使用字节码asm将pojo转换成Map，直接构造mongodb bsonobject

package com.skmbw.yinlei.mongo;import java.util.Date;import java.util.HashMap;import java.util.Map;import java.util.Map.Entry;import java.util.concurrent.ConcurrentHashMap;import java.util.concurrent.ConcurrentMap;import org.apache.commons.lang3.StringUtils;import org.springframework.cglib.beans.BeanMap;import com.alibaba.fastjson.JSON;import com.alibaba.fastjson.JSONObject;import com.esotericsoftware.reflectasm.MethodAccess;public class JSONUtils {public static ConcurrentMap<String, BeanMap> beanMapCache = new ConcurrentHashMap<String, BeanMap>();//JSONObject就是个Map，它实现了Map接口public static Map<String, ?> toMap(Object object) {JSONObject jsonObject = (JSONObject)JSON.toJSON(object);return jsonObject;}//去掉null，最差public static Map<String, ?> toMaps(Object object) {Map<String, Object> map = new HashMap<String, Object>();JSONObject jsonObject = (JSONObject) JSON.toJSON(object);for (Entry<String, Object> entry : jsonObject.entrySet()) {if (entry.getValue() != null) {map.put(entry.getKey(), entry.getValue());}}return map;}public static void main(String[] aa) {User user = new User();user.setAccount("asdf");user.setAge(22);user.setDate(new Date());Map<String, Object> result = new HashMap<String, Object>();Map<String, Object> result2 = new HashMap<String, Object>();long d2 = System.nanoTime();JSONObject jsonObject = (JSONObject)JSON.toJSON(user);String json = jsonObject.toJSONString();Map<String, Object> jsonMap = JSON.parseObject(json);System.out.println(System.nanoTime() - d2);long dd = System.nanoTime();Map<String, Object> map = (Map<String, Object>)jsonObject;result.putAll(map);System.out.println(System.nanoTime() - dd);long d = System.nanoTime();for (Entry<String, Object> entry : jsonObject.entrySet()) {if (entry.getValue() != null) {result2.put(entry.getKey(), entry.getValue());}}System.out.println(System.nanoTime() - d);Map<String, Object> toMap = new HashMap<String, Object>();beanToMap(user, toMap);Map<String, Object> toMap2 = beanToMap(user);System.out.println(toMap2);}//性能次之public static void beanToMap(Object fromBean, Map<String, Object> toMap) {        //MethodAccess要缓存MethodAccess methodAccess = MethodAccess.get(fromBean.getClass());        String[] methodNames = methodAccess.getMethodNames();         for (String methodName : methodNames){             if (methodName.startsWith("get")){                 Object value = methodAccess.invoke(fromBean, methodName, (Object[])null);                 toMap.put(StringUtils.uncapitalize(methodName.substring(3)), value);             }         }    }public static BeanMap getBeanMap(Object object) {BeanMap beanMap = beanMapCache.get(object.getClass().getName());if (beanMap == null) {beanMap = BeanMap.create(object);beanMapCache.put(object.getClass().getName(), beanMap);}return beanMap;}//如果使用BeanMap缓存，这个性能最好。public static Map<String, Object> beanToMap(Object object) {BeanMap beanMap = getBeanMap(object);beanMap.setBean(object);@SuppressWarnings("unchecked")Map<String, Object> toMap = beanMap;for (Entry<String, Object> entry : toMap.entrySet()) {if (entry.getValue() != null) {toMap.put(entry.getKey(), entry.getValue());}}return toMap;}}

因为mongodb的bosnobject，有一个putAll(Map)的方法，可以快速构建BsonObject。