com.atguigu.spring.jdbc;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.sql.DataSource;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.jdbc.core.namedparam.BeanPropertySqlParameterSource;
import org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate;
import org.springframework.jdbc.core.namedparam.SqlParameterSource;
public class JDBCTest {
private ApplicationContext ctx =
null;
private JdbcTemplate jdbcTemplate;
private EmployeeDao employeeDao;
private DepartmentDao departmentDao;
private NamedParameterJdbcTemplate namedParameterJdbcTemplate;
{
ctx =
new ClassPathXmlApplicationContext("applicationContext.xml"
);
jdbcTemplate = (JdbcTemplate) ctx.getBean("jdbcTemplate"
);
employeeDao = ctx.getBean(EmployeeDao.
class);
departmentDao = ctx.getBean(DepartmentDao.
class);
namedParameterJdbcTemplate = ctx.getBean(NamedParameterJdbcTemplate.
class);
}
/**
* 使用具名参数时, 可以使用 update(String sql, SqlParameterSource paramSource) 方法进行更新操作
* 1. SQL 语句中的参数名和类的属性一致!
* 2. 使用 SqlParameterSource 的 BeanPropertySqlParameterSource 实现类作为参数.
*/
@Test
public void testNamedParameterJdbcTemplate2(){
String sql = "INSERT INTO employees(last_name, email, dept_id) "
+ "VALUES(:lastName,:email,:dpetId)"
;
Employee employee =
new Employee();
employee.setLastName("XYZ"
);
employee.setEmail("xyz@sina.com"
);
employee.setDpetId(3
);
SqlParameterSource paramSource =
new BeanPropertySqlParameterSource(employee);
namedParameterJdbcTemplate.update(sql, paramSource);
}
/**
* 可以为参数起名字.
* 1. 好处: 若有多个参数, 则不用再去对应位置, 直接对应参数名, 便于维护
* 2. 缺点: 较为麻烦.
*/
@Test
public void testNamedParameterJdbcTemplate(){
String sql = "INSERT INTO employees(last_name, email, dept_id) VALUES(:ln,:email,:deptid)"
;
Map<String, Object> paramMap =
new HashMap<>
();
paramMap.put("ln", "FF"
);
paramMap.put("email", "ff@atguigu.com"
);
paramMap.put("deptid", 2
);
namedParameterJdbcTemplate.update(sql, paramMap);
}
@Test
public void testDepartmentDao(){
System.out.println(departmentDao.get(1
));
}
@Test
public void testEmployeeDao(){
System.out.println(employeeDao.get(1
));
}
/**
* 获取单个列的值, 或做统计查询
* 使用 queryForObject(String sql, Class<Long> requiredType)
*/
@Test
public void testQueryForObject2(){
String sql = "SELECT count(id) FROM employees"
;
long count = jdbcTemplate.queryForObject(sql, Long.
class);
System.out.println(count);
}
/**
* 查到实体类的集合
* 注意调用的不是 queryForList 方法
*/
@Test
public void testQueryForList(){
String sql = "SELECT id, last_name lastName, email FROM employees WHERE id > ?"
;
RowMapper<Employee> rowMapper =
new BeanPropertyRowMapper<>(Employee.
class);
List<Employee> employees = jdbcTemplate.query(sql, rowMapper,5
);
System.out.println(employees);
}
/**
* 从数据库中获取一条记录, 实际得到对应的一个对象
* 注意不是调用 queryForObject(String sql, Class<Employee> requiredType, Object... args) 方法!
* 而需要调用 queryForObject(String sql, RowMapper<Employee> rowMapper, Object... args)
* 1. 其中的 RowMapper 指定如何去映射结果集的行, 常用的实现类为 BeanPropertyRowMapper
* 2. 使用 SQL 中列的别名完成列名和类的属性名的映射. 例如 last_name lastName
* 3. 不支持级联属性. JdbcTemplate 到底是一个 JDBC 的小工具, 而不是 ORM 框架
*/
@Test
public void testQueryForObject(){
String sql = "SELECT id, last_name lastName, email, dept_id as \"department.id\" FROM employees WHERE id = ?"
;
RowMapper<Employee> rowMapper =
new BeanPropertyRowMapper<>(Employee.
class);
Employee employee = jdbcTemplate.queryForObject(sql, rowMapper, 1
);
System.out.println(employee);
}
/**
* 执行批量更新: 批量的 INSERT, UPDATE, DELETE
* 最后一个参数是 Object[] 的 List 类型: 因为修改一条记录需要一个 Object 的数组, 那么多条不就需要多个 Object 的数组吗
*/
@Test
public void testBatchUpdate(){
String sql = "INSERT INTO employees(last_name, email, dept_id) VALUES(?,?,?)"
;
List<Object[]> batchArgs =
new ArrayList<>
();
batchArgs.add(new Object[]{"AA", "aa@atguigu.com", 1
});
batchArgs.add(new Object[]{"BB", "bb@atguigu.com", 2
});
batchArgs.add(new Object[]{"CC", "cc@atguigu.com", 3
});
batchArgs.add(new Object[]{"DD", "dd@atguigu.com", 3
});
batchArgs.add(new Object[]{"EE", "ee@atguigu.com", 2
});
jdbcTemplate.batchUpdate(sql, batchArgs);
}
/**
* 执行 INSERT, UPDATE, DELETE
*/
@Test
public void testUpdate(){
String sql = "UPDATE employees SET last_name = ? WHERE id = ?"
;
jdbcTemplate.update(sql, "Jack", 5
);
}
@Test
public void testDataSource()
throws SQLException {
DataSource dataSource = ctx.getBean(DataSource.
class);
System.out.println(dataSource.getConnection());
}
}
JDBCTest
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