package com.example.billmanagerfront.config.encoder;

import java.lang.reflect.Field;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.TimeZone;
import java.util.concurrent.ConcurrentHashMap;
import java.util.stream.Collectors;
import org.springframework.format.annotation.DateTimeFormat;
import feign.Param;
import feign.QueryMapEncoder;
import feign.codec.EncodeException;
public class PowerfulQueryMapEncoder implements QueryMapEncoder {
    private final Map<Class<?>, ObjectParamMetadata> classToMetadata = new ConcurrentHashMap<>();
    @Override
    public Map<String, Object> encode(Object object) throws EncodeException {
        ObjectParamMetadata metadata = classToMetadata.computeIfAbsent(object.getClass(),
                ObjectParamMetadata::parseObjectType);
        return metadata.objectFields.stream()
                .map(field -> this.FieldValuePair(object, field))
                .filter(fieldObjectPair -> fieldObjectPair.right.isPresent())
                .collect(Collectors.toMap(this::fieldName, this::fieldObject));
    }
    private String fieldName(Pair<Field, Optional<Object>> pair) {
        Param alias = pair.left.getAnnotation(Param.class);
        return alias != null ? alias.value() : pair.left.getName();
    // 可擴展為策略模式，支持更多的格式轉(zhuǎn)換
    private Object fieldObject(Pair<Field, Optional<Object>> pair) {
        Object fieldObject = pair.right.get();
        DateTimeFormat dateTimeFormat = pair.left.getAnnotation(DateTimeFormat.class);
        if (dateTimeFormat != null) {
            DateFormat format = new SimpleDateFormat(dateTimeFormat.pattern());
            format.setTimeZone(TimeZone.getTimeZone("GMT+8")); // TODO: 最好不要寫死時區(qū)
            fieldObject = format.format(fieldObject);
        } else {
        }
        return fieldObject;
    private Pair<Field, Optional<Object>> FieldValuePair(Object object, Field field) {
        try {
            return Pair.pair(field, Optional.ofNullable(field.get(object)));
        } catch (IllegalAccessException e) {
            throw new EncodeException("Failure encoding object into query map", e);
    private static class ObjectParamMetadata {
        private final List<Field> objectFields;
        private ObjectParamMetadata(List<Field> objectFields) {
            this.objectFields = Collections.unmodifiableList(objectFields);
        private static ObjectParamMetadata parseObjectType(Class<?> type) {
            List<Field> allFields = new ArrayList<Field>();
            for (Class<?> currentClass = type; currentClass != null; currentClass = currentClass.getSuperclass()) {
                Collections.addAll(allFields, currentClass.getDeclaredFields());
            }
            return new ObjectParamMetadata(allFields.stream()
                    .filter(field -> !field.isSynthetic())
                    .peek(field -> field.setAccessible(true))
                    .collect(Collectors.toList()));
    private static class Pair<T, U> {
        private Pair(T left, U right) {
            this.right = right;
            this.left = left;
        public final T left;
        public final U right;
        public static <T, U> Pair<T, U> pair(T left, U right) {
            return new Pair<>(left, right);
}

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>

package com.example.billmanagerfront.config;

import com.example.billmanagerfront.config.encoder.PowerfulQueryMapEncoder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import feign.Feign;
import feign.Retryer;
@Configuration
public class FeignConfig {
    @Bean
    public Feign.Builder feignBuilder() {
        return Feign.builder()
                .queryMapEncoder(new PowerfulQueryMapEncoder())
                .retryer(Retryer.NEVER_RETRY);
    }
}

package com.example.billmanagerfront.client;

import java.util.List;
import com.example.billmanagerfront.config.FeignConfig;
import com.example.billmanagerfront.pojo.Bill;
import com.example.billmanagerfront.pojo.BillType;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.cloud.openfeign.SpringQueryMap;
import org.springframework.web.bind.annotation.DeleteMapping;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
@FeignClient(name = "BILL-MANAGER", path = "bill", configuration = FeignConfig.class)
public interface BillClient {
    @GetMapping("list")
    List<Bill> list(@SpringQueryMap(true) Bill b);
    @GetMapping("type")
    List<BillType> type();
    @DeleteMapping("delete/{id}")
    public String delete(@PathVariable("id") Long id);
}