JSON与Java对象互转工具类

忘是亡心i 2022-05-27 07:11 246阅读 0赞

话不多说，上代码~

import java.io.Serializable;
 import java.lang.reflect.Field;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
 import java.lang.reflect.ParameterizedType;
 import java.lang.reflect.Type;
 import java.text.ParseException;
 import java.text.SimpleDateFormat;
 import java.util.ArrayList;
 import java.util.Date;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 
 import org.apache.log4j.Logger;
 import org.json.JSONArray;
 import org.json.JSONObject;
 
 
 class shop implements Serializable{
 	private static final long serialVersionUID = 1L;
 	String name;
 	Date openTime;
 	Date closeTime;
 	public String getName() {
 		return name;
 	}
 	public void setName(String name) {
 		this.name = name;
 	}
 	public Date getOpenTime() {
 		return openTime;
 	}
 	public void setOpenTime(Date openTime) {
 		this.openTime = openTime;
 	}
 	public Date getCloseTime() {
 		return closeTime;
 	}
 	public void setCloseTime(Date closeTime) {
 		this.closeTime = closeTime;
 	}
 	
 }
 
 public class JSON { 
 	static Logger logger = Logger.getLogger(JSON.class);
 	
 	
 	public static void main(String[] args) {
 		shop s1 = new shop();
 		s1.setName("1..");
 		s1.setOpenTime(new Date());
 		try {
 			System.out.println(JSON.toJson(s1));
 			String s = "{\"name\":\"1..\",\"openTime\":\"2018-4-13 16:36:27\"}";
 			shop ss = (shop)JSON.toObject(s, shop.class);
 			System.out.println(ss.getOpenTime());
 			System.out.println(ss.getCloseTime());
 		} catch (Exception e) {
 			// TODO Auto-generated catch block
 			e.printStackTrace();
 		}
 	}
 	
 	
 /** 
 * JSON字符串转成Object对象 
 * 此方法假设没有把子类当成父类去使用 
 * 不然会出现解析出来的对象没有子类属性 
 * @param json 
 * @param clazz 
 * @return 
 */ 
 public static Object toObject(String json, Class<?> clazz) { 
 return toObject(json, clazz, null, null); 
 } 
 
 /** 
 * JSON字符串转成Object对象 
 * 此方法可以把子类当成父类去使用 
 * 但是需要提供一个map 
 * 告诉程序对应的(子)类 
 * @param json 
 * @param map 
 * @return 
 */ 
 public static Object toObject(String json, Map<String,String> map) { 
 return toObject(json, null, null, map); 
 } 
 
 /** 
 * JSON字符串转成Object对象 
 * 此方法可以把子类当成父类去使用 
 * 但是需要提供一个基础的basePackage 
 * 并且在生成JSON的时候,也需要传入这个basePackage 
 * @param json 
 * @return 
 */ 
 public static Object toObject(String json, String basePackage) { 
 return toObject(json, null, basePackage, null); 
 } 
 
 /** 
 * JSON字符串转成Object对象 
 * 此方法可以把子类当成父类去使用 
 * 但是需要提供一个基础的basePackage 
 * 并且在生成JSON的时候,也需要传入这个basePackage 
 * @param json 
 * @return 
 */ 
 public static Object toObject(String json, Class<?> clazz, String basePackage) { 
 return toObject(json, clazz, basePackage, null); 
 } 
 
 /** 
 * Object对象转成JSON字符串 
 * 此方法假设没有把子类当成父类去使用 
 * 不然反转的时候可能会出现解析出来的对象没有子类属性 
 * @param obj 
 * @return 
 */ 
 public static String toJson(Object obj) { 
 return toJson(obj, null, false); 
 } 
 
 /** 
 * Object对象转成JSON字符串 
 * 对应反转方法：toObject(String json, Map<String,String> map) 
 * @param obj 
 * @param createClassInfo 
 * @return 
 */ 
 public static String toJson(Object obj, boolean createClassInfo) { 
 return toJson(obj, null, createClassInfo); 
 } 
 
 /** 
 * Object对象转成JSON字符串 
 * 对应反转方法：toObject(String json, String basePackage) 
 * @param obj 
 * @return 
 */ 
 public static String toJson(Object obj, String basePackage) { 
 return toJson(obj, basePackage, false); 
 } 
 
 public static String format(String json) { 
 String fillStringUnit = " "; 
 if (json == null || json.trim().length() == 0) { 
 return null; 
 } 
 
 int fixedLenth = 0; 
 ArrayList<String> tokenList = new ArrayList<String>(); 
 { 
 String jsonTemp = json; 
 // 预读取 
 while (jsonTemp.length() > 0) { 
 String token = getToken(jsonTemp); 
 jsonTemp = jsonTemp.substring(token.length()); 
 token = token.trim(); 
 tokenList.add(token); 
 } 
 } 
 
 for (int i = 0; i < tokenList.size(); i++) { 
 String token = tokenList.get(i); 
 int length = token.getBytes().length; 
 if (length > fixedLenth && i < tokenList.size() - 1 
 && tokenList.get(i + 1).equals(":")) { 
 fixedLenth = length; 
 } 
 } 
 
