map2bean & bean2map

1，自己实现；

/**
 * @author xx
 * @since 2020/7/8
 */
@Slf4j
public class JavaBeanUtils {

    /**
     * 实体类转map
     * 效率较低
     *
     * @param obj
     * @return
     */
    public static Map<String, Object> convertBeanToMap(Object obj) {
        if (obj == null) {
            return null;
        }
        Map<String, Object> map = new HashMap<String, Object>(16);
        try {
            BeanInfo beanInfo = Introspector.getBeanInfo(obj.getClass());
            PropertyDescriptor[] propertyDescriptors = beanInfo.getPropertyDescriptors();
            for (PropertyDescriptor property : propertyDescriptors) {
                String key = property.getName();
                // 过滤class属性
                if (!key.equals("class")) {
                    // 得到property对应的getter方法
                    Method getter = property.getReadMethod();
                    Object value = getter.invoke(obj);
                    if (null == value) {
                        map.put(key, "");
                    } else {
                        map.put(key, value);
                    }
                }
            }
        } catch (Exception e) {
            log.error("convertBean2Map Error：", e);
        }
        return map;
    }

    /**
     * map 转实体类
     *
     * @param clazz
     * @param map
     * @param <T>
     * @return
     */
    public static <T> T convertMapToBean(Class<T> clazz, Map<String, Object> map) {
        T obj = null;
        try {
            BeanInfo beanInfo = Introspector.getBeanInfo(clazz);
            // 创建 JavaBean 对象
            obj = clazz.newInstance();
            // 给 JavaBean 对象的属性赋值
            PropertyDescriptor[] propertyDescriptors = beanInfo.getPropertyDescriptors();
            for (PropertyDescriptor descriptor : propertyDescriptors) {
                String propertyName = descriptor.getName();
                if (map.containsKey(propertyName)) {
                    // 下面一句可以 try 起来，这样当一个属性赋值失败的时候就不会影响其他属性赋值。
                    Object value = map.get(propertyName);
                    if ("".equals(value)) {
                        value = null;
                    }
                    Object[] args = new Object[1];
                    args[0] = value;
                    descriptor.getWriteMethod().invoke(obj, args);
                }
            }
        } catch (IllegalAccessException e) {
            log.error("convertMapToBean 实例化JavaBean失败 Error：", e);
        } catch (IntrospectionException e) {
            log.error("convertMapToBean 分析类属性失败 Error：", e);
        } catch (IllegalArgumentException e) {
            log.error("convertMapToBean 映射错误 Error：", e);
        } catch (InstantiationException e) {
            log.error("convertMapToBean 实例化 JavaBean 失败 Error：", e);
        } catch (InvocationTargetException e) {
            log.error("convertMapToBean字段映射失败 Error：", e);
        } catch (Exception e) {
            log.error("convertMapToBean Error：", e);
        }
        return (T) obj;
    }

    /**
     * 将map通过反射转化为实体
     *
     * @param map
     * @param obj
     * @return
     * @throws Exception
     */
    public static Object mapToModel(Map<String, Object> map, Object obj) throws Exception {
        if (!map.isEmpty()) {
            for (String key : map.keySet()) {
                Object value = null;
                if (!key.isEmpty()) {
                    value = map.get(key);
                }
                Field[] fields = null;
                fields = obj.getClass().getDeclaredFields();
                String clzName = obj.getClass().getSimpleName();
                for (Field field : fields) {
                    int mod = field.getModifiers();
                    if (field.getName().toUpperCase().equals(key.toUpperCase())) {
                        field.setAccessible(true);
                        //进行类型判断
                        String type = field.getType().toString();
                        if (Objects.isNull(value)) {
                            continue;
                        }
                        if (type.endsWith("String")) {
                            value = value.toString();
                        }
                        if (type.endsWith("Date")) {
                            value = new Date(value.toString());
                        }
                        if (type.endsWith("Boolean")) {
                            value = Boolean.getBoolean(value.toString());
                        }
                        if (type.endsWith("int")) {
                            value = new Integer(value.toString());
                        }
                        if (type.endsWith("Long")) {
                            value = new Long(value.toString());
                        }
                        field.set(obj, value);
                    }
                }
            }
        }
        return obj;
    }

    /**
     * 实体对象转成Map
     *
     * @param obj 实体对象
     * @return
     */
    public static Map<String, Object> object2Map(Object obj) {
        Map<String, Object> map = new HashMap<>(16);
        if (obj == null) {
            return map;
        }
        Class clazz = obj.getClass();
        Field[] fields = clazz.getDeclaredFields();
        try {
            for (Field field : fields) {
                field.setAccessible(true);
                map.put(field.getName(), field.get(obj));
            }
        } catch (Exception e) {
            log.error("object2Map Error：", e);
        }
        return map;
    }

    /**
     * Map转成实体对象
     *
     * @param map   map实体对象包含属性
     * @param clazz 实体对象类型
     * @return
     */
    public static Object map2Object(Map<String, Object> map, Class<?> clazz) {
        if (map == null) {
            return null;
        }
        Object obj = null;
        try {
            obj = clazz.newInstance();
            Field[] fields = obj.getClass().getDeclaredFields();
            for (Field field : fields) {
                int mod = field.getModifiers();
                if (Modifier.isStatic(mod) || Modifier.isFinal(mod)) {
                    continue;
                }
                field.setAccessible(true);
                field.set(obj, map.get(field.getName()));
            }
        } catch (Exception e) {
            log.error("map2Object Error：", e);
        }
        return obj;
    }

    public static void main(String[] args) {

        Student s = new Student();
        s.setUserName("ZHH");
        s.setUserName2("ZHH");
        s.setUserName3("ZHH");
        s.setUserName4("ZHH");
        s.setUserName5("ZHH");
        s.setDate(new Date());
        s.setAge(24);
        long sss = System.currentTimeMillis();
        System.out.println("==" + object2Map(s));
        long ddd = System.currentTimeMillis();
        //0ms
        System.out.println(ddd - sss);

        Map<String, Object> map = new HashMap<>(4);
        map.put("userName", "zhh");
        map.put("userName2", "zhh");
        map.put("userName3", "zhh");
        map.put("userName4", "zhh");
        map.put("userName5", "zhh");
        map.put("age", 24);
        map.put("date", new Date());

        long aaa = System.currentTimeMillis();
        System.out.println("++" + map2Object(map, Student.class));
        long www = System.currentTimeMillis();
        //0ms
        System.out.println(www - aaa);

        long q = System.currentTimeMillis();
        System.out.println("==22++" + convertBeanToMap(s));
        long f = System.currentTimeMillis();
        //16ms
        System.out.println(f - q);

        try {
//            DateTime parse = DateUtil.parse(new Date().toString());
//
//            System.out.println("date:" + parse);
        } catch (Exception e) {
            e.printStackTrace();
        }

        long c = System.currentTimeMillis();
        System.out.println("==22++" + convertBeanToMap(s));
        long d = System.currentTimeMillis();
        //0ms
        System.out.println(d - c);

        long a = System.currentTimeMillis();
        System.out.println("++22==" + convertMapToBean(Student.class, map));
        long b = System.currentTimeMillis();
        //0ms
        System.out.println(b - a);

        try {
            long start = System.currentTimeMillis();
            System.out.println("++3333333==" + mapToModel(map, new Student()).toString());
            long end = System.currentTimeMillis();
            //0ms
            System.out.println(end - start);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}

2,也可以直接使用Hutool提供的MapUtil实现