Spring JdbcTemplate

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JdbcTemplate 概述

它是 Spring 框架中提供的一个对象，是对原始 Jdbc API 对象的简单封装。Spring 框架提供了很多的操作模板类。

操作关系型数据的：JdbcTemplate、HibernateTemplate

操作 NoSQL 数据库的：RedisTemplate

操作消息队列的：JmsTemplate

要使用 JdbcTemplate，需要 spring-jdbc 包。

JdbcTemplate CRUD

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"

       xmlns:context="http://www.springframework.org/schema/context"

       xsi:schemaLocation="http://www.springframework.org/schema/beans

        https://www.springframework.org/schema/beans/spring-beans.xsd

        http://www.springframework.org/schema/context

        https://www.springframework.org/schema/context/spring-context.xsd">

    <context:component-scan base-package="cn.parzulpan"/>

    <!-- 添加继承 JdbcDaoSupport 的实现类到容器，并注入 jdbcTemplate-->

    <bean id="accountDAO2" class="cn.parzulpan.dao.AccountDAOImpl2">

        <property name="jdbcTemplate" ref="jdbcTemplate"/>

    </bean>

    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">

        <property name="dataSource" ref="dataSource"/>

    </bean>

    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">

        <property name="driverClassName" value="com.mysql.jdbc.Driver"/>

        <property name="url" value="jdbc:mysql://localhost:3306/springT?useSSL=false"/>

        <property name="username" value="root"/>

        <property name="password" value="root"/>

    </bean>

</beans>

JdbcTemplate 对象的创建和基本使用：

package cn.parzulpan;

import org.springframework.context.support.ClassPathXmlApplicationContext;

import org.springframework.jdbc.core.JdbcTemplate;

/**

 * @Author : parzulpan

 * @Time : 2020-12

 * @Desc : JdbcTemplate 对象的创建和基本使用

 */

public class JdbcTemplateTest {

    public static void main(String[] args) {

        ClassPathXmlApplicationContext ac = new ClassPathXmlApplicationContext("bean.xml");

        JdbcTemplate jt = ac.getBean("jdbcTemplate", JdbcTemplate.class);

        jt.execute("insert into bankAccount(name, money) values ('caf', 25415.6)");

    }

}

AccountDAOImpl.java

package cn.parzulpan.dao;

import domain.Account;

import org.springframework.jdbc.core.BeanPropertyRowMapper;

import org.springframework.jdbc.core.JdbcTemplate;

import org.springframework.stereotype.Repository;

import javax.annotation.Resource;

import java.util.List;

/**

 * @Author : parzulpan

 * @Time : 2020-12

 * @Desc : 账户持久层实现类，这种方式即可以实现注解配置，也可以使用 xml 配置

 */

@Repository("accountDAO")

public class AccountDAOImpl implements AccountDAO {

    @Resource(name = "jdbcTemplate")

    JdbcTemplate jdbcTemplate;

    @Override

    public List<Account> findAll() {

        return jdbcTemplate.query("select * from bankAccount",

                new BeanPropertyRowMapper<>(Account.class));

    }

    @Override

    public Account findById(Integer id) {

        List<Account> accounts = jdbcTemplate.query("select * from bankAccount where id = ?",

                new BeanPropertyRowMapper<>(Account.class),

                id);

        return accounts.isEmpty() ? null : accounts.get(0);

    }

    @Override

    public Account findByName(String name) {

        List<Account> accounts = jdbcTemplate.query("select * from bankAccount where name = ?",

                new BeanPropertyRowMapper<>(Account.class),

                name);

        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 update(Account account) {

        jdbcTemplate.update("update bankAccount set name = ? , money = ? where id = ?",

                account.getName(), account.getMoney(), account.getId());

    }

    @Override

    public void insert(Account account) {

        jdbcTemplate.update("insert into bankAccount(name, money) values (?, ?)",

                account.getName(), account.getMoney());

    }

    @Override

    public void delete(Integer id) {

        jdbcTemplate.update("delete from bankAccount where id = ?",

                id);

