Expected one result (or null) to be returned by selectOne(), but found: 3 at org.apache.ibatis.session.defaults.DefaultSqlSession.selectOne(DefaultS qlSession.java:70) selectList 可以查询一条或多条记录。 1.6.7 SqlSession；使用完毕就要关闭它。通常把这个关闭操作放到 finally 块中以 确保每次都能执行关闭。如下： SqlSession session = sqlSessionFactory.openSession(); try { // do work } finally { session.close(); } 2.3 原始 Dao 开发方式 原始 Dao 开发方法需要程序员编写 Dao 接口和 Dao Exception { SqlSession session = sqlSessionFactory.openSession(); User user = null; try { //通过sqlsession调用selectOne方法获取一条结果集 //参数1：指定定义的statement的id,参数2：指定向statement中传递的参 数 user = session.selectOne("test.findUserById"

can invoke the ‘insert’ mapped query using Java API as shown below − //Assume session is an SqlSession object. session.insert("Student.insert", student); Update To update values of an existing record You can invoke the update mapped query using Java API as shown below − //Assume session is an SqlSession object. session.update("Student.update",student); Delete To delete the values of an existing of SqlSession interface provided by MyBatis Java API as shown below − //Assume session is an SqlSession object. session.delete("Student.deleteById", 18); Select To retrieve data, ‘select’ mapper statement

sqlSession SqlSession session = sessionFactory.openSession(); //映射 sql 的标识字符串 String statement = "com.atguigu.mybatis.bean.userMapper"+".selectUser"; //执行查询返回一个唯一 user 对象的 sql User user = session.selectOne(statement com 下载区】 3). 在 dao 中调用： public User getUserById(int id) { SqlSession session = sessionFactory.openSession(); User user = session.selectOne(URI+".selectUser", id); return user; } 3.2. 注解的实现 1). 定义 sql 下载区】 3). 在 dao 类中调用 public User getUserById(int id) { SqlSession session = sessionFactory.openSession(); UserMapper mapper = session.getMapper(UserMapper.class); User user = mapper.getUserById(id); return

private InputStream in ; private SqlSessionFactory factory; private SqlSession session; private IUserDao userDao; @Test public void testFindOne() { //6.执行操作 factory = builder.build(in); //4.创建 SqlSession 对象 session = factory.openSession(); //5.创建 Dao 的代理对象 userDao = session.getMapper(IUserDao.class); } 传智播客——专注于 Java、.Net 和 电话：400-618-9090 @After//在测试方法执行完成之后执行 public void destroy() throws Exception{ session.commit(); //7.释放资源 session.close(); in.close(); } } 2.2 保存操作 2.2.1 在持久层接口中添加新增方法 /**

语句。例如： SqlSession session = sqlSessionFactory.openSession(); try { Blog blog = (Blog) session.selectOne("org.mybatis.example.BlogMapper.selectBlog", 101); } finally { session.close(); } 诚然这种方式能够正常工作，并且对于使用旧版本 例如： SqlSession session = sqlSessionFactory.openSession(); try { BlogMapper mapper = session.getMapper(BlogMapper.class); Blog blog = mapper.selectBlog(101); } finally { session.close(); } 使用指定的完全限定 名“org.mybatis.example.BlogMapper.selectBlog”来调用映射语句，就像上面的例子中做的那样： Blog blog = (Blog) session.selectOne("org.mybatis.example.BlogMapper.selectBlog", 101); 你可能注意到这和使用完全限定名调用 Java 对象的方法是相似的，之

; SqlSession session = sqlSessionFactory.openSession(); try { JAVAEE 课程系列 ————————————————————————————— 7 更多 Java –大数据 –前端 –python 人工智能资料下载，可访问百度：尚硅谷官网 Employee employee = session.selectOne("suibian selectOne("suibian.selectEmployee", 1001); System.out.println(employee); } finally { session.close(); } } 2.6 Mapper 接口开发 MyBatis HelloWorld 1) 编写 Mapper 接口 public interface EmployeeMapper { public Employee SqlSessionFactoryBuilder() .build(inputStream); SqlSession session = sqlSessionFactory.openSession(); try { //Mapper接口:获取Mapper接口的 代理实现类对象 EmployeeMapper mapper = session.getMapper(EmployeeMapper.class); JAVAEE 课程系列

apache.ibatis.io.Resources; import org.apache.ibatis.session.SqlSession; import org.apache.ibatis.session.SqlSessionFactory; import org.apache.ibatis.session.SqlSessionFactoryBuilder; public class GetRecordByName SqlSession session = sqlSessionFactory.openSession(); Student stud = new Student(); stud.setName(req_name); //select contact all contacts //List student = session.sel selectList("getRecByName",stud); stud.setId(1); List student = session.selectList("getRecByName_Id",stud); for(Student st : student ){

interval maxRetries Str ing 3 Maximum number of retries sessionTim eoutMillisec‐ onds int 60000 Session timeout in milliseconds connectionTim eoutMil‐ liseconds int 15000 Connection timeout in milliseconds namespace Yes base‐sleep‐time‐milliseconds No max‐sleep‐time‐milliseconds No max‐retries No session‐timeout‐milliseconds No connection‐timeout‐milliseconds No digest No Reference: YAML elasticjob: namespace Yes base‐sleep‐time‐milliseconds No max‐sleep‐time‐milliseconds No max‐retries No session‐timeout‐milliseconds No connection‐timeout‐milliseconds No digest No Job Configuration

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Optional Plugins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278 4.2.7 Session Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280 Usage . . . . . ooq-provider, JooQ SQL translator 4.2.7 Session Management ShardingSphere supports session management. You can view the current session or kill the session through the SQL of the native database. At are supported. 4.2. ShardingSphere-Proxy 280 Apache ShardingSphere document, v5.2.1 Usage View Session Different methods of viewing sessions are supported for different associated databases. The SHOW

Optional Plugins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 394 9.2.7 Session Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395 Usage . . . . . com/, and install into ShardingSphere. 9.2.7 Session Management ShardingSphere supports session management. You can view the current session or kill the session through the SQL of the native database. At commands are supported. 9.2. ShardingSphere-Proxy 395 Apache ShardingSphere document Usage View Session Different methods of viewing sessions are supported for different associated databases. The SHOW