spring学习笔记之---bean管理的注解方式

bean管理的注解方式

（一）使用注解定义bean

（1）常用注解

（2）实例

1.在pom.xml中进行配置

<dependencies>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-jdbc</artifactId>
    <version>5.1.5.RELEASE</version>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-context</artifactId>
    <version>5.1.5.RELEASE</version>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-aop</artifactId>
    <version>5.1.5.RELEASE</version>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-core</artifactId>
    <version>5.1.5.RELEASE</version>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-beans</artifactId>
    <version>5.1.5.RELEASE</version>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-tx</artifactId>
    <version>5.1.5.RELEASE</version>
  </dependency>
  <dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.11</version>
  </dependency>
</dependencies>

2.创建一个类，在类中写一个方法，在类上加一个注解@Component

package service;

import org.junit.Test;

import org.springframework.stereotype.Component;

import sun.misc.Contended;

@Component("UserService")

public class UserService {

    public String Hello(){

        return "hello";

    }

}

3.创建一个applicationContext.xml，在里面配置包扫描

<?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">

    <!--开启注解扫描=======================-->

    <context:component-scan base-package="service"></context:component-scan>

        </beans>

4.创建一个log4j.properties

### direct log messages to stdout ###

log4j.appender.stdout=org.apache.log4j.ConsoleAppender

log4j.appender.stdout.Target=System.err

log4j.appender.stdout.layout=org.apache.log4j.PatternLayout

log4j.appender.stdout.layout.ConversionPattern=%d{ABSOLUTE} %5p %c{1}:%L - %m%n

### direct messages to file mylog.log ###

log4j.appender.file=org.apache.log4j.FileAppender

log4j.appender.file.File=c\:mylog.log

log4j.appender.file.layout=org.apache.log4j.PatternLayout

log4j.appender.file.layout.ConversionPattern=%d{ABSOLUTE} %5p %c{1}:%L - %m%n

### set log levels - for more verbose logging change 'info' to 'debug' ###

log4j.rootLogger=info, stdout

5.创建一个测试类

package test;

import org.junit.Test;

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

import service.UserService;

public class UserTest {

    @Test

    public void hellotest(){

        ApplicationContext applicationContext=new ClassPathXmlApplicationContext("applicationContext.xml");

        UserService userService=(UserService)applicationContext.getBean("UserService");

        String s=userService.Hello();

        System.out.println(s);

    }

}

（二）属性注入的注解

（1）常用注解

1.属性注入

package service;

import org.junit.Test;

import org.springframework.beans.factory.annotation.Value;

import org.springframework.stereotype.Component;

import sun.misc.Contended;

@Component("UserService")

public class UserService {

    @Value("小欢")

    private String name;

    public String Hello(){

        return "hello"+name;

    }

}
 

2.类注入

（a）UserService.java

package service;

import dao.UserDao;

import org.junit.Test;

import org.springframework.beans.factory.annotation.Value;

import org.springframework.stereotype.Component;

import sun.misc.Contended;

import javax.annotation.Resource;

@Component("UserService")

public class UserService {

    @Value("小欢")

    private String name;

    @Resource(name="UserDao")

    private UserDao userDao;

    public String Hello(){

        System.out.println("service中的hello");

        return "hello"+name;

    }

}

（b）UserDao.java

package dao;

import org.springframework.stereotype.Repository;

@Repository("UserDao")

public class UserDao {

    public void Hello(){

        System.out.println("dao 中的hello");

    }

}

（c）applicationContext.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">

    <!--开启注解扫描=======================-->

    <context:component-scan base-package="service,dao"></context:component-scan>

        </beans>

（d）UserTest.java

package test;

import org.junit.Test;

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

import service.UserService;

public class UserTest {

    @Test

    public void hellotest(){

        ApplicationContext applicationContext=new ClassPathXmlApplicationContext("applicationContext.xml");

        UserService userService=(UserService)applicationContext.getBean("UserService");

        String s=userService.Hello();

        System.out.println(s);

    }

}

（三）其他注解

（四）xml和注解整合开发

1.UserService2.java

package service;

import dao.UserDao2;

import org.springframework.stereotype.Repository;

import javax.annotation.Resource;

public class UserService2 {

    @Resource(name="UserDao2")

    private UserDao2 userDao2;

    public void He(){

        userDao2.He();

        System.out.println("userservice2中的he");

    }

}

2.UserDao2.java

package dao;

public class UserDao2 {

    public void He(){

        System.out.println("userdao2中的he");

    }

}

3.applicationContext.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">

    <context:annotation-config/>

    <bean id="UserService2" class="service.UserService2"/>

    <bean id="UserDao2" class="dao.UserDao2"/>

        </beans>

4.UserTest.java

package test;

import org.junit.Test;

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

import service.UserService;

import service.UserService2;

public class UserTest {

    @Test

    public void hetest(){

        ApplicationContext applicationContext=new ClassPathXmlApplicationContext("applicationContext.xml");

        UserService2 userService2=(UserService2)applicationContext.getBean("UserService2");

        userService2.He();

    }

}