Spring
- 一、xml方式访问数据库
- 1.1 Spring的JdbcTemplate
- 1.2 创建user表并添加数据
- 1.3 pom.xml导入相关依赖
- 1.3 编写pojo
- 1.4 编写dao
- 1.5 编写service
- 1.6 编写controller
- 1.7 jdbc.properties配置文件
- 1.8 applicationContext.xml配置文件
- 1.9 测试
- 二、注解方式访问数据库
- 2.1 Spring中的注解
- 2.2 创建pojo,dao,service,controller
- 2.3 创建jdbc.properties配置文件
- 2.5 创建SpringConfiguration.java作为注解配置类,它的作用和bean.xml是一样的
- 2.6 使用Spring整合junit测试
- 2.7 编写测试类进行测试
一、xml方式访问数据库
1.1 Spring的JdbcTemplate
Spring的JdbcTemplate(了解会用)
在Spring中提供了一个可以操作数据库的对象org.springframework.jdbc.core.JdbcTemplate,对象封装了jdbc技术,JDBC的模板对象与DBUtils中的QueryRunner非常相似.测试:
在pom.xml中导入依赖<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>5.0.2.RELEASE</version>
</dependency>
编写测试类:
JdbcTemplate jt = new JdbcTemplate();
jt.setDataSource(dataSource);
List<User> list = jt.query("select * from user where id =?",new BeanPropertyRowMapper<User>(User.class),1);
System.out.println(list.get(0));
//jt.update("delete from user where id =?",4);
1.2 创建user表并添加数据
CREATE TABLE USER(
id INT,
username VARCHAR(20),
PASSWORD VARCHAR(20)
)
1.3 pom.xml导入相关依赖
<dependencies>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.12</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>5.2.6.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>5.2.6.RELEASE</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.20</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.1.19</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
</dependencies>
1.3 编写pojo
package com.qf.pojo;
import lombok.Data;
@Data
public class User {
private Integer id;
private String name;
private String password;
}
1.4 编写dao
package com.qf.dao;
import com.qf.pojo.User;
import java.util.List;
public interface UserDao {
List<User> findAll();
}package com.qf.dao.impl;
import com.qf.dao.UserDao;
import com.qf.pojo.User;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Repository;
import java.util.ArrayList;
import java.util.List;
public class UserDaoImpl implements UserDao {
private JdbcTemplate jdbcTemplate;
public List<User> findAll() {
return jdbcTemplate.query("select * from user",new BeanPropertyRowMapper<User>(User.class));
}
public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
this.jdbcTemplate = jdbcTemplate;
}
}
1.5 编写service
package com.qf.service;
import com.qf.pojo.User;
import java.util.List;
public interface UserService {
List<User> findAll();
}package com.qf.service.impl;
import com.qf.dao.UserDao;
import com.qf.pojo.User;
import com.qf.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
public class UserServiceImpl implements UserService {
private UserDao userDao;
public List<User> findAll() {
return userDao.findAll();
}
public void setUserDao(UserDao userDao) {
this.userDao = userDao;
}
}
1.6 编写controller
package com.qf.cotroller;
import com.qf.pojo.User;
import com.qf.service.UserService;
import java.util.List;
public class UserController {
private UserService userService;
public List<User> findAll(){
return userService.findAll();
}
public void setUserService(UserService userService) {
this.userService = userService;
}
}
1.7 jdbc.properties配置文件
jdbc.username = root
jdbc.password= root
jdbc.url = jdbc:mysql:///java2001?serverTimezone=Asia/Shanghai
jdbc.driverClassName = com.mysql.cj.jdbc.Driver
1.8 applicationContext.xml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"
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">
<!-- 引入jdbc.properties配置文件 -->
<context:property-placeholder location="classpath:jdbc.properties"/>
<!-- 配置druid数据库连接池 -->
<bean name="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
<property name="username" value="${jdbc.username}"></property>
<property name="password" value="${jdbc.password}"></property>
<property name="url" value="${jdbc.url}"></property>
<property name="driverClassName" value="${jdbc.driverClassName}"></property>
<!-- 配置spring的jdbcTemplate-->
<bean name="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
<property name="dataSource" ref="dataSource"></property>
</bean>
<!-- dao -->
<bean name="userDao" class="com.qf.dao.impl.UserDaoImpl">
<property name="jdbcTemplate" ref="jdbcTemplate"></property>
</bean>
<!-- service -->
<bean name="userService" class="com.qf.service.impl.UserServiceImpl">
<property name="userDao" ref="userDao"></property>
</bean>
<!-- controller -->
<bean name="userController" class="com.qf.cotroller.UserController">
<property name="userService" ref="userService"></property>
</bean>
</beans>
1.9 测试
package com.qf.test;
