java - 通用 CRUD（增、删、改、查）工具类，代码高效复用

比眉伴天荒 2021-12-15 01:17 437阅读 0赞

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1. 基本 CRUD 方法实现：

package com.xxx.xxx.ls.xxx.utils;
    
    import com.alibaba.fastjson.JSON;
    import com.google.common.collect.ImmutableMap;
    import com.xxx.xxx.ls.xxx.dto.LSResultDTO;
    import com.xxx.xxx.ls.xxx.model.BaseModel;
    import com.xxx.xxx.ls.xxx.dto.BaseDTO;
    import com.xxx.xxx.ls.xxx.dto.LSExceptionResultDTO;
    import com.xxx.xxx.ls.xxx.enums.ResponseStatusEnum;
    import com.xxx.xxx.ls.xxx.exceptions.InstitutionException;
    import com.xxx.xxx.ls.xxx.model.BaseInfo;
    import lombok.extern.slf4j.Slf4j;
    import org.apache.commons.lang3.StringUtils;
    import org.apache.cxf.common.util.CollectionUtils;
    import tk.mybatis.mapper.common.Mapper;
    import tk.mybatis.mapper.entity.Example;
    
    import java.util.Date;
    import java.util.List;
    
    @Slf4j
    public class BaseMethodUtils {
        /**
         * 根据id查询数据
         *
         * @param id
         * @param tClass
         * @param mapper
         * @param <T>
         * @param <E>
         * @return
         */
        public static <T, E> LSResultDTO<T> queryById(String id, Class<T> tClass, Mapper<E> mapper) {
            log.info("根据id查询:{}", id);
            if (StringUtils.isBlank(id)) {
                return LSExceptionResultDTO.fail(ResponseStatusEnum.PARAMETERS_ERROR);
            }
            try {
                E e = mapper.selectByPrimaryKey(id);
                log.info("查询的信息:{}", JSON.toJSONString(e));
                T t = JSON.parseObject(JSON.toJSONString(e), tClass);
                if (t == null) {
                    return LSExceptionResultDTO.fail(ResponseStatusEnum.WRONG_CONFIGURATION);
                }
                return LSResultDTO.ok(t);
            } catch (Exception e) {
                return LSExceptionResultDTO.fail(ResponseStatusEnum.EXEC_FAILURE);
            }
        }
    
        /**
         * 查数据列表
         *
         * @param tClass
         * @param mapper
         * @param <T>
         * @param <E>
         * @return
         */
        public static <T, E> List<T> queryAll(Class<T> tClass, Mapper<E> mapper) {
            List<E> infoList = mapper.selectAll();
            return JsonTransUtils.list2OtherList(infoList, tClass);
        }
    
        /**
         * 根据条件查数据列表,条件为“等于”
         *
         * @param tClass
         * @param eClass
         * @param map    封装条件
         * @param mapper
         * @param <T>
         * @param <E>
         * @return
         */
        public static <T, E> List<T> queryAll(Class<T> tClass, Class<E> eClass, ImmutableMap<String, Object> map, Mapper<E> mapper) {
            Example e = new Example(eClass);
            Example.Criteria criteria = e.createCriteria();
            map.forEach(criteria::andEqualTo);
            List<E> infoList = mapper.selectByExample(e);
            return JsonTransUtils.list2OtherList(infoList, tClass);
        }
    
        /**
         * 根据条件查单条数据
         *
         * @param queryModel
         * @param tClass     返回类对象
         * @param eClass     数据库映射类对象
         * @param mapper
         * @param <T>
         * @param <E>
         * @return
         */
        public static <T, E> T queryOne(BaseModel queryModel, Class<T> tClass, Class<E> eClass, Mapper<E> mapper) {
            log.info("根据条件查询一条,参数query:{}", JSON.toJSONString(queryModel));
            if (queryModel == null) {
                throw new InstitutionException(400, "请求参数有误");
            }
            E e = JSON.parseObject(JSON.toJSONString(queryModel), eClass);
            E returnInfo = null;
            try {
                returnInfo = mapper.selectOne(e);
            } catch (Exception e1) {
                throw new InstitutionException(500, "执行异常,数据库可能存在多个相同条件的数据");
            }
            if (returnInfo == null) {
                log.error("没找到该条件的配置信息");
                throw new InstitutionException(404, "该条件的配置不存在");
            }
            return JSON.parseObject(JSON.toJSONString(returnInfo), tClass);
        }
    
        /**
         * 根据条件查询列表
         *
         * @param queryModel
         * @param eClass     映射类对象
         * @param tClass     返回类对象
         * @param mapper
         * @param <T>
         * @param <E>
         * @return
         */
        public static <T, E> List<T> queryListByWhere(BaseModel queryModel, Class<E> eClass, Class<T> tClass, Mapper<E> mapper) {
            log.info("根据条件查询,参数AppQuery:{}", JSON.toJSONString(queryModel));
            if (queryModel == null) {
                throw new InstitutionException(400, "请求参数有误");
            }
            E e = JSON.parseObject(JSON.toJSONString(queryModel), eClass);
            List<E> infoList = mapper.select(e);
            if (CollectionUtils.isEmpty(infoList)) {
                log.error("没找到该条件的配置信息");
                throw new InstitutionException(404, "该条件的配置不存在");
            }
            return JsonTransUtils.list2OtherList(infoList, tClass);
        }
    
