spring操作数据库

1、JdbcTemplate

spring对数据库的操作在jdbc上做了更深层次的封装JdbcTemplate，处理了资源的建立和释放(不需要我们管理连接了),我们只需要提供SQL语句(不需要我们设置参数了)和提取结果(查询时候可以直接返回对应的实体类),使JDBC更加易于使用。它也可以使用spring的注入功能，将数据源注入JdbcTemplate，来实现操作数据库。

2、JdbcTemplate常用方法

• update(更新数据)
• batchUpdate(批量更新数据)
• queryForObject(查询单行数据或者单值数据)
• query(查询多行数据)

3、Spring中实现jdbcTemplate对数据库操作(采用c3p0连接池)

1、需要导入的jar包

• spring-jdbc-5.0.6.RELEASE.jar
• spring-tx-5.0.6.RELEASE.jar
• mysql-connector-java-5.0.7.jar
• c3p0-0.9.5.2.jar

2、springxml配置

    <context:property-placeholder
    		location="classpath:jdbc.properties" />
    	<!-- 配置c3p0数据源 -->
    	<bean id="dataSource"
    		class="com.mchange.v2.c3p0.ComboPooledDataSource">
    		<property name="user" value="${jdbc.user}"></property>
    		<property name="password" value="${jdbc.password}"></property>
    		<property name="driverClass" value="${jdbc.driverClass}"></property>
    		<property name="jdbcUrl" value="${jdbc.jdbcUrl}"></property>
    	</bean>
    
    	<!-- 将c3p0数据源注入jdbcTemplate -->
    	<bean id="jdbcTemplate"
    		class="org.springframework.jdbc.core.JdbcTemplate">
    		<property name="dataSource" ref="dataSource"></property>
    	</bean>

3、User实体类

    public class User {
    
    	private int id;
    	private String username;
    	private String password;
    
    	public User() {
    		super();
    	}
    
    	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 "User [id=" + id + ", username=" + username + ", password=" + password + "]";
    	}
    
    }

4、测试类

    public void testUserServiceImpl() {
    		//获取IOC容器
    		ApplicationContext context = new ClassPathXmlApplicationContext("bean.xml");	
    		
    		//通过ApplicationContext对象的getBean方法来获取对象实例
    		//获取数据连接模板JdbcTemplate
    		JdbcTemplate jdbcTemplate = (JdbcTemplate) context.getBean("jdbcTemplate");
    		
    		//增加
    		String sql1 = "insert into user(username,password) values(?,?)";
    		System.out.println(jdbcTemplate.update(sql1, "user","user123"));
    		
    		//修改
    		String sql2 = "update user set username = ? where id = 10000";
    		System.out.println(jdbcTemplate.update(sql2, "adminadmin"));
    		
    		//查询基本数据
    		String sql3 = "select count(*) from user";
    		System.out.println(jdbcTemplate.queryForObject(sql3, Integer.class));
    		
    		//查询单条记录
    		String sql4 = "select * from user where id = 10000";
    		RowMapper<User> rowMapper = new BeanPropertyRowMapper<>(User.class);
    		User user = jdbcTemplate.queryForObject(sql4, rowMapper);
    		System.out.println(user);
    		
    		//查询多条记录
    		String sql5 = "select * from user";
    		List<User> list = jdbcTemplate.query(sql5, rowMapper);
    		for (User user2 : list) {
    			System.out.println(user2);
    		}
    		
    		//批量插入
    		String sql6 = "insert into user(username,password) values(?,?)";
    		List<Object[]> batchArgs=new ArrayList<Object[]>();
    		batchArgs.add(new Object[]{"aaaa","aaa123"});
    		batchArgs.add(new Object[]{"bbbb","bbb123"});
    		batchArgs.add(new Object[]{"cccc","ccc123"});
    		jdbcTemplate.batchUpdate(sql6, batchArgs);
    	}