java常用的对象转map的几种方式

清疚 2021-09-25 02:46 462阅读 0赞

创建对象User

package com.xqc;
     
    import java.util.Date;
     
    public class User {
        /**
         *
         * ID
         */
        private Integer id;
        /**
         *
         * 用户名
         */
        private String userName;
        /**
         *
         * 岗位ID
         */
        private Long jobId;
        /**
         * 生日
         */
        private Date birthday;
        /**
         *
         * 薪水
         */
        private Double salary;
     
        public Integer getId() {
            return id;
        }
     
        public void setId(Integer id) {
            this.id = id;
        }
     
        public String getUserName() {
            return userName;
        }
     
        public void setUserName(String userName) {
            this.userName = userName;
        }
     
        public Long getJobId() {
            return jobId;
        }
     
        public void setJobId(Long jobId) {
            this.jobId = jobId;
        }
     
        public Date getBirthday() {
            return birthday;
        }
     
        public void setBirthday(Date birthday) {
            this.birthday = birthday;
        }
     
        public Double getSalary() {
            return salary;
        }
     
        public void setSalary(Double salary) {
            this.salary = salary;
        }
     
        public User setUser(){
            User user = new User();
            user.setId(123);
            user.setUserName("王二");
            user.setSalary(2344.4D);
            user.setBirthday(new Date());
            user.setJobId(99999L);
            return user;
        }
    }

1.使用反射

import java.lang.reflect.Field;
    import java.util.HashMap;
    import java.util.Map;
     
    /**
     *使用反射
     */
    public class Method01 {
        public static void main(String[] args) {
            long s1 = System.currentTimeMillis();
            Map<String, Object> dataMap = objectToMap(new User().setUser());
            long s2 = System.currentTimeMillis();
            System.out.println("花费时间毫秒："+(s2-s1));
            System.out.println(dataMap);
        }
     
        public static Map<String, Object> objectToMap(Object object){
            Map<String,Object> dataMap = new HashMap<>();
            Class<?> clazz = object.getClass();
            for (Field field : clazz.getDeclaredFields()) {
                try {
                    field.setAccessible(true);
                    dataMap.put(field.getName(),field.get(object));
                } catch (IllegalAccessException e) {
                    e.printStackTrace();
                }
            }
            return dataMap;
        }
    }

![20210117143143439.png][]

执行多次耗时一般在4-7毫秒左右  
  
2.使用org.apache.commons.beanutils包下的BeanUtils.describe()方法,需要引入commons-beanutils包

import org.apache.commons.beanutils.BeanUtils;
    import java.lang.reflect.InvocationTargetException;
    import java.util.HashMap;
    import java.util.Map;
     
    public class Method02 {
     
        public static void main(String[] args) {
            long s1 = System.currentTimeMillis();
            Map<String, String> dataMap = objectToMap(new User().setUser());
            long s2 = System.currentTimeMillis();
            System.out.println("花费时间毫秒："+(s2-s1));
            System.out.println(dataMap);
        }
     
        public static Map<String, String> objectToMap(Object object){
            try {
                Map<String, String> dataMap = BeanUtils.describe(object);
                dataMap.remove("class");//移除多出来的class字段
                return dataMap;
            } catch (IllegalAccessException e) {
                e.printStackTrace();
            } catch (InvocationTargetException e) {
                e.printStackTrace();
            } catch (NoSuchMethodException e) {
                e.printStackTrace();
            }
            return new HashMap<>();
        }
    }

![20210117150125461.png][]

执行多次耗时一般在150毫秒左右，甚至更多  
  
3.直接使用put方法往map对象里一个个赋值

import java.util.HashMap;
    import java.util.Map;
    
    public class Method03 {
        public static void main(String[] args) {
            long s1 = System.currentTimeMillis();
            User user = new User().setUser();
            Map<String,Object> dataMap = new HashMap<>();
            dataMap.put("id",user.getId());
            dataMap.put("userName",user.getUserName());
            dataMap.put("salary",user.getSalary());
            dataMap.put("birthday",user.getBirthday());
            dataMap.put("jobId",user.getJobId());
            long s2 = System.currentTimeMillis();
            System.out.println("花费时间毫秒："+(s2-s1));
            System.out.println(dataMap);
        }
    }

![20210117150406113.png][]

执行多次耗时一般在3-9毫秒左右

4.使用BeanMap.create方法，需要引入spring相关jar

import org.apache.commons.beanutils.BeanUtils;
    import org.springframework.cglib.beans.BeanMap;
    
    import java.lang.reflect.InvocationTargetException;
    import java.util.HashMap;
    import java.util.Map;
    
    public class Method04 {
        public static void main(String[] args) {
            long s1 = System.currentTimeMillis();
            Map<String, Object> dataMap = objectToMap(new User().setUser());
            long s2 = System.currentTimeMillis();
            System.out.println("花费时间毫秒："+(s2-s1));
            System.out.println(dataMap);
        }
    
        public static Map<String, Object> objectToMap(Object object){
            Map<String,Object> dataMap = new HashMap<>();
            BeanMap beanMap = BeanMap.create(object);
            for (Object key : beanMap.keySet()) {
                dataMap.put(key+"",beanMap.get(key));
            }
            return dataMap;
        }
    }

![202101171558494.png][]

执行多次耗时一般在180-280毫秒之间，甚至更多

[20210117143143439.png]: /images/20210923/da8d073e2455408ba22782c0176571e7.png
[20210117150125461.png]: /images/20210923/5a2b278ebd504e17be15eb399dd632de.png
[20210117150406113.png]: /images/20210923/dddd9d4df4304959ab03da1a5dd989dd.png
[202101171558494.png]: /images/20210923/62194f36b608422eb23c9c2f51cae9da.png