mybatis如何开启batch模式

男娘i 2022-02-01 00:49 667阅读 0赞

一般来说，对于SSM项目工程来说，mybatis的ExectoryType默认是simple，那么又如何能动态使用batch模式呢？  
直接上源码实现干货：

import org.apache.ibatis.session.ExecutorType;
    import org.apache.ibatis.session.SqlSession;
    import org.apache.ibatis.session.SqlSessionFactory;
    import org.mybatis.spring.SqlSessionTemplate;
    import org.springframework.stereotype.Component;
    
    import javax.annotation.Resource;
    import java.util.List;
    import java.util.function.BiConsumer;
    
    import static org.mybatis.spring.SqlSessionUtils.closeSqlSession;
    
    
    /** * 启动mybatis的Batch模式的批量新增、更新 * * @author sunchangtan */
    @Component
    public class MybatisBatchExecutor { 
        /** * 拼写成SQL的最大数据量 * 比如： 如果insert，把batchCount条数的数据拼写成一个大SQL * 如果update，把batchCount条数的数据拼写成case when方式的大SQL */
        private static final int batchCountToSQL = 100;
    
        /** * 每多少次时开始commit */
        private static final int batchCountToSubmit = 100;
    
        @Resource
        private SqlSessionTemplate sqlSessionTemplate;
    
    
        /** * 批量更新、新增 * @param dbList * @param mapperClass * @param func * @param <T> * @param <M> */
        public <T, M> void insertOrUpdateBatch(List<T> dbList, Class<M> mapperClass, BiConsumer<M, List<T>> func) { 
            int batchLastIndex = batchCountToSQL;
            int batchLastIndexToSubmit = 0;
            int total = dbList.size();
    
            SqlSessionFactory sqlSessionFactory = sqlSessionTemplate.getSqlSessionFactory();
            SqlSession sqlSession = sqlSessionFactory.openSession(ExecutorType.BATCH, false);
            M modelMapper = sqlSession.getMapper(mapperClass);
            try { 
                if (total > batchCountToSQL) { 
                    for (int index = 0; index < total; ) { 
                        if (batchLastIndex > total) { 
                            List<T> list = dbList.subList(index, total);
    
                            func.accept(modelMapper, list);
    
                            sqlSession.flushStatements();
                            sqlSession.commit();
                            break;
                        } else { 
                            List<T> list = dbList.subList(index, batchLastIndex);
                            func.accept(modelMapper, list);
    
                            if (batchLastIndexToSubmit++ >= batchCountToSubmit) { 
                                //如果可以批量提交，则提交
                                sqlSession.flushStatements();
                                sqlSession.commit();
                                batchLastIndexToSubmit = 0;
                            }
                            index = batchLastIndex;// 设置下一批下标
                            batchLastIndex = index + (batchCountToSQL - 1);
                        }
                    }
                } else { 
                    func.accept(modelMapper, dbList);
                    sqlSession.commit();
                }
            } finally { 
                closeSqlSession(sqlSession, sqlSessionFactory);
            }
        }
    }

使用例子：

//批量插入
     mybatisBatchExecutor.insertOrUpdateBatch(list, BatchTestMapper.class, (mapper, data)-> { 
                mapper.insertList(data);
            });
    
    //批量更新
    mybatisBatchExecutor.insertOrUpdateBatch(list, BatchTestMapper.class, (mapper, data)-> { 
                mapper.updateBatchByPrimaryKeySelective(data);
            });