Java中如何优雅的把Map转为对象

小咪咪 2023-09-30 23:40 20阅读 0赞

在项目开发中，经常碰到map转实体对象或者对象转map的场景，工作中，很多时候我们可能比较喜欢使用第三方jar包的API对他们进行转化，而且用起来也还算方便，比如像fastJson就可以轻松实现map和对象的互转，但这里，我想通过反射的方式对他们做转化，也算是对反射的学习和研究吧；

1、map转java对象

import com.alibaba.fastjson.JSON;
    import com.alibaba.fastjson.JSONObject;
    import com.mes.common.core.utils.StringUtils;
    
    import java.beans.BeanInfo;
    import java.beans.IntrospectionException;
    import java.beans.Introspector;
    import java.beans.PropertyDescriptor;
    import java.lang.reflect.Method;
    import java.util.HashMap;
    import java.util.Iterator;
    import java.util.Map;
    import java.util.logging.Level;
    import java.util.logging.Logger;

/**
         * @Author: best_liu
         * @Description: map转java对象
         * @Date: 8:35 2022/3/22
         **/
        public static Object convertToObject(Class clazz, Map<String, Object> map) throws
                IntrospectionException, InstantiationException, IllegalAccessException {
            BeanInfo bi = Introspector.getBeanInfo(clazz);
    
            Object obj = clazz.newInstance();
    
            PropertyDescriptor[] pds = bi.getPropertyDescriptors();
    
            String pName;
            for (PropertyDescriptor pd : pds) {
                pName = pd.getName();
                if (map.containsKey(pName)) {
                    try {
                        if (pd.getPropertyType().getName().equals("java.lang.Long")) {
                            if(StringUtils.isNotEmpty(map.get(pName).toString())){
                                pd.getWriteMethod().invoke(obj, Long.parseLong(map.get(pName).toString()));
                            }
    //                        else{
    //                            pd.getWriteMethod().invoke(obj, map.get(pName));
    //                        }
    
                        } else {
                            pd.getWriteMethod().invoke(obj, map.get(pName));
                        }
                    } catch (Exception ex) {
                        Logger.getLogger(MapUtil.class.getName()).log(Level.SEVERE, null, ex);
                    }
                }
            }
    
            return obj;
        }

2、java对象转map

/**
         * @Author: best_liu
         * @Description: java对象转map
         * @Date: 8:35 2022/3/22
         **/
        public static Map<String, String> objectToMap(Object obj) {
            if (obj == null) {
                return null;
            }
    
            Map<String, String> map = new HashMap<String, String>();
            try {
                BeanInfo beanInfo = Introspector.getBeanInfo(obj.getClass());
                PropertyDescriptor[] propertyDescriptors = beanInfo.getPropertyDescriptors();
                for (PropertyDescriptor property : propertyDescriptors) {
                    String key = property.getName();
                    if (key.compareToIgnoreCase("class") == 0) {
                        continue;
                    }
                    Method getter = property.getReadMethod();
                    Object value = getter != null ? getter.invoke(obj) : null;
                    String v = null;
                    if (value != null) {
                        v = value.toString();
                    }
                    map.put(key, v);
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
            return map;
        }
    
        /**
         * @Author: best_liu
         * @Description: java对象转map
         * @Date: 8:35 2022/3/22
         **/
        public static Map<String, Object> objectToMapObj(Object obj) {
            if (obj == null) {
                return null;
            }
    
            Map<String, Object> map = new HashMap<String, Object>();
            try {
                BeanInfo beanInfo = Introspector.getBeanInfo(obj.getClass());
                PropertyDescriptor[] propertyDescriptors = beanInfo.getPropertyDescriptors();
                for (PropertyDescriptor property : propertyDescriptors) {
                    String key = property.getName();
                    if (key.compareToIgnoreCase("class") == 0) {
                        continue;
                    }
                    Method getter = property.getReadMethod();
                    Object value = getter != null ? getter.invoke(obj) : null;
                    map.put(key, value);
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
            return map;
        }

3、Map转换为Json字符串

/**
         * @Author: best_liu
         * @Description: Map转换为Json字符串
         * @Date: 8:35 2022/3/22
         **/
        public static String mapToJsonString(Map map) {
            JSONObject json = new JSONObject();
            Iterator<Map.Entry<String, String>> entries = map.entrySet().iterator();
            while (entries.hasNext()) {
                Map.Entry<String, String> entry = entries.next();
                json.put(entry.getKey(), entry.getValue());
            }
            return json.toString();
        }

4、Json字符串转换为Map

/**
         * @Author: best_liu
         * @Description: Json字符串转换为Map
         * @Date: 8:35 2022/3/22
         **/
        public static Map<String, Long> jsonStringToMap(String str) {
            Map<String, Long> map = (Map<String, Long>) JSON.parse(str);
            return map;
        }