#JdbcDaoSupport #提取多个dao的公共代码 @FDDLC

项目结构：

 

pom.xml的内容：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>P035_JdbcDaoSupport</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.16</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>5.1.8.RELEASE</version>
        </dependency>
        <!--注意：spring-jdbc和spring-context有一部分依赖相同，易导致冲突，因此要让二者版本相同-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.1.8.RELEASE</version>
        </dependency>
    </dependencies>

</project>

 

MySQL数据库：

database：test        port：3306        table：id_name

 

bean.xml的内容:

<?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 class="org.springframework.jdbc.datasource.DriverManagerDataSource" id="dataSource">
        <property name="driverClassName" value="com.mysql.cj.jdbc.Driver"></property>
        <property name="url" value="jdbc:mysql://localhost:3306/test?characterEncoding=UTF8&amp;serverTimezone=Asia/Shanghai"></property>
        <property name="username" value="root"></property>
        <property name="password" value="123456"></property>
    </bean>

    <!--<bean class="org.springframework.jdbc.core.JdbcTemplate" id="template">
        <property name="dataSource" ref="dataSource"></property>
    </bean>-->

    <bean class="cn.liuxingchang.dao.impl.AccountDaoImplMy" id="accountDao">
        <!--<property name="jdbcTemplate" ref="template"></property>-->
        <property name="dataSource" ref="dataSource"></property>
    </bean>
</beans>

 

Account.java的内容：

package cn.liuxingchang.domain;

import java.io.Serializable;

public class Account implements Serializable {
    private Integer id;
    private String name;
    private Double 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 Double getMoney() {
        return money;
    }

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

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

 

AccountDao.java的内容：

package cn.liuxingchang.dao;

import cn.liuxingchang.domain.Account;

public interface AccountDao {
    Account findAccountById(Integer id);
    Account findAccountByName(String name);
    void update(Account account);
}

 

AccountDaoImpl.java的内容：

package cn.liuxingchang.dao.impl;

import cn.liuxingchang.dao.AccountDao;
import cn.liuxingchang.domain.Account;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.support.JdbcDaoSupport;

import java.util.List;

//public class AccountDaoImplMy extends JdbcDaoSupport implements AccountDao {
    //上面的JdbcDaoSupport是Spring提供，一般用xml(而非注解)配置；下面的MyJdbcDaoSupport是自定义，xml和注解均可配置
public class AccountDaoImpl extends MyJdbcDaoSupport implements AccountDao {
    /*
    private JdbcTemplate template;
    public void setJdbcTemplate(JdbcTemplate template) {
        this.template = template;
    }
    */
    public Account findAccountById(Integer id) {
        List<Account> accounts = super.getJdbcTemplate().query("select * from account where id = ?",
                new BeanPropertyRowMapper<Account>(Account.class), id);
        if(accounts.isEmpty()) {
            return null;
        } else {
            return accounts.get(0);
        }
    }

    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;
        } else if(accounts.size() > 1) {
            throw new RuntimeException("结果不唯一！");
        } else {
            return accounts.get(0);
        }
    }

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

 

MyJdbcDaoSupport.java的内容：

package cn.liuxingchang.dao.impl;

import org.springframework.jdbc.core.JdbcTemplate;

import javax.sql.DataSource;

/**
 * Spring对下述功能提供官方支持，故本类可视作多余！
 */
public class MyJdbcDaoSupport {
    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);
        }
    }

    public JdbcTemplate createJdbcTemplate(DataSource dataSource) {
        return new JdbcTemplate(dataSource);
    }
}

 

Main.java的内容：

package cn.liuxingchang;

import cn.liuxingchang.dao.AccountDao;
import cn.liuxingchang.domain.Account;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Main {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("bean.xml");
        AccountDao accountDao = context.getBean("accountDao", AccountDao.class);
        System.out.println(accountDao.findAccountById(1));
        //System.out.println(accountDao.findAccountByName("Zhao"));

        /*
        Account account = accountDao.findAccountById(1);
        account.setMoney(111.0);
        accountDao.update(account);
         */
    }
}