Acquaintance Spring JdbcTemplate

Others 2019-10-04 20:54:35 views: null

JdbcTemplate

Outline

Spring JdbcTemplate is provided a template class, which is the encapsulation of jdbc. Persistence layer for supporting the operation. Simple, and convenient.

pom.xml

<!--依赖版本-->
<properties>
    <!-- spring版本 -->
    <spring.version>5.0.2.RELEASE</spring.version>
    <!-- mysql版本 -->
    <mysql.version>5.1.30</mysql.version>
</properties>

<!--依赖包-->
<dependencies>
    <!--spring ioc依赖-->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>${spring.version}</version>
    </dependency>

    <!--spring jdbc依赖-->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-jdbc</artifactId>
        <version>${spring.version}</version>
    </dependency>

    <!-- mysql数据库依赖 -->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>${mysql.version}</version>
    </dependency>

</dependencies>

Getting Case

/**
 * spring JdbcTemplate入门案例
 */
public class JdbcTemplateDemo {

    public static void main(String[] args) {
        /**
         * 需求：通过JdbcTemplate实现添加一条账户记录，到账户表account中
         */
        // 创建JdbcTemplate对象
        JdbcTemplate jdbcTemplate = new JdbcTemplate();

        // 设置数据源对象
        DriverManagerDataSource dataSource = new DriverManagerDataSource();
        dataSource.setDriverClassName("com.mysql.jdbc.Driver");
        dataSource.setUrl("jdbc:mysql://127.0.0.1:3306/spring");
        dataSource.setUsername("root");
        dataSource.setPassword("root");

        jdbcTemplate.setDataSource(dataSource);

        // 添加账户信息
        jdbcTemplate.update("insert into account(name,money) values('小黄',2000)");
    }
}

SpringIOC management JdbcTemplate

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"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd">

    <!--配置JdbcTemplate-->
    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <!--注入数据源对象-->
        <property name="dataSource" ref="dataSource"></property>
    </bean>

    <!--配置数据源对象-->
    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <!--注入连接数据库的四个基本要素-->
        <property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
        <property name="url" value="jdbc:mysql://127.0.0.1:3306/spring"></property>
        <property name="username" value="root"></property>
        <property name="password" value="root"></property>
    </bean>

</beans>

Case

/**
 * spring JdbcTemplate入门案例
 */
public class JdbcTemplateDemo {

    public static void main(String[] args) {
        /**
         * 通过spring IOC容器管理JdbcTemplate对象
         */
        // 1.加载spring配置文件，创建spring IOC容器
        ApplicationContext context = new ClassPathXmlApplicationContext("classpath:bean.xml");

        // 2.从spring IOC容器中，获取JdbcTemplate
        JdbcTemplate jdbcTemplate = (JdbcTemplate)context.getBean("jdbcTemplate");

        // 3.添加账户
        jdbcTemplate.update("insert into account(name,money) values('小敏',2000)");

    }
}

Integration of data sources

When using JdbcTemplate, you need to set up a data source object database operation to complete

Built-in data source

<!-- 内置数据源 -->
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
    <!--注入连接数据库的四个基本要素-->
    <property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
    <property name="url" value="jdbc:mysql://127.0.0.1:3306/spring"></property>
    <property name="username" value="root"></property>
    <property name="password" value="root"></property>
</bean>

c3p0 data source

<!-- pom.xml -->
<!--c3p0版本-->
<c3p0.version>0.9.5</c3p0.version>

<!--c3p0依赖-->
<dependency>
    <groupId>com.mchange</groupId>
    <artifactId>c3p0</artifactId>
    <version>${c3p0.version}</version>
</dependency>


<!-- c3p0数据源 -->
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
    <!--注入连接数据库的四个基本要素-->
    <property name="driverClass" value="com.mysql.jdbc.Driver"></property>
    <property name="jdbcUrl" value="jdbc:mysql://127.0.0.1:3306/spring"></property>
    <property name="user" value="root"></property>
    <property name="password" value="root"></property>
</bean>

dbcp data source

<!-- pom.xml -->
<!--dbcp版本-->
<dbcp.version>1.4</dbcp.version>

<!--dbcp依赖-->
<dependency>
    <groupId>commons-dbcp</groupId>
    <artifactId>commons-dbcp</artifactId>
    <version>${dbcp.version}</version>
</dependency>


