Spring学习——JDBC数据库操作

JDBC Java数据库连接(Java Data Base Connectivity)，是一种执行SQL语句的API，提供关系型数据库的统一访问

1、配置beans.xml配置文件
      需要jar包 spring-jdbc-release.jar 、mysql-connect-java.jar
   

<!-- 初始化数据库配置文件 -->
   <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
      <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
      <property name="url" value="jdbc:mysql://localhost:3306/test"/>
      <property name="username" value="root"/>
      <property name="password" value=""/>
   </bean>

 <!-- 注册jdbc核心实现类 -->
   <bean id="userJdbcTemplate" class="com.spring.jdbc.demo.UserJdbcTemplate" >
           <!-- 注入数据库配置文件 不然在实现时报空指针-->
           <property name="dataSource"  ref="dataSource" /> 
   </bean>

2、核心实现类

private JdbcTemplate jdbcTemplate;
    
    private DataSource dataSource;
    //JdbcTemplate 需要提供jdbc配置数据，否则使用时空指针异常
    public void setDataSource(DataSource dataSource) {
        this.dataSource = dataSource;
        this.jdbcTemplate = new JdbcTemplate(dataSource);
    }

3、JdbcTemplate程序执行

    1>JdbcTemplate操作数据库分两种:更新数据库(insert,update,delete)和查询数据库(select)
    2>sql语句,可以使用"id = ?" 和  "id = "+ id 两种
        "id = ?"    在jdbcTemplate执行操作时,需要另赋值;
        "id = "+ id 只需要执行SQL便可

 4、JdbcTemplate查询操作

/*方法一重写
		List<UserPO> list = jdbcTemplate.query(sql,new RowMapper() {
			
			public UserPO mapRow(ResultSet rs, int rownum) throws SQLException {
				UserPO user = new UserPO();
				user.setId(rs.getInt("id"));
				user.setPassword(rs.getString("password"));
				user.setUsername(rs.getString("username"));
				return user;
			}
		});
		*/

/*方法二自定义
		List<UserPO> list = jdbcTemplate.query(sql, new UserMapper());
		*/


package com.spring.jdbc.demo;

import java.sql.ResultSet;
import java.sql.SQLException;

import org.springframework.jdbc.core.RowMapper;

public class UserMapper implements RowMapper<UserPO>{

	@Override
	public UserPO mapRow(ResultSet rs, int rownum) throws SQLException {
		UserPO user = new UserPO();
		user.setId(rs.getInt("id"));
		user.setUsername(rs.getString("username"));
		user.setPassword(rs.getString("password"));
		return user;
	}
	
}

/*
    使用list<map>查询后转化为目标对象
 */
List<Map<String, Object>> mapList = jdbcTemplate.queryForList(sql);
		List<UserPO> list = new ArrayList();
		for (int i = 0; i < mapList.size(); i++) {
			UserPO user = new UserPO();
			user.setId((Integer)mapList.get(i).get("id"));
			user.setUsername(mapList.get(i).get("username").toString());
			user.setPassword(mapList.get(i).get("password").toString());
			list.add(user);
		}
		return list;

JDBCBeans.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-3.0.xsd ">

   <!-- 初始化数据库配置文件 -->
   <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
      <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
      <property name="url" value="jdbc:mysql://localhost:3306/test"/>
      <property name="username" value="root"/>
      <property name="password" value=""/>
   </bean>
	
	<!-- 配置jdbc实现类 -->
   <bean id="userJdbcTemplate" class="com.spring.jdbc.demo.UserJdbcTemplate" >
   		<!-- 注入数据库配置文件 -->
   		<property name="dataSource"  ref="dataSource" /> 
   </bean>
      

</beans>

UserJdbcTemplate.java 核心操作类

package com.spring.jdbc.demo;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import javax.sql.DataSource;

import org.springframework.jdbc.core.JdbcTemplate;

public class UserJdbcTemplate{
	
	private JdbcTemplate jdbcTemplate;
	//@Autowired
	private DataSource dataSource;
	
