后台SpringBoot + Mybatis开发遇到的一些坑

目录

一、首先介绍一下开发框架，SpringBoot+Mybatis，SpringBoot集成了Tomcat因此，不需要下载Tomcat服务运行，开发完直接build出jar包运行即可，Mybatis-Plus增加条件构造器EntityWrapper很好用，可以把需要查询的条件全部放构造器里，执行就好。

二、下面回顾一下开发中遇到的一些坑，希望互相参考

   2.1 properties配置文件错误导致无法启动

比较典型就是数据库地址配置有误，导致服务启动不起来，需要我们连接检查，二报错却会显示是mapper或者sql注入等错误，需要格外注意。

 2.2 Mapper.xml文件映射出错

由于字段映射出现的错误，由于Mapper作为数据库和Entity的桥梁，字段检查是必须的，随便一个写错，系统及可能跑不起来。

2.3 Mybatis-Plus 语句异常总结

​
/**
 * Copyright (c) 2011-2016, hubin ([email protected]).
 * 

 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * 

 * http://www.apache.org/licenses/LICENSE-2.0
 * 

 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package com.baomidou.mybatisplus.service.impl;

import java.io.Serializable;
import java.util.List;
import java.util.Map;

import org.apache.ibatis.binding.MapperMethod;
import org.apache.ibatis.logging.Log;
import org.apache.ibatis.logging.LogFactory;
import org.apache.ibatis.session.SqlSession;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.transaction.annotation.Transactional;

import com.baomidou.mybatisplus.entity.TableInfo;
import com.baomidou.mybatisplus.enums.SqlMethod;
import com.baomidou.mybatisplus.exceptions.MybatisPlusException;
import com.baomidou.mybatisplus.mapper.BaseMapper;
import com.baomidou.mybatisplus.mapper.Condition;
import com.baomidou.mybatisplus.mapper.SqlHelper;
import com.baomidou.mybatisplus.mapper.Wrapper;
import com.baomidou.mybatisplus.plugins.Page;
import com.baomidou.mybatisplus.service.IService;
import com.baomidou.mybatisplus.toolkit.CollectionUtils;
import com.baomidou.mybatisplus.toolkit.MapUtils;
import com.baomidou.mybatisplus.toolkit.ReflectionKit;
import com.baomidou.mybatisplus.toolkit.StringUtils;
import com.baomidou.mybatisplus.toolkit.TableInfoHelper;

/**
 * 

 * IService 实现类（ 泛型：M 是 mapper 对象，T 是实体 ， PK 是主键泛型 ）
 * 
 *
 * @author hubin
 * @Date 2016-04-20
 */
public class ServiceImpl, T> implements IService {

    private static final Log logger = LogFactory.getLog(ServiceImpl.class);

    @Autowired
    protected M baseMapper;

    /**
     * 

     * 判断数据库操作是否成功
     * 
     * 

     * 注意！！ 该方法为 Integer 判断，不可传入 int 基本类型
     * 
     *
     * @param result 数据库操作返回影响条数
     * @return boolean
     */
    protected static boolean retBool(Integer result) {
        return SqlHelper.retBool(result);
    }

    @SuppressWarnings("unchecked")
    protected Class currentModelClass() {
        return ReflectionKit.getSuperClassGenricType(getClass(), 1);
    }

    /**
     * 

     * 批量操作 SqlSession
     * 
     */
    protected SqlSession sqlSessionBatch() {
        return SqlHelper.sqlSessionBatch(currentModelClass());
    }

    /**
     * 获取SqlStatement
     *
     * @param sqlMethod
     * @return
     */
    protected String sqlStatement(SqlMethod sqlMethod) {
        return SqlHelper.table(currentModelClass()).getSqlStatement(sqlMethod.getMethod());
    }

    @Transactional
    public boolean insert(T entity) {
        return retBool(baseMapper.insert(entity));
    }

    @Transactional
    public boolean insertAllColumn(T entity) {
        return retBool(baseMapper.insertAllColumn(entity));
    }

    @Transactional
    public boolean insertBatch(List entityList) {
        return insertBatch(entityList, 30);
    }

