Java操作json的通用类

http://blog.csdn.net/cyjchao/article/details/4397894

注：除了依赖com.baiyyy.polabs.util.DateUtil;包相关的方法之外，其他方法都在MyEclipse2015+JDK1.7中验证通过

package com.baiyyy.polabs.util.json;

import java.text.ParseException;

import java.util.ArrayList;

import java.util.Date;

import java.util.HashMap;

import java.util.Iterator;

import java.util.List;

import java.util.Map;

import com.baiyyy.polabs.util.DateUtil;

import net.sf.json.JSONArray;

import net.sf.json.JSONObject;

import net.sf.json.JsonConfig;

import net.sf.json.util.CycleDetectionStrategy;

/**

* 处理json的工具类，负责json数据转换成java对象和java对象转换成json

*

* @author yongtree

* @date 2008-11-22 上午10:47:13

* @version 1.0

*/

public class JsonUtil {

/**

* 从一个JSON 对象字符格式中得到一个java对象

*

* @param jsonString

* @param pojoCalss

* @return

*/

public static Object getObject4JsonString(String jsonString, Class pojoCalss) {

Object pojo;

JSONObject jsonObject = JSONObject.fromObject(jsonString);

pojo = JSONObject.toBean(jsonObject, pojoCalss);

return pojo;

}

/**

* 从json HASH表达式中获取一个map，改map支持嵌套功能

*

* @param jsonString

* @return

*/

public static Map getMap4Json(String jsonString) {

JSONObject jsonObject = JSONObject.fromObject(jsonString);

Iterator keyIter = jsonObject.keys();

String key;

Object value;

Map valueMap = new HashMap();

while (keyIter.hasNext()) {

key = (String) keyIter.next();

value = jsonObject.get(key);

valueMap.put(key, value);

}

return valueMap;

}

/**

* 从json数组中得到相应java数组

*

* @param jsonString

* @return

*/

public static Object[] getObjectArray4Json(String jsonString) {

JSONArray jsonArray = JSONArray.fromObject(jsonString);

return jsonArray.toArray();

}

/**

* 从json对象集合表达式中得到一个java对象列表

*

* @param jsonString

* @param pojoClass

* @return

*/

public static List getList4Json(String jsonString, Class pojoClass) {

JSONArray jsonArray = JSONArray.fromObject(jsonString);

JSONObject jsonObject;

Object pojoValue;

List list = new ArrayList();

for (int i = 0; i < jsonArray.size(); i++) {

jsonObject = jsonArray.getJSONObject(i);

pojoValue = JSONObject.toBean(jsonObject, pojoClass);

list.add(pojoValue);

}

return list;

}

/**

* 从json数组中解析出java字符串数组

*

* @param jsonString

* @return

*/

public static String[] getStringArray4Json(String jsonString) {

JSONArray jsonArray = JSONArray.fromObject(jsonString);

String[] stringArray = new String[jsonArray.size()];

for (int i = 0; i < jsonArray.size(); i++) {

stringArray[i] = jsonArray.getString(i);

}

return stringArray;

}

/**

* 从json数组中解析出javaLong型对象数组

*

* @param jsonString

* @return

*/

public static Long[] getLongArray4Json(String jsonString) {

JSONArray jsonArray = JSONArray.fromObject(jsonString);

Long[] longArray = new Long[jsonArray.size()];

for (int i = 0; i < jsonArray.size(); i++) {

longArray[i] = jsonArray.getLong(i);

}

return longArray;

}

/**

* 从json数组中解析出java Integer型对象数组

*

* @param jsonString

* @return

*/

public static Integer[] getIntegerArray4Json(String jsonString) {

JSONArray jsonArray = JSONArray.fromObject(jsonString);

Integer[] integerArray = new Integer[jsonArray.size()];

for (int i = 0; i < jsonArray.size(); i++) {

integerArray[i] = jsonArray.getInt(i);

}

return integerArray;

}

/**

* 从json数组中解析出java Date 型对象数组，使用本方法必须保证

*

* @param jsonString

* @return

* @throws ParseException

*/

public static Date[] getDateArray4Json(String jsonString, String DataFormat)

throws ParseException {

JSONArray jsonArray = JSONArray.fromObject(jsonString);

Date[] dateArray = new Date[jsonArray.size()];

String dateString;

Date date;

for (int i = 0; i < jsonArray.size(); i++) {

dateString = jsonArray.getString(i);

date = DateUtil.parseDate(dateString, DataFormat);

dateArray[i] = date;

}

return dateArray;

}

/**

* 从json数组中解析出java Integer型对象数组

*

* @param jsonString

* @return

*/

public static Double[] getDoubleArray4Json(String jsonString) {

JSONArray jsonArray = JSONArray.fromObject(jsonString);

Double[] doubleArray = new Double[jsonArray.size()];

for (int i = 0; i < jsonArray.size(); i++) {

doubleArray[i] = jsonArray.getDouble(i);

}

return doubleArray;

}

/**

* 将java对象转换成json字符串

*

* @param javaObj

* @return

*/

public static String getJsonString4JavaPOJO(Object javaObj) {

JSONObject json;

json = JSONObject.fromObject(javaObj);

return json.toString();

}

/**

* 将java对象转换成json字符串,并设定日期格式

*

* @param javaObj

* @param dataFormat

* @return

*/

public static String getJsonString4JavaPOJO(Object javaObj,

String dataFormat) {

JSONObject json;

JsonConfig jsonConfig = configJson(dataFormat);

json = JSONObject.fromObject(javaObj, jsonConfig);

return json.toString();

}

/**

* JSON 时间解析器具

*

* @param datePattern

* @return

*/

public static JsonConfig configJson(String datePattern) {

JsonConfig jsonConfig = new JsonConfig();

jsonConfig.setExcludes(new String[] { "" });

jsonConfig.setIgnoreDefaultExcludes(false);

jsonConfig.setCycleDetectionStrategy(CycleDetectionStrategy.LENIENT);

jsonConfig.registerJsonValueProcessor(Date.class,

new JsonDateValueProcessor(datePattern));

return jsonConfig;

}

/**

* 除去不想生成的字段（特别适合去掉级联的对象）+时间转换

* @param excludes 除去不想生成的字段

* @param datePattern

* @return

*/

public static JsonConfig configJson(String[] excludes, String datePattern) {

JsonConfig jsonConfig = new JsonConfig();

jsonConfig.setExcludes(excludes);

jsonConfig.setIgnoreDefaultExcludes(true);

jsonConfig.setCycleDetectionStrategy(CycleDetectionStrategy.LENIENT);

jsonConfig.registerJsonValueProcessor(Date.class,

new JsonDateValueProcessor(datePattern));

return jsonConfig;

}

}

package com.baiyyy.polabs.util.json;

import java.text.SimpleDateFormat;

import java.util.Date;

import net.sf.json.JsonConfig;

import net.sf.json.processors.JsonValueProcessor;

/**

*

* @author yongtree

* @date 2008-11-22 上午10:54:19

* @version 1.0

*/

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) {

String[] obj = {};

if (value instanceof Date[]) {

SimpleDateFormat sf = new SimpleDateFormat(format);

Date[] dates = (Date[]) value;

obj = new String[dates.length];

for (int i = 0; i < dates.length; i++) {

obj[i] = sf.format(dates[i]);

}

}

return obj;

}

public Object processObjectValue(String key, 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;

}

}