java实现把一个bean的属性复制到另一个bean中的几种实现方案

本文链接：https://blog.youkuaiyun.com/qq_35340078/article/details/111165080

本文介绍了Java中将一个bean的属性复制到另一个bean的七种实现方式，包括Spring BeanUtils工具类、Apache Commons BeanUtils、反射、CGLIB的BeanCopier、Spring的CGLIB BeanCopier、ModelMapper以及MapStruct。每种方法都有其特点和适用场景，如BeanUtils的完全复制、反射的灵活性以及MapStruct的接口定义等。

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java使用 org.springframework.beans.BeanUtils 工具类，把一个bean的属性值复制到另一个bean中，前提是这个复制的bean的字段要完全包含在被复制的bean中

代码如下

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Person {

    private String name;

    private String city;

    private Integer age;
}

@Data
public class Child extends Person{

    private String hobby;

    private String work;

}

import org.springframework.beans.BeanUtils;

public class CopyBean {

    public static void main(String[] args) {
        Person person = new Person("jack", "北京", 12);

        Child child = new Child();

        BeanUtils.copyProperties(person,child);

        child.setHobby("看电视");
        child.setWork("看门");

        System.out.println(child.getCity());
    }
}

可以实现bean之间的属性的完全复制

2.使用org.apache.commons.beanutils.BeanUtils.copyProperties

需要的jar包

<dependency> <groupId>commons-beanutils</groupId> <artifactId>commons-beanutils</artifactId> <version>1.9.3</version> </dependency>

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Person {

    private String name;

    private String city;

    private Integer age;
}

@Data
public class Child extends Person{

    private String hobby;

    private String work;

}

import org.apache.commons.beanutils.BeanUtils;

public class CopyBean {

    public static void main(String[] args) throws Exception{
        Person person = new Person("jack", "北京", 12);
        Child child = new Child();
        BeanUtils.copyProperties(child,person);

        System.out.println(child.getName());
    }
}

与第一种实现方式的不同在于，source和target的位置相反

3.反射实现

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Person {

    private String name;

    private String city;

    private Integer age;
}

@Data
public class Child extends Person{

    private String hobby;

    private String work;

}



import java.beans.BeanInfo;
import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.lang.reflect.Method;

public class CopyBean {

    public static void main(String[] args) throws Exception{
        Person person = new Person("jack", "北京", 12);

        Child child = new Child();

        child = copyBean(child,person);

        System.out.println(child.getName());
    }

    public static <T extends PO, PO> T copyBean(T dest, PO source) throws             IntrospectionException {
        BeanInfo beanInfo = Introspector.getBeanInfo(dest.getClass()) ;
        PropertyDescriptor[] pdes = beanInfo.getPropertyDescriptors() ;
        for(int i = 0,length =pdes.length ;i<length ;i++ ){
            PropertyDescriptor pd = pdes[i] ;
            try {
                PropertyDescriptor sourcePd = new PropertyDescriptor(pd.getName(), source.getClass()) ;
                Method sourceMethod = sourcePd.getReadMethod() ;
                Object result = sourceMethod.invoke(source) ;
                Method pdWriteMethod = pd.getWriteMethod() ;
                pdWriteMethod.invoke(dest, result) ;
            } catch (Exception e) {
                continue ;
            }
        }
        return dest ;
    }
}

4.使用 net.sf.cglib.beans.BeanCopier.copy的方式，需要自定义转换器Converter实现类

需要的jar包

<dependency>
    <groupId>cglib</groupId>
    <artifactId>cglib</artifactId>
    <version>3.1</version>
</dependency>

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Person {

    private String name;

    private String city;

    private Integer age;
}

@Data
public class Child extends Person{

    private String hobby;

    private String work;

}

//自定义转换类 converter的具体实现类

import net.sf.cglib.core.Converter;
import org.springframework.util.StringUtils;

import java.math.BigDecimal;
import java.util.Date;

public class CopyConverter implements Converter {
    @Override
    public Object convert(Object value, Class target, Object context) {

        String s = value.toString();
        if (target.equals(int.class) || target.equals(Integer.class)) {
            return Integer.parseInt(s);
        }
        if (target.equals(long.class) || target.equals(Long.class)) {
            return Long.parseLong(s);
        }
        if (target.equals(float.class) || target.equals(Float.class)) {
            return Float.parseFloat(s);
        }
        if (target.equals(double.class) || target.equals(Double.class)) {
            return Double.parseDouble(s);
        }
        if (target.equals(Date.class)) {
            while (s.indexOf("-") > 0) {
                s = s.replace("-", "/");
            }
            return new Date(s);
        }
        if (target.equals(BigDecimal.class)) {
            if (!StringUtils.isEmpty(s) && !s.equals("NaN")) {
                return new BigDecimal(s);
            }
        }
        return value;
    }
}



import net.sf.cglib.beans.BeanCopier;


public class CopyBean {

    public static void main(String[] args) throws Exception{
        Person person = new Person("jack", "北京", 12);
        Child child = new Child();

        BeanCopier beanCopier = BeanCopier.create(Person.class,
                Child.class, true);

        beanCopier.copy(person, child, new CopyConverter());

        System.out.println(child.getCity());
    }


}

5.使用org.springframework.cglib.beans.BeanCopier.copy

实现方式同4

6.Orika实现方式 Orika 是 Java Bean 映射框架，可以实现从一个对象递归拷贝数据至另一个对象。它的优点是：名字相同类型不同也能直接复制

需要的jar包

<dependency>
    <groupId>ma.glasnost.orika</groupId>
    <artifactId>orika-core</artifactId>
    <version>1.5.4</version>
</dependency>

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Person {

    private String name;

    private String city;

    private Integer age;
}


@Data
public class Child extends Person{

    private String hobby;

    private String work;

}


import ma.glasnost.orika.impl.DefaultMapperFactory;

public class CopyBean {

    public static void main(String[] args) throws Exception{
        Person person = new Person("jack", "北京", 12);
        Child child = new Child();

        new DefaultMapperFactory.Builder().build().getMapperFacade().map(person,child);

        System.out.println(child.getName());
    }
}

7.使用MapStruct实现

需要的jar 包

<dependency>
    <groupId>org.mapstruct</groupId>
    <artifactId>mapstruct-jdk8</artifactId>
    <version>1.3.0.Final</version>
</dependency>
<dependency>
    <groupId>org.mapstruct</groupId>
    <artifactId>mapstruct-processor</artifactId>
    <version>1.3.0.Final</version>
</dependency>

首先定义Mapper转换接口

import org.mapstruct.Mapper;
import org.mapstruct.Mapping;

@Mapper
public interface CopyMapper {

    @Mapping(source = "name",target = "name")
    Child mapperToBean(Person person);

}

再通过反射机制实现复制bean

import org.mapstruct.factory.Mappers;

public class CopyBean {

    public static void main(String[] args) throws Exception {
        Person person = new Person("jack", "北京", 12);

        CopyMapper copyMapper = Mappers.getMapper(CopyMapper.class);
        Child child = copyMapper.mapperToBean(person);

        System.out.println(child.getAge());
    }
}