反射获取对象中的list数据

工具类:

package com.wm.javayu.utils;

import com.wm.javayu.model.Student;
import com.wm.javayu.model.Teacher;
import org.springframework.util.CollectionUtils;
import org.springframework.util.ObjectUtils;

import java.lang.reflect.*;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;

/**
 * @class_name: ReFlectUtil
 * @description:
 * @author: wm_yu
 * @create: 2019/07/19
 **/
public class ReFlectUtil {

    /**
     *反射获取List中的数据
     * @param args
     */

    public static void main(String[] args) {
        Teacher teacher = new Teacher();
       List list = new ArrayList();
        list.add(new Student("张三", "男"));
        list.add(new Student("李四", "女"));
        list.add(new Student("王五", "女"));
       teacher.setList(list);
        getList(teacher,Student.class);
    }


    /**
     * 反射获取对象中的list数据
     * @param object
     * @param dateClass
     * @param 
     */
    public static void getList(Object object,T dateClass){
       List resultList = new ArrayList<>();
        if(!ObjectUtils.isEmpty(object)){

            Field[] fields = getAllFields(object.getClass());
            Field[] filterList= filterField(fields);
            Arrays.stream(filterList).forEach(var -> {
                //List集合
                if(List.class.isAssignableFrom(var.getType())){
                    Type type = var.getGenericType();
                    if(type instanceof ParameterizedType){
                        if(!var.isAccessible()){
                            var.setAccessible(true);
                        }
                        //获取到属性值的字节码
                        try {
                            Class clzz = var.get(object).getClass();
                            //反射调用获取到list的size方法来获取到集合的大小
                            Method sizeMethod = clzz.getDeclaredMethod("size");
                            if(!sizeMethod.isAccessible()){
                                sizeMethod.setAccessible(true);
                            }
                            //集合长度
                            int size = (int) sizeMethod.invoke(var.get(object));
                            //循环遍历获取到数据
                            for (int i = 0; i < size; i++) {
                                //反射获取到list的get方法
                                Method getMethod = clzz.getDeclaredMethod("get", int.class);
                                //调用get方法获取数据
                                if(!getMethod.isAccessible()){
                                    getMethod.setAccessible(true);
                                }
                                T var1 = (T) getMethod.invoke(var.get(object), i);
                                resultList.add(var1);
                            }

                        } catch (Exception e) {
                            e.printStackTrace();
                        }
                    }
                }
            });

            resultList.stream().forEach(var -> {
                System.out.println("反射获取到的数据是什么:" + var);
            });
        }
    }


    /**
     * 反射获取所有的字段
     * @param c
     * @return
     */
    public static Field[] getAllFields(Class c){
        List fieldList = new ArrayList<>();
        while (c!= null){
            fieldList.addAll(new ArrayList<>(Arrays.asList(c.getDeclaredFields())));
            c= c.getSuperclass();
        }
        Field[] fields = new Field[fieldList.size()];
        fieldList.toArray(fields);
        return fields;
    }





    /**
     * 过滤字段
     * @param
     * @return
     */
    public static Field[] filterField(Field[] fields){
        List tempList = Arrays.stream(fields).filter(field -> null != field
                && !Modifier.isFinal(field.getModifiers())
                && !Modifier.isStatic(field.getModifiers())
                && !Modifier.isAbstract(field.getModifiers())).collect(Collectors.toList());


        int arrLength = CollectionUtils.isEmpty(tempList) ? 1:tempList.size();

        Field[] resultArr = new Field[arrLength];
        if(!CollectionUtils.isEmpty(tempList)){
            tempList.toArray(resultArr);
        }
        return resultArr;
    }



}

实体类:

package com.wm.javayu.model;

/**
 * @class_name: Student
 * @description:
 * @author: wm_yu
 * @create: 2019/07/19
 **/
public class Student {

    public Student(String name, String gender) {
        this.name = name;
        this.gender = gender;
    }

    private String name;

    private String gender;

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }


    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @Override
    public String toString() {
        return "Student{" +
                "name='" + name + '\'' +
                ", gender='" + gender + '\'' +
                '}';
    }
}

package com.wm.javayu.model;

import java.util.List;

/**
 * @class_name: Teacher
 * @description:
 * @author: wm_yu
 * @create: 2019/07/19
 **/
public class Teacher {


    List list;


    public List getList() {
        return list;
    }

    public void setList(List list) {
        this.list = list;
    }
}