SSM2.2【Spring：Spring注解开发】
Spring原始注解
1 | Spring是轻代码而重配置的框架，配置比较繁重，影响开发效率，所以注解开发是一种趋势，注解代替xml配置文件可以简化配置，提高开发效率。 |
1 <?xml version="1.0" encoding="UTF-8"?> 2 <beans xmlns="http://www.springframework.org/schema/beans" 3 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 4 xmlns:context="http://www.springframework.org/schema/context" 5 xsi:schemaLocation=" 6 http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd 7 http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd"> 8 9 10 <bean id="dataSource_c3p0" class="com.mchange.v2.c3p0.ComboPooledDataSource"> 11 <property name="driverClass" value="com.mysql.jdbc.Driver"></property> 12 <property name="jdbcUrl" value="jdbc:mysql://localhost:3306/test"></property> 13 <property name="user" value="root"></property> 14 <property name="password" value="root"></property> 15 </bean> 16 17 <!--加载外部的properties文件--> 18 <!--需要在顶部beans中配置命名空间context，并在xsi中添加对应的约束路径--> 19 <context:property-placeholder location="classpath:jdbc.properties"/> 20 <bean id="dataSource_druid" class="com.alibaba.druid.pool.DruidDataSource"> 21 <property name="driverClassName" value="${jdbc.driver}"></property> 22 <property name="url" value="${jdbc.url}"></property> 23 <property name="username" value="${jdbc.username}"></property> 24 <property name="password" value="${jdbc.password}"></property> 25 </bean> 26 27 28 <!--<bean id="userDao" class="com.haifei.dao.impl.UserDaoImpl"></bean>--> 29 <!--<bean id="userService" class="com.haifei.service.impl.UserServiceImpl">--> 30 <!--<property name="userDao" ref="userDao"></property>--> 31 <!--</bean>--> 32 33 <!--配置组件扫描--> 34 <!--使用注解进行开发时（代替配置bean方式开发），需要在applicationContext.xml中配置组件扫描， 35 作用是指定哪个包及其子包下的Bean需要进行扫描以便识别使用注解配置的类、字段和方法 36 不配置这个的话，运行会报异常NoSuchBeanDefinitionException--> 37 <context:component-scan base-package="com.haifei" /> 38 39 </beans>
1 package com.haifei.dao; 2 3 public interface UserDao { 4 5 public void save(); 6 }
1 package com.haifei.dao.impl; 2 3 import com.haifei.dao.UserDao; 4 import org.springframework.stereotype.Component; 5 import org.springframework.stereotype.Repository; 6 7 //<bean id="userDao" class="com.haifei.dao.impl.UserDaoImpl"></bean> 8 //@Component("userDao") 9 @Repository("userDao") 10 public class UserDaoImpl implements UserDao { 11 12 @Override 13 public void save() { 14 System.out.println("UserDaoImpl: save running..."); 15 } 16 }
1 package com.haifei.service; 2 3 public interface UserService { 4 5 public void save(); 6 }
1 package com.haifei.service.impl; 2 3 import com.haifei.dao.UserDao; 4 import com.haifei.dao.impl.UserDaoImpl; 5 import com.haifei.service.UserService; 6 import org.springframework.beans.factory.annotation.Autowired; 7 import org.springframework.beans.factory.annotation.Qualifier; 8 import org.springframework.beans.factory.annotation.Value; 9 import org.springframework.context.annotation.Scope; 10 import org.springframework.stereotype.Component; 11 import org.springframework.stereotype.Service; 12 13 import javax.annotation.PostConstruct; 14 import javax.annotation.PreDestroy; 15 import javax.annotation.Resource; 16 17 //<bean id="userService" class="com.haifei.service.impl.UserServiceImpl"></bean> 18 //@Component("userService") 19 @Service("userService") 20 @Scope("prototype") //默认（不设置时也是）是singleton单例；可以设置为prototype多例 21 public class UserServiceImpl implements UserService { 22 23 //<property name="userDao" ref="userDao"></property> 24 /*@Autowired //按照数据类型从Spring容器中进行匹配的（只写Autowired，不写Qualifier，也能注入） 25 // @Qualifier("userDao") //是按照id值从容器中进行匹配的 但是主要此处@Qualifier结合@Autowired一起使用*/ 26 @Resource(name="userDao") //@Resource相当于@Qualifier+@Autowired 