Object转成map对象

1、Object转换成map的方法

import java.lang.reflect.Field;
import java.util.HashMap;
import java.util.Map;


/**
     * 将Object对象里面的属性和值转化成Map对象
     *
     * @param obj
     * @return
     * @throws IllegalAccessException
     */
    public static Map<String, Object> objectToMap(Object obj) throws IllegalAccessException {
        Map<String, Object> map = new HashMap<String,Object>();
        Class<?> clazz = obj.getClass();
        for (Field field : clazz.getDeclaredFields()) {
            field.setAccessible(true);
            String fieldName = field.getName();
            Object value = field.get(obj);
            map.put(fieldName, value);
        }
        return map;
    }

2、转换前的数据格式

SearchHit{id='awQWpXgBwGXBeoctg1F5', score=2.1747518, sortValues=[], content=User(id=awQWpXgBwGXBeoctg1F5, name=吴京, msg=我是演员, job=演员, sex=男, age=12, createDate=Tue Apr 06 08:00:00 CST 2021), highlightFields={}}

3、转换后的数据

{score=2.1747518, innerHits={}, highlightFields={}, index=user, id=awQWpXgBwGXBeoctg1F5, nestedMetaData=null, sortValues=[], content=User(id=awQWpXgBwGXBeoctg1F5, name=吴京, msg=我是演员, job=演员, sex=男, age=12, createDate=Tue Apr 06 08:00:00 CST 2021)}

4、取map中的值

map.get("content")

5、map转实体对象

List searchHits = user.getSearchHits();

List<User> users = new ArrayList<>();
        for (Object o : searchHits) {
            Map<String, Object> map = new HashMap<>();
            map = objectToMap(o);
            Map<String, Object> userMap = objectToMap(map.get("content"));
            User user1 = mapToBean(userMap);
            System.out.println("哈哈哈哈哈转换成功："+user1.getMsg());
            users.add(user1);
        }

6、map转实体类对象利用的方法

参数类型按实际的实体类进行增加

/**
     * map 转 实体类
     *
     * @param map
     * @return
     * @throws Exception
     */
    public User mapToBean(Map<String, Object> map)
            throws Exception {
        User permission = new User();
        if (map != null) {
            Field[] declaredFields = User.class.getDeclaredFields();
            if (declaredFields != null) {

                for (Field declaredField : declaredFields) {
                    declaredField.setAccessible(true);
                    Set<String> mapKeys = map.keySet();

                    for (String mapKey : mapKeys) {

                        if (declaredField.getType().toString().contains("Integer"))//判断属性类型 进行转换,map中存放的是Object对象需要转换 实体类中有多少类型就加多少类型,实体类属性用包装类;
                            if (declaredField.getName().equals(mapKey)) {
                                declaredField.set(permission, Integer.valueOf(map.get(mapKey).toString()));
                                break;
                            }
                        if (declaredField.getType().toString().contains("String"))//判断属性类型 进行转换;
                            if (declaredField.getName().equals(mapKey)) {
                                declaredField.set(permission, map.get(mapKey));

                                break;
                            }
                        if (declaredField.getType().toString().contains("Float"))//判断属性类型 进行转换;
                            if (declaredField.getName().equals(mapKey)) {
                                declaredField.set(permission, Float.valueOf(map.get(mapKey).toString()));

                                break;
                            }

                        if (declaredField.getType().toString().contains("Long"))//判断属性类型 进行转换;
                            if (declaredField.getName().equals(mapKey)) {
                                declaredField.set(permission, Long.valueOf(map.get(mapKey).toString()));
                                break;
                            }

                        if (declaredField.getType().toString().contains("Date"))//判断属性类型 进行转换;
                            if (declaredField.getName().equals(mapKey)) {
                                String s = map.get(mapKey).toString();
                                Date parse = parse(s, "EEE MMM dd HH:mm:ss zzz yyyy", Locale.US);
                                declaredField.set(permission, parse);
                                break;
                            }

                    }
                }
            }

        }

        return permission;

7、里面用到的时间格式是格林威治，实体类存的是Date，具体方法如下：

// 格林威治时间转Date
    private Date parse(String str, String pattern, Locale locale) {
        if (str == null || pattern == null) {
            return null;
        }
        try {
            return new SimpleDateFormat(pattern, locale).parse(str);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        return null;
    }

8、完整代码在下面，因为我用的是springboot+es，所以，根据具体情况灵活变动

package com.springboot.demo.es;

import com.springboot.demo.entity.User;
import com.springboot.demo.mapper.UserResipotry;
import org.apache.tomcat.util.buf.StringUtils;
import org.elasticsearch.index.query.BoolQueryBuilder;
import org.elasticsearch.index.query.QueryBuilders;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.data.elasticsearch.core.ElasticsearchRestTemplate;
import org.springframework.data.elasticsearch.core.SearchHits;
import org.springframework.data.elasticsearch.core.mapping.IndexCoordinates;
import org.springframework.data.elasticsearch.core.query.GetQuery;
import org.springframework.data.elasticsearch.core.query.NativeSearchQueryBuilder;

import javax.xml.crypto.Data;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.*;
import java.lang.reflect.Field;
import java.util.HashMap;
import java.util.Map;