 StringBuilder buf = new StringBuilder(); 
 int count = 0; 
 for (int i = 0; i < tokenList.size(); i++) { 
 
 String token = tokenList.get(i); 
 
 if (token.equals(",")) { 
 buf.append(token); 
 doFill(buf, count, fillStringUnit); 
 continue; 
 } 
 if (token.equals(":")) { 
 buf.append(" ").append(token).append(" "); 
 continue; 
 } 
 if (token.equals("{")) { 
 String nextToken = tokenList.get(i + 1); 
 if (nextToken.equals("}")) { 
 i++; 
 buf.append("{ }"); 
 } else { 
 count++; 
 buf.append(token); 
 doFill(buf, count, fillStringUnit); 
 } 
 continue; 
 } 
 if (token.equals("}")) { 
 count--; 
 doFill(buf, count, fillStringUnit); 
 buf.append(token); 
 continue; 
 } 
 if (token.equals("[")) { 
 String nextToken = tokenList.get(i + 1); 
 if (nextToken.equals("]")) { 
 i++; 
 buf.append("[ ]"); 
 } else { 
 count++; 
 buf.append(token); 
 doFill(buf, count, fillStringUnit); 
 } 
 continue; 
 } 
 if (token.equals("]")) { 
 count--; 
 doFill(buf, count, fillStringUnit); 
 buf.append(token); 
 continue; 
 } 
 
 buf.append(token); 
 // 左对齐 
 if (i < tokenList.size() - 1 && tokenList.get(i + 1).equals(":")) { 
 int fillLength = fixedLenth - token.getBytes().length; 
 if (fillLength > 0) { 
 for (int j = 0; j < fillLength; j++) { 
 buf.append(" "); 
 } 
 } 
 } 
 } 
 return buf.toString(); 
 } 
 
 /** 
 * 
 * @param json 
 * JSONObject的字符串形式 
 * @param clazz 
 * Object的class 
 * @return 
 */ 
 private static final String ENTER_REPLACE_STR = "\\n"; 
 private static Object toObject(String json, Class<?> clazz, String basePackage, Map<String,String> map) { 
 if (json == null || json.equals("")) { 
 return json; 
 } else { 
 json = json.replace("\r\n", ENTER_REPLACE_STR).replace("\n", ENTER_REPLACE_STR); 
 } 
 Object object = null; 
 try { 
 if (json.charAt(0) == '[') { 
 object = toList(json, clazz, basePackage, map); 
 } else if (json.charAt(0) == '{'){ 
 JSONObject infoObject = new JSONObject(json); 
 // 
 // 
 if (infoObject.has("class")) { 
 String className = infoObject.getString("class"); 
 if (className != null) { 
 if (map != null && map.get(className) != null) { 
 clazz = Class.forName(map.get(className)); 
 } else if (basePackage != null) { 
 clazz = Class.forName(basePackage + className); 
 } 
 } 
 } 
 if (clazz == null) { 
 throw new NullPointerException("clazz, basePackage, map不能全部为空。"); 
 } 
 object = clazz.newInstance(); 
 // 
 // 
 Iterator<?> iterator = infoObject.keys(); 
 while (iterator.hasNext()) { 
 String key = (String) iterator.next(); 
 Object fieldValue = null; 
 List<Field> fields = getAllFields(null, clazz); 
 for (int i = 0; i < fields.size(); i++) { 
 Field field = fields.get(i); 
 if (field.getName().equalsIgnoreCase(key)) { 
 field.setAccessible(true); 
 fieldValue = getFieldValue(field, infoObject, key, basePackage, map); 
 if (null != fieldValue) { 
 field.set(object, fieldValue); 
 } 
 field.setAccessible(false); 
 } 
 } 
 } 
 } else { 
 return json; 
 } 
 } catch (Exception e) { 
 	e.printStackTrace();
 	logger.error("=====JSON EXCEPTION=====", e); 
 } 
 if (object instanceof List<?>) { 
 List<?> list = (List<?>) object; 
 for (int i = 0; i < list.size(); i++) { 
 replaceObjectBr(list.get(i)); 
 } 
 } else { 
 replaceObjectBr(object); 
 } 
 return object; 
 } 
 