import com.alibaba.druid.pool.vendor.SybaseExceptionSorter;
import com.qf.cotroller.UserController;
import com.qf.pojo.User;
import org.junit.Test;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import java.util.List;
public class TestUserController {
@Test
public void test_findAll(){
ClassPathXmlApplicationContext applicationContext =
new ClassPathXmlApplicationContext("applicationContext.xml");
UserController userController =
(UserController)applicationContext.getBean("userController");
List<User> list = userController.findAll();
System.out.println(list);
}
}
二、注解方式访问数据库
2.1 Spring中的注解
@Configuration
作用:指定当前类是一个配置类
细节:当配置类作为AnnotationConfigApplicationContext对象创建的参数时,该注解可以不写。@ComponentScan
作用:用于通过注解指定spring在创建容器时要扫描的包
属性:value:它和basePackages的作用是一样的,都是用于指定创建容器时要扫描的包。
等同于xml中: <context:component-scan base-package=“com.qf”/>@PropertySource
作用:用于指定properties文件的位置
属性:value:指定文件的名称和路径。
关键字:classpath,表示类路径下等同于xml中: <context:property-placeholder location=“classpath:jdbc.properties”/>
@Bean
作用:用于把当前方法的返回值作为bean对象存入spring的ioc容器中
属性:name:用于指定bean的id。当不写时,默认值是当前方法的名称
细节:当我们使用注解配置方法时,如果方法有参数,在参数前加:@Qualifier("@Bean注解中name的值"),spring框架会去容器中查找有没有可用的bean对象查找的方式和Autowired注解的作用是一样的。@Bean("dataSource1")
public DataSource getDataSource1(){
try{
Properties pro = new Properties();
pro.setProperty("url",url);
pro.setProperty("username",username);
pro.setProperty("password",password);
pro.setProperty("driverClassName",driver);
DataSource dataSource = DruidDataSourceFactory.createDataSource(pro);
return dataSource;
} catch (Exception e){
}
return null;
}
@Bean("dataSource2")
public DataSource getDataSource2(){
try{
Properties pro = new Properties();
pro.setProperty("url",url);
pro.setProperty("username",username);
pro.setProperty("password",password);
pro.setProperty("driverClassName",driver);
DataSource dataSource = DruidDataSourceFactory.createDataSource(pro);
return dataSource;
} catch (Exception e){
}
return null;
}
@Bean("dataSource")
public DataSource getDataSource(@Qualifier("dataSource1") DataSource ds){
return ds;
}
@Import
作用:用于导入其他的配置类
属性:value:用于指定其他配置类的字节码。
当我们使用Import的注解之后,有Import注解的类就父配置类,而导入的都是子配置类 等同于xml中:
2.2 创建pojo,dao,service,controller
使用@Repository,@Service,@Controller以及@Autowired 配置所需代码
2.3 创建jdbc.properties配置文件
jdbc.username = root
jdbc.password= root
jdbc.url = jdbc:mysql:///java2001?serverTimezone=Asia/Shanghai
jdbc.driverClassName = com.mysql.cj.jdbc.Driver
2.5 创建SpringConfiguration.java作为注解配置类,它的作用和bean.xml是一样的
package com.qf.config;
import com.alibaba.druid.pool.DruidDataSourceFactory;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;
import org.springframework.jdbc.core.JdbcTemplate;
import javax.sql.DataSource;
import java.util.Properties;
@PropertySource(value = "classpath:jdbc.properties")
@ComponentScan("com.qf")
@Configuration
public class SpringConfiguration {
@Value("${jdbc.driverClassName}")
private String driverClassName;
@Value("${jdbc.url}")
private String url;
@Value("${jdbc.username}")
private String username;
@Value("${jdbc.password}")
private String password;
@Bean("jdbcTemplate")
public JdbcTemplate getJdbcTemplate(){
try{
Properties pro = new Properties();
pro.setProperty("url",url);
pro.setProperty("username",username);
pro.setProperty("password",password);
pro.setProperty("driverClassName",driverClassName);
DataSource dataSource = DruidDataSourceFactory.createDataSource(pro);
JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource);
return jdbcTemplate;
} catch (Exception e){
}
return null;
}
}
2.6 使用Spring整合junit测试
Spring整合junit的配置
1. 导入spring整合junit坐标
org.springframework
spring-test
5.0.2.RELEASE
2. 使用Junit提供的一个注解把原有的main方法替换了,替换成spring提供的
@RunWith(SpringJUnit4ClassRunner.class)1. 告知spring的运行器,spring和ioc创建是基于xml还是注解的,并且说明位置
@ContextConfiguration(locations = “classpath:applicationContext.xml”)
locations:指定xml文件的位置,classpath关键字表示在类路径下
@ContextConfiguration(classes = SpringConfiguration.class)
classes:指定注解配置类(需要手动编写配置类)注意:当我们使用spring 5.x版本的时候,要求junit的jar必须是4.12及以上,spring版本必须保持一致
2.7 编写测试类进行测试
package com.qf.test;
import com.qf.config.SpringConfiguration;
import com.qf.cotroller.UserController;
import com.qf.pojo.User;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import java.util.List;
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = SpringConfiguration.class)
public class TestUserController {
@Autowired
private UserController userController;
@Test
public void test_findAll() throws Exception{
List<User> list = userController.findAll();
System.out.println(list);
}
}