    }

    @Override

    public Long getCount() {

        return jdbcTemplate.queryForObject("select count(*) from bankAccount;",

                Long.class);

    }

}

AccountDAOImpl2.java

package cn.parzulpan.dao;

import domain.Account;

import org.springframework.jdbc.core.BeanPropertyRowMapper;

import org.springframework.jdbc.core.support.JdbcDaoSupport;

import org.springframework.stereotype.Repository;

import java.util.List;

/**

 * @Author : parzulpan

 * @Time : 2020-12

 * @Desc : 账户持久层实现类，继承 JdbcDaoSupport

 *

 * JdbcDaoSupport 是 Spring 框架提供的一个类，该类中定义了一个 JdbcTemplate 对象，

 * 可以直接获取使用，但是要想创建该对象，需要为其提供一个数据源。

 *

 * 这种的好处是当有很多个 DAO 时，不需要注入很多 jdbcTemplate

 *

 * 注意：这种方式只能使用 xml 配置，因为 JdbcDaoSupport 中已经定义了 jdbcTemplate，且提供其 setter

 */

public class AccountDAOImpl2 extends JdbcDaoSupport implements AccountDAO {

    @Override

    public List<Account> findAll() {

        return super.getJdbcTemplate().query("select * from bankAccount",

                new BeanPropertyRowMapper<>(Account.class));

    }

    @Override

    public Account findById(Integer id) {

        List<Account> accounts = getJdbcTemplate().query("select * from bankAccount where id = ?",

                new BeanPropertyRowMapper<>(Account.class),

                id);

        return accounts.isEmpty() ? null : accounts.get(0);

    }

    @Override

    public Account findByName(String name) {

        List<Account> accounts = getJdbcTemplate().query("select * from bankAccount where name = ?",

                new BeanPropertyRowMapper<>(Account.class),

                name);

        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 update(Account account) {

        getJdbcTemplate().update("update bankAccount set name = ? , money = ? where id = ?",

                account.getName(), account.getMoney(), account.getId());

    }

    @Override

    public void insert(Account account) {

        getJdbcTemplate().update("insert into bankAccount(name, money) values (?, ?)",

                account.getName(), account.getMoney());

    }

    @Override

    public void delete(Integer id) {

        getJdbcTemplate().update("delete from bankAccount where id = ?",

                id);

    }

    @Override

    public Long getCount() {

        return getJdbcTemplate().queryForObject("select count(*) from bankAccount;",

                Long.class);

    }

}

AccountDAOImplTest.java

package cn.parzulpan.dao;

import domain.Account;

import org.junit.Test;

import org.springframework.context.support.ClassPathXmlApplicationContext;

import java.util.List;

/**

 * @Author : parzulpan

 * @Time : 2020-12

 * @Desc : 账户持久层实现类的测试

 */

public class AccountDAOImplTest {

    ClassPathXmlApplicationContext ac = new ClassPathXmlApplicationContext("bean.xml");

//    AccountDAO ad = ac.getBean("accountDAO1", AccountDAO.class);

    AccountDAO ad = ac.getBean("accountDAO2", AccountDAO.class);

    @Test

    public void findAll() {

        List<Account> accounts = ad.findAll();

        for (Account account : accounts) {

            System.out.println(account);

        }

    }

    @Test

    public void findById() {

        Account account = ad.findById(1);

        System.out.println(account);

    }

    @Test

    public void findByName() {

        Account account = ad.findByName("aaa");

        System.out.println(account);

    }

    @Test

    public void update() {

        ad.update(new Account(6, "update", 214.0));

    }

    @Test

    public void insert() {

        ad.insert(new Account(99, "insert", 3125616.425));

    }

    @Test

    public void delete() {

        ad.delete(7);

    }

    @Test

    public void getCount() {

        Long count = ad.getCount();

        System.out.println(count);

    }

}

巴特西

【Spring】Spring JdbcTemplate

Spring JdbcTemplate

JdbcTemplate 概述

JdbcTemplate CRUD

总结和练习

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