CryptoUtils类getKey(String,String)方法未定义问题求助

问题原因 #

你提供的CryptoUtils类里，flatMap方法调用了getKey(String, String)方法，但该方法并未在类中实现，导致编译报错。

解决方案 #

在CryptoUtils类中添加getKey方法的实现。根据代码逻辑，这个方法的作用是拼接嵌套键名（父键与子键用.分隔，若父键为空则直接返回子键）。

修改后的完整代码 #

在flatMap方法上方添加以下getKey方法：

private static String getKey(String rootKey, String subKey) {
    if (rootKey == null || rootKey.isEmpty()) {
        return subKey;
    }
    return rootKey + "." + subKey;
}

完整的CryptoUtils类代码如下：

package normjsn;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import java.text.Collator;
import java.util.*;

public class CryptoUtils {
    private final static ObjectMapper mapper = new ObjectMapper();
    public static byte[] hexStringToByteArray(String s) {
        int len = s.length();
        byte[] data = new byte[len / 2];
        for (int i = 0; i < len; i += 2) {
            data[i / 2] = (byte) ((Character.digit(s.charAt(i), 16) << 4) + Character.digit(s.charAt(i + 1), 16));
        }
        return data;
    }

    public static String normalJson(Object object, Map<String, Object> header) {
        if (object == null && header == null) return null;

        Map<String, Object> map = null;
        if (object != null) {
            if (object instanceof String) {
                try {
                    object = mapper.readValue((String) object, Object.class);
                } 
                catch (JsonProcessingException e) {
                    throw new RuntimeException(e.getMessage());
                }
            }
            if (object instanceof Collection) {
                /// @SuppressWarnings("rawtypes")  /// Skip non generic var s warning
                PacketsWrapper packetsWrapper = new PacketsWrapper((Collection) object);
                map = mapper.convertValue(packetsWrapper, Map.class);
            } else {
                map = mapper.convertValue(object, Map.class);
            }
        }
        if (map == null && header != null) {
            map = header;
        }
        if (map != null && header != null) {
            for (Map.Entry<String, Object> entry : header.entrySet()) {
                map.put(entry.getKey(), entry.getValue());
            }   
        }

        Map<String, Object> result = new HashMap<>();
        flatMap(result, null, map);
        StringBuilder sb = new StringBuilder();
        List<String> keys = new ArrayList<>(result.keySet());
        Collections.sort(keys, Collator.getInstance(Locale.ENGLISH));
        for (String key : keys) {
            String textValue;
            Object value = result.get(key);
            if (value != null) {
                textValue = value.toString();
                if (textValue == null || textValue.equals("")) {
                    textValue = "#";
                } else {
                    textValue = textValue.replaceAll("#", "##");
                }
            } else {
                textValue = "#";
            }
            sb.append(textValue).append('#');
        }
        return sb.deleteCharAt(sb.length() - 1).toString();
    }

    // 新增的getKey方法
    private static String getKey(String rootKey, String subKey) {
        if (rootKey == null || rootKey.isEmpty()) {
            return subKey;
        }
        return rootKey + "." + subKey;
    }

    private static void flatMap(Map<String, Object> result, String rootKey, Object input) {
            if (input instanceof Collection) {
                Collection list = (Collection) input;
                int i = 0;
                for (Object e : list) {
                    String key = getKey(rootKey, "E" + i++);
                    flatMap(result, key, e);
                }
            } else if (input instanceof Map) {
                Map<String, Object> map = (Map) input;
                for (Map.Entry<String, Object> entry : map.entrySet()) {
                    flatMap(result, getKey(rootKey, entry.getKey()), entry.getValue());
                }
            } else {
                result.put(rootKey, input);
            }
    }

    private static class PacketsWrapper {
        private Collection packets;
        public PacketsWrapper() {}
        public PacketsWrapper(Collection packets) {
            this.packets = packets;
        }
        public Collection getPackets() {
            return packets;
        }
        public void setPackets(Collection packets) {
            this.packets = packets;
        }
    }
}

说明 #

这个getKey方法的逻辑：

• 若rootKey为空（顶级键场景），直接返回subKey
• 若rootKey不为空，将父键与子键用.拼接，形成类似user.name、list.E0.id的嵌套键名，符合JSON扁平化处理的常规规则。

内容的提问来源于stack exchange，提问作者nima tehrani