JSON和JAVA相互转换

java代码：package util;

import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import org.apache.commons.beanutils.BeanUtils;
import org.codehaus.jackson.JsonParseException;
import org.codehaus.jackson.map.JsonMappingException;
import org.codehaus.jackson.map.ObjectMapper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import net.sf.json.JSONArray;
import net.sf.json.JSONObject;

/**
* ClassName: JSONHelper <br/>
* Function: JSON和JAVA的POJO的相互转换. <br/>
* Reason: TODO ADD REASON(可选). <br/>
* date: 2016年6月4日 上午11:09:19 <br/>
*
* @author liuweiying
* @version
* @since JDK 1.6
*/
public final class JSONHelper {
private static final Logger logger = LoggerFactory.getLogger(JSONHelper.class);

// 将数组转换成JSON
public static String array2json(Object object) {
JSONArray jsonArray = JSONArray.fromObject(object);
return jsonArray.toString();
}

// 将JSON转换成数组,其中valueClz为数组中存放的对象的Class
public static Object json2Array(String json, Class valueClz) {
JSONArray jsonArray = JSONArray.fromObject(json);
return JSONArray.toArray(jsonArray, valueClz);
}

// 将Collection转换成JSON
public static String collection2json(Object object) {
JSONArray jsonArray = JSONArray.fromObject(object);
return jsonArray.toString();
}

// 将Map转换成JSON
public static String map2json(Object object) {
JSONObject jsonObject = JSONObject.fromObject(object);
return jsonObject.toString();
}

// 将JSON转换成Map,其中valueClz为Map中value的Class,keyArray为Map的key
public static Map json2Map(Object[] keyArray, String json, Class valueClz) {
JSONObject jsonObject = JSONObject.fromObject(json);
Map classMap = new HashMap();

for (int i = 0; i < keyArray.length; i++) {
classMap.put(keyArray[i], valueClz);
}

return (Map) JSONObject.toBean(jsonObject, Map.class, classMap);
}

// 将POJO转换成JSON
public static String bean2json(Object object) {
JSONObject jsonObject = JSONObject.fromObject(object);
return jsonObject.toString();
}

// 将JSON转换成POJO,其中beanClz为POJO的Class
public static Object json2Object(String json, Class beanClz) {
return JSONObject.toBean(JSONObject.fromObject(json), beanClz);
}

/**
* json转换为java对象
*
* <pre>
* return JackJson.fromJsonToObject(this.answersJson, JackJson.class);
* </pre>
*
* @param <T>
* 要转换的对象
* @param json
* 字符串
* @param valueType
* 对象的class
* @return 返回对象
*/
public static <T> T fromJsonToObject(String json, Class<T> valueType) {
ObjectMapper mapper = new ObjectMapper();
try {
return mapper.readValue(json, valueType);
} catch (JsonParseException e) {
logger.error("JsonParseException: ", e);
} catch (JsonMappingException e) {
logger.error("JsonMappingException: ", e);
} catch (IOException e) {
logger.error("IOException: ", e);
}
return null;
}

// 将String转换成JSON
public static String string2json(String key, String value) {
JSONObject object = new JSONObject();
object.put(key, value);
return object.toString();
}

// 将JSON转换成String
public static String json2String(String json, String key) {
JSONObject jsonObject = JSONObject.fromObject(json);
return jsonObject.get(key).toString();
}

/***
* 将List对象序列化为JSON文本
*/
public static <T> String toJSONString(List<T> list) {
JSONArray jsonArray = JSONArray.fromObject(list);

return jsonArray.toString();
}

/***
* 将对象序列化为JSON文本
*
* @param object
* @return
*/
public static String toJSONString(Object object) {
JSONArray jsonArray = JSONArray.fromObject(object);

return jsonArray.toString();
}

/***
* 将JSON对象数组序列化为JSON文本
*
* @param jsonArray
* @return
*/
public static String toJSONString(JSONArray jsonArray) {
return jsonArray.toString();
}