    /**
     * 批量插入
     *
     * @param entityList
     * @param batchSize
     * @return
     */
    @Transactional
    public boolean insertBatch(List entityList, int batchSize) {
        if (CollectionUtils.isEmpty(entityList)) {
            throw new IllegalArgumentException("Error: entityList must not be empty");
        }
        try (SqlSession batchSqlSession = sqlSessionBatch()) {
            int size = entityList.size();
            String sqlStatement = sqlStatement(SqlMethod.INSERT_ONE);
            for (int i = 0; i < size; i++) {
                batchSqlSession.insert(sqlStatement, entityList.get(i));
                if (i >= 1 && i % batchSize == 0) {
                    batchSqlSession.flushStatements();
                }
            }
            batchSqlSession.flushStatements();
        } catch (Throwable e) {
            throw new MybatisPlusException("Error: Cannot execute insertBatch Method. Cause", e);
        }
        return true;
    }

    /**
     * 

     * TableId 注解存在更新记录，否插入一条记录
     * 
     *
     * @param entity 实体对象
     * @return boolean
     */
    @Transactional
    public boolean insertOrUpdate(T entity) {
        if (null != entity) {
            Class cls = entity.getClass();
            TableInfo tableInfo = TableInfoHelper.getTableInfo(cls);
            if (null != tableInfo && StringUtils.isNotEmpty(tableInfo.getKeyProperty())) {
                Object idVal = ReflectionKit.getMethodValue(cls, entity, tableInfo.getKeyProperty());
                if (StringUtils.checkValNull(idVal)) {
                    return insert(entity);
                } else {
                    /*
                     * 更新成功直接返回，失败执行插入逻辑
					 */
                    return updateById(entity) || insert(entity);
                }
            } else {
                throw new MybatisPlusException("Error:  Can not execute. Could not find @TableId.");
            }
        }
        return false;
    }

    @Transactional
    public boolean insertOrUpdateAllColumn(T entity) {
        if (null != entity) {
            Class cls = entity.getClass();
            TableInfo tableInfo = TableInfoHelper.getTableInfo(cls);
            if (null != tableInfo && StringUtils.isNotEmpty(tableInfo.getKeyProperty())) {
                Object idVal = ReflectionKit.getMethodValue(cls, entity, tableInfo.getKeyProperty());
                if (StringUtils.checkValNull(idVal)) {
                    return insertAllColumn(entity);
                } else {
                    /*
                     * 更新成功直接返回，失败执行插入逻辑
					 */
                    return updateAllColumnById(entity) || insertAllColumn(entity);
                }
            } else {
                throw new MybatisPlusException("Error:  Can not execute. Could not find @TableId.");
            }
        }
        return false;
    }

    @Transactional
    public boolean insertOrUpdateBatch(List entityList) {
        return insertOrUpdateBatch(entityList, 30);
    }

    @Transactional
    public boolean insertOrUpdateBatch(List entityList, int batchSize) {
        return insertOrUpdateBatch(entityList, batchSize, true);
    }

    @Transactional
    public boolean insertOrUpdateAllColumnBatch(List entityList) {
        return insertOrUpdateBatch(entityList, 30, false);
    }

    @Transactional
    public boolean insertOrUpdateAllColumnBatch(List entityList, int batchSize) {
        return insertOrUpdateBatch(entityList, batchSize, false);
    }

    /**
     * 批量插入修改
     *
     * @param entityList 实体对象列表
     * @param batchSize  批量刷新个数
     * @param selective  是否滤掉空字段
     * @return boolean
     */
    private boolean insertOrUpdateBatch(List entityList, int batchSize, boolean selective) {
        if (CollectionUtils.isEmpty(entityList)) {
            throw new IllegalArgumentException("Error: entityList must not be empty");
        }
        try (SqlSession batchSqlSession = sqlSessionBatch()) {
            int size = entityList.size();
            for (int i = 0; i < size; i++) {
                if (selective) {
                    insertOrUpdate(entityList.get(i));
                } else {
                    insertOrUpdateAllColumn(entityList.get(i));
                }
                if (i >= 1 && i % batchSize == 0) {
                    batchSqlSession.flushStatements();
                }
            }
            batchSqlSession.flushStatements();
        } catch (Throwable e) {
            throw new MybatisPlusException("Error: Cannot execute insertOrUpdateBatch Method. Cause", e);
        }
        return true;
    }

