format) {
this.format = format;
}

public Object processArrayValue(Object value, JsonConfig jsonConfig) {
return process(value, jsonConfig);
}

public Object processObjectValue(String key, Object value,
JsonConfig jsonConfig) {
return process(value, jsonConfig);
}

private Object process(Object value, JsonConfig jsonConfig) {
if (value instanceof Date) {
String str = new SimpleDateFormat(format).format((Date) value);
return str;
}
return value == null ? null : value.toString();
}

public String getFormat() {
return format;
}

public void setFormat(String format) {
this.format = format;
}

}