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Spring JdbcTemplate 案例详解教程

夏天的枫_ 03-21 16:30 阅读 2

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Spring JdbcTemplate

Spring提供的数据访问模板,提供了很多方便操作数据库的方法

  • update (更新数据)
  • batchUpdate (批量更新数据库)
  • queryForObject (查询单行)
  • query (查询多行)
  • queryForObject (单值查询)不同的

步骤:

1. 添加依赖

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-orm</artifactId>
    <version>5.3.9</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-context</artifactId>
    <version>5.3.9</version>
</dependency>

完整 pom.xml 如下:

<?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>Spring06-JdbcTemplated</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-orm</artifactId>
            <version>5.3.9</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.3.9</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.26</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.20</version>
        </dependency>
    </dependencies>
</project>

2. Spring 配置文件

spring.xml 文件配置如下:

<?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 http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd">
    <!--
        JdbcTempldate
        datasource - JdbcTempldate - Dao -Service -Controller
    -->
    <context:component-scan base-package="com.wdzl"/>

    <bean name="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="username" value="root"></property>
        <property name="password" value="root"></property>
        <property name="url" value="jdbc:mysql://127.0.0.1:3306/booksys"></property>
        <property name="driverClassName" value="com.mysql.cj.jdbc.Driver"></property>
    </bean>
    <bean name="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <property name="dataSource" ref="dataSource"/>
    </bean>
</beans>

3. 编写类

实体类 Book :

@Data
public class Book {
    private Integer bookid;
    private String bookname;
    private Float price;
    private String author;
    private Date pubDate;
}

Dao 接口 IBookDao :

public interface IBookDao {
    List<Book> queryAll();
    Book get(Integer bookid);
    void save(Book book);
}

Dao 接口实现类 BookDaoImpl:

@Repository("bookDao")
public class BookDaoImpl implements IBookDao {
    @Autowired
    private JdbcTemplate template;

    @Override
    public List<Book> queryAll() {
        String sql = "select bookid,bookname,pubdate,price,authorid from book";
        List<Book> list = template.query(sql, new BookRowMapper());
        return list;
    }

    @Override
    public Book get(Integer bookid) {
        return null;
    }

    @Override
    public void save(Book book) {

    }

    // 内部类 实现 RowMapper 接口
    class BookRowMapper implements RowMapper{
        @Override
        public Book mapRow(ResultSet resultSet, int i) throws SQLException {
            Book book = new Book();
            book.setBookname(resultSet.getString("bookname"));
            book.setPrice(resultSet.getFloat("price"));
//            book.setAuthor(resultSet.getString("author"));
            book.setPubDate(resultSet.getDate("pubdate"));
            return book;
        }
    }
}

业务类接口 IBookService :

public interface IBookService {
    List<Book> queryAll();
    Book get(Integer bookid);
    void save(Book book);
}

业务类 BookService :

@Service
public class BookService implements IBookService {
    @Autowired
    @Qualifier("bookDao")
    private IBookDao bookDao;
    @Override
    public List<Book> queryAll() {
        return bookDao.queryAll();
    }

    @Override
    public Book get(Integer bookid) {
        return bookDao.get(bookid);
    }

    @Override
    public void save(Book book) {
        bookDao.save(book);
    }
}

4. 测试类

public class TestJdbc {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("sping.xml");
        IBookService bookSerice = context.getBean("bookService", IBookService.class);
        bookSerice.queryAll().forEach(System.out::println);
    }
}

BeanPropertyRowMapper 用法

@Override
    public Book get(Integer bookid) {
        String sql = "select bookid ,bookname,pubdate,price,authorid from book where bookid=?";
//        Book book = template.queryForObject(sql, Book.class,bookid);
        Book book = template.queryForObject(sql, new BeanPropertyRowMapper<>(Book.class),bookid);

        return book;
    }

批量更新

public void batchSave(List<Book> list){
    String sql = "insert into book (bookname,price,authorid,pubdate)values(?,?,?,?)";
    List<Object[]> params = new ArrayList<>();

    for (Book book : list) {
        Object[] param = {book.getBookname(),book.getPrice(),2,new Date()};
        params.add(param);
    }

    int[] ints = template.batchUpdate(sql, params);
    System.out.println(Arrays.toString(ints));
}

c3p0 连接池

添加依赖

<dependency>
    <groupId>com.mchange</groupId>
    <artifactId>c3p0</artifactId>
    <version>0.9.5.2</version>
</dependency>

配置更换数据源

<!-- c3p0 连接 -->
<bean name="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
    <property name="user" value="root"></property>
    <property name="password" value="root"></property>
    <property name="jdbcUrl" value="jdbc:mysql://127.0.0.1:3306/booksys"></property>
    <property name="driverClass" value="com.mysql.cj.jdbc.Driver"></property>
    <property name="initialPoolSize" value="3"/>
</bean>

更换完成后,直接使用之前的测试类运行即可!

属性文件引用

配置引入文件

<context:property-placeholder location="db.properties"/>

修改数据源配置

<bean name="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
    <property name="user" value="${username}"></property>
    <property name="password" value="${password}"></property>
    <property name="jdbcUrl" value="${url}"></property>
    <property name="driverClass" value="${driver}"></property>
    <property name="initialPoolSize" value="3"/>
</bean>

上面问题的解决办法如下:

属性文件文件 db.properties 如下:

jdbc.url=jdbc:mysql://127.0.0.1:3306/booksys?serverTimezone=GMT
jdbc.driver=com.mysql.cj.jdbc.Driver
jdbc.username=root
jdbc.password=root

spring.xml 配置文件中使用 ${} 引用上面的键即可

<bean name="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
    <property name="user" value="${jdbc.username}"></property>
    <property name="password" value="${jdbc.password}"></property>
    <property name="jdbcUrl" value="${jdbc.url}"></property>
    <property name="driverClass" value="${jdbc.driver}"></property>
    <property name="initialPoolSize" value="3"/>
</b
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