27 private UserDao userDao; 28 29 /*public void setUserDao(UserDao userDao) { 30 this.userDao = userDao; 31 }*/ 32 /* 33 通过xml配置bean的方式开发时： 34 如果使用set进行依赖注入，则set方法必须有，不能省略 35 通过注解的方式开发时： 36 set方法可以省略，因为注解可以通过反射给userDao赋值 37 */ 38 39 40 //通过注解注入普通数据类型 41 @Value("itcast") 42 private String heima; // private String heima = "itcast" 43 @Value("${jdbc.driver}") //通过键从jdbc.properties中获取值 44 private String driver; 45 46 47 @Override 48 public void save() { 49 System.out.println(heima); //itcast 50 System.out.println(driver); //com.mysql.jdbc.Driver 51 userDao.save(); 52 } 53 54 55 @PostConstruct 56 public void init(){ 57 System.out.println("UserServiceImpl: 初始化方法"); 58 } 59 @PreDestroy 60 public void destory(){ 61 System.out.println("UserServiceImpl: 销毁方法"); 62 } 63 }
1 package com.haifei.web; 2 3 import com.haifei.service.UserService; 4 import org.springframework.context.ApplicationContext; 5 import org.springframework.context.support.ClassPathXmlApplicationContext; 6 import org.springframework.stereotype.Controller; 7 8 /** 9 * 假的servlet 10 * 用于测试 11 */ 12 //@Controller 13 public class UserController { 14 15 public static void main(String[] args) { 16 // ApplicationContext app = new ClassPathXmlApplicationContext("applicationContext.xml"); 17 ClassPathXmlApplicationContext app = new ClassPathXmlApplicationContext("applicationContext.xml"); 18 UserService userService = app.getBean(UserService.class); 19 userService.save(); 20 app.close(); 21 22 /* 23 UserServiceImpl: 初始化方法 24 itcast 25 com.mysql.jdbc.Driver 26 UserDaoImpl: save running... 27 七月 15, 2021 7:37:53 下午 org.springframework.context.support.AbstractApplicationContext doClose 28 信息: Closing org.springframework.context.support.ClassPathXmlApplicationContext@e2144e4: startup date [Thu Jul 15 19:37:52 CST 2021]; root of context hierarchy 29 */ 30 } 31 32 }
Spring新注解
1
1 package com.haifei.config; 2 3 import com.alibaba.druid.pool.DruidDataSource; 4 import com.mchange.v2.c3p0.ComboPooledDataSource; 5 import org.springframework.beans.factory.annotation.Value; 6 import org.springframework.context.annotation.Bean; 7 import org.springframework.context.annotation.ComponentScan; 8 import org.springframework.context.annotation.Configuration; 9 import org.springframework.context.annotation.PropertySource; 10 11 import javax.sql.DataSource; 12 import java.beans.PropertyVetoException; 13 14 @Configuration //标志该类是Spring的核心配置类 15 @ComponentScan("com.haifei") //组件扫描<context:component-scan base-package="com.haifei" /> 16 @PropertySource("classpath:jdbc.properties")//加载外部的properties文件<context:property-placeholder location="classpath:jdbc.properties"/> 17 public class SpringConfiguration { 18 19 @Bean("dataSource1") //Spring会将当前方法的返回值以指定名称dataSource1存储到Spring容器中 20 public DataSource getDataSource1() throws PropertyVetoException { 21 ComboPooledDataSource dataSource = new ComboPooledDataSource(); 22 dataSource.setDriverClass("com.mysql.jdbc.Driver"); 23 dataSource.setJdbcUrl("jdbc:mysql://localhost:3306/test"); 24 dataSource.setUser("root"); 25 dataSource.setPassword("root"); 26 return dataSource; 27 } 28 29 @Value("${jdbc.driver}") 30 private String driver; 31 @Value("${jdbc.url}") 32 private String url; 33 @Value("${jdbc.username}") 34 private String username; 35 @Value("${jdbc.password}") 36 private String password; 37 38 @Bean("dataSource2") 39 public DataSource getDataSource2() { 40 DruidDataSource dataSource = new DruidDataSource(); 41 dataSource.setDriverClassName(driver); 42 dataSource.setUrl(url); 43 dataSource.setUsername(username); 44 dataSource.setPassword(password); 45 return dataSource; 46 } 47 48 }