 /** 
 * 
 * @param json 
 * JSONArray的字符串形式 
 * @param clazz 
 * List内对象的class 
 * @return 
 */ 
 private static List<?> toList(String json, Class<?> clazz, String basePackage, Map<String,String> map) { 
 List<Object> list = null; 
 try { 
 JSONArray jsonArray = (JSONArray) new JSONArray(json); 
 list = new ArrayList<Object>(); 
 for (int i = 0; i < jsonArray.length(); i++) { 
 String jsonvalue = jsonArray.getJSONObject(i).toString(); 
 switch (getJSONType(jsonvalue)) { 
 case JSON_TYPE_OBJECT: { 
 /* JSONObject subObject = new JSONObject(jsonvalue); 
 Class<?> newClazz = null; 
 if (subObject.has("class")) { 
 String className = subObject.getString("class"); 
 if (className != null) { 
 if (map != null && map.get(className) != null) { 
 newClazz = Class.forName(map.get(className)); 
 } else if (basePackage != null) { 
 newClazz = Class.forName(basePackage + className); 
 } 
 } 
 }*/ 
 list.add(toObject(jsonvalue, clazz, basePackage, map)); 
 break; 
 } 
 case JSON_TYPE_ARRAY: { 
 List<?> infoList = toList(jsonvalue, clazz, basePackage, map); 
 list.add(infoList); 
 break; 
 } 
 default: 
 break; 
 } 
 } 
 } catch (Exception e) { 
 	e.printStackTrace();
 logger.error("=====JSON EXCEPTION=====", e); 
 } 
 return list; 
 } 
 
 private static String toJson(Object obj, String basePackage, boolean createClass) { 
 if (obj instanceof String) { 
 return obj.toString(); 
 } else { 
 StringBuffer xmlBuffer = new StringBuffer(""); 
 if (obj instanceof List<?>) { 
 xmlBuffer.append("["); 
 List<?> list = (List<?>) obj; 
 for (int i = 0; i < list.size(); i++) { 
 addObjectToBuffer(xmlBuffer, list.get(i), basePackage, createClass); 
 if (i < list.size() - 1) { 
 xmlBuffer.append(","); 
 } 
 } 
 xmlBuffer.append("]"); 
 } else { 
 addObjectToBuffer(xmlBuffer, obj, basePackage, createClass); 
 } 
 return xmlBuffer.toString(); 
 } 
 } 
 
 /** 
 * 在JSON->Object的时候 
 * 根据JSON的键(key) 
 * 生成Field的值(value) 
 * @param field 
 * @param infoObject 
 * @param key 
 * @param basePackage 
 * @return 
 * @throws Exception 
 */ 
 private static Object getFieldValue(Field field, JSONObject infoObject, String key, String basePackage, Map<String,String> map) throws Exception { 
 Object fieldValue = null; 
 Class<?> fieldClass = field.getType(); 
 if (fieldClass.getSimpleName().toString().equals("int") 
 || fieldClass.getSimpleName().toString().equals( 
 "Integer")) { 
 fieldValue = infoObject.getInt(key); 
 } else if (fieldClass.getSimpleName().toString() 
 .equalsIgnoreCase("String")) { 
 fieldValue = infoObject.getString(key); 
 } else if (fieldClass.getSimpleName().toString() 
 .equalsIgnoreCase("double")) { 
 fieldValue = infoObject.getDouble(key); 
 } else if (fieldClass.getSimpleName().toString() 
 .equalsIgnoreCase("boolean")) { 
 fieldValue = infoObject.getBoolean(key); 
 } else if (fieldClass.getSimpleName().toString() 
 .equalsIgnoreCase("long")) { 
 fieldValue = infoObject.getLong(key); 
 } else if (fieldClass.getSimpleName().toString() 
 .equalsIgnoreCase("Date")) { 
 fieldValue = DateFormatUtil.toDate(infoObject.getString(key)); 
 } else { 
 String jsonvalue = infoObject.getString(key); 
 switch (getJSONType(jsonvalue)) { 
 case JSON_TYPE_OBJECT: { 
 fieldValue = toObject(jsonvalue, fieldClass, basePackage, map); 
 break; 
 } 
 case JSON_TYPE_ARRAY: { 
 // 获取泛型的class 
 Type genericFieldType = field.getGenericType(); 
 if (genericFieldType instanceof ParameterizedType) { 
 ParameterizedType aType = (ParameterizedType) genericFieldType; 
 Type[] fieldArgTypes = aType 
 .getActualTypeArguments(); 
 for (Type fieldArgType : fieldArgTypes) { 
 Class<?> fieldArgClass = (Class<?>) fieldArgType; 
 // if (map != null && map.get(key) != null) { 
 // fieldArgClass = Class.forName(map.get(key)); 
 // } 
 fieldValue = toList(jsonvalue, fieldArgClass, basePackage, map); 
 } 
 } 
 break; 
 } 
 default: 
 break; 
 } 
 } 
 return fieldValue; 
 } 
 