	//@ConstructorProperties("dataSource")
	public void setDataSource(DataSource dataSource) {
		this.dataSource = dataSource;
		this.jdbcTemplate = new JdbcTemplate(dataSource);
	}
	
	public int createUser(UserPO user) {
		//System.out.println(user.getUsername()+";"+user.getPassword());
		String sql = "insert into user(username,password) values(?,?)";
		int rownum = jdbcTemplate.update(sql,user.getUsername(),user.getPassword());
		return rownum;
	}

	
	public int deleteUserById(int id) {
		String sql = "delete table user where id = ?";
		int rownum = jdbcTemplate.update(sql,id);
		return rownum;
	}

	
	public int updateUserById(UserPO user) {
		String sql ="update user set username=?,password=? where id = ?";
		int rownum = jdbcTemplate.update(sql, user.getUsername(),user.getPassword(),user.getId());
		return rownum;
	}

	
	public List<UserPO> getUserListAll() {
		String sql = "select * from user";
		/*方法一重写
		List<UserPO> list = jdbcTemplate.query(sql,new RowMapper() {
			
			public UserPO mapRow(ResultSet rs, int rownum) throws SQLException {
				UserPO user = new UserPO();
				user.setId(rs.getInt("id"));
				user.setPassword(rs.getString("password"));
				user.setUsername(rs.getString("username"));
				return user;
			}
		});
		*/
		/*方法二自定义
		List<UserPO> list = jdbcTemplate.query(sql, new UserMapper());
		*/
		List<Map<String, Object>> mapList = jdbcTemplate.queryForList(sql);
		List<UserPO> list = new ArrayList();
		for (int i = 0; i < mapList.size(); i++) {
			UserPO user = new UserPO();
			user.setId((Integer)mapList.get(i).get("id"));
			user.setUsername(mapList.get(i).get("username").toString());
			user.setPassword(mapList.get(i).get("password").toString());
			list.add(user);
		}
		return list;
	}

	
	public UserPO getUserById(Integer id) {
		String sql = "select * from user where id = ?";
		//UserPO user = (UserPO) jdbcTemplate.query(sql,new Object[]{id},new UserMapper());
		
		//Object obj =jdbcTemplate.queryForObject(sql, UserPO.class,id);
		List<Map<String, Object>> mapList = jdbcTemplate.queryForList(sql,id);
		List<UserPO> list = new ArrayList();
		for (int i = 0; i < mapList.size(); i++) {
			UserPO user = new UserPO();
			user.setId((Integer)mapList.get(i).get("id"));
			user.setUsername(mapList.get(i).get("username").toString());
			user.setPassword(mapList.get(i).get("password").toString());
			list.add(user);
		}
		return list.get(0);
	}
	
}

PO类

package com.spring.jdbc.demo;

public class UserPO {
	private int id;
	private String username;
	private String password;
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getUsername() {
		return username;
	}
	public void setUsername(String username) {
		this.username = username;
	}
	public String getPassword() {
		return password;
	}
	public void setPassword(String password) {
		this.password = password;
	}
	@Override
	public String toString() {
		return "UserPO [id=" + id + ", username=" + username + ", password=" + password + "]";
	}
	
}

主函数

package com.spring.jdbc.demo;

import java.util.List;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class SpringMain {
	public static void main(String[] args){
		ApplicationContext context = new ClassPathXmlApplicationContext("JDBCBeans.xml");
		UserJdbcTemplate ujt = (UserJdbcTemplate) context.getBean("userJdbcTemplate");
		
		UserPO user = new UserPO();
		user.setUsername("lg");
		user.setPassword("12345");
		int rownum = ujt.createUser(user);
		
		user.setUsername("zdj");
		user.setPassword("12345");
		rownum += ujt.createUser(user);
		
		user.setUsername("zh");
		user.setPassword("12345");
		rownum += ujt.createUser(user);
		System.out.println("插入条数："+rownum);
		
		List<UserPO> list = ujt.getUserListAll();
		for(UserPO u : list){
			System.out.println(u.toString());
		}
		System.out.println("----------------");
		user.setId(1);
		user.setUsername("hm");
		rownum = ujt.updateUserById(user);
		user = ujt.getUserById(1);
		System.out.println(user);
	}
}