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初探MyBatis之HelloWorld(二)
二、不使用 XML 构建 SqlSessionFactory
不使用xml构建SqlSessionFactory的话,就要用java代码来连接数据库。我这里直接new DataSorce()接口实现getConnection()方法(不知道对不对,反正实验证明,可行)。
EmployeeDataSourceFactory.java:
1 package yyc.mybatis.util; 2 3 import java.io.PrintWriter; 4 import java.sql.Connection; 5 import java.sql.DriverManager; 6 import java.sql.SQLException; 7 import java.sql.SQLFeatureNotSupportedException; 8 import java.util.logging.Logger; 9 10 import javax.sql.DataSource; 11 12 public class EmployeeDataSourceFactory { 13 14 public static DataSource getEmployeeDataSorce(){ 15 DataSource ds=new DataSource() { 16 17 public <T> T unwrap(Class<T> iface) throws SQLException { 18 // TODO Auto-generated method stub 19 return null; 20 } 21 22 public boolean isWrapperFor(Class<?> iface) throws SQLException { 23 // TODO Auto-generated method stub 24 return false; 25 } 26 27 public void setLoginTimeout(int seconds) throws SQLException { 28 // TODO Auto-generated method stub 29 30 } 31 32 public void setLogWriter(PrintWriter out) throws SQLException { 33 // TODO Auto-generated method stub 34 35 } 36 37 public Logger getParentLogger() throws SQLFeatureNotSupportedException { 38 // TODO Auto-generated method stub 39 return null; 40 } 41 42 public int getLoginTimeout() throws SQLException { 43 // TODO Auto-generated method stub 44 return 0; 45 } 46 47 public PrintWriter getLogWriter() throws SQLException { 48 // TODO Auto-generated method stub 49 return null; 50 } 51 52 public Connection getConnection(String username, String password) throws SQLException { 53 // TODO Auto-generated method stub 54 return null; 55 } 56 57 public Connection getConnection() throws SQLException { 58 try { 59 Class.forName("com.mysql.jdbc.Driver"); 60 String url="jdbc:mysql:///mybatis"; 61 String user="root"; 62 String password="123"; 63 Connection connection = DriverManager.getConnection(url, user, password); 64 return connection; 65 } catch (ClassNotFoundException e) { 66 e.printStackTrace(); 67 } 68 return null; 69 } 70 }; 71 return ds; 72 } 73 }
在第一种时,写了一个xml的SQL映射文件(EmployeeMapperXml.xml),现在既然不用xml了,就需要另一种你方式来映射SQL吧,mybatis提供面向接口编程的方式。官方文档中是这样说的:
它们的映射的语句可以不需要用 XML 来做,取而代之的是可以使用 Java 注解。比如: package org.mybatis.example; public interface BlogMapper { @Select("SELECT * FROM blog WHERE id = #{id}") Blog selectBlog(int id); }
我这里写一接口:
EmployeeMapper.java:
package yyc.mybatis.mapper; import org.apache.ibatis.annotations.Select; import yyc.mybatis.bean.Employee; public interface EmployeeMapper { @Select("SELECT id,last_name lastName,gender,email FROM tb1_employee WHERE id= #{id}") public Employee selectOne(Integer id); }
测试方法(不用xml来得到SqlSessionFactory的方式也不一样):
@Test public void testJavaConfig(){ DataSource dataSource = EmployeeDataSourceFactory.getEmployeeDataSorce(); TransactionFactory transactionFactory = new JdbcTransactionFactory(); Environment environment = new Environment("development", transactionFactory, dataSource); Configuration configuration = new Configuration(environment); configuration.addMapper(EmployeeMapper.class); SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(configuration); //2.获取sqlSession实例,能直接执行已经映射的sql语句 SqlSession openSession = sqlSessionFactory.openSession(); try { EmployeeMapper mapper = openSession.getMapper(EmployeeMapper.class); Employee employee = mapper.selectOne(3); System.out.println(employee); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); }finally { openSession.close(); } }
输出:
Employee [id=3, lastName=mac, gender=1, email=cc@163.com]
这样就完全脱离了两个xml配置文件实现查询数据库。
初探MyBatis之HelloWorld(二)
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