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spring学习笔记（二）

admin 11月 12, 2020 0

DAO（Data Access Object）代表数据访问对象，它一般会包含一些数据访问的接口，针对接口做出不同实现。

ORM（Object Relation Mapping）代表对象关系映射，将数据库种的一行记录转换为一个Java对象。

DataSource配置

<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
    <property name="driverClassName" value="${jdbc.driverClassName}"/>
    <property name="url" value="${jdbc.url}"/>
    <property name="username" value="${jdbc.username}"/>
    <property name="password" value="${jdbc.password}"/>
</bean>
<context:property-placeholder location="db.properties"/>

<bean id="headerProperties" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
    <property name="location" value="classpath:db.properties" />
</bean>

JdbcTemplate

// 查
int rowCount = this.jdbcTemplate.queryForObject(
        "select count(*) from user", Integer.class);
int countOfNameJoe = this.jdbcTemplate.queryForObject(
		"select count(*) from user where first_name = ?", 
		Integer.class, "Joe"_);
String lastName = this.jdbcTemplate.queryForObject(
		"select last_name from user where id = ?",
		new Object[]{1212L}, String.class);
// 增
this.jdbcTemplate.update(
	"insert into user (first_name, last_name) values (?, ?)",
	"Meimei", "Han");
// 改
this.jdbcTemplate.update(
	"update user set last_name = ? where id = ?", "Li", 5276L);
// 删
this.jdbcTemplate.update(
	"delete from user where id = ?", Long.valueOf(userId));
// 创建表
this.jdbcTemplate.execute("create table user (id integer,
    first_name varchar(100), last_name varchar(100))");