Spring 框架下的 JDBC

Spring JDBC

Spring 对JDBC技术规范做了进一步封装，它又叫Spring JDBCTemplate(jdbc模板技术)

纯JDBC：代码清晰的、效率最高、代码是最烦的、
    Spring JDBCTemplate:代码相对来说就不那么清晰，效率要低一点，代码相对简单

如何进行Spring和jdbc的集合？（数据库的连接池）
        (1) 导入jar 包：spring-jdbc.jar  驱动类   连接池 DruidUtil2(框架的原型)
        (2) 配置类：@Configuration
        (3) @Spring IOC + JDBC 实现
            JdbcConfig： a.配置属性  b.配置DataSource Bean
        (4) 配置JdbcTemplate Bean  @Bean

1.pom.xml 所需要的jar包

    <!-- https://mvnrepository.com/artifact/org.springframework/spring-jdbc -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-jdbc</artifactId>
        <version>${spring.version}</version>
    </dependency>
<!-- MySQL数据库连接池 -->
        <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.48</version>
        </dependency>

        <!-- Druid -->
        <!-- https://mvnrepository.com/artifact/com.alibaba/druid -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.20</version>
        </dependency>

2. 一个实体类：Account.java

public class Account {
    private int id;
    private String name;
    private Double balance;
    public Account( String name, Double balance) {
        super();
        this.name = name;
        this.balance = balance;
    }
    public Account(int id, String name, Double balance) {
        super();
        this.id = id;
        this.name = name;
        this.balance = balance;
    }
    public Account() {
        super();
    }
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Double getBalance() {
        return balance;
    }
    public void setBalance(Double balance) {
        this.balance = balance;
    }
    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((balance == null) ? 0 : balance.hashCode());
        result = prime * result + id;
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        return result;
    }
    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Account other = (Account) obj;
        if (balance == null) {
            if (other.balance != null)
                return false;
        } else if (!balance.equals(other.balance))
            return false;
        if (id != other.id)
            return false;
        if (name == null) {
            if (other.name != null)
                return false;
        } else if (!name.equals(other.name))
            return false;
        return true;
    }
    @Override
    public String toString() {
        return "Account [id=" + id + ", name=" + name + ", balance=" + balance + "]";
    }

}

3. 接口：IAccount.java

import java.util.List;

/**
 * AccountDao接口
 * @author 张泽
 */
public interface IAccountDao {
    List<Account> findAll();
    void delete(Account act);
    void saveOrUpdate(Account act);
}

4.1 接口实现类(JDBC)：AccountDaoJdbcImpl.java

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;

import javax.sql.DataSource;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Repository;
//@Component
@Repository("accountDaoJdbcImpl") //-- 存储、仓库/  做存储服务
public class AccountDaoJdbcImpl implements IAccountDao {
    @Autowired
    private DataSource ds;

    @Override
    public List<Account> findAll() {
        try {
            Connection con = ds.getConnection();
            String sql = "select * from account";
            Statement stmt = con.createStatement();
            ResultSet rs = stmt.executeQuery(sql);
            List<Account> acts = new ArrayList<>();
            while(rs.next()) {
                Account act = new Account(rs.getInt(1),rs.getString(2),rs.getDouble(3));
                acts.add(act);
            }
            return acts;

        } catch (Exception e) {e.printStackTrace();}

        return null;
    }

    @Override
    public void delete(Account act) {
        // TODO Auto-generated method stub

    }

    @Override
    public void saveOrUpdate(Account act) {
        // TODO Auto-generated method stub

    }

}

4.2 接口实现类(Spring JDBCTemplate)：AccountDaoTemplateImpl.java

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Repository;

@Repository("accountDaoTemplateImpl")
public class AccountDaoTemplateImpl implements IAccountDao {
    @Autowired
    private JdbcTemplate jdbcTemplate;

    @Override
    public List<Account> findAll() {
        System.out.println("accountDaoTemplateImpl");
        return jdbcTemplate.query(
                "select * from account",
                new BeanPropertyRowMapper<Account>(Account.class)
                );
    }

    @Override
    public void saveOrUpdate(Account act) {

        if(act.getId()==0) {
            jdbcTemplate.update(
                    "insert into account(name,balance) values(?,?)",
                    new Object[] {act.getName(),act.getBalance()}
                    );
        }else {
            jdbcTemplate.update(
                    "update account set name=?,balance=? where id=?",
                    new Object[] {act.getName(),act.getBalance(),act.getId()}
                    );
        }

    }

    @Override
    public void delete(Account act) {
        jdbcTemplate.update(
                "delete from account where id=?",
                new Object[] {act.getId()}
                );
    }

}

5.1 JDBC 配置资源：jdbc.properties

jdbc.driverClass=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/demo
jdbc.username=root
jdbc.password=root

pool.maxActive=10

5.2 JDBC 配置类：JdbcConfig.java

import javax.sql.DataSource;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;
import org.springframework.jdbc.core.JdbcTemplate;

import com.alibaba.druid.pool.DruidDataSource;

/**
 * JdbcConfig类
 * @author 张泽
 *
 */
@Configuration
@PropertySource("classpath:jdbc.properties")
                //--你的配置信息的位置
public class JdbcConfig {
    //-- 1. 获取配置信息
    @Value("${jdbc.driverClass}")
    private String driver;
    @Value("${jdbc.url}")
    private String url;
    @Value("${jdbc.username}")
    private String username;
    @Value("${jdbc.password}")
    private String password;

    @Value("${pool.maxActive}")
    private int maxActive;

    //-- 2. 数据库连接池对象
    @Bean(name="dataSource")
    public DataSource createDataSource() {
        DruidDataSource ds = new DruidDataSource();
        ds.setDriverClassName(driver);
        ds.setUrl(url);
        ds.setUsername(username);
        ds.setPassword(password);
        ds.setMaxActive(maxActive);

        return ds;
    }

    //-- 3. 配置JdbcTemplate
    @Bean(name="jdbcTemplate")
    public JdbcTemplate createJdbcTemplate(DataSource ds) {
        return new JdbcTemplate(ds);//-- 利用数据源构造JdbcTemplate
    }

}

6. Spring 配置类：SpringConfig.java

/**
 * Spring 配置类
 * 多配置的使用方式
 */
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;

@Configuration
@ComponentScan("day")//--所在包名
@Import(JdbcConfig.class)  //-- 在主配置中导入子配置
public class SpringConfig {

}

7. 主函数入口：Invoker.java

import javax.sql.DataSource;

import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class Invoker {
    public static void main(String[] args) {
        ApplicationContext ctx=
                new AnnotationConfigApplicationContext(SpringConfig.class);
        DataSource ds = (DataSource)ctx.getBean("dataSource");
        System.out.println(ds);
    }
}

8. 测试类：TestAccountDao.java

import java.util.List;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes= {SpringConfig.class})
public class TestAccountDao {
    @Autowired
    @Qualifier("accountDaoTemplateImpl")//-- 选择要调用 接口的实现类
    private IAccountDao actDao;

    @Test
    public void testFind() {
        List<Account> acts = actDao.findAll();
        for (Account account : acts) {
            System.out.println(account);
        }
    }

    @Test
    public void testSave() {
        actDao.saveOrUpdate(new Account("xx",12.0));
    }

    @Test
    public void testUpdate() {
        actDao.saveOrUpdate(new Account(8,"xx",22.0));
    }

    @Test
    public void testDelete() {
        actDao.delete(new Account(8,"xx",22.0));
    }

}