Spring Annotations light into the light - do not brag force is not loaded to force

Spring Annotations light into the light - do not brag force is not loaded to force

Recap

The instruments we say " Spring light into the light ," Spring's core idea read Part friends should already know, Cipian spend bedding articles, the introduction of notes, for further study.

 

The introduction of notes

In the Spring framework, despite the use of XML configuration files can be simply fitted Bean, but if there are a large number of applications need to assemble Bean, will lead to an XML configuration file is too large, the future is not convenient to upgrade and maintain, therefore, we recommend developers use Notes ways to assemble Bean.

 

Detailed notes

Of notes is not clear you can see my blog " Notes ", in fact, is a class annotated, use annotations replace the XML configuration file in development.

1. @Component substituted <bean class = ""> </ the bean>
    @Component ( "ID value")

2. Web development, provides annotations derived annotation @Component 3 (function as) a substituted <bean class = "" > </ bean>
    the @Repository: DAO layer
    @Service: service layer
    @Controller: web layer
        Note: SpringMVC recommended using annotations Oh!
3. dependency injection, is provided to the private field, may be provided to setter methods
    Normal values: @Value ( "")
    reference value:
        Embodiment 1: [type] according to the injection
            @Autowired
        Embodiment 2: [type + according to Title 1] implanted
            @ Autowired is
            @Qualifier ( "name")
        mode 3: injection according to [name] 2
            @Resource ( "name")
4. life cycle
    @PostConstruct: initialization
    @PreDestroy: destruction
5.

 

Configuration Notes

With the use of annotations Bean implementation class, but now does not know where to go Spring container scanning Bean object, you need to configure comment in the configuration file.

<?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"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       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
       http://www.springframework.org/schema/tx
       http://www.springframework.org/schema/tx/spring-tx.xsd
       http://www.springframework.org/schema/mvc 
       http://www.springframework.org/schema/mvc/spring-mvc.xsd 
        "> 
    <-! using the context namespace specified by Spring scanning and annotation sub-packet all packages Bean implementation class, annotated parse -> 
    <context: Component Base-package-Scan = "com.my"> </ context: Scan-Component> 

</ Beans>

　　

Practice Case

A, Pom.xml

<dependencies>

  <dependency>

    <groupId>junit</groupId>

    <artifactId>junit</artifactId>

    <version>4.11</version>

    <scope>test</scope>

  </dependency>

  <dependency>

    <groupId>javax.servlet</groupId>

    <artifactId>javax.servlet-api</artifactId>

    <version>3.1.0</version>

  </dependency>

  <dependency>

    <groupId>javax.servlet</groupId>

    <artifactId>jstl</artifactId>

    <version>1.2</version>

  </dependency>

  <dependency>

    <groupId>commons-logging</groupId>

    <artifactId>commons-logging</artifactId>

    <version>1.2</version>

  </dependency>



  <!--spring核心依赖-->

  <dependency>

    <groupId>mysql</groupId>

    <artifactId>mysql-connector-java</artifactId>

    <version>5.1.38</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-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-jdbc</artifactId>

    <version>5.1.5.RELEASE</version>

  </dependency>

  <dependency>

    <groupId>org.springframework</groupId>

    <artifactId>spring-web</artifactId>

    <version>5.1.5.RELEASE</version>

  </dependency>

  <dependency>

    <groupId>org.springframework</groupId>

    <artifactId>spring-webmvc</artifactId>

    <version>5.1.5.RELEASE</version>

  </dependency>

  <dependency>

    <groupId>org.springframework</groupId>

    <artifactId>spring-expression</artifactId>

    <version>5.1.5.RELEASE</version>

  </dependency>

  <dependency>

    <groupId>org.springframework</groupId>

    <artifactId>spring-tx</artifactId>

    <version>5.1.5.RELEASE</version>

  </dependency>



</dependencies>

　　

 

 

二、spring-config.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"

       xmlns:tx="http://www.springframework.org/schema/tx"

       xmlns:mvc="http://www.springframework.org/schema/mvc"

       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

       http://www.springframework.org/schema/tx

       http://www.springframework.org/schema/tx/spring-tx.xsd 

       http://www.springframework.org/schema/mvc 

       http://www.springframework.org/schema/mvc/spring-mvc. XSD 

        "> 

    ! <- annotations arranged to scan packages -> 

    <context: Component Base-package-scan =" com.my "> </ context: scan-Component> 
</ Beans>

　　

三、UserDao

package com.my.dao;



public interface UserDao {

    public void add();

    public void delete();

    public void update();

    public void query();

}

　　

 

Four, UserDaoImpl

com.my.dao.impl Package; 



Import com.my.dao.UserDao; 

Import org.springframework.stereotype.Repository; 



@Repository 

public class UserDaoImpl the implements UserDao { 

    @Override 

    public void the Add () { 

        System.out.println ( " add functionality in UserDao achieved "); 

    } 



    @Override 

    public void delete () { 

        System.out.println (" deletion function is achieved UserDao "); 

    } 



    @Override 

    public void Update () { 

        System.out.println ( "the editing UserDao achieved"); 

    } 



    @Override 

    public void query () { 

        System.out.println ( "search function in UserDao achieved"); 

    } 

}

　　

 

Five, UserService

package com.my.service;



public interface UserService {

    public void add();

    public void delete();

    public void update();

    public void query();

}

　　

 

Six, UserServiceImpl

package com.my.service.impl;



import com.my.dao.UserDao;

import com.my.dao.impl.UserDaoImpl;

import com.my.service.UserService;

import org.springframework.stereotype.Service;



@Service

public class UserServiceImpl implements UserService {



    private UserDao userDao = new UserDaoImpl();

    @Override

    public void add() {

        userDao.add();

    }



    @Override

    public void delete() {

        userDao.delete();

    }



    @Override

    public void update() {

        userDao.update();

    }



    @Override

    public void query() {

        userDao.query();

    }

}

　　

 

七、UserController

package com.my.controller;



import com.my.service.UserService;

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

import org.springframework.stereotype.Component;

import org.springframework.stereotype.Controller;

import org.springframework.stereotype.Service;



@Controller

public class UserController {

    @Autowired

    private UserService userService;



    public void add(){

        userService.add();

    }



    public void delete(){

        userService.delete();

    }



    public void update(){

        userService.update();

    }



    public void query(){

        userService.query();

    }

}

　　

 

Eight, test Test2

package com.my.test;



import com.my.controller.UserController;

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;



public class Test2 {

    public static void main(String[] args) {

        ApplicationContext appCon = new ClassPathXmlApplicationContext("spring-config.xml");

        UserController userController = (UserController) appCon.getBean("userController");



        userController.add();

        userController.delete();

        userController.update();

        userController.query();

    }

}

　　

 

 

Nine, the test results

 

 

 

 

End summary

After reading this post and articles on Bean's friends should have two common assembly methods, which is based on assembly and annotation of assembly XML-based configuration, which Cipian annotation-based assembly method is particularly important, it is the current mainstream assembly method.

 

 

 

 

 

 

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