 private static List<Field> getAllFields(List<Field> fields, Class<?> clazz) { 
 if (fields == null) { 
 fields = new ArrayList<Field>(); 
 } 
 try { 
 if (clazz.getSuperclass() != null) { 
 Field[] fieldsSelf = clazz.getDeclaredFields(); 
 for (Field field : fieldsSelf) { 
 if (!Modifier.isFinal(field.getModifiers())) { 
 fields.add(field); 
 } 
 } 
 getAllFields(fields, clazz.getSuperclass()); 
 } 
 } catch (Exception e) { 
 	e.printStackTrace();
 logger.error("=====JSON Exception=====", e); 
 } 
 return fields; 
 } 
 
 private static void addObjectToBuffer(StringBuffer xmlBuffer, Object obj, String basePackage, boolean createClass) { 
 xmlBuffer.append("{"); 
 // 获取所有属性 
 List<Field> fields = new ArrayList<Field>(); 
 getAllFields(fields, obj.getClass()); 
 for (int i = -1; i < fields.size(); i++) { 
 if (i == -1) { 
 if (basePackage != null || createClass) { 
 // 加入类信息 
 xmlBuffer.append("\""); 
 xmlBuffer.append("class"); 
 xmlBuffer.append("\":"); 
 xmlBuffer.append("\""); 
 if (basePackage != null) { 
 xmlBuffer.append(obj.getClass().getName().replace(basePackage, "")); 
 } else { 
 xmlBuffer.append(obj.getClass().getSimpleName()); 
 } 
 xmlBuffer.append("\","); 
 } 
 continue; 
 } 
 Field field = fields.get(i); 
 String fieldName = field.getName(); 
 // 拼接GET方法名 
 Object fieldValue = null; 
 Method method = null; 
 try { 
 String methodName = "get" + ((char) (fieldName.charAt(0) - 32)) 
 + fieldName.substring(1); 
 // System.out.println("methodName->" + methodName); 
 method = obj.getClass().getMethod(methodName); 
 } catch (Exception e) { 
 String methodName = "is" + ((char) (fieldName.charAt(0) - 32)) 
 + fieldName.substring(1); 
 try { 
 method = obj.getClass().getMethod(methodName); 
 } catch (Exception e1) { 
 	e1.printStackTrace();
 logger.error("=====To JSON Object Exception=====", e); 
 } 
 } 
 if (method != null) { 
 try { 
 fieldValue = method.invoke(obj); 
 } catch (Exception e) { 
 	e.printStackTrace();
 logger.error("=====To JSON Object Exception=====", e); 
 } 
 } 
 if (null != fieldValue) { 
 xmlBuffer.append("\""); 
 xmlBuffer.append(fieldName); 
 xmlBuffer.append("\":"); 
 if (fieldValue instanceof Date) { 
 xmlBuffer.append("\""); 
 xmlBuffer.append((DateFormatUtil.toTimeFormat((Date) fieldValue))); 
 xmlBuffer.append("\""); 
 } else if (fieldValue instanceof Integer 
 || fieldValue instanceof Double 
 || fieldValue instanceof Long 
 || fieldValue instanceof Boolean) { 
 xmlBuffer.append("\""); 
 xmlBuffer.append(fieldValue.toString()); 
 xmlBuffer.append("\""); 
 } else if (fieldValue instanceof String) { 
 xmlBuffer.append("\""); 
 String str = fieldValue.toString(); 
 xmlBuffer.append(str); 
 xmlBuffer.append("\""); 
 } else if (fieldValue instanceof List<?>) { 
 addListToBuffer(xmlBuffer, fieldValue, basePackage, createClass); 
 } else { 
 addObjectToBuffer(xmlBuffer, fieldValue, basePackage, createClass); 
 } 
 xmlBuffer.append(","); 
 } 
 if (i == fields.size() - 1 && xmlBuffer.charAt(xmlBuffer.length() - 1) == ',') { 
 xmlBuffer.deleteCharAt(xmlBuffer.length() - 1); 
 } 
 } 
 xmlBuffer.append("}"); 
 } 
 
