使用场景

mybatisplus Iservice接口下的saveOrUpdateBatch方法默认是根据主键来决定是要更新还是插入的，如果要根据其他字段（必须是唯一约束，唯一约束字段可以是多个）更新的话，则需要在项目的service层重写该方法。

方法源码

@Transactional(
        rollbackFor = {Exception.class}
    )
    public boolean saveOrUpdateBatch(Collection<T> entityList, int batchSize) {
        TableInfo tableInfo = TableInfoHelper.getTableInfo(this.entityClass);
        Assert.notNull(tableInfo, "error: can not execute. because can not find cache of TableInfo for entity!", new Object[0]);
        String keyProperty = tableInfo.getKeyProperty();
        Assert.notEmpty(keyProperty, "error: can not execute. because can not find column for id from entity!", new Object[0]);
        return SqlHelper.saveOrUpdateBatch(this.entityClass, this.mapperClass, this.log, entityList, batchSize, (sqlSession, entity) -> {
            Object idVal = ReflectionKit.getFieldValue(entity, keyProperty);
            return StringUtils.checkValNull(idVal) || CollectionUtils.isEmpty(sqlSession.selectList(this.getSqlStatement(SqlMethod.SELECT_BY_ID), entity));
        }, (sqlSession, entity) -> {
            MapperMethod.ParamMap<T> param = new MapperMethod.ParamMap();
            param.put("et", entity);
            sqlSession.update(this.getSqlStatement(SqlMethod.UPDATE_BY_ID), param);
        });
    }

从源码中可以看出实现saveOrUpdateBatch的主要方法就是SqlHelper.saveOrUpdateBatch

public static <E> boolean saveOrUpdateBatch(Class<?> entityClass, Class<?> mapper, Log log, Collection<E> list, int batchSize, BiPredicate<SqlSession, E> predicate, BiConsumer<SqlSession, E> consumer) {
        String sqlStatement = getSqlStatement(mapper, SqlMethod.INSERT_ONE);
        return executeBatch(entityClass, log, list, batchSize, (sqlSession, entity) -> {
            if (predicate.test(sqlSession, entity)) {
                sqlSession.insert(sqlStatement, entity);
            } else {
                consumer.accept(sqlSession, entity);
            }

        });
    }

该方法的最后两个参数predicate，consumer
predicate 这个函数是用于判断是否要进行插入操作 true插入，false：则通过consumer 函数执行更新

方法改造

注意：写在项目操作对应表的service层
首先在service层定义接口

boolean saveOrUpdateBatchByAgentIdAndPeriodAndType(List<Entity> list);

类为数据库表对应的实体类，agentId，period，type，这个三个字段为表的唯一约束，即当表中存在这三个字段组合对应的记录时则进行更新操作，不存在则进行插入操作
service层接口实现

@Transactional(rollbackFor = Exception.class)
    @DS("XXXX")//如果为多数据源，这里要指明具体操作的数据源名称
    public boolean saveOrUpdateBatchByAgentIdAndPeriodAndType(List<Entity> list) {

        return SqlHelper.saveOrUpdateBatch(entityClass, this.mapperClass, super.log, list, DEFAULT_BATCH_SIZE, (sqlSession, entity) -> {//这里主要是查询唯一约束对应的记录是否存在
            LambdaQueryWrapper<Entity> queryWrapper = Wrappers.<Entity>lambdaQuery()
                    .eq(Entity::getAgentId, entity.getAgentId()).eq(Entity::getPeriod,entity.getPeriod())
                    .eq(Entity::getType,entity.getType());
            Map<String, Object> map = CollectionUtils.newHashMapWithExpectedSize(1);
            map.put(Constants.WRAPPER, queryWrapper);
            return CollectionUtils.isEmpty(sqlSession.selectList(getSqlStatement(SqlMethod.SELECT_LIST), map));
        }, (sqlSession, entity) -> {
            LambdaUpdateWrapper<Entity> lambdaUpdateWrapper = new LambdaUpdateWrapper<>();
            lambdaUpdateWrapper.eq(Entity::getAgentId, entity.getAgentId()).eq(Entity::getPeriod,entity.getPeriod())
                    .eq(Entity::getType,entity.getType());
            Map<String, Object> param = CollectionUtils.newHashMapWithExpectedSize(2);
            param.put(Constants.ENTITY, entity);
            param.put(Constants.WRAPPER, lambdaUpdateWrapper);
            sqlSession.update(getSqlStatement(SqlMethod.UPDATE), param);
        });
    }

非批量的saveOrUpdate也可以按照这种方式进行改造