Spring核心

方法区与常量池

BeanFactoryPostProcessor与BeanPostProcessor使用 创建pc过程

https://www.liangzl.com/get-article-detail-8613.html

BeanFactory 与ApplicationContext 设计思想

https://www.chkui.com/article/spring/spring_core_context_and_ioc

非侵入式扩展功能

https://www.chkui.com/article/spring/spring_core_bean_post_processors

Spring在Bean Validation

@Configuration
@ComponentScan("chkui.springcore.example.hybrid.springvalidation.service")
public class SpringValidationConfig {
	@Bean("validator")
	public Validator validator() {
		return new LocalValidatorFactoryBean();
	}

	@Bean
	public MethodValidationPostProcessor methodValidationPostProcessor(Validator validator) {
		MethodValidationPostProcessor postProcessor = new MethodValidationPostProcessor();
		postProcessor.setValidator(validator);
		return postProcessor;
	}
}

//对方法进行参数校验
		try {
			PersonService personService = ctx.getBean(PersonService.class);
			personService.execute(null, 1);//传递参数
		} catch (ConstraintViolationException error) {
			error.getConstraintViolations().forEach(err -> {//输出校验错误信息
				print("Field: ", err.getPropertyPath());
				print("Error: ", err.getMessage());
			});
		}

@Validated({Creation.class}) @RequestBody UserDTO userDTO

但是出现其他字段不执行验证的问题，找了一大圈，发现@Validated在分组验证时并没有添加Default.class的分组，而其他字段默认都是Default分组，所以需要让分组接口继承Default:

    public interface Creation extends Default {
    }

https://www.cnblogs.com/hujihon/p/5357481.html

PropertyEditor 字符串到实体转换

使用Spring的BeanWrapper接口，可以快速的将Properties数据结构转换为一个JavaBean实体。

https://www.chkui.com/article/spring/spring_core_string_to_entity

数据的类型转换

Spring的类型转换的基础是Converter<S, T>（以下简称转换器）接口

ConverterFactory<S, R>

ConversionService 为数据转换预设了大量的Converter 包含了几乎所有Java常规类型的数据格式转换

public abstract class Device {
	public void pares(String text){ //字符串转换为实体
		Field[] fields = this.getClass().getDeclaredFields();
		for (Field field : fields) {
			int begIndex = text.indexOf(field.getName());
			int endIndex = text.indexOf(";", begIndex);
			String sub = text.substring(begIndex, endIndex), value = sub.split("=")[1];
			field.setAccessible(true);
		    field.set(this, value);
		}
	};

	public String value(){ //实体转换为字符串
		Field[] fields = this.getClass().getDeclaredFields();
		StringBuilder sb = new StringBuilder();
		for (Field field : fields) {
			sb.append(field.getName());
			sb.append("=");
			sb.append(field.get(this).toString());
			sb.append(";");
		}
		return sb.toString();
	}
}

public interface ConverterFactory<S, R> {

    <T extends R> Converter<S, T> getConverter(Class<T> targetType);
}

public class String2DeviceConverterFactory implements ConverterFactory<String, Device> {
	public <T extends Device> Converter<String, T> getConverter(Class<T> targetType) {
		return new String2DeviceConverter(targetType);
	}

    // Device的通用转换器
	static class String2DeviceConverter<T extends Device> implements Converter<String, Device> {
		private Class<? extends Device> klass;
		public String2DeviceConverter(Class<? extends Device> klass) {
			this.klass = klass;
		}

		public T convert(String source) {
			Device device = null;
			device = klass.newInstance();
			device.pares(source);
			return (T) device;
		}
	}
}

ConfigurableApplicationContext ctx = new AnnotationConfigApplicationContext(ConversionConfig.class);
        // 获取ConversionService
		ConversionService service = ctx.getBean(ConversionService.class);
		// 字符串转换为整型
		int i = service.convert("123456", Integer.class);
		// 字符串转换为浮点
		float f = service.convert("1234.56", Float.class);
		// 源生列表转换为List
		List<?> list = service.convert(new int[] { 1, 2, 3, 4, 5, 6 }, List.class);
		// 源生列表转换为Set
		Set<?> set = service.convert(new int[] { 1, 2, 3, 4, 5, 6 }, Set.class);
		// 枚举转换
		Gender gender = service.convert("Male", Gender.class);
		// 使用自定义转换器
		PC pc = service.convert("cpu=amd;ram=kingston;graphic=Navidia;", PC.class);
		// UUID转换
		UUID uuid = service.convert("f51b4b95-0925-4ad0-8c62-4daf3ea7918f", UUID.class);
		// 字符串转换为Optional<PC>
		Optional<PC> options = service.convert("cpu=amd;ram=kingston;graphic=Navidia;", Optional.class);
		// 使用TypeDescriptor描述进行转换
		String source = "123456789";
		int result = (int) service.convert(source, TypeDescriptor.valueOf(source.getClass()),
				TypeDescriptor.valueOf(Integer.class));
		_G.print(result);
	}

	enum Gender {
		Male, Female, Other
	}

https://www.chkui.com/article/spring/spring_core_type_conversion

https://www.chkui.com/article/spring/spring_core_data_validation

https://www.chkui.com/article/java/java_bean_validation

https://www.chkui.com/article/spring/spring_core_jsr250_and_resource