12 Spring JdbcTemplate的使用

1.项目搭建

<1>数据库表account对应的账户实体类

package domain;

import java.io.Serializable;

/**
 * 账户实体类
 */
public class Account implements Serializable {
    private Integer id;
    private String name;
    private Float money;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Float getMoney() {
        return money;
    }

    public void setMoney(Float money) {
        this.money = money;
    }

    @Override
    public String toString() {
        return "Account{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", money=" + money +
                '}';
    }
}

<2>账户的持久层接口及其实现类

接口类 IAccountDao

package dao;
import domain.Account;

/**
 * 账户的持久层接口
 */
public interface IAccountDao {

    /**
     * 根据Id查询账户
     * @param accountId
     * @return
     */
    Account findAccountById(Integer accountId);

    /**
     * 根据名称查询账户
     * @param accountName
     * @return
     */
    Account findAccountByName(String accountName);

    /**
     * 更新账户
     * @param account
     */
    void updateAccount(Account account);
}

AccountDaoImpl.java

package dao.impl;
import dao.IAccountDao;
import domain.Account;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.support.JdbcDaoSupport;

import java.util.List;

/**
 * 账户的持久层实现类
 */
public class AccountDaoImpl extends JdbcDaoSupport implements IAccountDao {

    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);
    }

    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);
    }

    public void updateAccount(Account account) {
        super.getJdbcTemplate().update("update account set name=?,money=? where id=?",account.getName(),account.getMoney(),account.getId());
    }
}

2.JdbcTemplate的使用

<1>JdbcTemplate最基本用法

package jdbcTemplate;

import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.datasource.DriverManagerDataSource;

/**
 * JdbcTemplate最基本用法
 */
public class JdbcTemplateTest01 {
    public static void main(String[] args) {
        //1.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/spring");
        ds.setUsername("root");
        ds.setPassword("plj824");

        //2.创建jdbcTemplate对象
        JdbcTemplate jdbcTemplate=new JdbcTemplate();
        //3.给jdbcTemplate对象设置数据源
        jdbcTemplate.setDataSource(ds);
        //2.执行操作
        jdbcTemplate.execute("insert into account(name,money)values ('ccc',1000)");
    }
}

<2>JdbcTemplate 用IOC进行依赖注入

package jdbcTemplate;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.datasource.DriverManagerDataSource;

/**
 * JdbcTemplate 用IOC进行依赖注入
 */
public class JdbcTemplateTest02 {
    public static void main(String[] args) {
        //1.获取容器
        ApplicationContext applicationContext=new ClassPathXmlApplicationContext("bean.xml");
        //2.获取对象
        JdbcTemplate jdbcTemplate = applicationContext.getBean("jdbcTemplate", JdbcTemplate.class);

        //3.执行操作
        jdbcTemplate.execute("insert into account(name,money)values ('eee',1250)");
    }
}

<3>JdbcTemplate的CRUD操作

package jdbcTemplate;

import domain.Account;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;

/**
 * JdbcTemplate的CRUD操作
 */
public class JdbcTemplateTest03 {
    public static void main(String[] args) {
        //1.获取容器
        ApplicationContext applicationContext=new ClassPathXmlApplicationContext("bean.xml");
        //2.获取对象
        JdbcTemplate jdbcTemplate = applicationContext.getBean("jdbcTemplate", JdbcTemplate.class);

        //3.执行操作
        //3.1保存
        //jdbcTemplate.update("insert into account(name,money)values ('eee',1250)");

        //3.2 更新
        //jdbcTemplate.update("update account set name=?,money=? where id=?","test",4567,6);

        //3.3 删除
        //jdbcTemplate.update("delete  from account where id=? ",4);

        //3.4 查询所有
//        List<Account> accounts = jdbcTemplate.query("select * from account where money > ?", new AccountRowMapper(), 1000f);
//        for (Account account : accounts) {
//            System.out.println(account);
//        }

//        //查询一个
//        List<Account> accounts = jdbcTemplate.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 = jdbcTemplate.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
     */
    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>bean.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.xsd">

    <!--配置账户的持久层-->
    <bean id="accountDao" class="dao.impl.AccountDaoImpl">
        <property name="dataSource" ref="dataSource"></property>
    </bean>

    <!--配置jdbcTemplate,注意：JdbcTemplate这个类是在jar包中，无法使用setter方法进行注入，只能用xml配置-->
    <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/spring"></property>
        <property name="username" value="root"></property>
        <property name="password" value="plj824"></property>
    </bean>
</beans>