<!-- dbcp数据源 -->
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">
        <!--注入连接数据库的四个基本要素-->
        <property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
        <property name="url" value="jdbc:mysql://127.0.0.1:3306/spring"></property>
        <property name="username" value="root"></property>
        <property name="password" value="root"></property>
</bean>

druid data source

<!-- pom.xml -->
<!--druid版本-->
<druid.version>1.0.29</druid.version>

<!--druid依赖-->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid</artifactId>
    <version>${druid.version}</version>
</dependency>


<!-- druid数据源 -->
 <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
        <!--注入连接数据库的四个基本要素-->
        <property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
        <property name="url" value="jdbc:mysql://127.0.0.1:3306/spring"></property>
        <property name="username" value="root"></property>
        <property name="password" value="root"></property>
 </bean>

RoeMapper

In the JdbcTemplate query method has one parameter: RowMapper result set for encapsulation

public <T> List<T> query(String sql, RowMapper<T> rowMapper) throws DataAccessException{
    return ....
}

BeanPropertyRowMapper

RowMapper generic implementation provided by the Spring Framework class

// 类结构
public class BeanPropertyRowMapper<T> implements RowMapper<T>{
    .....
}

/**
 * 关键方法一
 *      1.根据传递进来的类型信息,通过反射技术,获取类的全部成员变量,以及set方法
 *      2.把类的成员变量名称,和对应的set方法,存在集合Map中
 *      3.等待执行完成数据库操作后,把对应字段的值,赋值到对应的成员变量上
 */
protected void initialize(Class<T> mappedClass){
    ......
}

/**
 * 关键方法二
 *      1.执行完成数据库操作后,拿到结果集ResultSet
 *      2.循环遍历ResultSet,每一行记录,调用一次该方法,进行结果集的封装
 */
 public T mapRow(ResultSet rs, int rowNumber) throws SQLException{
     ......
 }

Custom RowMapper

Sometimes in order to code more concise, consider using custom RowMapper

/**
 * 自定义结果集隐射:RowMapper
 */
public class CustomRowMapper implements RowMapper<T>{
    /**
     * 实现结果集封装方法: mapRow
     * 该方法每一行结果集记录就调用一次
     */
    public T mapRow(ResultSet rs, int rowNumber) throws SQLException{
    Object object = new Object();
    
    object.setXXX(XXX);
    
    return object;
    }
}

SpringIOC case realization

pom.xml

<properties>
    <!--spring版本-->
    <spring.version>5.0.2.RELEASE</spring.version>
    <!--druid版本-->
    <druid.version>1.0.29</druid.version>
    <!--mysql驱动版本-->
    <mysql.version>5.1.30</mysql.version>
</properties>

<dependencies>
    <!--spring ioc依赖-->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>${spring.version}</version>
    </dependency>
    <!--spring jdbc依赖-->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-jdbc</artifactId>
        <version>${spring.version}</version>
    </dependency>
    <!--druid依赖-->
    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>druid</artifactId>
        <version>${druid.version}</version>
    </dependency>
    <!--mysql驱动依赖-->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>${mysql.version}</version>
    </dependency>
</dependencies>

Xml version complete

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"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd">

    <!--配置客户service-->
    <bean id="Service" class="com.XXX.service.impl.ServiceImpl">
        <!--注入客户dao-->
        <property name="Dao" ref="Dao"></property>
    </bean>

    <!--配置客户dao-->
    <bean id="Dao" class="com.XXX.dao.impl.DaoImpl">
        <!--注入JdbcTemplate-->
        <property name="jdbcTemplate" ref="jdbcTemplate"></property>
    </bean>

    <!--配置JdbcTemplate-->
    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <!--注入数据源对象-->
        <property name="dataSource" ref="dataSource"></property>
    </bean>

