1. 使用org.apache.commons.beanutils转换

用到的主要jar包：commons-beanutils-1.9.3.jar。

  1. //map转java对象
  2. public static Object mapToObject(Map<String, Object> map, Class<?> beanClass)
  3.             throws Exception {
  4.         if (map == null) {
  5.             return null;
  6.         }
  7.         Object obj = beanClass.newInstance();
  8.         BeanUtils.populate(obj, map);
  9.         return obj;
  10.     }
  12. //java对象转map
  13. public static Map<?, ?> objectToMap(Object obj) {
  14.         if (obj == null)
  15.             return null;
  16.         return new BeanMap(obj);
  17. }

在使用该方法进行java对象转map时，可能会发生以下错误：

  1. Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/collections/Transformer
  2. ....
  3. Caused by: java.lang.ClassNotFoundException: org.apache.commons.collections.Transformer
  4. ....

解决方法： https://blog.csdn.net/liuyunyihao/article/details/86596595

2. 使用Introspector转换

  1. //map转java对象
  2. public static Object mapToObject(Map<String, Object> map, Class<?> beanClass) throws Exception {
  3.         if (map == null)
  4.             return null;
  5.         Object obj = beanClass.newInstance();
  6.         BeanInfo beanInfo = Introspector.getBeanInfo(obj.getClass());
  7.         PropertyDescriptor[] propertyDescriptors = beanInfo.getPropertyDescriptors();
  8.         for (PropertyDescriptor property : propertyDescriptors) {
  9.             Method setter = property.getWriteMethod();
  10.             if (setter != null) {
  11.                 setter.invoke(obj, map.get(property.getName()));
  12.             }
  13.         }
  14.         return obj;
  15.     }
  17. //java对象转map
  18. public static Map<String, Object> objectToMap(Object obj) throws Exception {
  19.     if (obj == null) {
  20.         return null;
  21.     }
  22.     Map<String, Object> map = new HashMap<String, Object>();
  23.     BeanInfo beanInfo = Introspector.getBeanInfo(obj.getClass());
  24.     PropertyDescriptor[] propertyDescriptors = beanInfo
  25.                 .getPropertyDescriptors();
  26.     for (PropertyDescriptor property : propertyDescriptors) {
  27.         String key = property.getName();
  28.         if (key.compareToIgnoreCase("class") == 0) {
  29.             continue;
  30.         }
  31.         Method getter = property.getReadMethod();
  32.         Object value = getter != null ? getter.invoke(obj) : null;
  33.         map.put(key, value);
  34.     }
  35.     return map;
  36. }

3. 使用reflect转换

  1. //map转java对象
  2. public static Object mapToObject(Map<String, Object> map, Class<?> beanClass) throws Exception {
  3.         if (map == null) {
  4.             return null;
  5.         }
  6.         Object object = beanClass.newInstance();
  7.         Field[] fields = beanClass.getDeclaredFields();
  8.         for (Field field : fields) {
  9.             int mod = field.getModifiers();
  10.             if (Modifier.isFinal(mod) || Modifier.isStatic(mod)) {
  11.                 continue;
  12.             }
  13.             field.setAccessible(true);
  14.             field.set(object, map.get(field.getName()));
  15.         }
  16.         return object;
  17.     }
  19. //java对象转map
  20. public static Map<String, Object> objectToMap(Object obj) throws Exception {
  21.     if (obj == null) {
  22.         return null;
  23.     }
  24.     Map<String, Object> map = new HashMap<String, Object>();
  25.     Field[] declaredFields = obj.getClass().getDeclaredFields();
  26.     for (Field field : declaredFields) {
  27.         field.setAccessible(true);
  28.         map.put(field.getName(), field.get(obj));
  29.     }
  30.     return map;
  31. }

4. 使用net.sf.cglib.beans.BeanMap转换

用到的主要jar包：cglib-2.2.2.jar。

  1. //map转java对象
  2. public static Object mapToObject(Map<String, Object> map, Class<?> beanClass) throws Exception {
  3.     Object object = beanClass.newInstance();
  4.     BeanMap beanMap = BeanMap.create(object);
  5.     beanMap.putAll(map);
  6.     return object;
  7. }
  9. //java对象转map
  10. public static Map<String, Object> objectToMap(Object obj) {
  11.     Map<String, Object> map = Maps.newHashMap();
  12.     if (obj != null) {
  13.         BeanMap beanMap = BeanMap.create(obj);
  14.         for (Object key : beanMap.keySet()) {
  15.             map.put(key + "", beanMap.get(key));
  16.         }
  17.     }
  18.     return map;
  19. }

在使用本方法进行map转java对象时，可能会发生以下错误：

  1. Exception in thread "main" java.lang.NoClassDefFoundError: org/objectweb/asm/Type
  2. ....
  3. Caused by: java.lang.ClassNotFoundException: org.objectweb.asm.Type
  4. ....

解决方法：https://blog.csdn.net/liuyunyihao/article/details/86593722

5. 使用json转换

用到的主要jar包：fastjson-1.2.54.jar。

  1. //map转java对象
  2. public static Object mapToObject(Map<String, Object> map, Class<?> beanClass) throws Exception {
  3.     String jsonStr = JSONObject.toJSONString(map);
  4.     return JSONObject.parseObject(jsonStr, beanClass);
  5. }
  7. //java对象转map
  8. public static Map<String, Object> objectToMap(Object obj) {
  9.     String jsonStr = JSONObject.toJSONString(obj);
  10.     return JSONObject.parseObject(jsonStr);
  11. }