        /**
         * 保存
         *
         * @param baseDTO
         * @param eClass  映射类对象
         * @param mapper
         * @param <E>
         * @return
         */
        public static <E extends BaseInfo> String save(BaseDTO baseDTO, Class<E> eClass, Mapper<E> mapper) {
            log.info("保存DTO:{}", JSON.toJSONString(baseDTO));
            if (baseDTO == null) {
                throw new InstitutionException(400, "请求参数异常");
            }
            try {
                E e = JSON.parseObject(JSON.toJSONString(baseDTO), eClass);
                e.setGmtCreate(new Date());
                e.setGmtUpdate(new Date());
                e.setUserCreate(baseDTO.getUserCreate());
                e.setUserUpdate(baseDTO.getUserCreate());
                mapper.insert(e);
                return e.getId();
            } catch (Exception e) {
                throw new InstitutionException(500, "保存失败");
            }
        }
    
        /**
         * 保存,null值取数据库默认值
         *
         * @param baseDTO
         * @param eClass  映射类对象
         * @param mapper
         * @param <E>
         * @return
         */
        public static <E extends BaseInfo> String saveSelective(BaseDTO baseDTO, Class<E> eClass, Mapper<E> mapper) {
            log.info("保存DTO:{}", JSON.toJSONString(baseDTO));
            if (baseDTO == null) {
                throw new InstitutionException(400, "请求参数异常");
            }
            try {
                E e = JSON.parseObject(JSON.toJSONString(baseDTO), eClass);
                e.setGmtCreate(new Date());
                e.setGmtUpdate(new Date());
                e.setUserCreate(baseDTO.getUserCreate());
                e.setUserUpdate(baseDTO.getUserCreate());
                mapper.insertSelective(e);
                return e.getId();
            } catch (Exception e) {
                throw new InstitutionException(500, "保存失败");
            }
        }
    
        /**
         * 更新
         *
         * @param baseDTO
         * @param eClass
         * @param mapper
         * @param <E>
         * @return
         */
        public static <E extends BaseInfo> Integer update(BaseDTO baseDTO, Class<E> eClass, Mapper<E> mapper) {
            log.info("更新AppDTO:{}", JSON.toJSONString(baseDTO));
            if (baseDTO == null) {
                throw new InstitutionException(400, "请求参数异常");
            }
            if (StringUtils.isBlank(baseDTO.getId())) {
                throw new InstitutionException(400, "id不能为空");
            }
            try {
                E e = JSON.parseObject(JSON.toJSONString(baseDTO), eClass);
                e.setGmtUpdate(new Date());
                e.setUserUpdate(baseDTO.getUserUpdate());
                return mapper.updateByPrimaryKey(e);
            } catch (Exception e) {
                throw new InstitutionException(500, "更新失败");
            }
        }
    
        /**
         * 更新，null值取数据库默认值
         *
         * @param baseDTO
         * @param eClass
         * @param mapper
         * @param <E>
         * @return
         */
        public static <E extends BaseInfo> Integer updateSelective(BaseDTO baseDTO, Class<E> eClass, Mapper<E> mapper) {
            log.info("更新AppDTO:{}", JSON.toJSONString(baseDTO));
            if (baseDTO == null) {
                throw new InstitutionException(400, "请求参数异常");
            }
            if (StringUtils.isBlank(baseDTO.getId())) {
                throw new InstitutionException(400, "id不能为空");
            }
            try {
                E e = JSON.parseObject(JSON.toJSONString(baseDTO), eClass);
                e.setGmtUpdate(new Date());
                e.setUserUpdate(baseDTO.getUserUpdate());
                return mapper.updateByPrimaryKeySelective(e);
            } catch (Exception e) {
                throw new InstitutionException(500, "更新失败");
            }
        }
    
        /**
         * 根据id删除
         *
         * @param id
         * @param mapper
         * @param <E>
         * @return
         */
        public static <E> Integer deleteById(String id, Mapper<E> mapper) {
            log.info("删除id：{}", id);
            return mapper.deleteByPrimaryKey(id);
        }
    }

2. json 转换类工具类：

package com.xxx.xxx.xxx.xxx.utils;
    
    import com.alibaba.fastjson.JSON;
    
    import java.util.ArrayList;
    import java.util.List;
    
    public class JsonTransUtils{
    
        /**
         *  转为新列表(对象属性名要相同)
         * @param originList 原列表
         * @param tClass 新列表类对象
         * @param <T>
         * @return
         */
        public static <T> List<T> list2OtherList(List originList,Class<T> tClass){
            List<T> list = new ArrayList<>();
            for (Object info : originList) {
                T t = JSON.parseObject(JSON.toJSONString(info),tClass);
                list.add(t);
            }
            return list;
        }
    }

3. sql 工具类：

package com.xxx.xxx.xxx.xxx.utils;
    
    import lombok.extern.slf4j.Slf4j;
    import org.apache.commons.lang3.StringUtils;
    import tk.mybatis.mapper.entity.Example;
    
    import java.lang.reflect.Field;
    
    @Slf4j
    public class SqlUtils {
    
        /**
         * 封装模糊查询条件,排序条件（不排序传“”或null）
         *
         * @param t              封装查询条件类
         * @param orderByContent
         * @param <T>
         * @return
         * @throws IllegalAccessException
         */
        public static <T> Example getSelectExample(T t, String orderByContent) throws IllegalAccessException {
    
            Example example = new Example(t.getClass());
            Example.Criteria criteria = example.createCriteria();
    
            if (!StringUtils.isBlank(orderByContent)) {
                example.setOrderByClause(orderByContent);
            }
    
            Field[] declaredFields = t.getClass().getDeclaredFields();
            for (Field field : declaredFields) {
                field.setAccessible(true);
                if (field.get(t) != null && !"serialVersionUID".equals(field.getName())) {
                    criteria.andLike(field.getName(), "%" + field.get(t).toString() + "%");
                }
            }
            return example;
        }
    }

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