简单Json字符串生成器

关于JSON的Java类库挺多的，但有时候不希望在项目里边引入这些JAR包，所以需要自己实现一些简单的工具类。本例就属于这种情况。本例中使用Java的反射机制，将简单的POJO对象转换成JSON字符串。

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/*** 将字符串首字母大写* @param str * @return */private static String transform(String str) {if (str == null || str.length() < 1) {return "";}return str.substring(0, 1).toUpperCase() + str.substring(1);}/** * 将POJO对象转换成JSON格式的字符串 * @param obj* @return */public static String pojo2Json(Object obj) {if (obj == null) {return "";}Class clazz = obj.getClass();Field[] fields = clazz.getDeclaredFields();StringBuilder buff = new StringBuilder();buff.append("{");for (Field f : fields) {try {String methodName = "get" + transform(f.getName());Object value=clazz.getDeclaredMethod(methodName).invoke(obj, null);buff.append("\"");buff.append(f.getName());buff.append("\":");if(value==null){buff.append("\"\",");continue;}if(value instanceof Boolean){buff.append((Boolean)value);buff.append(",");}else if(value instanceof Number){buff.append((Number)value);buff.append(",");}else if(value instanceof Date){buff.append("\"");buff.append(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format((Date)value));buff.append("\",");}else{buff.append("\"");buff.append(value.toString());buff.append("\",");}} catch (SecurityException e) {//e.printStackTrace();} catch (NoSuchMethodException e) {//e.printStackTrace();} catch (IllegalArgumentException e) {//e.printStackTrace();} catch (IllegalAccessException e) {//e.printStackTrace();} catch (InvocationTargetException e) {//e.printStackTrace();}}if (buff.length() > 1) {buff = buff.deleteCharAt(buff.length() - 1);}buff.append("}");return buff.toString();}