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 protected]]
这样就完全脱离了两个xml配置文件实现查询数据库。
时间： 2024-10-13 21:56:36