2018.12.25 Spring中JDBCTemplate模版API学习

Posted 2021-01-30 Legend

1 Spring整合JDBC模版

1.1 spring中土拱了一个可以操作数据库的对象。对象封装了jdbc技术

JDBCTemplateJDBC模板对象

1.2 与DBUtils中的QueryRunner非常相似

1.3 准备工作

1.导包 4+2 基础包+日志包。 junit5+spring-test、spring-aop、c3p0连接池、JDBC驱动、spring-jdbc、spring-tx事务

JDBC演示

1.4 JDBC模版实现增删改查操作

准备接口UserDao

编写实现类 UserDaoImpl

增

删

改

查

---

主配置文件applicationContext.xml

测试

1.5 代码优化

1.6 spring整合JDBC --读取properties配置

准备properties文件

主要代码提供参考(下面是优化之前的代码)

UserDao接口

package com.legend.a_jdbctemplate;

import java.util.List;

import com.legend.bean.User;

public interface UserDao {
	//增
	void save(User u);
	
	//删
	void delete(Integer id);
	
	//改
	void update(User u);
	
	//查
	User getById(Integer id);//通过ID
	int getTotalCount();//查找总记录数
	List<User> getAll();//获取所有的记录
}

UserDaoImpl实现类

package com.legend.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 com.legend.bean.User;
/**
 * 使用JDBC模版实现增删改查
 * @author qichunlin
 *
 */
public class UserDaoImpl implements UserDao {

	//声明模版
	private JdbcTemplate jt;
	
	public void setJt(JdbcTemplate jt) {
		this.jt = jt;
	}

	//增
	@Override
	public void save(User u) { 
		String sql = "insert into t_user values(null,?)";
		jt.update(sql,u.getName());
		System.out.println("执行完毕");
	}

	//删
	@Override
	public void delete(Integer id) {
		// TODO Auto-generated method stub
		String sql = "delete from t_user where id=?";
		jt.update(sql,id);
		System.out.println("执行完毕");
	}

	//改
	@Override
	public void update(User u) {
		// TODO Auto-generated method stub
		String sql = "update t_user set name=? where id=?";
		jt.update(sql,u.getName(),u.getId());
		System.out.println("执行完毕");
	}

	//通过id查找用户
	@Override
	public User getById(Integer id) {
		// TODO Auto-generated method stub
		String sql = "select * from t_user where id=?";
		return jt.queryForObject(sql, new RowMapper<User>() {

			@Override
			public User mapRow(ResultSet rs, int arg1) throws SQLException {
				// 不需要判断是否有值
				User user = new User();
				user.setId(rs.getInt("id"));
				user.setName(rs.getString("name"));
				
				System.out.println("执行完毕");	
				
				return user;
			}},id);
			
	}

	//获取所有的行数
	@Override
	public int getTotalCount() {
		// TODO Auto-generated method stub
		String sql = "select count(*) from t_user ";
		
		//当返回的是值类型， 后面的Class对象就是
		Integer count = jt.queryForObject(sql, Integer.class);
		System.out.println("执行完毕");
		return count;
	}

	//获取所有的对象记录
	@Override
	public List<User> getAll() {
		String sql = "select * from t_user ";
		List<User> list = jt.query(sql, new RowMapper<User>() {

			@Override
			public User mapRow(ResultSet rs, int arg1) throws SQLException {
				// 不需要判断是否有值
				User user = new User();
				user.setId(rs.getInt("id"));
				user.setName(rs.getString("name"));
				return user;
			}});
		return list;
	}

}

applicationContext.xml主配置文件

<?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 ">

	<!-- 1.将连接池放入spring容器 -->
	<bean name="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
		<property name="jdbcUrl" value="jdbc:mysql:///crm"></property>
		<property name="driverClass" value="com.mysql.jdbc.Driver"></property>
		<property name="user" value="root"></property>
		<property name="password" value="123456"></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="com.legend.a_jdbctemplate.UserDaoImpl">
		<property name="jt" ref="jdbcTemplate"></property>
	</bean>
</beans>

DemoTest测试类

package com.legend.a_jdbctemplate;

import java.util.List;

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;

import com.legend.bean.User;
import com.mchange.v2.c3p0.ComboPooledDataSource;
/**
 * SpringJDBC演示
 * @author qichunlin
 *
 */
//创建容器
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:applicationContext.xml")
public class DemoTest2 {
	
	//操作userDao对象
	@Resource(name="userDao")
	private UserDao ud;

	@Test
	public void fun2() throws Exception {
		User u = new User();
		u.setName("ATencent");
		ud.save(u);
	}

	@Test
	public void fun3() throws Exception {
		User u = new User();
		u.setId(10);
		u.setName("hhhh");
		ud.update(u);
	}	
	
	@Test
	public void fun4() throws Exception {
		List<User> all = ud.getAll();
		System.out.println(all.size());
	}	

	
	@Test
	public void fun5() throws Exception {
		ud.delete(1);
	}
	
	@Test
	public void fun6() throws Exception {
		System.out.println(ud.getTotalCount());
	}
	
	

	//最原始的方法
	@Test
	public void fun1() throws Exception {
		//准备连接池
		ComboPooledDataSource dataSource = new ComboPooledDataSource();
		dataSource.setDriverClass("com.mysql.jdbc.Driver");
		dataSource.setJdbcUrl("jdbc:mysql:///crm");
		dataSource.setUser("root");
		dataSource.setPassword("123456");
		
		//1.创建JDBC模版对象
		JdbcTemplate jt = new JdbcTemplate();
		jt.setDataSource(dataSource);
		
		//2.书写sql，并执行
		String sql = "insert into t_user values(3,\'legend\')";
		jt.update(sql);
		System.out.println("执行完毕");
	}
	
	
}