Java框架學習_Spring(六)Spring_Dao層解決方案:JDBC模板的配置、模板的CRUD操作
阿新 • • 發佈:2019-01-14
Spring在Dao層的解決方案,採用JDBC模板和資料庫交換資料
按照之前學JDBC的步驟,建立連線並交給Spring管理(這裡是用xml配置的方式):
- 配置原始連線(就是自帶的連結,沒有用到連線池)
- 配置DBCP版連線池
- 配置c3p0版連線池
- 將連線資訊單獨放到properties檔案裡面進一步解耦和
==========================================================
- 先建立原始連線
package cn.nupt;
import java.util.Map;
import org.junit.Test;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.datasource.DriverManagerDataSource;
public class Spring_JDBC_demo01 {
@Test
public void test01() {
// 建立普通版連線池
DriverManagerDataSource dataSource = new DriverManagerDataSource ();
dataSource.setDriverClassName("com.mysql.jdbc.Driver");
dataSource.setUrl("jdbc:mysql:///mybatis");
dataSource.setUsername("root");
dataSource.setPassword("1111");
// 建立JDBC模板
JdbcTemplate template = new JdbcTemplate(dataSource);
template.update("insert into user values (null,?,?,?,?)" , "程奕迅", "2019-2-2", 1, "哈爾濱");
}
}
- 將這個連線交給Spring的xml檔案管理(這裡直接配置了原始連線、DBCP版連線池、c3p0版連線池,按照自己的資料庫該相應的使用者名稱、密碼就行了)
<?xml version="1.0" encoding="utf-8"?>
<beans xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:context="http://www.springframework.org/schema/context" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.springframework.org/schema/beans">
<!-- 配置普通版連線池========================= -->
<!--
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
<property name="url" value="jdbc:mysql:///mybatis"></property>
<property name="username" value="root"></property>
<property name="password" value="1111"></property>
</bean> -->
<!-- 配置DBCP版連線池========================= -->
<!--
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
<property name="url" value="jdbc:mysql:///mybatis"></property>
<property name="username" value="root"></property>
<property name="password" value="1111"></property>
</bean>
-->
<!-- 配置C3P0版連線池========================= -->
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
<property name="driverClass" value="com.mysql.jdbc.Driver"></property>
<property name="jdbcUrl" value="jdbc:mysql:///mybatis"></property>
<property name="user" value="root"></property>
<property name="password" value="1111"></property>
</bean>
<!-- 配置JDBC模板的 ================================-->
<bean id="template" class="org.springframework.jdbc.core.JdbcTemplate">
<property name="dataSource" ref="dataSource"></property>
</bean>
</beans>
更近一步,將配置單獨放到一個jdbc.properties檔案裡面:
jdbc.driverClass=com.mysql.jdbc.Driver
jdbc.jdbcUrl=jdbc:mysql:///mybatis
jdbc.user=root
jdbc.password=1111
然後在xml中引入這個properties配置檔案,然後在出c3p0連線池裡面引用相應的變數,也能達到同樣的效果(變成動態的配置):
<!-- 配置檔案放到properties方式一=============================== -->
<!-- <bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="location" value="classpath:jdbc.properties"></property>
</bean> -->
<!-- 配置檔案放到properties方式二:常用=============================== -->
<context:property-placeholder location="classpath:jdbc.properties"/>
<!-- 配置C3P0版連線池========================= -->
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
<property name="driverClass" value="${jdbc.driverClass}"></property>
<property name="jdbcUrl" value="${jdbc.jdbcUrl}"></property>
<property name="user" value="${jdbc.user}"></property>
<property name="password" value="${jdbc.password}"></property>
</bean>
最後,編寫測試類:
package cn.nupt.test;
import javax.annotation.Resource;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:applicationContext.xml")
public class JdbcTest {
@Resource(name="template")
private JdbcTemplate template;
@Test
public void test() {
template.update("insert into user values (null,?,?,?,?)","海賊黑鬍子","2019-2-2" ,1,"東海" );
}
//上面用到了junit和aop的整合,這裡是原始的
/*
@Test
public void test() {
ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");
//根據ID找到相應的類
JdbcTemplate template = (JdbcTemplate) applicationContext.getBean("template");
template.update("insert into user values (null,?,?,?,?)","程bingbing","2019-2-2" ,1,"哈濱" );
}
*/
}
2、模板的CRUD操作:
模板的增刪改查操作中,只有查詢比較特殊,下面在前面已經配置好的情況下寫幾種查詢情況(最主要的是RowMapper這個介面的用法,一如JDBC中的ResultHandler)
- 插入資料,增刪改都是一樣的,在這裡就不一一演示了
- 查詢一群人(輸出一個集合)
- 查詢一個人(輸出一個Bean)
- 查詢一個人的一個屬性,比如name
- 統計查詢(聚合函式)
具體演示程式碼如下:
package cn.nupt.test;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;
import javax.annotation.Resource;
import javax.swing.tree.TreePath;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import cn.nupt.domain.User;
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:applicationContext.xml")
public class JdbcTest {
@Resource(name = "template")
private JdbcTemplate template;
@Test
//插入資料,增刪改都是一樣的,在這裡就不一一演示了
public void test01() {
template.update("insert into user values (null,?,?,?)", "海賊白鬍子", "2019-2-2", "東海");
}
@Test
//查詢一群人
public void test02() {
List<User> list = template.query("select * from user", new RowMapper<User>() {
public User mapRow(ResultSet rs, int rowNum) throws SQLException {
User user = new User();
user.setId(rs.getInt("id"));
user.setAddress(rs.getString("address"));
user.setBirthday(rs.getDate("birthday"));
user.setUsername(rs.getString("username"));
return user;
}
});
for (User user : list) {
System.out.println(user);
}
}
@Test
//查詢一個人
public void test03() {
User user = template.queryForObject("select * from user where id = ? ", new RowMapper<User>() {
public User mapRow(ResultSet rs, int rowNum) throws SQLException {
User user = new User();
user.setId(rs.getInt("id"));
user.setAddress(rs.getString("address"));
user.setBirthday(rs.getDate("birthday"));
user.setUsername(rs.getString("username"));
return user;
}
}, 46);
System.out.println(user);
}
@Test
//查詢一個人的一個屬性,比如name
public void test04() {
String name = template.queryForObject("select username from user where id = ?",String.class,46);
System.out.println(name);
}
@Test
//統計查詢
public void test05() {
long num = template.queryForObject("select count(*) from user ",long.class);
System.out.println(num);
}
}