java bean的拷贝

1.bean copy

package com.qimh.springbootfiledemo.utils;

import org.apache.poi.ss.formula.functions.T;

import java.lang.reflect.Field;

/**
 * @author
 * bean 复制
 */
public class BeanCopy {

    /**
     * bean 的拷贝
     * @param srcBean--原始bean
     * @param destClazz--目标class对象
     * 这个<T> T 表示的是返回值T是泛型
     *  T是一个占位符，用来告诉编译器，这个东西先给我留着，等我编译的时候，告诉你。
     *  https://www.cnblogs.com/jpfss/p/9929108.html
     */
    public static <T> T beanCopy(Object srcBean,Class<T> destClazz) throws IllegalAccessException, InstantiationException, NoSuchFieldException {
        if (null != srcBean && null != destClazz){
            //获取目标bean的实例
            T destBean = destClazz.newInstance();
            //获取目标bean所有字段
            Field[] fields = destClazz.getDeclaredFields();
            for (int i = 0;i < fields.length;i++){
                Field field = fields[i];
                Object value = BeanEquals.getClassValue(srcBean,field.getName());

                //获取目标类的字段
                Field destField = destClazz.getDeclaredField(field.getName());
                //可访问私有属性
                destField.setAccessible(true);
                //给目标类属性设置值
                destField.set(destBean,value);
            }

            return destBean;

        }
        return null;
    }


}

2.拷贝工具类

package com.qimh.springbootfiledemo.utils;

import com.alibaba.fastjson.JSONObject;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.util.StringUtils;

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

/**
 * @author ex-qiminhui001
 * 判断两个bean是否相等
 */
public class BeanEquals {
    /**
     * 日志操作类
     */
    private static Logger logger = LoggerFactory.getLogger(BeanEquals.class);


    /**
     * 比较两个BEAN或MAP对象的值是否相等
     * 如果是BEAN与MAP对象比较时MAP中的key值应与BEAN的属性值名称相同且字段数目要一致
     * @param source
     * @param target
     * @return
     */
    public static boolean domainEquals(Object source, Object target) {
        if (source == null || target == null) {
            return false;
        }
        boolean rv = true;
        if (source instanceof Map) {
            rv = mapOfSrc(source, target, rv);
        } else {
            rv = classOfSrc(source, target, rv);
        }
        logger.info("THE EQUALS RESULT IS " + rv);
        return rv;
    }

    /**
     * 源目标为MAP类型时
     * @param source
     * @param target
     * @param rv
     * @return
     */
    private static boolean mapOfSrc(Object source, Object target, boolean rv) {
        HashMap<String, String> map = new HashMap<String, String>();
        map = (HashMap) source;
        for (String key : map.keySet()) {
            if (target instanceof Map) {
                HashMap<String, String> tarMap = new HashMap<String, String>();
                tarMap = (HashMap) target;
                if(tarMap.get(key)==null){
                    rv = false;
                    break;
                }
                if (!map.get(key).equals(tarMap.get(key))) {
                    rv = false;
                    break;
                }
            } else {
                String tarValue = getClassValue(target, key) == null ? "" : getClassValue(target, key).toString();
                if (!tarValue.equals(map.get(key))) {
                    rv = false;
                    break;
                }
            }
        }
        return rv;
    }

    /**
     * 源目标为非MAP类型时
     * @param source
     * @param target
     * @param rv
     * @return
     */
    private static boolean classOfSrc(Object source, Object target, boolean rv) {
        Class<?> srcClass = source.getClass();
        Field[] fields = srcClass.getDeclaredFields();
        for (Field field : fields) {
            String nameKey = field.getName();
            if (target instanceof Map) {
                HashMap<String, String> tarMap = new HashMap<String, String>();
                tarMap = (HashMap) target;
                String srcValue = getClassValue(source, nameKey) == null ? "" : getClassValue(source, nameKey)
                        .toString();
                if(tarMap.get(nameKey)==null){
                    rv = false;
                    break;
                }
                if (!tarMap.get(nameKey).equals(srcValue)) {
                    rv = false;
                    break;
                }
            } else {
                if (nameKey.equals("carts")){
                    System.out.println("field:" + nameKey);
                }
                if (nameKey.equals("friends")){
                    System.out.println("field:" + nameKey);
                }