/**
 * @author dt
 * @date 2021年04月06日10:47
 */
@SpringBootTest
public class EsDemo01 {


    @Autowired
    private ElasticsearchRestTemplate elasticsearchRestTemplate;

   
    @Test
    void test4() throws Exception {

        //组合条件对象
        BoolQueryBuilder boolQuery = QueryBuilders.boolQuery();
        boolQuery.must(QueryBuilders.matchQuery("name", "吴京"));

        NativeSearchQueryBuilder nativeSearchQueryBuilder = new NativeSearchQueryBuilder();
        nativeSearchQueryBuilder.withQuery(boolQuery);
        SearchHits user = elasticsearchRestTemplate.search(nativeSearchQueryBuilder.build(), User.class, IndexCoordinates.of("user"));
        List searchHits = user.getSearchHits();

        List<User> users = new ArrayList<>();
        for (Object o : searchHits) {
            Map<String, Object> map = new HashMap<>();
            map = objectToMap(o);
            Map<String, Object> userMap = objectToMap(map.get("content"));
            User user1 = mapToBean(userMap);
            System.out.println("哈哈哈哈哈转换成功："+user1.getMsg());
            users.add(user1);
        }

        System.out.println(users);

    }


    /**
     * 将Object对象里面的属性和值转化成Map对象
     *
     * @param obj
     * @return
     * @throws IllegalAccessException
     */
    public static Map<String, Object> objectToMap(Object obj) throws IllegalAccessException {
        Map<String, Object> map = new HashMap<String, Object>();
        Class<?> clazz = obj.getClass();
        for (Field field : clazz.getDeclaredFields()) {
            field.setAccessible(true);
            String fieldName = field.getName();
            Object value = field.get(obj);
            map.put(fieldName, value);
        }
        return map;
    }


    /**
     * map 转 实体类
     *
     * @param map
     * @return
     * @throws Exception
     */
    public User mapToBean(Map<String, Object> map)
            throws Exception {
        User permission = new User();
        if (map != null) {
            Field[] declaredFields = User.class.getDeclaredFields();
            if (declaredFields != null) {

                for (Field declaredField : declaredFields) {
                    declaredField.setAccessible(true);
                    Set<String> mapKeys = map.keySet();

                    for (String mapKey : mapKeys) {

                        if (declaredField.getType().toString().contains("Integer"))//判断属性类型 进行转换,map中存放的是Object对象需要转换 实体类中有多少类型就加多少类型,实体类属性用包装类;
                            if (declaredField.getName().equals(mapKey)) {
                                declaredField.set(permission, Integer.valueOf(map.get(mapKey).toString()));
                                break;
                            }
                        if (declaredField.getType().toString().contains("String"))//判断属性类型 进行转换;
                            if (declaredField.getName().equals(mapKey)) {
                                declaredField.set(permission, map.get(mapKey));

                                break;
                            }
                        if (declaredField.getType().toString().contains("Float"))//判断属性类型 进行转换;
                            if (declaredField.getName().equals(mapKey)) {
                                declaredField.set(permission, Float.valueOf(map.get(mapKey).toString()));

                                break;
                            }

                        if (declaredField.getType().toString().contains("Long"))//判断属性类型 进行转换;
                            if (declaredField.getName().equals(mapKey)) {
                                declaredField.set(permission, Long.valueOf(map.get(mapKey).toString()));
                                break;
                            }

                        if (declaredField.getType().toString().contains("Date"))//判断属性类型 进行转换;
                            if (declaredField.getName().equals(mapKey)) {
                                String s = map.get(mapKey).toString();
                                Date parse = parse(s, "EEE MMM dd HH:mm:ss zzz yyyy", Locale.US);
                                declaredField.set(permission, parse);
                                break;
                            }

                    }
                }
            }

        }

        return permission;
    }


    @Test
    public void getTime() throws ParseException {
        String str = "Tue Apr 06 08:00:00 CST 2021";
        Date date = parse(str, "EEE MMM dd HH:mm:ss zzz yyyy", Locale.US);

    }

    // 格林威治时间转Date
    private Date parse(String str, String pattern, Locale locale) {
        if (str == null || pattern == null) {
            return null;
        }
        try {
            return new SimpleDateFormat(pattern, locale).parse(str);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        return null;
    }
}

9、那些转换方法都可以单独用

参考文章链接：

https://blog.csdn.net/qq_15204179/article/details/86677123

https://www.cnblogs.com/zktww/p/14296407.html

https://www.cnblogs.com/tobeymarshall/p/10217410.html