    <!--配置数据源对象DataSource-->
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
        <!--注入四个基本属性-->
        <property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
        <property name="url" value="jdbc:mysql://127.0.0.1:3306/spring"></property>
        <property name="username" value="root"></property>
        <property name="password" value="root"></property>

        <!--数据库连接池常用属性-->
        <!-- 初始化连接数量 -->
        <property name="initialSize" value="6" />
        <!-- 最小空闲连接数 -->
        <property name="minIdle" value="3" />
        <!-- 最大并发连接数(最大连接池数量) -->
        <property name="maxActive" value="50" />
        <!-- 配置获取连接等待超时的时间 -->
        <property name="maxWait" value="60000" />
        <!-- 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒 -->
        <property name="timeBetweenEvictionRunsMillis" value="60000" />
    </bean>

</beans>

dao

public class Dao{
    // 定义JdbcTemplate
    private JdbcTemplate jdbcTemplate;
    
    public void setJdbcTemplate(JdbcTemplate jdbcTemplate){
        this.jdbcTemplate = jdbcTemplate;
    }
    
    public List<T> findAll(){
        // 定义sql
        String sql = "select * from table";
        
        // 返回执行结果
        return jdbcTemplate.query(sql, new CustomRowMapper());
    }
}

service

public class Service{
    // 定义dao
    private Dao dao;
    
    public void setDao(Dao dao){
        this.dao = dao;
    }
    
    public List<T> findAll(){
        return dao.findAll();
    }
}

Controller

public class Controller {
    public static void main(String[] args) {
        // 1.加载spring配置文件，创建spring容器
        ApplicationContext context = new ClassPathXmlApplicationContext("classpath:bean.xml");

        // 2.获取客户service对象
        Service Service = (Service) context.getBean("Service");

        // 3.查询全部客户列表数据
        List<T> list = Service.findAll();
        for(T t:list){
            System.out.println(t);
        }
    }
}

xml version mixed with notes

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

    <!--配置包扫描dao/service，说明：
        第一步：导入context名称空间和约束
        第二步：通过<context:component-scan>标签配置包扫描，spring框架在
        初始化IOC容器的时候，会扫描指定的包和它的子包
    -->
    <context:component-scan base-package="com.XXX"></context:component-scan>

    <!--配置JdbcTemplate-->
    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <!--注入数据源对象-->
        <property name="dataSource" ref="dataSource"></property>
    </bean>

    <!--配置数据源对象DataSource-->
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
        <!--注入四个基本属性-->
        <property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
        <property name="url" value="jdbc:mysql://127.0.0.1:3306/spring"></property>
        <property name="username" value="root"></property>
        <property name="password" value="root"></property>

        <!--数据库连接池常用属性-->
        <!-- 初始化连接数量 -->
        <property name="initialSize" value="6" />
        <!-- 最小空闲连接数 -->
        <property name="minIdle" value="3" />
        <!-- 最大并发连接数(最大连接池数量) -->
        <property name="maxActive" value="50" />
        <!-- 配置获取连接等待超时的时间 -->
        <property name="maxWait" value="60000" />
        <!-- 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒 -->
        <property name="timeBetweenEvictionRunsMillis" value="60000" />
    </bean>

</beans>

dao

@Repository("dao")
public class Dao{
    // 定义JdbcTemplate
    @Autowired
    private JdbcTemplate jdbcTemplate;
    
    public List<T> findAll(){
        // 定义sql
        String sql = "select * from table";
        
        // 返回查询结果
        return jdbcTemplate.query(sql, new CustomRowMapper());
    }
}

service

@Service("service")
public class Service{
    // 定义dao
    private Dao dao;
    
    public List<T> findAll(){
        return dao.findAll();
    }
}

Fully annotated basic version

Spring configuration class

/**
 * 注解说明
 *      @Configuration: 标记当前java类是一个Spring的配置类
 *      @ComponentScan: 配置扫描包,相当于xml配置中<context:component-scan/>标签
 */
@Configuration
@ComponentScan(value = {"com.XXX"})
public class SpringConfiguration{
    // 配置JdbcTemplate
    @Bean(value = "jdbcTemplate")
    public JdbcTemplate createJdbcTemplate(DataSource dataSource){
        // 创建JdbcTemplate对象
        JdbcTemplate jdbcTemplate = new JdbcTemplate();
        jdbcTemplate.setDataSource(dataSource);
        return jdbcTemplate;
    }
    
