Spring中的JdbcTemplate_setjdbctemplate-优快云博客

本文链接：https://blog.youkuaiyun.com/qq_43085979/article/details/105881289

作用：
用于和数据库交互的，实现对表大CRUD操作。
基于JdbcTemplate对象的创建以及其中的常用方法应用测试如下：
实体类：

public class Account implements Serializable {
    private Integer id;
    private String name;
    private Float money;

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

测试一：JdbcTemplate的基本用法

/*
* jdbctemplate的基本用法*/
public class JdbcTemplateDemo1 {
    public static void main(String[] args) {
        //准备数据源 spring内置数据源
        DriverManagerDataSource ds = new DriverManagerDataSource();
        ds.setDriverClassName("com.mysql.jdbc.Driver");
        ds.setUrl("jdbc:mysql://localhost:3307/spring");
        ds.setUsername("root");
        ds.setPassword("123");

        //1.创建jdbc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('aiyaya',122)");
    }
}

测试二：使用配置文件

<?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
       					   ">

    <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:3307/spring"></property>
        <property name="username" value="root"></property>
        <property name="password" value="123"></property>
    </bean>

</beans>

public class JdbcTemplateDemo2 {
    public static void main(String[] args) {

        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("bean.xml");
        JdbcTemplate jt=(JdbcTemplate)applicationContext.getBean("jdbctemplate",JdbcTemplate.class);
        //执行操作
        jt.execute("delete from account where id=6");
    }
}

测试三：jdbctemplate的CRUD操作

public class JdbcTemplateDemo3 {
    public static void main(String[] args) {

        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("bean.xml");
        JdbcTemplate jt=(JdbcTemplate)applicationContext.getBean("jdbctemplate",JdbcTemplate.class);
        //执行操作
        //保存
//        jt.update("INSERT into Account(name,money)VALUES (?,?)","eee",342f);
        //更新
        //jt.update("UPDATE account SET name=?,money= ? WHERE id=?","茶茶",123f,3);
        //删除
        //查询所有    也可以用  new AccountRowMapper()
     /* List<Account> accounts = jt.query("select * from account where money >?",new BeanPropertyRowMapper<Account>(Account.class),298f);
       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),3);
        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，但是不加group by子句）
        Long count =jt.queryForObject("select count(*) from account where money >?",Long.class,100f);
        System.out.println(count);
    }
}
//定义account的封装工具策略，
class AccountRowMapper implements RowMapper<Account>{
   //含义：把结果集的数据封装到Account中，由spring把每个Account加到集合中去
    @Override
    public Account mapRow(ResultSet rs, int i) throws SQLException {
        Account account = new Account();
        account.setId(rs.getInt("id"));
        account.setName(rs.getString("name"));
        account.setMoney(rs.getFloat("money"));
        return account;
    }
}

测试四：JdbcDaoSupport的使用及Dao的两种编写方法
JdbcDaoSupport用去除掉定义和那些重复的代码，当有多个Dao时不用重复的定义JdbcTemplate,
使用spring原生的JdbcDaoSupport时使用注解配置属性注入时会比较麻烦，所以如果采用注解配置，请使用2那个方式，如果使用xml请使用1的那种方式
之前：

public class AccountDaoImpl2 implements IAccountDao {
    private JdbcTemplate jdbcTemplate;

    public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
        this.jdbcTemplate = jdbcTemplate;
    }

    @Override
    public Account findAccountById(int id) {
        List<Account> accounts =jdbcTemplate.query("select * from account where id = ?",new BeanPropertyRowMapper<Account>(Account.class),id);
        return accounts.isEmpty()?null:accounts.get(0);
    }

    @Override
    public Account findAccountByName(String name) {
        List<Account> accounts =jdbcTemplate.query("select * from account where NAME = ?",new BeanPropertyRowMapper<Account>(Account.class),name);
        if(accounts.isEmpty()){
            return null;
        }
        if (accounts.size() >1){
            throw new RuntimeException("结果不唯一");
        }
        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());

    }
}

之后，这个是使用继承来实现的

public class AccountDaoImpl extends JdbcDaoSupport implements IAccountDao {

    @Override
    public Account findAccountById(int id) {
        List<Account> accounts =super.getJdbcTemplate().query("select * from account where id = ?",new BeanPropertyRowMapper<Account>(Account.class),id);
        return accounts.isEmpty()?null:accounts.get(0);
    }

    @Override
    public Account findAccountByName(String name) {
        List<Account> accounts =super.getJdbcTemplate().query("select * from account where NAME = ?",new BeanPropertyRowMapper<Account>(Account.class),name);
        if(accounts.isEmpty()){
            return null;
        }
        if (accounts.size() >1){
            throw new RuntimeException("结果不唯一");
        }
        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());

    }
}

手动实现JdbcDaoSupport

/*
* 此类用于抽取Dao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);
    }
}
*/

配置类的改动：

<?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.selan.dao.impl.AccountDaoImpl">
        <!--<property name="jdbcTemplate" ref="jdbctemplate"></property>-->
        <property name="dataSource" ref="dataSource"></property>
    </bean>

    <!--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:3307/spring"></property>
        <property name="username" value="root"></property>
        <property name="password" value="123"></property>
    </bean>
</beans>