Java 反射：为集合类型 Object 调用 Setter 和 Getter 方法

Question

我有两个不同的用户定义对象包.....

1) ws.lender.dto (all Objects exists in this package are source side).
2) copl.com.dto (all Objects exists in this package are destination side).

对象层次结构和对象名称在两侧不同。我想 逐个字段将源端对象复制到目标端对象或 通过使用反射的 getter 和 setter。

举例

源端对象

   package ws.lender.dto;

    @XmlAccessorType(XmlAccessType.FIELD)
    @XmlType(name = "CustomerAddresses", propOrder = {
        "previousAddresses"
    })
    public class CustomerAddresses {

        protected PreviousAddresses previousAddresses;

        public PreviousAddresses getPreviousAddresses() {
            return previousAddresses;
        }

        public void setPreviousAddresses(PreviousAddresses value) {
            this.previousAddresses = value;
        }

    }


@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "PreviousAddresses", propOrder = {
    "previousAddress"
})
public class PreviousAddresses {

    @XmlElement(name = "PreviousAddress", required = true)
    protected List<PreviousAddress> previousAddress;

    public List<PreviousAddress> getPreviousAddress() {
        if (previousAddress == null) {
            previousAddress = new ArrayList<PreviousAddress>();
        }
        return this.previousAddress;
    }
}


@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "PreviousAddress", propOrder = {

    "streetNo",
    "streetName"
})
public class PreviousAddress {

    @XmlElement(name = "StreetNo", required = true)
    protected String streetNo;
    @XmlElement(name = "StreetName", required = true)
    protected String streetName;

    public String getStreetNo() {
        return streetNo;
    }
    public void setStreetNo(String value) {
        this.streetNo = value;
    }
    public String getStreetName() {
        return streetName;
    }
    public void setStreetName(String value) {
        this.streetName = value;
    }
}

目标端对象

package copl.com.dto;

@javax.persistence.Entity
public class Customer implements java.io.Serializable
{
private Set<CustomerAddress> customerAddresses;

   public Set<CustomerAddress> getCustomerAddresses()
    {
        return customerAddresses;
    }

        public void setCustomerAddresses(Set<CustomerAddress> customerAddresses)
    {
        this.customerAddresses = customerAddresses;
    }
}

@javax.persistence.Entity
public class CustomerAddress implements java.io.Serializable
{   
    private String unitNumber;
    private String streetName;
    private String streetNumber;

   public String getUnitNumber()
    {
        return unitNumber;
    }   
        public void setUnitNumber(String unitNumber)
    {
        this.unitNumber = unitNumber;
    }
        public String getStreetName()
    {
        return streetName;
    }
       public String getStreetNumber()
    {
        return streetNumber;
    }
        public void setStreetName(String streetName)
    {
        this.streetName = streetName;
    }

    public void setStreetNumber(String streetNumber)
    {
        this.streetNumber = streetNumber;
    }
}   

Answer 1

我研究了很多对象映射框架来完成这个任务，比如

• Orika
• MapStruct
• ModelMapper
• Dozer
• Commons-BeanUtils

最后我选择Orika框架来完成上面的Objects to Objects映射。我们可以通过其他映射器框架进行映射，但我喜欢 Orika 框架，因为这个框架非常容易用于将对象映射到对象。

我会一步一步解释。

1.创建源端对象和目标端对象的对象。

像这样..

    Customer destination = new Customer();
    CustomerAddresses source = new CustomerAddresses();
    source = filledCustomerAddressesObject();

2。构造 DefaultMapperFactory

MapperFactory mapperFactory = new DefaultMapperFactory.Builder().build();

3.映射字段

    ClassMapBuilder<CustomerAddresses, Customer> builder;
    
    builder= mapperFactory.classMap(CustomerAddresses.class, Customer.class).constructorA();

    builder.field("previousAddresses.previousAddress{streetNo}","customerAddresses{streetNumber}");
    builder.field("previousAddresses.previousAddress{streetName}","customerAddresses{streetName}");
    
    builder.register();

