Spring源码阅读----从SSM开始熟悉Spring

作者: singleZhang2010 | 来源:发表于2021-01-18 16:56 被阅读0次

概述

Spring Framework

Spring是什么想必大家都很熟悉了，就不再多描述了。使用了很久的Spring，是不是很多人连原理都还没有弄清楚呢？这个系列开始，将通过一个基于SSM的demo项目来了解Spring的工作原理。前边我们已经分析过MyBatis的原理和源码了，这里开始分析Spring的原理和源码,此后再补上SpringMVC和SpringBoot。

用IDEA搭建SSM项目----整合Spirng、SpringMVC

通过IDEA创建web项目

maven-webapp

填写groupId和artifactId

maven-webapp

directory

我们按springboot项目的习惯，增加java和resources目录，并设置Sources Root和Resources Root，创建包

package

开始引入相关依赖,在pom.xml中添加依赖
先来引入Spring的各类依赖,包括SpringMVC包

    <!-- Spring相关包 -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-core</artifactId>
      <version>${spring.version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-aop</artifactId>
      <version>${spring.version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-web</artifactId>
      <version>${spring.version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-jdbc</artifactId>
      <version>${spring.version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-tx</artifactId>
      <version>${spring.version}</version>
    </dependency>
    <!-- Spring MVC相关包 -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>${spring.version}</version>
    </dependency>

5.创建一个TestController类,如下

package com.zhlab.ssm.demo.web.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;

/**
 * @ClassName TestController
 * @Description //TestController
 * @Author singleZhang
 * @Email 405780096@qq.com
 * @Date 2021/1/18 0018 下午 4:05
 **/

@Controller
@RequestMapping("/")
public class TestController {

    @GetMapping("/test")
    public String test(){
        System.out.println("this is a test demo !");
        return "test";
    }

}

因为返回视图,所以在WEB-INF下，我们创建一个jsp文件夹,添加test.jsp文件

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>test</title>
</head>
<body>
hello spring mvc
</body>
</html>

开始设置Spring相关配置信息
往WEB-INF下的web.xml中添加dispatcherServlet信息

  <!-- springMVC核心配置 -->
  <servlet>
    <servlet-name>dispatcherServlet</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
      <param-name>contextConfigLocation</param-name>
      <!--spingMVC的配置路径   如果是classspath：资源是在resources下面-->
      <param-value>/WEB-INF/spring-mvc.xml</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
  </servlet>
  <!-- 拦截设置 -->
  <servlet-mapping>
    <servlet-name>dispatcherServlet</servlet-name>
    <url-pattern>/</url-pattern>
  </servlet-mapping>

注意到上边的spring-mvc.xml,是spring的配置信息,在WEB-INF中创建一个spring-mvc.xml文件,内容如下:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:p="http://www.springframework.org/schema/p"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="
    http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
    http://www.springframework.org/schema/context
    http://www.springframework.org/schema/context/spring-context-3.2.xsd
    http://www.springframework.org/schema/mvc
    http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd">

    <!-- 扫描controller（controller层注入） -->
    <context:component-scan base-package="com.zhlab.ssm.demo.web.controller" use-default-filters="false">
        <context:include-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
    </context:component-scan>

    <mvc:annotation-driven />

    <!-- 内容协商管理器  -->
    <!--1、首先检查路径扩展名
        2、其次检查Parameter
        3、检查Accept Header-->
    <bean id="contentNegotiationManager" class="org.springframework.web.accept.ContentNegotiationManagerFactoryBean">
        <!-- 扩展名至mimeType的映射,即 /user.json => application/json -->
        <property name="favorPathExtension" value="true"/>
        <!-- 用于开启 /userinfo/123?format=json 的支持 -->
        <property name="favorParameter" value="true"/>
        <property name="parameterName" value="format"/>
        <!-- 是否忽略Accept Header -->
        <property name="ignoreAcceptHeader" value="false"/>

