问题描述

当使用Mybatis 进行Page分页，再使用Page< map >作为接受参数。此时尝试修改map则会报错。

报错为

javascript 复制代码

java.lang.UnsupportedOperationException: A TupleBackedMap cannot be modified

解决方案

使用新的数组，使用反射，构建工具类，自动将原值拷贝到对应的类上，完成转换。直接上代码

javascript 复制代码

/**
 * 用于解决mybatis 查询List<map>后无法修改的问题
 * @author hh
 * @date 2023/8/3
 */
public class MybatisMapUpdateUtils {

    public static void main(String[] args) throws Exception {

        Map<String,Object> map  = new HashMap<>();
        map.put("userName","吉吉强");
        List<Map<String,Object>>list = new ArrayList<>();
        list.add(map);
        List<UserDto> object = (List<UserDto>) getObject(list, UserDto.class);
        System.out.println(object);

    }

    public static Object getObject(List<Map<String,Object>>map, Class className) throws Exception {
        List<Object> arrayList = new ArrayList<>();
        for (Map<String,Object> vo: map){
            Constructor constructors = className.getConstructor();
            Object instance = constructors.newInstance();
            for (String key:vo.keySet()){
                System.out.println("key=  "+key+"   and value=  "+vo.get(key));
                try {
                    Field field = className.getDeclaredField(key);
                    field.setAccessible(true);
                    field.set(instance,vo.get(key));
                } catch (Exception e){
                    System.out.println("field not found");
                }
            }
            arrayList.add(instance);
            }
        return  arrayList;
    }

}

测试打印后，结果正常

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key=  userName   and value=  吉吉强
[UserDto(userName=吉吉强)]

进程已结束,退出代码0