JSON实用类，用来实现对象和JSON字符串的互相转换

JSON实用类，用来实现对象和JSON字符串的互相转换

import java.beans.IntrospectionException;import java.beans.Introspector;import java.beans.PropertyDescriptor;import java.lang.reflect.Field;import java.math.BigDecimal;import java.math.BigInteger;import java.util.ArrayList;import java.util.List;import java.util.Map;import java.util.Set;/** * JSON实用类 * 用来实现对象和JSON字符串的互相转换 *  * @author aven * @date 2015-01-14 */public class JSONUtil {public static String object2json(Object obj) {StringBuilder json = new StringBuilder();if (obj == null) {json.append("\"\"");} else if (obj instanceof String || obj instanceof Integer|| obj instanceof Float || obj instanceof Boolean|| obj instanceof Short || obj instanceof Double|| obj instanceof Long || obj instanceof BigDecimal|| obj instanceof BigInteger || obj instanceof Byte) {json.append("\"").append(string2json(obj.toString())).append("\"");} else if (obj instanceof Object[]) {json.append(array2json((Object[]) obj));} else if (obj instanceof List) {json.append(list2json((List<?>) obj));} else if (obj instanceof Map) {json.append(map2json((Map<?, ?>) obj));} else if (obj instanceof Set) {json.append(set2json((Set<?>) obj));} else {json.append(bean2json(obj));}return json.toString();}public static String bean2json(Object bean) {StringBuilder json = new StringBuilder();json.append("{");PropertyDescriptor[] props = null;try {props = Introspector.getBeanInfo(bean.getClass(), Object.class).getPropertyDescriptors();} catch (IntrospectionException e) {}if (props != null) {for (int i = 0; i < props.length; i++) {try {String name = object2json(props[i].getName());String value = object2json(props[i].getReadMethod().invoke(bean));json.append(name);json.append(":");json.append(value);json.append(",");} catch (Exception e) {}}json.setCharAt(json.length() - 1, '}');} else {json.append("}");}return json.toString();}public static String list2json(List<?> list) {StringBuilder json = new StringBuilder();json.append("[");if (list != null && list.size() > 0) {for (Object obj : list) {json.append(object2json(obj));json.append(",");}json.setCharAt(json.length() - 1, ']');} else {json.append("]");}return json.toString();}public static String array2json(Object[] array) {StringBuilder json = new StringBuilder();json.append("[");if (array != null && array.length > 0) {for (Object obj : array) {json.append(object2json(obj));json.append(",");}json.setCharAt(json.length() - 1, ']');} else {json.append("]");}return json.toString();}public static String map2json(Map<?, ?> map) {StringBuilder json = new StringBuilder();json.append("{");if (map != null && map.size() > 0) {for (Object key : map.keySet()) {json.append(object2json(key));json.append(":");json.append(object2json(map.get(key)));json.append(",");}json.setCharAt(json.length() - 1, '}');} else {json.append("}");}return json.toString();}public static String set2json(Set<?> set) {StringBuilder json = new StringBuilder();json.append("[");if (set != null && set.size() > 0) {for (Object obj : set) {json.append(object2json(obj));json.append(",");}json.setCharAt(json.length() - 1, ']');} else {json.append("]");}return json.toString();}public static String string2json(String s) {if (s == null)return "";StringBuilder sb = new StringBuilder();for (int i = 0; i < s.length(); i++) {char ch = s.charAt(i);switch (ch) {case '"':sb.append("\\\"");break;case '\\':sb.append("\\\\");break;case '\b':sb.append("\\b");break;case '\f':sb.append("\\f");break;case '\n':sb.append("\\n");break;case '\r':sb.append("\\r");break;case '\t':sb.append("\\t");break;case '/':sb.append("\\/");break;default:if (ch >= '\u0000' && ch <= '\u001F') {String ss = Integer.toHexString(ch);sb.append("\\u");for (int k = 0; k < 4 - ss.length(); k++) {sb.append('0');}sb.append(ss.toUpperCase());} else {sb.append(ch);}}}return sb.toString();}public static <T> T json2Object(String jsonString, Class<T> pojoCalss) {if (pojoCalss == null || jsonString == null || jsonString.trim().isEmpty()){return null;}try {T pojo = (T)pojoCalss.newInstance();Field[] fields = pojo.getClass().getDeclaredFields();String simpleName = "";for (Field f : fields) {try{if (f.getName() == null) {continue;}if (f.getModifiers() > 2) {continue;}f.setAccessible(true);simpleName = f.getType().getSimpleName();String propName = "\"" + f.getName() + "\":";Integer idx = jsonString.indexOf(propName);if (idx == -1){continue;}Integer idxStart = idx + propName.length();if (jsonString.length() < idxStart){continue;}String valStart = jsonString.substring(idxStart, idxStart+1);if (valStart.equals("[")){valStart = "]"; }else if (valStart.equals("{")){valStart = "}";}else{if (!valStart.equals("\"")){valStart = ","; }}String propValue = null;Integer idxEnd = -1;if (valStart.equals(",")){idxEnd = jsonString.indexOf(valStart, idxStart);if (idxEnd == -1){continue;}propValue = jsonString.substring(idxStart, idxEnd);}else{idxEnd = jsonString.indexOf(valStart, idxStart + 1);if (idxEnd == -1){continue;}propValue = jsonString.substring(idxStart + 1, idxEnd);}if (propValue == null){continue;}if (simpleName.equals("String") || simpleName.equals("Object")) {f.set(pojo, propValue);continue;}if (simpleName.equals("Long") || simpleName.equals("long")) {f.set(pojo, getLong(propValue));continue;}if (simpleName.equals("Integer") || simpleName.equals("int")) {f.set(pojo, getInteger(propValue));continue;}if (simpleName.equals("Boolean")) {f.set(pojo, getBoolean(propValue));continue;}if (simpleName.equals("Double")) {f.set(pojo, getDouble(propValue));continue;}if (simpleName.equals("Float")) {f.set(pojo, getFloat(propValue));continue;}if (simpleName.equals("Byte")) {f.set(pojo, getByte(propValue));continue;}if (simpleName.equals("List")) {f.set(pojo, getList(propValue));continue;}}catch(Exception ex){ex.printStackTrace();}}return pojo;} catch (Exception e) {e.printStackTrace();return null;}}public static Long getLong(String propValue){Long val = 0L;try{val = Long.parseLong(propValue);}catch(Exception el){}return val;}public static Integer getInteger(String propValue){Integer val = 0;try{val = Integer.parseInt(propValue);}catch(Exception el){}return val;}public static Boolean getBoolean(String propValue){Boolean val = ("1".equals(propValue) || "true".equalsIgnoreCase(propValue));return val;}public static Double getDouble(String propValue){Double val = 0D;try{val = Double.parseDouble(propValue);}catch(Exception el){}return val;}public static Float getFloat(String propValue){Float val = 0F;try{val = Float.parseFloat(propValue);}catch(Exception el){}return val;}public static Byte getByte(String propValue){Byte val = 0;try{val = Byte.parseByte(propValue);}catch(Exception el){}return val;}public static List<String> getList(String propValue){List<String> valList = new ArrayList<String>();if (propValue != null && !propValue.trim().isEmpty()){try{String[] aptEvents = propValue.replace("\"", "").toLowerCase().split(",");valList = java.util.Arrays.asList(aptEvents);}catch(Exception ex){ex.printStackTrace();}}return valList;}public static void main(String[] args) {String json = JSONUtil.object2json(new Data());System.out.println(json);}}