Spring中的底层架构核心概念类型转换器详解

/**
 * @program ZJYSpringBoot1
 * @description: 把string字符串转换成user对象
 * @author: zjy
 * @create: 2022/12/27 05:38
 */
public class StringToUserPropertyEditor extends PropertyEditorSupport implements PropertyEditor {
    
    @Override
    public void setAsText(String text) throws java.lang.IllegalArgumentException{
        User user = new User();
        user.setName(text);
        this.setValue(user);
    }
}

public static void main(String[] args) {

    StringToUserPropertyEditor propertyEditor = new StringToUserPropertyEditor();
    propertyEditor.setAsText("aaaaa");
    User user = (User) propertyEditor.getValue();
    System.out.println(user.getName());

}

@Component
public class UserService  {

    @Value("zjy")
    private User user;

public void test(){
    System.out.println(user.getName());
}

}

public static void main(String[] args) {

        AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(AppConfig.class);

        UserService userService = (UserService) context.getBean(
               "userService");
        userService.test();

    }

public class StringToUserConverter implements ConditionalGenericConverter {

    public boolean matches(TypeDescriptor sourceType, TypeDescriptor targetType) {
        return sourceType.getType().equals(String.class) && targetType.getType().equals(User.class);
    }

    public Set<ConvertiblePair> getConvertibleTypes() {
        return Collections.singleton(new ConvertiblePair(String.class,User.class));
    }

    public Object convert(Object source,TypeDescriptor sourceType, TypeDescriptor targetType) {
        User user = new User();
        user.setName((String) source);

        return user;
    }
}

public static void main(String[] args) {

    DefaultConversionService conversionService = new DefaultConversionService();
    conversionService.addConverter(new StringToUserConverter());
    User user = conversionService.convert("zjyyyyy",User.class);
    System.out.println(user.getName());
    
}