/***
* 将JSON对象序列化为JSON文本
*
* @param jsonObject
* @return
*/
public static String toJSONString(JSONObject jsonObject) {
return jsonObject.toString();
}

/***
* 将对象转换为List对象
*
* @param object
* @return
*/
public static List toArrayList(Object object) {
List arrayList = new ArrayList();

JSONArray jsonArray = JSONArray.fromObject(object);

Iterator it = jsonArray.iterator();
while (it.hasNext()) {
JSONObject jsonObject = (JSONObject) it.next();

Iterator keys = jsonObject.keys();
while (keys.hasNext()) {
Object key = keys.next();
Object value = jsonObject.get(key);
arrayList.add(value);
}
}

return arrayList;
}

/* *//***
* 将对象转换为Collection对象
*
* @param object
* @return
*/
/*
* public static Collection toCollection(Object object) { JSONArray
* jsonArray = JSONArray.fromObject(object);
*
* return JSONArray.toCollection(jsonArray); }
*/

/***
* 将对象转换为JSON对象数组
*
* @param object
* @return
*/
public static JSONArray toJSONArray(Object object) {
return JSONArray.fromObject(object);
}

/***
* 将对象转换为JSON对象
*
* @param object
* @return
*/
public static JSONObject toJSONObject(Object object) {
return JSONObject.fromObject(object);
}

/***
* 将对象转换为HashMap
*
* @param object
* @return
*/
public static HashMap toHashMap(Object object) {
HashMap<String, Object> data = new HashMap<String, Object>();
JSONObject jsonObject = JSONHelper.toJSONObject(object);
Iterator it = jsonObject.keys();
while (it.hasNext()) {
String key = String.valueOf(it.next());
Object value = jsonObject.get(key);
data.put(key, value);
}

return data;
}

/**
* 将json格式的字符串解析成Map对象 <li>
* json格式：{"name":"admin","retries":"3fff","testname":"ddd","testretries":"fffffffff"}
*/
public static Map<String, Object> json2Map(String jsonStr) {
Map<String, Object> data = new HashMap<String, Object>();
// 将json字符串转换成jsonObject
JSONObject jsonObject = JSONObject.fromObject(jsonStr);
Iterator it = jsonObject.keys();
// 遍历jsonObject数据，添加到Map对象
while (it.hasNext())
{
String key = String.valueOf(it.next());
Object value = jsonObject.get(key);
data.put(key, value);
}
return data;
}

/**
* 将json格式的字符串解析成Map对象 <li>
* json格式：{"name":"admin","retries":"3fff","testname":"ddd","testretries":"fffffffff"}
*/
public static Map<String, List<Map<String, Object>>> json2MapList(String jsonStr) {
Map<String, List<Map<String, Object>>> data = new HashMap<String, List<Map<String, Object>>>();
// 将json字符串转换成jsonObject
JSONObject jsonObject = JSONObject.fromObject(jsonStr);
Iterator it = jsonObject.keys();
// 遍历jsonObject数据，添加到Map对象
while (it.hasNext())
{
String key = String.valueOf(it.next());
Object value = jsonObject.get(key);
List<Map<String, Object>> list = toList(value);
data.put(key, list);
}
return data;
}

/***
* 将对象转换为List<Map<String,Object>>
*
* @param object
* @return
*/
// 返回非实体类型(Map<String,Object>)的List
public static List<Map<String, Object>> toList(Object object) {
List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
JSONArray jsonArray = JSONArray.fromObject(object);
for (Object obj : jsonArray) {
JSONObject jsonObject = (JSONObject) obj;
Map<String, Object> map = new HashMap<String, Object>();
Iterator it = jsonObject.keys();
while (it.hasNext()) {
String key = (String) it.next();
Object value = jsonObject.get(key);
map.put((String) key, value);
}
list.add(map);
}
return list;
}

