标签：public 创建 ota bug cti std 代理 apache rom
1、Mybatis与hibernate的不同
（1）Mybatis和hibernate不同，它不完全是一个ORM框架，因为MyBatis需要程序员自己编写Sql语句。mybatis可以通过XML或注解方式灵活配置要运行的sql语句，并将java对象和sql语句映射生成最终执行的sql，最后将sql执行的结果再映射生成java对象。
mybatis需要在配置文件中书写sql语句：
<delete id="deleteStudentById" parameterType="Integer"> delete from student where studentno = #{value} </delete>
（2）Mybatis学习门槛低，简单易学，程序员直接编写原生态sql，可严格控制sql执行性能，灵活度高，非常适合对关系数据模型要求不高的软件开发，例如互联网软件、企业运营类软件等，因为这类软件需求变化频繁，一但需求变化要求成果输出迅速。但是灵活的前提是mybatis无法做到数据库无关性，如果需要实现支持多种数据库的软件则需要自定义多套sql映射文件，工作量大。
（3）Hibernate对象/关系映射能力强，数据库无关性好，对于关系模型要求高的软件（例如需求固定的定制化软件）如果用hibernate开发可以节省很多代码，提高效率。但是Hibernate的学习门槛高，要精通门槛更高，而且怎么设计O/R映射，在性能和对象模型之间如何权衡，以及怎样用好Hibernate需要具有很强的经验和能力才行。总之，按照用户的需求在有限的资源环境下只要能做出维护性、扩展性良好的软件架构都是好架构，所以框架只有适合才是最好。
2、原始Dao开发
（1）创建接口：
public interface StudentDao { public Student selectStudentById(Integer id); }
（2）创建接口的实现类：
public class StudentDaoImp implements StudentDao{ private SqlSessionFactory sqlSessionFactory; public StudentDaoImp(SqlSessionFactory sqlSessionFactory) { this.sqlSessionFactory = sqlSessionFactory; } public Student selectStudentById(Integer studentno){ SqlSession sqlSession = sqlSessionFactory.openSession(); return sqlSession.selectOne("test.findStudentById", studentno); } }
（3）创建测试类：
public class Test1 { public SqlSessionFactory sqlSessionFactory; public void before() throws Exception { String resource = "sqlMapConfig.xml"; InputStream in = Resources.getResourceAsStream(resource); sqlSessionFactory = new SqlSessionFactoryBuilder().build(in); } public void testDao() throws Exception { StudentDao studentDao = new StudentDaoImp(sqlSessionFactory); Student student=studentDao.selectStudentById(201811); System.out.println(student); } public static void main(String args []){ Test1 test1=new Test1(); try { test1.before(); test1.testDao(); } catch (Exception e) { e.printStackTrace(); } } }
DEBUG [main] - Logging initialized using ‘class org.apache.ibatis.logging.slf4j.Slf4jImpl‘ adapter. DEBUG [main] - PooledDataSource forcefully closed/removed all connections. DEBUG [main] - PooledDataSource forcefully closed/removed all connections. DEBUG [main] - PooledDataSource forcefully closed/removed all connections. DEBUG [main] - PooledDataSource forcefully closed/removed all connections. DEBUG [main] - Opening JDBC Connection DEBUG [main] - Created connection 1750905143. DEBUG [main] - Setting autocommit to false on JDBC Connection [com.mysql.jdbc.JDBC4Connection@685cb137] DEBUG [main] - ==> Preparing: select * from student where studentno = ? DEBUG [main] - ==> Parameters: 201811(Integer) DEBUG [main] - <== Total: 1 Student [studentno=201811, sname=zhai, sex=男, birthday=1998-11-11, classno=tx171, point=890, phone=1234567890, email=null]
3、mapper动态代理开发
（1）接口：
public interface StudentMapper { Student findStudentById(Integer studentno); }
Mapper接口方法名和xml中定义的每个statement的id相同
Mapper接口方法的输入参数类型和mapper.xml中定义的每个sql 的parameterType的类型相同
Mapper接口方法的输出参数类型和mapper.xml中定义的每个sql的resultType的类型相同
（2）配置文件（注意命名空间）：
<mapper namespace="pers.zhb.mapper.StudentMapper"> <select id="findStudentById" parameterType="Integer" resultType="pers.zhb.pojo.Student"> select * from student where studentno = #{v} </select>
注意：xml文件中的namespace与mapper接口的类路径相同
（3）测试：
public class StudentMapperTest { public void testMapper() throws Exception { //加载核心配置文件 String resource = "sqlMapConfig.xml"; InputStream in = Resources.getResourceAsStream(resource); //创建SqlSessionFactory SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(in); //创建SqlSession SqlSession sqlSession = sqlSessionFactory.openSession(); //SqlSEssion帮我生成一个实现类 （给接口） StudentMapper studentMapper = sqlSession.getMapper(StudentMapper.class); Student student = studentMapper.findStudentById(201811); System.out.println(student); }
DEBUG [main] - Logging initialized using ‘class org.apache.ibatis.logging.slf4j.Slf4jImpl‘ adapter. DEBUG [main] - PooledDataSource forcefully closed/removed all connections. DEBUG [main] - PooledDataSource forcefully closed/removed all connections. DEBUG [main] - PooledDataSource forcefully closed/removed all connections. DEBUG [main] - PooledDataSource forcefully closed/removed all connections. DEBUG [main] - Opening JDBC Connection DEBUG [main] - Created connection 1291286504. DEBUG [main] - Setting autocommit to false on JDBC Connection [com.mysql.jdbc.JDBC4Connection@4cf777e8] DEBUG [main] - ==> Preparing: select * from student where studentno = ? DEBUG [main] - ==> Parameters: 201811(Integer) DEBUG [main] - <== Total: 1 Student [studentno=201811, sname=zhai, sex=男, birthday=1998-11-11, classno=tx171, point=890, phone=1234567890, email=null]
mybatis（Mybatis与hibernate的不同、原始Dao开发、Mapper动态代理开发）
标签：public 创建 ota bug cti std 代理 apache rom
原文地址：https://www.cnblogs.com/zhai1997/p/12529996.html
