java - ModelMapper 字段映射

Question

我在使用 ModelMapper 框架时遇到了麻烦。请解释为什么我看到以下行为。

我在 build.gradle 中有以下依赖项

compile group: 'org.modelmapper', name: 'modelmapper', version: '2.0.0'

还有一个类 Customer:

public class Customer {

    private String name;
    private int age;

    public Customer() {
    }

    public String getName() {
        return name;
    }

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

    public int getAge() {
        return age;
    }

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

    @Override
    public String toString() {
        return MoreObjects.toStringHelper(this)
                .add("name", name)
                .add("age", age)
                .toString();
    }
}

我还有一个映射器:

public class CustomerPropertyMap extends PropertyMap<Customer, Customer> {

    private final Condition<String, String> isFred = s -> isFred(s.getSource());

    @Override
    protected void configure() {
        when(isFred).map(source.getName()).setName("George");
        map(source.getAge(), destination.getAge());
    }

    boolean isFred(String s) {
        return "Fred".equals(s);
    }
}

还有一个测试

public class PropertyMapTest {
    CustomerPropertyMap customerPropertyMap = new CustomerPropertyMap();
    ModelMapper modelMapper = new ModelMapper();

    @Before
    public void init() {
        modelMapper.addMappings(customerPropertyMap);
    }

    @Test
    public void fred() {
        Customer customer = new Customer();
        customer.setAge(40);
        customer.setName("Fred");
        Customer mapped = modelMapper.map(customer, Customer.class);
        System.out.println(mapped);
    }

    @Test
    public void nonFred() {
        Customer customer = new Customer();
        customer.setAge(40);
        customer.setName("Qwerty");
        Customer mapped = modelMapper.map(customer, Customer.class);
        System.out.println(mapped);
    }
}

fred() 方法的输出是 nonFred("Customer{name=null,age=40}") 中的 "Customer{name=Fred,age=40}"。你能解释一下为什么吗？为什么我在第一种方法中看不到输出“George”？

Answer 1

何时用于源类型和目标类型之间的条件映射

在您的情况下，仅当满足条件“Fred”.equals(name) 时才会映射名称