// 返回非实体类型(Map<String,Object>)的List
public static List<Map<String, Object>> toList(JSONArray jsonArray) {
List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
for (Object obj : jsonArray) {
JSONObject jsonObject = (JSONObject) obj;
Map<String, Object> map = new HashMap<String, Object>();
Iterator it = jsonObject.keys();
while (it.hasNext()) {
String key = (String) it.next();
Object value = jsonObject.get(key);
map.put((String) key, value);
}
list.add(map);
}
return list;
}

/***
* 将JSON对象数组转换为传入类型的List
*
* @param <T>
* @param jsonArray
* @param objectClass
* @return
*/
public static <T> List<T> toList(JSONArray jsonArray, Class<T> objectClass) {
return JSONArray.toList(jsonArray, objectClass);
}

/***
* 将对象转换为传入类型的List
*
* @param <T>
* @param jsonArray
* @param objectClass
* @return
*/
public static <T> List<T> toList(Object object, Class<T> objectClass) {
JSONArray jsonArray = JSONArray.fromObject(object);

return JSONArray.toList(jsonArray, objectClass);
}

/***
* 将JSON对象转换为传入类型的对象
*
* @param <T>
* @param jsonObject
* @param beanClass
* @return
*/
public static <T> T toBean(JSONObject jsonObject, Class<T> beanClass) {
return (T) JSONObject.toBean(jsonObject, beanClass);
}

/***
* 将将对象转换为传入类型的对象
*
* @param <T>
* @param object
* @param beanClass
* @return
*/
public static <T> T toBean(Object object, Class<T> beanClass) {
JSONObject jsonObject = JSONObject.fromObject(object);

return (T) JSONObject.toBean(jsonObject, beanClass);
}

/***
* 将JSON文本反序列化为主从关系的实体
*
* @param <T>
* 泛型T 代表主实体类型
* @param <D>
* 泛型D 代表从实体类型
* @param jsonString
* JSON文本
* @param mainClass
* 主实体类型
* @param detailName
* 从实体类在主实体类中的属性名称
* @param detailClass
* 从实体类型
* @return
*/
public static <T, D> T toBean(String jsonString, Class<T> mainClass,
String detailName, Class<D> detailClass) {
JSONObject jsonObject = JSONObject.fromObject(jsonString);
JSONArray jsonArray = (JSONArray) jsonObject.get(detailName);

T mainEntity = JSONHelper.toBean(jsonObject, mainClass);
List<D> detailList = JSONHelper.toList(jsonArray, detailClass);

try {
BeanUtils.setProperty(mainEntity, detailName, detailList);
} catch (Exception ex) {
throw new RuntimeException("主从关系JSON反序列化实体失败！");
}

return mainEntity;
}

/***
* 将JSON文本反序列化为主从关系的实体
*
* @param <T>泛型T 代表主实体类型
* @param <D1>泛型D1 代表从实体类型
* @param <D2>泛型D2 代表从实体类型
* @param jsonString
* JSON文本
* @param mainClass
* 主实体类型
* @param detailName1
* 从实体类在主实体类中的属性
* @param detailClass1
* 从实体类型
* @param detailName2
* 从实体类在主实体类中的属性
* @param detailClass2
* 从实体类型
* @return
*/
public static <T, D1, D2> T toBean(String jsonString, Class<T> mainClass,
String detailName1, Class<D1> detailClass1, String detailName2,
Class<D2> detailClass2) {
JSONObject jsonObject = JSONObject.fromObject(jsonString);
JSONArray jsonArray1 = (JSONArray) jsonObject.get(detailName1);
JSONArray jsonArray2 = (JSONArray) jsonObject.get(detailName2);

