spring-mybatis与mybatis区别

1，spring-mybatis一级缓存失效，因为是sqlsesstionTemplate，其使用了一个代理proxysession，每次请求都会关闭session;

spring-mybatis扩展了一个类sqlsessiontemplate，这个类在spring容器启动时被注入给mapper，这个类替代了原来的mybatis的DefaultSqlSession，sqlsessiontemplate的所有查询并不直接查询，而是经过一个代理对象，代理对象增加了查询方法，主要是每次关闭了session

public SqlSessionTemplate(SqlSessionFactory sqlSessionFactory, ExecutorType executorType, PersistenceExceptionTranslator exceptionTranslator) {
    Assert.notNull(sqlSessionFactory, "Property 'sqlSessionFactory' is required");
    Assert.notNull(executorType, "Property 'executorType' is required");
    this.sqlSessionFactory = sqlSessionFactory;
    this.executorType = executorType;
    this.exceptionTranslator = exceptionTranslator;
    this.sqlSessionProxy = (SqlSession)Proxy.newProxyInstance(SqlSessionFactory.class.getClassLoader(), new Class[]{SqlSession.class}, new SqlSessionTemplate.SqlSessionInterceptor());
}

............

private class SqlSessionInterceptor implements InvocationHandler {
    private SqlSessionInterceptor() {
    }

    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        SqlSession sqlSession = SqlSessionUtils.getSqlSession(SqlSessionTemplate.this.sqlSessionFactory, SqlSessionTemplate.this.executorType, SqlSessionTemplate.this.exceptionTranslator);

        Object unwrapped;
        try {
            Object result = method.invoke(sqlSession, args);//其中sqlsession是mybatis的defaultSession,加了代理是为增加关闭功能
            if (!SqlSessionUtils.isSqlSessionTransactional(sqlSession, SqlSessionTemplate.this.sqlSessionFactory)) {
                sqlSession.commit(true);
            }

            unwrapped = result;
        } catch (Throwable var11) {
            unwrapped = ExceptionUtil.unwrapThrowable(var11);
            if (SqlSessionTemplate.this.exceptionTranslator != null && unwrapped instanceof PersistenceException) {
                SqlSessionUtils.closeSqlSession(sqlSession, SqlSessionTemplate.this.sqlSessionFactory);
                sqlSession = null;
                Throwable translated = SqlSessionTemplate.this.exceptionTranslator.translateExceptionIfPossible((PersistenceException)unwrapped);
                if (translated != null) {
                    unwrapped = translated;
                }
            }

            throw (Throwable)unwrapped;
        } finally {
            if (sqlSession != null) { //每次都会关闭
                SqlSessionUtils.closeSqlSession(sqlSession, SqlSessionTemplate.this.sqlSessionFactory);
            }

        }

        return unwrapped;
    }
}

2，mybatis的sqlsession是defaultSqlSession，是实类，同一个session不关闭，直到结束，session暴露在代码，可以随时close, 相当于关闭session可控

而spring-mybatis的每次session要关闭是因为session不在ioc容器中,加上集成后无接口关闭session,没暴露api，所以使用代理增加了关闭session, 所以为了资源的可重复利用，防止不关，每次要关闭

来源：CSDN

作者：xiaoza7

链接：https://blog.csdn.net/xiaoza7/article/details/104592578

标签

MyBatis

session

session对象