类相关工具类

import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.List;

/**
 * 类相关工具类
 */
public class ClassUtil {

    /**
     * 获取类私有字段名称
     */
    public static String[] getPrivateFields(Class<?> cla) {
        Field[] fields = cla.getDeclaredFields();
        List<String> list = new ArrayList<>();
        for (Field field : fields) {
            if (field.getModifiers() == Modifier.PRIVATE) {
                list.add(field.getName());
            }
        }
        return list.toArray(new String[0]);
    }

    /**
     * 根据类名获取表名
     */
    public static String getTableName(Class<?> cla) {
        String simpleName = cla.getSimpleName();
        StringBuilder result = new StringBuilder();
        boolean nextLowerCase = false;
        boolean firstCharacter = true;
        for (int i = 0; i < simpleName.length(); i++) {
            char ch = simpleName.charAt(i);
            if (ch == '_') {
                nextLowerCase = true;
            } else {
                if (nextLowerCase || firstCharacter) {
                    result.append(Character.toLowerCase(ch));
                    nextLowerCase = false;
                    firstCharacter = false;
                } else {
                    result.append(ch);
                }
            }
        }
        return result.toString();
    }

}

获取字段名称

import java.io.Serializable;
import java.lang.invoke.SerializedLambda;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Objects;
import java.util.function.Function;

/**
 * Java8通过Function函数获取字段名称（获取实体类的字段名称）
 */
public class FieldUtil {

    /**
     * 使Function获取序列化能力
     */
    @FunctionalInterface
    public interface SFunction<T, R> extends Function<T, R>, Serializable {
    }

    /**
     * 获取实体类的字段名称
     */
    public static <T> String get(SFunction<T, ?> fn) {
        SerializedLambda serializedLambda = getSerializedLambda(fn);
        // 从lambda信息取出method、field、class等
        String fieldName = serializedLambda.getImplMethodName().substring("get".length());
        fieldName = fieldName.replaceFirst(fieldName.charAt(0) + "", (fieldName.charAt(0) + "").toLowerCase());
        // 对ID进行处理
        if (Objects.equals("id", fieldName)) {
            fieldName = "_id";
        }
        return fieldName;
    }

    private static <T> SerializedLambda getSerializedLambda(SFunction<T, ?> fn) {
        // 从function取出序列化方法
        Method writeReplaceMethod;
        try {
            writeReplaceMethod = fn.getClass().getDeclaredMethod("writeReplace");
        } catch (NoSuchMethodException e) {
            throw new RuntimeException(e);
        }
        // 从序列化方法取出序列化的lambda信息
        boolean isAccessible = writeReplaceMethod.isAccessible();
        writeReplaceMethod.setAccessible(true);
        SerializedLambda serializedLambda;
        try {
            serializedLambda = (SerializedLambda) writeReplaceMethod.invoke(fn);
        } catch (IllegalAccessException | InvocationTargetException e) {
            throw new RuntimeException(e);
        }
        writeReplaceMethod.setAccessible(isAccessible);
        return serializedLambda;
    }

}