    @Transactional
    public boolean deleteById(Serializable id) {
        return retBool(baseMapper.deleteById(id));
    }

    @Transactional
    public boolean deleteByMap(Map columnMap) {
        if (MapUtils.isEmpty(columnMap)) {
            throw new MybatisPlusException("deleteByMap columnMap is empty.");
        }
        return retBool(baseMapper.deleteByMap(columnMap));
    }

    @Transactional
    public boolean delete(Wrapper wrapper) {
        return retBool(baseMapper.delete(wrapper));
    }

    @Transactional
    public boolean deleteBatchIds(List idList) {
        return retBool(baseMapper.deleteBatchIds(idList));
    }

    @Transactional
    public boolean updateById(T entity) {
        return retBool(baseMapper.updateById(entity));
    }

    @Transactional
    public boolean updateAllColumnById(T entity) {
        return retBool(baseMapper.updateAllColumnById(entity));
    }

    @Transactional
    public boolean update(T entity, Wrapper wrapper) {
        return retBool(baseMapper.update(entity, wrapper));
    }

    @Transactional
    public boolean updateBatchById(List entityList) {
        return updateBatchById(entityList, 30);
    }

    @Transactional
    public boolean updateBatchById(List entityList, int batchSize) {
        return updateBatchById(entityList, batchSize, true);
    }

    @Transactional
    public boolean updateAllColumnBatchById(List entityList) {
        return updateAllColumnBatchById(entityList, 30);
    }

    @Transactional
    public boolean updateAllColumnBatchById(List entityList, int batchSize) {
        return updateBatchById(entityList, batchSize, false);
    }

    /**
     * 根据主键ID进行批量修改
     *
     * @param entityList 实体对象列表
     * @param batchSize  批量刷新个数
     * @param selective  是否滤掉空字段
     * @return boolean
     */
    private boolean updateBatchById(List entityList, int batchSize, boolean selective) {
        if (CollectionUtils.isEmpty(entityList)) {
            throw new IllegalArgumentException("Error: entityList must not be empty");
        }
        try (SqlSession batchSqlSession = sqlSessionBatch()) {
            int size = entityList.size();
            SqlMethod sqlMethod = selective ? SqlMethod.UPDATE_BY_ID : SqlMethod.UPDATE_ALL_COLUMN_BY_ID;
            String sqlStatement = sqlStatement(sqlMethod);
            for (int i = 0; i < size; i++) {
                MapperMethod.ParamMap param = new MapperMethod.ParamMap<>();
                param.put("et", entityList.get(i));
                batchSqlSession.update(sqlStatement, param);
                if (i >= 1 && i % batchSize == 0) {
                    batchSqlSession.flushStatements();
                }
            }
            batchSqlSession.flushStatements();
        } catch (Throwable e) {
            throw new MybatisPlusException("Error: Cannot execute updateBatchById Method. Cause", e);
        }
        return true;
    }

    public T selectById(Serializable id) {
        return baseMapper.selectById(id);
    }

    public List selectBatchIds(List idList) {
        return baseMapper.selectBatchIds(idList);
    }

    public List selectByMap(Map columnMap) {
        return baseMapper.selectByMap(columnMap);
    }

    public T selectOne(Wrapper wrapper) {
        return SqlHelper.getObject(baseMapper.selectList(wrapper));
    }

    public Map selectMap(Wrapper wrapper) {
        return SqlHelper.getObject(baseMapper.selectMaps(wrapper));
    }

    public Object selectObj(Wrapper wrapper) {
        return SqlHelper.getObject(baseMapper.selectObjs(wrapper));
    }

    public int selectCount(Wrapper wrapper) {
        return SqlHelper.retCount(baseMapper.selectCount(wrapper));
    }

    public List selectList(Wrapper wrapper) {
        return baseMapper.selectList(wrapper);
    }

    @SuppressWarnings("unchecked")
    public Page selectPage(Page page) {
        return selectPage(page, Condition.EMPTY);
    }

    public List> selectMaps(Wrapper wrapper) {
        return baseMapper.selectMaps(wrapper);
    }

    public List