java基于反射JSONUtil类

在java中json用的很广泛了。但是适中官方不提供json>bean和bean>json的工具类，在此次编写过程中发现为啥官方不提供，在有些类（包括自定义）很难json>bean。但是我还是写了一部分，希望和大家分享，共同把这个类完善好。此次还没有考虑Data数据类型，不多说了，贴代码：

package org.json;import java.lang.reflect.Field;/** * @name org.json.JSONUtil * @describe 提供json转javabean和javebean转json方法 * @author JEFF * @since 2012/11/15  * JSON 即 JavaScript Object Natation，它是一种轻量级的数据交换格式 除了字符 "，\，/ * 和一些控制符（\b，\f，\n，\r，\t）需要编码外，其他 Unicode 字符可以直接输出 Object 对象在 JSON 中是用 {} * 包含一系列无序的 Key-Value 键值对表示的，实际上此处的 Object 相当于 Java 中的 Map<String,Object>， * 而不是 Java 的 Class 。注意 Key 只能用 String 表示。 * Prototype提供了 evalJSON() 方法，能直接将服务器返回的 JSON 文本变成一个 JavaScript 变量 */public class JSONUtil {/** * 把对象封装为JSON格式 *  * @param o *            对象 * @return JSON格式 */@SuppressWarnings("unchecked")public static String toJson(final Object o) {if (o == null) {return "null";}if (o instanceof String) // String{return string2Json((String) o);}if (o instanceof Boolean) // Boolean{return boolean2Json((Boolean) o);}if (o instanceof Number) // Number{return number2Json((Number) o);}if (o instanceof Map) // Map{return map2Json((Map<String, Object>) o);}if (o instanceof Collection) // List Set{return collection2Json((Collection<Object>) o);}if (o instanceof Object[]) // 对象数组{return array2Json((Object[]) o);}if (o instanceof int[])// 基本类型数组{return intArray2Json((int[]) o);}if (o instanceof boolean[])// 基本类型数组{return booleanArray2Json((boolean[]) o);}if (o instanceof long[])// 基本类型数组{return longArray2Json((long[]) o);}if (o instanceof float[])// 基本类型数组{return floatArray2Json((float[]) o);}if (o instanceof double[])// 基本类型数组{return doubleArray2Json((double[]) o);}if (o instanceof short[])// 基本类型数组{return shortArray2Json((short[]) o);}if (o instanceof byte[])// 基本类型数组{return byteArray2Json((byte[]) o);}if (o instanceof Object) // 保底收尾对象{return Bean2Json(o);}throw new RuntimeException("不支持的类型: " + o.getClass().getName());}/** * 将 String 对象编码为 JSON格式，只需处理好特殊字符 *  * @param s *            String 对象 * @return JSON格式 */static String string2Json(final String s) {final StringBuilder sb = new StringBuilder(s.length() + 20);sb.append('\"');for (int i = 0; i < s.length(); i++) {final char c = s.charAt(i);switch (c) {case '\"':sb.append("\\\"");break;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;default:sb.append(c);}}sb.append('\"');return sb.toString();}/** * 将 Number 表示为 JSON格式 *  * @param number *            Number * @return JSON格式 */static String number2Json(final Number number) {return number.toString();}/** * 将 Boolean 表示为 JSON格式 *  * @param bool *            Boolean * @return JSON格式 */static String boolean2Json(final Boolean bool) {return bool.toString();}/** * 将 Collection 编码为 JSON 格式 (List,Set) *  * @param c * @return */static String collection2Json(final Collection<Object> c) {final Object[] arrObj = c.toArray();return toJson(arrObj);}/** * 将 Map<String, Object> 编码为 JSON 格式 *  * @param map * @return */static String map2Json(final Map<String, Object> map) {if (map.isEmpty()) {return "{}";}final StringBuilder sb = new StringBuilder(map.size() << 4); // 4次方sb.append('{');final Set<String> keys = map.keySet();for (final String key : keys) {final Object value = map.get(key);sb.append('\"');sb.append(key); // 不能包含特殊字符sb.append('\"');sb.append(':');sb.append(toJson(value)); // 循环引用的对象会引发无限递归sb.append(',');}// 将最后的 ',' 变为 '}':sb.setCharAt(sb.length() - 1, '}');return sb.toString();}/** * 将数组编码为 JSON 格式 *  * @param array *            数组 * @return JSON 格式 */static String array2Json(final Object[] array) {if (array.length == 0) {return "[]";}final StringBuilder sb = new StringBuilder(array.length << 4); // 4次方sb.append('[');for (final Object o : array) {sb.append(toJson(o));sb.append(',');}// 将最后添加的 ',' 变为 ']':sb.setCharAt(sb.length() - 1, ']');return sb.toString();}static String intArray2Json(final int[] array) {if (array.length == 0) {return "[]";}final StringBuilder sb = new StringBuilder(array.length << 4);sb.append('[');for (final int o : array) {sb.append(Integer.toString(o));sb.append(',');}// set last ',' to ']':sb.setCharAt(sb.length() - 1, ']');return sb.toString();}static String longArray2Json(final long[] array) {if (array.length == 0) {return "[]";}final StringBuilder sb = new StringBuilder(array.length << 4);sb.append('[');for (final long o : array) {sb.append(Long.toString(o));sb.append(',');}// set last ',' to ']':sb.setCharAt(sb.length() - 1, ']');return sb.toString();}static String booleanArray2Json(final boolean[] array) {if (array.length == 0) {return "[]";}final StringBuilder sb = new StringBuilder(array.length << 4);sb.append('[');for (final boolean o : array) {sb.append(Boolean.toString(o));sb.append(',');}// set last ',' to ']':sb.setCharAt(sb.length() - 1, ']');return sb.toString();}static String floatArray2Json(final float[] array) {if (array.length == 0) {return "[]";}final StringBuilder sb = new StringBuilder(array.length << 4);sb.append('[');for (final float o : array) {sb.append(Float.toString(o));sb.append(',');}// set last ',' to ']':sb.setCharAt(sb.length() - 1, ']');return sb.toString();}static String doubleArray2Json(final double[] array) {if (array.length == 0) {return "[]";}final StringBuilder sb = new StringBuilder(array.length << 4);sb.append('[');for (final double o : array) {sb.append(Double.toString(o));sb.append(',');}// set last ',' to ']':sb.setCharAt(sb.length() - 1, ']');return sb.toString();}static String shortArray2Json(final short[] array) {if (array.length == 0) {return "[]";}final StringBuilder sb = new StringBuilder(array.length << 4);sb.append('[');for (final short o : array) {sb.append(Short.toString(o));sb.append(',');}// set last ',' to ']':sb.setCharAt(sb.length() - 1, ']');return sb.toString();}static String byteArray2Json(final byte[] array) {if (array.length == 0) {return "[]";}final StringBuilder sb = new StringBuilder(array.length << 4);sb.append('[');for (final byte o : array) {sb.append(Byte.toString(o));sb.append(',');}// set last ',' to ']':sb.setCharAt(sb.length() - 1, ']');return sb.toString();}public static String Bean2Json(final Object bean) {// 数据检查if (bean == null) {return "{}";}final Method[] methods = bean.getClass().getMethods(); // 方法数组final StringBuilder sb = new StringBuilder(methods.length << 4); // 4次方sb.append('{');for (final Method method : methods) {try {final String name = method.getName();String key = "";if (name.startsWith("get")) {key = name.substring(3);// 防死循环final String[] arrs = { "Class" };boolean bl = false;for (final String s : arrs) {if (s.equals(key)) {bl = true;continue;}}if (bl) {continue; // 防死循环}} else if (name.startsWith("is")) {key = name.substring(2);}if (key.length() > 0 && Character.isUpperCase(key.charAt(0))&& method.getParameterTypes().length == 0) {if (key.length() == 1) {key = key.toLowerCase();} else if (!Character.isUpperCase(key.charAt(1))) {key = key.substring(0, 1).toLowerCase()+ key.substring(1);}final Object elementObj = method.invoke(bean);// System.out.println("###" + key + ":" +// elementObj.toString());sb.append('\"');sb.append(key); // 不能包含特殊字符sb.append('\"');sb.append(':');sb.append(toJson(elementObj)); // 循环引用的对象会引发无限递归sb.append(',');}} catch (final Exception e) {// e.getMessage();throw new RuntimeException("在将bean封装成JSON格式时异常："+ e.getMessage(), e);}}if (sb.length() == 1) {return bean.toString();} else {sb.setCharAt(sb.length() - 1, '}');return sb.toString();}}static void setJson2Field(Object object, JSONObject jsonObject, Field field) {field.setAccessible(true);try {setField(object, jsonObject, field);} catch (Exception e1) {e1.printStackTrace();}}@SuppressWarnings({ "rawtypes", "unchecked" })private static void setField(Object object, JSONObject jsonObject,Field field) throws IllegalArgumentException,IllegalAccessException, JSONException {String name = field.getName();String type = field.getType().getSimpleName();Object value = jsonObject.get(name);if (value instanceof String) // String{field.set(object, jsonObject.getString(name));} else if (value instanceof Boolean) // Boolean{field.set(object, jsonObject.getBoolean(name));} else if (value instanceof