Spring整合JDBC
Spring提供了很多模板整合Dao技术,包括JDBC,Hibernate,MyBatis,JPA等
spring中提供了一个可以操作数据库的对象.对象封装了jdbc技术,JDBCTemplate是JDBC的一个模板对象,与DBUtils中的QueryRunner非常相似。本文就JDBCTemplate进行相应的阐述及代码演示
准备工作
- 表设计
- 准备User实体类
package cn.itcast.bean;
public class User {
private Integer id;
private String name;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public String toString() {
return "User [id=" + id + ", name=" + name + "]";
}
}
导包
基础包4个+日志包2个+spring-test,spring-aop,junit4类库+c3p0连接池,JDBC驱动+spring-jdbc,spring-tx事务
编写Dao层代码
//Dao层接口
package cn.itcast.a_jdbctemplate;
import java.util.List;
import cn.itcast.bean.User;
public interface UserDao {
//增
void save(User u);
//删
void delete(Integer id);
//改
void update(User u);
//通过ID查找
User getById(Integer id);
//查找总记录数
int getTotalCount();
//查询所有
List<User> getAll();
}
Spring中提供了一个JdbcDaoSupport类,Dao层继承该类后,不需要手动准备JDBC模板,直接根据DataSource创建JDBC模板,从父类方法中直接获得JDBCTemplate对象。
//Dao层实现类
package cn.itcast.a_jdbctemplate;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.jdbc.core.support.JdbcDaoSupport;
import cn.itcast.bean.User;
//使用JDBC模板实现增删改查,继承了JdbcDaoSupport类。
public class UserDaoImpl extends JdbcDaoSupport implements UserDao {
@Override
public void save(User u) {
String sql = "insert into t_user values(null,?) ";
super.getJdbcTemplate().update(sql, u.getName());
}
@Override
public void delete(Integer id) {
String sql = "delete from t_user where id = ? ";
super.getJdbcTemplate().update(sql,id);
}
@Override
public void update(User u) {
String sql = "update t_user set name = ? where id=? ";
super.getJdbcTemplate().update(sql, u.getName(),u.getId());
}
@Override
public User getById(Integer id) {
String sql = "select * from t_user where id = ? ";
return super.getJdbcTemplate().queryForObject(sql,new RowMapper<User>(){
@Override
public User mapRow(ResultSet rs, int arg1) throws SQLException {
User u = new User();
u.setId(rs.getInt("id"));
u.setName(rs.getString("name"));
return u;
}}, id);
}
@Override
public int getTotalCount() {
String sql = "select count(*) from t_user ";
Integer count = super.getJdbcTemplate().queryForObject(sql, Integer.class);
return count;
}
@Override
public List<User> getAll() {
String sql = "select * from t_user ";
List<User> list = super.getJdbcTemplate().query(sql, new RowMapper<User>(){
@Override
public User mapRow(ResultSet rs, int arg1) throws SQLException {
User u = new User();
u.setId(rs.getInt("id"));
u.setName(rs.getString("name"));
return u;
}});
return list;
}
}
- 配置文件
通过读取外部的Properties文件,来加载连接数据库的参数值
jdbc.jdbcUrl=jdbc:mysql:///hibernate_32
jdbc.driverClass=com.mysql.jdbc.Driver
jdbc.user=root
jdbc.password=1234
配置文件
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.2.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.2.xsd ">
<!-- 指定spring读取db.properties配置 -->
<context:property-placeholder location="classpath:db.properties" />
<!-- 1.将连接池放入spring容器 -->
<bean name="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" >
<property name="jdbcUrl" value="${jdbc.jdbcUrl}" ></property>
<property name="driverClass" value="${jdbc.driverClass}" ></property>
<property name="user" value="${jdbc.user}" ></property>
<property name="password" value="${jdbc.password}" ></property>
</bean>
<!-- 2.将JDBCTemplate放入spring容器
<bean name="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate" >
<property name="dataSource" ref="dataSource" ></property>
</bean> -->
<!-- 3.将UserDao放入spring容器 -->
<bean name="userDao" class="cn.itcast.a_jdbctemplate.UserDaoImpl" >
<!-- 继承了JdbcDaoSupport,就不需要注入jdbcTemplate,直接注入连接池就可以了 -->
<!-- <property name="jt" ref="jdbcTemplate" ></property> -->
<property name="dataSource" ref="dataSource" ></property>
</bean>
</beans>
测试
package cn.itcast.a_jdbctemplate;
import javax.annotation.Resource;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import cn.itcast.bean.User;
//演示JDBC模板
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:applicationContext.xml")
public class Demo {
@Resource(name="userDao")
private UserDao ud;
@Test
public void fun1() throws Exception{
User u = new User();
u.setName("tom");
ud.save(u);
}
@Test
public void fun2() throws Exception{
User u = new User();
u.setId(2);
u.setName("jack");
ud.update(u);
}
@Test
public void fun3() throws Exception{
ud.delete(2);
}
@Test
public void fun4() throws Exception{
System.out.println(ud.getTotalCount());
}
@Test
public void fun5() throws Exception{
System.out.println(ud.getById(1));
}
@Test
public void fun6() throws Exception{
System.out.println(ud.getAll());
}
}