    BoundMapperFacade<CustomerAddresses, Customer> boundMapper;
    
    boundMapper = mapperFactory.getMapperFacade(CustomerAddresses.class, Customer.class);
    
    destination = boundMapper.map(source, destination);

干得好干杯

Answer 2

您可以尝试Object Mapper 更好地进行投射或复制。对象到其他包中的其他类，您可以添加一些属性值，如

senderClass 和 rvcClass

稍后您可以阅读这些属性并继续转换类。可能您已经准备好发送者类与接收者类的映射。

Answer 3

我认为您可以使用MapStruct 在具有不同属性名称的 POJO 之间进行映射。

但是您的情况很复杂，因为您想将ws.lender.dto.CustomerAddresses 转换为copl.com.dto.Customer，这意味着将包含在ws.lender.dto.PreviousAddresses 对象中的List<ws.lender.dto.PreviousAddress> 转换为包含在copl.com.dto.Customer 中的Set<copl.com.dto.CustomerAddress>对象。

所以，我会一步一步解释。

1。从ws.lender.dto.PreviousAddress 转换为copl.com.dto.CustomerAddress

要进行此转换，您需要一个接口（MapStruct 将为此创建一个实例）负责从源对象映射到目标对象：

import ws.lender.dto.PreviousAddress;
import copl.com.dto.CustomerAddress;

@Mapper
public interface CustomerAddressesMapper{

    CustomerAddressesMapper INSTANCE = Mappers.getMapper( CustomerAddressesMapper.class );

    @Mappings(@Mapping(source = "streetNo", target = "streetNumber")
    CustomerAddress previousToCustomerObject(PreviousAddress address);
}

考虑到streetNo 属性必须映射到streetNumber，此接口会将PreviousAddress 对象映射到CustomerAddress。 unitNumber 属性没有映射，因为它没有来源。

2。将List<ws.lender.dto.PreviousAddress> 转换为Set<copl.com.dto.CustomerAddress>

现在您必须向现有的CustomerAddressesMapper 接口添加另一个映射方法：

Set<CustomerAddress> previousToCustomerSet(List<PreviousAddress> addresses);

此方法将使用以前的previousToCustomerObject 将源列表的每个元素转换为目标集。

3。从ws.lender.dto.CustomerAddresses 转换为copl.com.dto.Customer

最后需要在CustomerAddressesMapper接口中添加最后一个映射方法：

@Mappings(@Mapping(source = "previousAddresses.previousAddress", target = "customerAddresses")
Customer customerAddrsToCustomerObject(CustomerAddresses addresses);

这是您映射原始对象的位置，将previousAddresses.previousAddress 属性转换为customerAddresses 属性，使用以前的方法。

4。使用映射器

要使用映射器，您必须编写如下代码：

CustomerAddressesMapper mapper = CustomerAddressesMapper.INSTANCE;
CustomerAddresses origin = //Retrieve it from anywhere
Customer dest = mapper.customerAddrsToCustomerObject(origin);

5。设置

MapStruct 是一个源代码生成器，因此您需要正确配置您的pom.xml 以包含 MapStruct 依赖项并调用此代码生成。你可以看看如何做到这一点here

好吧，我不构建和运行这段代码，但这是实现它的方法。

希望对你有帮助！

Answer 4

如果我理解正确，您需要一种将所有同名属性从一个对象复制到另一个对象的方法。类似命名的属性是指源对象有一个名为 getPropertyName() 的方法，而目标对象有一个名为 setPropertyName() 的方法。

如果这是正确的，那么您想使用 Apache Commons 库中 BeanUtils 类的 copyProperties 方法。文档是here。

现在，在您的示例中，您有一些名称不同的对应属性，例如 StreetNumber 和 StreetNo。恐怕没有简单的方法可以通过反射自动处理这类事情。您需要自己定义源属性和目标属性之间的映射，可能通过定义一个帮助类来进行复制。