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Spring jdbcTemplate使用到的spring包
1.最简单用法 (开发时,不常用)
/**
* JdbcTemplate的最基本用法
*/
public class JdbcTemplateDemo1 {
public static void main(String[] args) {
//准备数据源:spring的内置数据源
DriverManagerDataSource ds = new DriverManagerDataSource();
ds.setDriverClassName("com.mysql.jdbc.Driver");
ds.setUrl("jdbc:mysql://localhost:3306/test");
ds.setUsername("root");
ds.setPassword("root");
//1.创建JdbcTemplate对象
JdbcTemplate jt = new JdbcTemplate();
//给jt设置数据源
jt.setDataSource(ds);
//2.执行操作
jt.execute("insert into account(name,money)values('ccc',1000)");
}
}
2.在Bean.xml内配置数据源
public class JdbcTemplateDemo2 {
public static void main(String[] args) {
//1.获取容器
ApplicationContext ac = new ClassPathXmlApplicationContext("bean.xml");
//2.获取对象
JdbcTemplate jt = ac.getBean("jdbcTemplate",JdbcTemplate.class);
//3.执行操作
jt.execute("insert into account(name,money)values('ddd',2222)");
/* //准备数据源:spring的内置数据源
DriverManagerDataSource ds = new DriverManagerDataSource();
ds.setDriverClassName("com.mysql.jdbc.Driver");
ds.setUrl("jdbc:mysql://localhost:3306/eesy");
ds.setUsername("root");
ds.setPassword("1234");
//1.创建JdbcTemplate对象
JdbcTemplate jt = new JdbcTemplate();
//给jt设置数据源
jt.setDataSource(ds);
//2.执行操作
jt.execute("insert into account(name,money)values('ccc',1000)");*/
}
}
<?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.xsd">
<!--配置JdbcTemplate-->
<bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
<property name="dataSource" ref="dataSource"></property>
</bean>
<!-- 配置数据源-->
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
<property name="url" value="jdbc:mysql://localhost:3306/eesy"></property>
<property name="username" value="root"></property>
<property name="password" value="1234"></property>
</bean>
</beans>
3.jdbcTemplate增删改操作
/**
* JdbcTemplate的CRUD操作
*/
public class JdbcTemplateDemo3 {
public static void main(String[] args) {
//1.获取容器
ApplicationContext ac = new ClassPathXmlApplicationContext("bean.xml");
//2.获取对象
JdbcTemplate jt = ac.getBean("jdbcTemplate",JdbcTemplate.class);
//3.执行操作
//保存
// jt.update("insert into account(name,money)values(?,?)","eee",3333f);
//更新
// jt.update("update account set name=?,money=? where id=?","test",4567,7);
//删除
// jt.update("delete from account where id=?",8);
//查询所有
// List<Account> accounts = jt.query("select * from account where money > ?",new AccountRowMapper(),1000f);
// List<Account> accounts = jt.query("select * from account where money > ?",new BeanPropertyRowMapper<Account>(Account.class),1000f);
// for(Account account : accounts){
// System.out.println(account);
// }
//查询一个
// List<Account> accounts = jt.query("select * from account where id = ?",new BeanPropertyRowMapper<Account>(Account.class),1);
// System.out.println(accounts.isEmpty()?"没有内容":accounts.get(0));
//查询返回一行一列(使用聚合函数,但不加group by子句)
Long count = jt.queryForObject("select count(*) from account where money > ?",Long.class,1000f);
System.out.println(count);
}
}
/**
* 定义Account的封装策略
*/
class AccountRowMapper implements RowMapper<Account>{
/**
* 把结果集中的数据封装到Account中,然后由spring把每个Account加到集合中
* @param rs
* @param rowNum
* @return
* @throws SQLException
*/
@Override
public Account mapRow(ResultSet rs, int rowNum) throws SQLException {
Account account = new Account();
account.setId(rs.getInt("id"));
account.setName(rs.getString("name"));
account.setMoney(rs.getFloat("money"));
return account;
}
}
4.web应用开发常用方法
/**
* JdbcTemplate的最基本用法
*/
public class JdbcTemplateDemo4 {