2
1 package com.haifei.config; 2 3 import com.alibaba.druid.pool.DruidDataSource; 4 import com.mchange.v2.c3p0.ComboPooledDataSource; 5 import org.springframework.beans.factory.annotation.Value; 6 import org.springframework.context.annotation.*; 7 8 import javax.sql.DataSource; 9 import java.beans.PropertyVetoException; 10 11 @Configuration //标志该类是Spring的核心配置类 12 @ComponentScan("com.haifei") //组件扫描<context:component-scan base-package="com.haifei" /> 13 @Import(DataSourceConfiguration.class)//引入其他配置文件（分模块开发）<import resource="" /> {xxx.class,yyy.class} 14 public class SpringConfiguration { 15 16 /*@Bean("dataSource1") //Spring会将当前方法的返回值以指定名称dataSource1存储到Spring容器中 17 public DataSource getDataSource1() throws PropertyVetoException { 18 ComboPooledDataSource dataSource = new ComboPooledDataSource(); 19 dataSource.setDriverClass("com.mysql.jdbc.Driver"); 20 dataSource.setJdbcUrl("jdbc:mysql://localhost:3306/test"); 21 dataSource.setUser("root"); 22 dataSource.setPassword("root"); 23 return dataSource; 24 }*/ 25 26 }
1 package com.haifei.config; 2 3 import com.alibaba.druid.pool.DruidDataSource; 4 import org.springframework.beans.factory.annotation.Value; 5 import org.springframework.context.annotation.Bean; 6 import org.springframework.context.annotation.PropertySource; 7 8 import javax.sql.DataSource; 9 10 @PropertySource("classpath:jdbc.properties")//加载外部的properties文件<context:property-placeholder location="classpath:jdbc.properties"/> 11 public class DataSourceConfiguration { 12 13 @Value("${jdbc.driver}") 14 private String driver; 15 @Value("${jdbc.url}") 16 private String url; 17 @Value("${jdbc.username}") 18 private String username; 19 @Value("${jdbc.password}") 20 private String password; 21 22 @Bean("dataSource2") 23 public DataSource getDataSource2() { 24 DruidDataSource dataSource = new DruidDataSource(); 25 dataSource.setDriverClassName(driver); 26 dataSource.setUrl(url); 27 dataSource.setUsername(username); 28 dataSource.setPassword(password); 29 return dataSource; 30 } 31 32 }
1 package com.haifei.web; 2 3 import com.haifei.config.SpringConfiguration; 4 import com.haifei.service.UserService; 5 import org.springframework.context.ApplicationContext; 6 import org.springframework.context.annotation.AnnotationConfigApplicationContext; 7 import org.springframework.context.support.ClassPathXmlApplicationContext; 8 import org.springframework.stereotype.Controller; 9 10 /** 11 * 假的servlet 12 * 用于测试 13 */ 14 //@Controller 15 public class UserController { 16 17 public static void main(String[] args) { 18 /*// ApplicationContext app = new ClassPathXmlApplicationContext("applicationContext.xml"); 19 ClassPathXmlApplicationContext app = new ClassPathXmlApplicationContext("applicationContext.xml"); 20 UserService userService = app.getBean(UserService.class); 21 userService.save(); 22 app.close();*/ 23 /* 24 UserServiceImpl: 初始化方法 25 itcast 26 com.mysql.jdbc.Driver 27 UserDaoImpl: save running... 28 七月 15, 2021 7:37:53 下午 org.springframework.context.support.AbstractApplicationContext doClose 29 信息: Closing org.springframework.context.support.ClassPathXmlApplicationContext@e2144e4: startup date [Thu Jul 15 19:37:52 CST 2021]; root of context hierarchy 30 */ 31 32 33 ApplicationContext app = new AnnotationConfigApplicationContext(SpringConfiguration.class); 34 UserService userService = app.getBean(UserService.class); 35 userService.save(); 36 /* 37 UserServiceImpl: 初始化方法 38 itcast 39 com.mysql.jdbc.Driver 40 UserDaoImpl: save running... 41 */ 42 } 43 44 }
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