T mainEntity = JSONHelper.toBean(jsonObject, mainClass);
List<D1> detailList1 = JSONHelper.toList(jsonArray1, detailClass1);
List<D2> detailList2 = JSONHelper.toList(jsonArray2, detailClass2);

try {
BeanUtils.setProperty(mainEntity, detailName1, detailList1);
BeanUtils.setProperty(mainEntity, detailName2, detailList2);
} catch (Exception ex) {
throw new RuntimeException("主从关系JSON反序列化实体失败！");
}

return mainEntity;
}

/***
* 将JSON文本反序列化为主从关系的实体
*
* @param <T>泛型T 代表主实体类型
* @param <D1>泛型D1 代表从实体类型
* @param <D2>泛型D2 代表从实体类型
* @param jsonString
* JSON文本
* @param mainClass
* 主实体类型
* @param detailName1
* 从实体类在主实体类中的属性
* @param detailClass1
* 从实体类型
* @param detailName2
* 从实体类在主实体类中的属性
* @param detailClass2
* 从实体类型
* @param detailName3
* 从实体类在主实体类中的属性
* @param detailClass3
* 从实体类型
* @return
*/
public static <T, D1, D2, D3> T toBean(String jsonString,
Class<T> mainClass, String detailName1, Class<D1> detailClass1,
String detailName2, Class<D2> detailClass2, String detailName3,
Class<D3> detailClass3) {
JSONObject jsonObject = JSONObject.fromObject(jsonString);
JSONArray jsonArray1 = (JSONArray) jsonObject.get(detailName1);
JSONArray jsonArray2 = (JSONArray) jsonObject.get(detailName2);
JSONArray jsonArray3 = (JSONArray) jsonObject.get(detailName3);

T mainEntity = JSONHelper.toBean(jsonObject, mainClass);
List<D1> detailList1 = JSONHelper.toList(jsonArray1, detailClass1);
List<D2> detailList2 = JSONHelper.toList(jsonArray2, detailClass2);
List<D3> detailList3 = JSONHelper.toList(jsonArray3, detailClass3);

try {
BeanUtils.setProperty(mainEntity, detailName1, detailList1);
BeanUtils.setProperty(mainEntity, detailName2, detailList2);
BeanUtils.setProperty(mainEntity, detailName3, detailList3);
} catch (Exception ex) {
throw new RuntimeException("主从关系JSON反序列化实体失败！");
}

return mainEntity;
}

/***
* 将JSON文本反序列化为主从关系的实体
*
* @param <T>
* 主实体类型
* @param jsonString
* JSON文本
* @param mainClass
* 主实体类型
* @param detailClass
* 存放了多个从实体在主实体中属性名称和类型
* @return
*/
public static <T> T toBean(String jsonString, Class<T> mainClass,
HashMap<String, Class> detailClass) {
JSONObject jsonObject = JSONObject.fromObject(jsonString);
T mainEntity = JSONHelper.toBean(jsonObject, mainClass);
for (Object key : detailClass.keySet()) {
try {
Class value = (Class) detailClass.get(key);
BeanUtils.setProperty(mainEntity, key.toString(), value);
} catch (Exception ex) {
throw new RuntimeException("主从关系JSON反序列化实体失败！");
}
}
return mainEntity;
}

public static String listtojson(String[] fields, int total, List list) throws Exception {
Object[] values = new Object[fields.length];
String jsonTemp = "{\"total\":" + total + ",\"rows\":[";
for (int j = 0; j < list.size(); j++) {
jsonTemp = jsonTemp + "{\"state\":\"closed\",";
for (int i = 0; i < fields.length; i++) {
String fieldName = fields[i].toString();
values[i] = org.jeecgframework.tag.core.easyui.TagUtil.fieldNametoValues(fieldName, list.get(j));
jsonTemp = jsonTemp + "\"" + fieldName + "\"" + ":\"" + values[i] + "\"";
if (i != fields.length - 1) {
jsonTemp = jsonTemp + ",";
}
}
if (j != list.size() - 1) {
jsonTemp = jsonTemp + "},";
} else {
jsonTemp = jsonTemp + "}";
}
}
jsonTemp = jsonTemp + "]}";
return jsonTemp;
}

}