public static void main(String[] args) {
//1.获取容器
ApplicationContext ac = new ClassPathXmlApplicationContext("bean.xml");
//2.获取对象
IAccountDao accountDao = ac.getBean("accountDao",IAccountDao.class);
Account account = accountDao.findAccountById(1);
System.out.println(account);
account.setMoney(30000f);
accountDao.updateAccount(account);
}
}
/**
* 账户的持久层实现类
*/
@Repository
public class AccountDaoImpl2 implements IAccountDao {
@Autowired
private JdbcTemplate jdbcTemplate;
@Override
public Account findAccountById(Integer accountId) {
List<Account> accounts = jdbcTemplate.query("select * from account where id = ?",new BeanPropertyRowMapper<Account>(Account.class),accountId);
return accounts.isEmpty()?null:accounts.get(0);
}
@Override
public Account findAccountByName(String accountName) {
List<Account> accounts = jdbcTemplate.query("select * from account where name = ?",new BeanPropertyRowMapper<Account>(Account.class),accountName);
if(accounts.isEmpty()){
return null;
}
if(accounts.size()>1){
throw new RuntimeException("结果集不唯一");
}
return accounts.get(0);
}
@Override
public void updateAccount(Account account) {
jdbcTemplate.update("update account set name=?,money=? where id=?",account.getName(),account.getMoney(),account.getId());
}
}
Bean.xml配置 继承的jdbcTemplate
<?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.xsd">
<!-- 配置账户的持久层-->
<bean id="accountDao" class="com.itheima.dao.impl.AccountDaoImpl">
<property name="dataSource" ref="dataSource"></property>
</bean>
<!-- 配置数据源-->
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
<property name="url" value="jdbc:mysql://localhost:3306/eesy"></property>
<property name="username" value="root"></property>
<property name="password" value="1234"></property>
</bean>
</beans>
有个小问题。就是我们的 dao 有很多时,每个 dao 都有一些重复性的代码。下面就是重复代码:
private JdbcTemplate jdbcTemplate;
public void setJdbcTemplate(JdbcTemplate jdbcTemplate)
{
this.jdbcTemplate = jdbcTemplate;
}
抽取出来修改如下:
/**
* 账户的持久层实现类
* 继承KdbcDapSupport 父类已经有了上述重复代码
*/
public class AccountDaoImpl extends JdbcDaoSupport implements IAccountDao {
@Override
public Account findAccountById(Integer accountId) {
List<Account> accounts = super.getJdbcTemplate().query("select * from account where id = ?",new BeanPropertyRowMapper<Account>(Account.class),accountId);
return accounts.isEmpty()?null:accounts.get(0);
}
@Override
public Account findAccountByName(String accountName) {
List<Account> accounts = super.getJdbcTemplate().query("select * from account where name = ?",new BeanPropertyRowMapper<Account>(Account.class),accountName);
if(accounts.isEmpty()){
return null;
}
if(accounts.size()>1){
throw new RuntimeException("结果集不唯一");
}
return accounts.get(0);
}
@Override
public void updateAccount(Account account) {
super.getJdbcTemplate().update("update account set name=?,money=? where id=?",account.getName(),account.getMoney(),account.getId());
}
}```
```java
/**
* 继承了JdbcDaoSupport,因为父类不是我们自己写的
* 因此无法修改,无法使用注解配置,要用Bean.xml,
* 但是自己写一个JdbcDaoSupport,就可以避免这些问题了
* 此类用于抽取dao中的重复代码
*/
public class JdbcDaoSupport {
private JdbcTemplate jdbcTemplate;
public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
this.jdbcTemplate = jdbcTemplate;
}
public JdbcTemplate getJdbcTemplate() {
return jdbcTemplate;
}
public void setDataSource(DataSource dataSource) {
if(jdbcTemplate == null){
jdbcTemplate = createJdbcTemplate(dataSource);
}
}
private JdbcTemplate createJdbcTemplate(DataSource dataSource){
return new JdbcTemplate(dataSource);
}
}