Number) // Number{if (value instanceof Integer) {field.set(object, jsonObject.getInt(name));} else if (value instanceof Float) {field.set(object, Float.parseFloat(value.toString()));} else if (value instanceof Double) {field.set(object, Float.parseFloat(value.toString()));} else if (value instanceof Long) {field.set(object, jsonObject.getLong(name));} else if (value instanceof Short) {field.set(object, Short.parseShort(value.toString()));}} else if (value instanceof JSONArray) {if (int[].class.getSimpleName().equals(type)) {JSONArray values = jsonObject.getJSONArray(name);int[] ss = new int[values.length()];for (int i = 0; i < values.length(); i++) {ss[i] = values.getInt(i);}field.set(object, ss);} else if (double[].class.getSimpleName().equals(type)) {JSONArray values = jsonObject.getJSONArray(name);double[] ss = new double[values.length()];for (int i = 0; i < values.length(); i++) {ss[i] = values.getDouble(i);}field.set(object, ss);} else if (float[].class.getSimpleName().equals(type)) {JSONArray values = jsonObject.getJSONArray(name);float[] ss = new float[values.length()];for (int i = 0; i < values.length(); i++) {ss[i] = Float.parseFloat(values.get(i).toString());}field.set(object, ss);} else if (long[].class.getSimpleName().equals(type)) {JSONArray values = jsonObject.getJSONArray(name);long[] ss = new long[values.length()];for (int i = 0; i < values.length(); i++) {ss[i] = values.getLong(i);}field.set(object, ss);} else if (String[].class.getSimpleName().equals(type)) {JSONArray values = jsonObject.getJSONArray(name);String[] ss = new String[values.length()];for (int i = 0; i < values.length(); i++) {ss[i] = values.getString(i);}field.set(object, ss);} else if (Object[].class.getSimpleName().equals(type)) {JSONArray values = jsonObject.getJSONArray(name);Object[] ss = new Object[values.length()];for (int i = 0; i < values.length(); i++) {ss[i] = Json2Bean(values.getJSONArray(i).toString(), values.get(i).getClass());}field.set(object, ss);} else if (List.class.getSimpleName().equals(type)|| ArrayList.class.getSimpleName().equals(type)) {JSONArray values = jsonObject.getJSONArray(name);ArrayList list = new ArrayList(values.length());for (int i = 0; i < values.length(); i++) {list.add(values.get(i));}field.set(object, list);}} else if (value instanceof JSONObject) // 保底收尾对象{ if (Map.class.getSimpleName().equals(type)) {JSONObject obj = jsonObject.getJSONObject(name);Map<String, Object> map = new HashMap<String, Object>();Iterator<String> keys = obj.keys();do {String s = keys.next();map.put(s, obj.get(s));} while (keys.hasNext());field.set(object, map);}else{try {JSONObject jo = jsonObject.getJSONObject(name);Object obj = Json2Bean(jo.toString(),Class.forName(field.getType().getName()));field.set(object, obj);} catch (Exception e) {e.printStackTrace();}}}}/** * 将json字符串转换为指定Class *  * @param json * @param clazz * @return */public static Object Json2Bean(final String json, Class<?> clazz) {Object object = null;JSONObject jsonObject = null;if (json != null && json.trim().length() > 0) {try {jsonObject = new JSONObject(json);} catch (JSONException e) {e.printStackTrace();}}try {object = clazz.newInstance();Field[] fields = clazz.getDeclaredFields();for (Field field : fields) {setJson2Field(object, jsonObject, field);}} catch (Exception e) {e.printStackTrace();}if (isNULL(jsonObject,object)) {throw new JsonParseClassException("转换对象错误，不能转换" + object.getClass());}return object;}@SuppressWarnings("unchecked")private static boolean isNULL(JSONObject jsonObject, Object clazz) {if (clazz == null || jsonObject == null) {return true;}Iterator<String> iterator = jsonObject.keys();List<String> s = new ArrayList<String>();do {s.add(iterator.next());} while (iterator.hasNext());int num = 0;try {Field[] fields = clazz.getClass().getDeclaredFields();for (int i = 0; i < fields.length; i++) {fields[i].setAccessible(true);String name = fields[i].getName();if(s.contains(name)){num++;}}} catch (Exception e) {}if (num == s.size())return false;return true;}}

        本人功力有限，希望大家帮我完善这个类。谢谢。