 private static void addListToBuffer(StringBuffer xmlBuffer, Object fieldvalue, String basePackage,boolean createClass) { 
 xmlBuffer.append("["); 
 List<?> v_list = (List<?>) fieldvalue; 
 for (int i = 0; i < v_list.size(); i++) { 
 addObjectToBuffer(xmlBuffer, v_list.get(i), basePackage, createClass); 
 if (i < v_list.size() - 1) { 
 xmlBuffer.append(","); 
 } 
 } 
 xmlBuffer.append("]"); 
 } 
 
 private static JSON_TYPE getJSONType(String str) { 
 final char[] strChar = str.substring(0, 1).toCharArray(); 
 final char firstChar = strChar[0]; 
 if (firstChar == '{') { 
 return JSON_TYPE.JSON_TYPE_OBJECT; 
 } else if (firstChar == '[') { 
 return JSON_TYPE.JSON_TYPE_ARRAY; 
 } else { 
 return JSON_TYPE.JSON_TYPE_ERROR; 
 } 
 } 
 
 private static String getToken(String json) { 
 StringBuilder buf = new StringBuilder(); 
 boolean isInYinHao = false; 
 while (json.length() > 0) { 
 String token = json.substring(0, 1); 
 json = json.substring(1); 
 
 if (!isInYinHao 
 && (token.equals(":") || token.equals("{") 
 || token.equals("}") || token.equals("[") 
 || token.equals("]") || token.equals(","))) { 
 if (buf.toString().trim().length() == 0) { 
 buf.append(token); 
 } 
 
 break; 
 } 
 
 if (token.equals("\\")) { 
 buf.append(token); 
 buf.append(json.substring(0, 1)); 
 json = json.substring(1); 
 continue; 
 } 
 if (token.equals("\"")) { 
 buf.append(token); 
 if (isInYinHao) { 
 break; 
 } else { 
 isInYinHao = true; 
 continue; 
 } 
 } 
 buf.append(token); 
 } 
 return buf.toString(); 
 } 
 
 private static void doFill(StringBuilder buf, int count, String fillStringUnit) { 
 buf.append("\n"); 
 for (int i = 0; i < count; i++) { 
 buf.append(fillStringUnit); 
 } 
 } 
 
 /** 
 * 替换掉/n 
 * @param obj 此Object不可以是List 
 */ 
 private static void replaceObjectBr(Object obj) { 
 // 获取所有属性 
 Field[] fields = obj.getClass().getDeclaredFields(); 
 for (int i = 0; i < fields.length; i++) { 
 Field field = fields[i]; 
 if (!Modifier.isFinal(field.getModifiers())) { 
 continue; 
 } 
 field.setAccessible(true); 
 Object fieldValue = null; 
 try { 
 fieldValue = field.get(obj); 
 if (fieldValue instanceof Integer) { 
 } else if (fieldValue instanceof Double) { 
 } else if (fieldValue instanceof Boolean) { 
 } else if (fieldValue instanceof Long) { 
 } else if (fieldValue instanceof Date) { 
 } else if (fieldValue instanceof String) { 
 if (fieldValue != null) { 
 String str = fieldValue.toString(); 
 field.set(obj, str.replaceAll(ENTER_REPLACE_STR, "\n")); 
 } 
 }else if (fieldValue instanceof List<?>) { 
 if (fieldValue != null) { 
 List<?> list = (List<?>) fieldValue; 
 for (int j = 0; j < list.size(); j++) { 
 replaceObjectBr(list.get(j)); 
 } 
 } 
 } else { 
 if (fieldValue != null) { 
 replaceObjectBr(fieldValue); 
 } 
 } 
 } catch (Exception e) { 
 	e.printStackTrace();
 logger.error("=====JSON Exception=====", e); 
 } finally { 
 field.setAccessible(false); 
 } 
 } 
 } 
 
 private enum JSON_TYPE { 
 /** JSONObject */ 
 JSON_TYPE_OBJECT, 
 /** JSONArray */ 
 JSON_TYPE_ARRAY, 
 /** 不是JSON格式的字符串 */ 
 JSON_TYPE_ERROR 
 } 
 } 
 class DateFormatUtil{
 
 	public static Object toDate(String string) {
 		// TODO Auto-generated method stub
 		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
 		Date date = null;
 		try {
 			date = sdf.parse(string);
 		} catch (ParseException e) {
 			// TODO Auto-generated catch block
 			e.printStackTrace();
 		}
 		return date;
 	}
 
 	public static Object toTimeFormat(Date fieldValue) {
 		
 		return fieldValue.toLocaleString();
 	}
 	
 }

自行删除不必要的部分~