Spring 参数绑定

一、枚举类型

1、枚举的声明和定义：

枚举类型是这样的，

public interface BaseEnum {
    Integer getCode();

    String getText();
}

继承自该接口的枚举类，

@AllArgsConstructor
@Getter
public enum CollectionOrNot implements BaseEnum {
    NO(0, "否"),
    YES(1, "是");

    private Integer code;
    @JsonValue
    private String text;

    @JsonCreator
    public static CollectionOrNot jsonCreate(Integer code) {
        return EnumUtils.codeOf(CollectionOrNot.class, code);
    }

    @JsonCreator
    public static CollectionOrNot jsonCreate(String text) {
        return EnumUtils.codeOf(CollectionOrNot.class, text);
    }

}

EnumUtils的代码：

public class EnumUtils {
    public static <T extends BaseEnum> T codeOf(Class<T> enumClass, int code) {
        T[] enumConstants = enumClass.getEnumConstants();
        for (T t : enumConstants) {
            if (t.getCode() == code) {
                return t;
            }
        }
        return null;
    }

    public static <T extends BaseEnum> T codeOf(Class<T> enumClass, String text) {
        T[] enumConstants = enumClass.getEnumConstants();
        for (T t : enumConstants) {
            if (t.getText().equals(text)) {
                return t;
            }
        }
        return null;
    }

}

2、ConverterFactory的声明和定义，

import com.tianji.tingcloudapi.common.enums.BaseEnum;
import org.springframework.core.convert.converter.Converter;
import org.springframework.core.convert.converter.ConverterFactory;

public class StringToEnumConverterFactory implements ConverterFactory<String, BaseEnum> {

    private static class StringToEnumConverter<T extends BaseEnum> implements Converter<String, T> {

        private Class<T> enumType;

        // 构造方法
        public StringToEnumConverter(Class<T> enumType) {
            this.enumType = enumType;
        }

        public T convert(String source) {
            T[] enumConstants = enumType.getEnumConstants();
            for (T t : enumConstants) {
                if (t.getText().equals(source)) return t;
            }
            throw new IllegalArgumentException("无法匹配对应的枚举类型");
        }
    }

    @Override
    public <T extends BaseEnum> Converter<String, T> getConverter(Class<T> targetType) {
        return new StringToEnumConverter<>(targetType);
    }
}

3、ConverterFactory的注册

@Configuration
public class WebMvcConfig implements WebMvcConfigurer {

    /**
     * 枚举类的转换器工厂 addConverterFactory
     */
    @Override
    public void addFormatters(FormatterRegistry registry) {
//        registry.addConverterFactory(new IntegerToEnumConverterFactory());
        registry.addConverterFactory(new StringToEnumConverterFactory());
    }
}

4、参数绑定

@RequestParam(name = "cpuGatherState", required = false) CollectionOrNot cpuGatherState,

5、相关链接

• Using Enums as Request Parameters in Spring
• Guide to Spring Type Conversions
• Spring Boot 使用枚举类型作为请求参数

二、JSR310的日期绑定