    // 配置DataSource
    @Bean(value = "dataSource")
    public DataSource createDataSource(){
        // 创建DataSource
        DruidDataSource dataSource = new DruidDataSource();
        
        // 注入属性
        dataSource.setDriverClassName("com.mysql.jdbc.Driver");
        dataSource.setUrl("jdbc:mysql://127.0.0.1:3306/spring");
        dataSource.setUsername("root");
        dataSource.setPassword("root");

        dataSource.setInitialSize(6);
        dataSource.setMinIdle(3);
        dataSource.setMaxActive(50);
        dataSource.setMaxWait(60000);
        dataSource.setTimeBetweenEvictionRunsMillis(60000);
        
        return dataSource;
    }
}

Controller

public class Controller{
    public static void main(String[] args){
        // 1.加载Spring配置类,创建Spring容器
        ApplicationContext context = new AnnotationConfigApplicationContext(SpringConfiguration.class);
        
        // 2.获取service对象
        Service service = (Service)context.getBean("service");
        
        // 调用方法得到结果
        List<T> list = service.findAll();
        for(T t : list){
            System.out.println(t);
        }
    }
}

Fully optimized version comment

Establish a relationship between class configuration

/**
 * spring配置类：
 *  注解说明：
 *      1.@Configuration：标记当前java类，是一个spring的配置类
 *      2.@ComponentScan：配置扫描包。相当于xml配置中<context:component-scan/>标签
 *      3.@Import：导入其他模块配置类
 *      4.@PropertySource：导入属性资源文件
 */
@Configuration
@ComponentScan(value = {"com.XXX"})
@Import(value={DaoConfiguration.class})
@PropertySource(value={"classpath:jdbc.properties"})

jdbc.properties

jdbc.driverClassName=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://127.0.0.1:3306/spring
jdbc.username=root
jdbc.password=root

jdbc.initialSize=6
jdbc.minIdle=3
jdbc.maxActive=50
jdbc.maxWait=60000
jdbc.timeBetweenERM=60000

Dao

public class DaoConfiguration {
    @Bean(value="jdbcTemplate")
    public JdbcTemplate createJdbcTemplate(DataSource dataSource){
        // 创建JdbcTemplate对象
        JdbcTemplate jdbcTemplate = new JdbcTemplate();
        jdbcTemplate.setDataSource(dataSource);

        return jdbcTemplate;
    }
    
    // 定义连接数据库的成员变量
    /**
     * 使用@Value注解，进行赋值
     * 使用格式：@Value("${}")
     */
    @Value("${jdbc.driverClassName}")
    private String driverClassName;
    @Value("${jdbc.url}")
    private String url;
    @Value("${jdbc.username}")
    private String username;
    @Value("${jdbc.password}")
    private String password;

    @Value("${jdbc.initialSize}")
    private Integer initialSize;
    @Value("${jdbc.minIdle}")
    private Integer minIdle;
    @Value("${jdbc.maxActive}")
    private Integer maxActive;
    @Value("${jdbc.maxWait}")
    private Integer maxWait;
    @Value("${jdbc.timeBetweenERM}")
    private Integer timeBetweenERM;

    @Bean(value="dataSource")
    public DataSource createDataSource(){
        // 创建DataSource
        DruidDataSource dataSource = new DruidDataSource();

        // 注入属性
        // 注入属性
        dataSource.setDriverClassName(driverClassName);
        dataSource.setUrl(url);
        dataSource.setUsername(username);
        dataSource.setPassword(password);

        dataSource.setInitialSize(initialSize);
        dataSource.setMinIdle(minIdle);
        dataSource.setMaxActive(maxActive);
        dataSource.setMaxWait(maxWait);
        dataSource.setTimeBetweenEvictionRunsMillis(timeBetweenERM);

        return dataSource;
    }
}

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