                //数组类型
                if (!StringUtils.isEmpty(getClassValue(source, nameKey))  && getClassValue(source, nameKey) instanceof Object[]){
                    rv = Arrays.equals((Object[])getClassValue(source, nameKey),(Object[])getClassValue(target, nameKey));
                    break;
                }
                String srcValue = getClassValue(source, nameKey) == null ? "" : getClassValue(source, nameKey)
                        .toString();
                String tarValue = getClassValue(target, nameKey) == null ? "" : getClassValue(target, nameKey)
                        .toString();
                if (!srcValue.equals(tarValue)) {
                    rv = false;
                    break;
                }
            }
        }
        return rv;
    }

    /**
     * 根据字段名称取值
     * @param obj
     * @param fieldName
     * @return
     */
    public static Object getClassValue(Object obj, String fieldName) {
        if (obj == null) {
            return null;
        }
        try {
            Class beanClass = obj.getClass();
            Method[] ms = beanClass.getMethods();
            for (int i = 0; i < ms.length; i++) {
                // 非get方法不取
                if (!ms[i].getName().startsWith("get")) {
                    continue;
                }
                Object objValue = null;
                try {
                    objValue = ms[i].invoke(obj, new Object[] {});
                } catch (Exception e) {
                    logger.info("反射取值出错：" + e.toString());
                    continue;
                }
                if (objValue == null) {
                    continue;
                }
                if (ms[i].getName().toUpperCase().equals(fieldName.toUpperCase())
                        || ms[i].getName().substring(3).toUpperCase().equals(fieldName.toUpperCase())) {
                    return objValue;
                } else if (fieldName.toUpperCase().equals("SID")
                        && (ms[i].getName().toUpperCase().equals("ID") || ms[i].getName().substring(3).toUpperCase()
                        .equals("ID"))) {
                    return objValue;
                }
            }
        } catch (Exception e) {
            // logger.info("取方法出错！" + e.toString());
        }
        return null;
    }

    public static void main(String args[]) {
        Person person1 = new Person();
        person1.setName("张三");
        person1.setAge(20);
        JSONObject carts = new JSONObject();
        carts.put("bmw","宝马");
        carts.put("audi","奥迪");
        person1.setCarts(carts);
        person1.setFriends(new String[]{"tom","jim"});

        Person person2 = new Person();
        person2.setName("张三");
        person2.setAge(20);
        JSONObject carts2 = new JSONObject();
        carts2.put("bmw","宝马");
        carts2.put("audi","奥迪");
        person2.setCarts(carts2);
        person2.setFriends(new String[]{"tom","jim2"});

        System.out.println(domainEquals(person1,person2));

    }

}

3.目标bean

package com.qimh.springbootfiledemo.bean;

public class JimPerson {
    private Integer age;
    private String name;

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @Override
    public String toString() {
        return "JimPerson{" +
                "age=" + age +
                ", name='" + name + '\'' +
                '}';
    }
}

4.原始bean

package com.qimh.springbootfiledemo.bean;

public class Person {
    private Integer age;
    private String name;

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @Override
    public String toString() {
        return "Person{" +
                "age=" + age +
                ", name='" + name + '\'' +
                '}';
    }
}

5.测试类

package com.qimh.springbootfiledemo;

import com.qimh.springbootfiledemo.bean.JimPerson;
import com.qimh.springbootfiledemo.bean.Person;
import com.qimh.springbootfiledemo.utils.BeanCopy;

public class BeanCopyMain {

    public static void main(String[] args) throws IllegalAccessException, NoSuchFieldException, InstantiationException {
        Person person = new Person();
        person.setName("张三");
        person.setAge(20);

       JimPerson jimPerson = BeanCopy.beanCopy(person, JimPerson.class);
       System.out.println("jimPerson:" + jimPerson);
    }
}

 

来源：oschina

链接：https://my.oschina.net/qimhkaiyuan/blog/4299528