【Spring笔记】六、JdbcTemplate

JdbcTemplate

JdbcTemplate是Spring框架中提供的一个对象，是对原始繁琐的JDBC API对象的简单封装，Spring框架提供了很多操作模板类。如：操作关系型数据的JdbcTemplate和HibernateTemplate，操作nosql数据库的RedisTemplate了，操作消息队列的JmsTemplate等

导入spring-jdbc和spring-tx的依赖创建数据库表和实体创建JDBCTemplate对象执行数据库操作

增删改，用update方法查询，多个用query方法，单个用queryForObject方法，需传入BeanPropertyRowMapper的泛型对象以自动将查询结果注入新建对象并返回

1、导入spring-jdbc和spring-tx的依赖

pom.xml

  org.springframework
  spring-jdbc
  5.0.5.RELEASE


  org.springframework
  spring-tx
  5.0.5.RELEASE

2、创建数据库表和实体

create table account(
	id int primary key auto_increment,
	name varchar(20) ,
    money decimal(20,2)
)

Account.java

public class Account {
    private String name;
    private double money;
    //....省略get、set、toString

3、4

    public void test1(){
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setDriverClassName("com.mysql.jdbc.Driver");
        dataSource.setUrl("jdbc:mysql://localhost:3306/test");
        dataSource.setUsername("root");
        dataSource.setPassword("123456");
//		3、创建JDBCTemplate对象
        JdbcTemplate jdbcTemplate = new JdbcTemplate();
//        设置数据源对象
        jdbcTemplate.setDataSource(dataSource);
//      4、执行操作
        int update = jdbcTemplate.update("insert into account(name,money) value(?,?)", "tom", 5000);
        System.out.println(update);
    }

applicationContext.xml下配置bean

jdbc.properties文件

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/test
jdbc.username=root
jdbc.password=123456

applicationContext.xml的beans标签头添加context命名空间

xmlns:context="http://www.springframework.org/schema/context"
 xsi:schemaLocation="http://www.springframework.org/schema/context  http://www.springframework.org/schema/context/spring-context.xsd"

抽取jdbc配置文件并配置数据源、模板对象**（重点）**

测试代码

public void test2(){
    ClassPathXmlApplicationContext app = new ClassPathXmlApplicationContext("applicationContext.xml");
    JdbcTemplate jdbcTemplate = app.getBean(JdbcTemplate.class);
    int update = jdbcTemplate.update("insert into account(name,money) value(?,?)", "zoe", 15000);
    System.out.println(update);
}

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:applicationContext.xml")
public class JdbcTemplateCRUDTest {
    @Autowired
    private JdbcTemplate jdbcTemplate;
    //更新
    @Test
    public void testUpdate(){
        jdbcTemplate.update("update account set money = ? where id = ?",6666,2);
    }
    //删除
    @Test
    public void testDelete(){
        jdbcTemplate.update("delete from account where id = ?",3);
    }
    //查询一个
    @Test
    public void testQueryOne(){
        Account account = jdbcTemplate.queryForObject("select * from account where id = ?", new BeanPropertyRowMapper(Account.class), 2);
        System.out.println(account);
    }
    //查询多个
    @Test
    public void testQueryAll(){
        List accountList = jdbcTemplate.query("select * from account", new BeanPropertyRowMapper(Account.class));
        System.out.println(accountList);
    }
    //查询特殊值
    @Test
    public void testQueryCount(){
        Long count = jdbcTemplate.queryForObject("select count(*) from account", Long.class);
        System.out.println("count = " + count);
    }    
}

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