eb-service-api/api-common/src/main/java/com/heyu/api/common/SanUtils.java

package com.heyu.api.common;

import com.alibaba.fastjson.JSON;
import com.heyu.api.common.test.AriseUser;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.collections.CollectionUtils;
import org.apache.commons.lang3.ClassUtils;

import java.lang.invoke.SerializedLambda;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

@Slf4j
public class SanUtils {


    public static <T, R, V> Map<R, V> list2Map(List<V> values, LBiFunction0<T, R> function) {
        try {
            if (CollectionUtils.isEmpty(values)) {
                return new HashMap<>();

            }
            Map<R, V> map = new HashMap<>();
            Method method = getMethod(function);
            for (V value : values) {
                map.put((R) method.invoke(value), value);
            }
            return map;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return new HashMap<>();
    }

    public static <T, R, V> List<R> list2listFilterNull(List<V> values, LBiFunction0<T, R> function) {

        List<R> list = list2list(values, function);

        List<R>  result = new ArrayList<>();

        if(CollectionUtils.isEmpty(list)){
            for (R r : list) {
                if(r!=null){
                    result.add(r);
                }
            }
        }

        return result;
    }



    public static <T, R, V> List<R> list2list(List<V> values, LBiFunction0<T, R> function) {
        List<R> list = new ArrayList<>();
        try {
            if (CollectionUtils.isEmpty(values)) {
                return list;

            }
            Map<R, V> map = new HashMap<>();
            Method method = getMethod(function);
            for (V value : values) {
                list.add((R) method.invoke(value));
            }
            return list;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return list;
    }

    public static <T, R, V> Map<R, List<V>> list2GroupBy(List<V> values, LBiFunction0<T, R> function) {
        Map<R, List<V>> listmap = new HashMap<>();
        Method method = getMethod(function);
        try {
            for (int i = 0; i < values.size(); i++) {
                V v = values.get(i);
                R r = (R) method.invoke(v);
                List<V> list = listmap.get(r);
                if (list == null) {
                    list = new ArrayList<>();
                }
                list.add(v);
                listmap.put(r, list);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return listmap;
    }

    private static <T, R> Method getMethod(LBiFunction0<T, R> function) {
        try {
            Method method = function.getClass().getDeclaredMethods()[1];
            method.setAccessible(true);
            SerializedLambda serializedLambda = (SerializedLambda) method.invoke(function);
            String methodName = serializedLambda.getImplMethodName();
            String className = serializedLambda.getImplClass().replace("/", ".");
            Class<?> clazz = Class.forName(className);

            Method methods[] = clazz.getDeclaredMethods();
            for (Method m : methods) {
                if (m.getName().equals(methodName)) {
                    return m;
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

        return null;
    }

    private static <T, R> List<Method> getMethods(LBiFunction0<T, R> function) {
        try {
            Method method = function.getClass().getDeclaredMethods()[1];
            method.setAccessible(true);
            SerializedLambda serializedLambda = (SerializedLambda) method.invoke(function);
            String methodName = serializedLambda.getImplMethodName();
            String className = serializedLambda.getImplClass().replace("/", ".");
            Class<?> clazz = Class.forName(className);

            List<Method> list = new ArrayList<>();
            Method methods[] = clazz.getDeclaredMethods();
            for (Method m : methods) {
                if (m.getName().equals(methodName)) {
                    list.add(m);
                }
            }
            return list;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    private static Method getRealMethod(List<Method> methods, Class paramClazz) {
        for (Method method : methods) {
            Class<?>[] parameterTypes = method.getParameterTypes();
            if (parameterTypes != null
                    && parameterTypes.length == 1
                    && ClassUtils.isAssignable(paramClazz, parameterTypes[0])) {
                return method;
            }
        }
        return null;
    }


    public static <T, R, V> List<R> convert(List<V> list, LBiFunction0<T, R> function) {
        List<Method> methods = getMethods(function);
        List result = new ArrayList<>();
        for (V v : list) {
            try {
                Class clazz = v.getClass();
                Method method = getRealMethod(methods, clazz);
                int modifiers = method.getModifiers();
                Object object = null;
                if (Modifier.isStatic(modifiers)) {
                    object = method.invoke(null, v);
                } else {
                    object = method.invoke(v);
                }
                result.add(object);
            } catch (Exception e) {
                log.error("convert exception", e);
            }
        }
        return result;
    }

    public static void main(String[] args) {
        AriseUser ai = new AriseUser();
        ai.setName("张三");
        ai.setAge(13);
        AriseUser ai2 = new AriseUser();
        ai2.setName("李四");
        ai2.setAge(23);

        AriseUser ai3 = new AriseUser();
        ai3.setName("李四");
        ai3.setAge(25);


        List<AriseUser> list = new ArrayList<>();
        list.add(ai);
        list.add(ai2);
        list.add(ai3);

        Map<String, List<AriseUser>> map = list2GroupBy(list, AriseUser::getName);
        System.out.println(JSON.toJSONString(map));


    }

}