spring入门到精通day01

前言：mvc框架在软件开发已经如日中天，不管是传统行业的ssh还是现今比较火热的ssm，spring都是不可或缺的“和事老”。由于本人也是spring学习的小白，本系列文档旨在记录spring学习的点点滴滴，如有错误，请各位大神多多斧正

环境：spring

1创建maven项目，结构如下图：

在pom.xml文件中导入两个依赖，pom.xml代码如下：

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion>
<groupId>com</groupId>
<artifactId>spring</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>war</packaging>

<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>4.3.8.RELEASE</version>
</dependency>

<!-- SpringJUnit4ClassRunner.class -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>4.3.8.RELEASE</version>
</dependency>
</dependencies>
</project>

2通过java代码装配bean

在testOnClass包下创建4个文件：

接口Student.java,

实现类SmallStudent.java,

配置类StudentConfig.java,

测试类StudentTest.java

代码分别如下：

Student.java

package testOnClass;

public interface Student {

void study();
}

SmallStudent.java

package testOnClass;

import org.springframework.stereotype.Component;

@Component //组件扫描
public class SmallStudent implements Student {

private String name = "王麻子";
private String subject = "该死的数学";
public void study() {
System.out.println(name + "学习" + subject);
}

}

StudentConfig.java

package testOnClass;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

@Configuration //配置组件扫描类
@ComponentScan //组件扫描同一包下的注解，如：@Component等
public class StudentConfig {

}

StudentTest.java

package testOnClass;

import static org.junit.Assert.*;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

@RunWith(SpringJUnit4ClassRunner.class) //需要导入spring-test
@ContextConfiguration(classes=StudentConfig.class) //导入组件扫描类
public class StudentTest {
@Autowired //自动装配含有@Component的类给student
private Student student;

@Test
public void componentScanTest() {
assertNotNull(student); //断言student对象是否存在
}

@Test
public void outTest() {
student.study(); //打印 王麻子学习该死的数学
}
}

3通过xml装配bean

由于spring默认读取根路径src下applicationContext.xml

在src/main/resources(注意：为什么是在如下路径，请自行百度maven项目结构)


在applicationContext.xml中配置如下信息：

<?xml version="1.0" encoding="UTF-8"?>
<beans default-autowire="byName"
xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:context="http://www.springframework.org/schema/context">

<!-- 扫描testOnXml中默认含有@Component注解的类 -->
<context:component-scan base-package="testOnXml"></context:component-scan>

</beans>

然后在web.xml

中配置如下信息：

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" version="3.0">
<display-name>spring test</display-name>
<welcome-file-list>
<welcome-file>/index.jsp</welcome-file>
</welcome-file-list>
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:applicationContext.xml</param-value>
</context-param>
</web-app>

接着同样的方式配置

接口Student.java

package testOnXml;

public interface Student {

void study();
}

实现类SmallStudent.java

package testOnXml;

import org.springframework.stereotype.Component;

@Component //组件扫描
public class SmallStudent implements Student {

private String name = "王麻子";
private String subject = "该死的数学";
public void study() {
System.out.println(name + "学习" + subject);
}

}

测试类StudentTest.java

package testOnXml;

import static org.junit.Assert.*;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

@RunWith(SpringJUnit4ClassRunner.class) //需要导入spring-test
@ContextConfiguration(locations={"classpath:applicationContext.xml"}) //导入组件扫描xml文件
public class StudentTest {
@Autowired //自动装配含有@Component的类给student
private Student student;

@Test
public void componentScanTest() {
assertNotNull(student); //断言student对象是否存在
}

@Test
public void outTest() {
student.study(); //打印 王麻子学习该死的数学
}
}

4结果