        <property name="mediaTypes"> <!--扩展名到MIME的映射；favorPathExtension, favorParameter是true时起作用  -->
            <value>
                json=application/json
                xml=application/xml
                html=text/html
            </value>
        </property>
        <!-- 默认的content type -->
        <property name="defaultContentType" value="text/html"/>
    </bean>

    <!-- 当在web.xml 中   DispatcherServlet使用 <url-pattern>/</url-pattern> 映射时，能映射静态资源 -->
    <mvc:default-servlet-handler />
    
    <!-- 静态资源映射 -->
    <mvc:resources mapping="/static/**" location="/WEB-INF/static/"/>

    <!-- 对模型视图添加前后缀 -->
    <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver"
          p:prefix="/WEB-INF/jsp/" p:suffix=".jsp"/>


</beans>

部署
tomcat的安装这里就不说了,我本地是tomcat-9.0.37
打开右上角的配置添加:

image.png

修改Deployment,+ ->artifact：ssmDemo_war_exploded

image.png

启动项目

start Spring

浏览器访问 http://localhost:8080/ssmDemo_war_exploded/test

image.png

用IDEA搭建SSM项目----整合MyBatis

添加MyBatis相关依赖

      <!-- MyBatis相关包 -->
      <dependency>
          <groupId>org.mybatis</groupId>
          <artifactId>mybatis</artifactId>
          <version>3.3.0</version>
      </dependency>

    <!--MySQL相关包 -->
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>5.1.26</version>
    </dependency>

    <!-- Spring集成MyBatis -->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis-spring</artifactId>
      <version>1.2.3</version>
    </dependency>

添加其他相关依赖,如日志、json解析、数据库连接池等依赖包

    <!--阿里数据库连接池 -->
    <dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>druid-spring-boot-starter</artifactId>
      <version>${druid.version}</version>
    </dependency>

    <!-- 日志相关包 -->
    <dependency>
      <groupId>log4j</groupId>
      <artifactId>log4j</artifactId>
      <version>1.2.17</version>
    </dependency>
    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-api</artifactId>
      <version>1.7.21</version>
    </dependency>

    <!-- json解析相关包 jackson -->
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-core</artifactId>
      <version>2.9.8</version>
    </dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-databind</artifactId>
      <version>2.9.8</version>
    </dependency>

    <!-- JSP标准标签库 -->
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>jstl</artifactId>
      <version>1.2</version>
    </dependency>

使用mybatis-generator插件,在pom.xml中加入插件

      <plugins>
        <plugin>
          <groupId>org.mybatis.generator</groupId>
          <artifactId>mybatis-generator-maven-plugin</artifactId>
          <version>1.3.7</version>
          <configuration>
            <configurationFile>
              ${basedir}/src/main/resources/generator/generatorConfig.xml
            </configurationFile>
            <overwrite>true</overwrite>
            <verbose>true</verbose>
          </configuration>
          <dependencies>
            <dependency>
              <groupId>mysql</groupId>
              <artifactId>mysql-connector-java</artifactId>
              <version>8.0.17</version>
            </dependency>
            <dependency>
              <groupId>com.itfsw</groupId>
              <artifactId>mybatis-generator-plugin</artifactId>
              <version>1.3.2</version>
            </dependency>
          </dependencies>
        </plugin>
      <plugins>

※这里有个坑，不要加在<pluginManagement>标签下
然后在resources/generator目录下创建generatorConfig.xml文件,内容如下:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE generatorConfiguration
        PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
        "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">

<generatorConfiguration>

    <context id="mysqlgenerator" targetRuntime="MyBatis3">
        <property name="autoDelimitKeywords" value="true"/>
        <!--可以使用``包括字段名，避免字段名与sql保留字冲突报错-->
        <property name="beginningDelimiter" value="`"/>
        <property name="endingDelimiter" value="`"/>

        <!-- 自动生成toString方法 -->
        <plugin type="org.mybatis.generator.plugins.ToStringPlugin"/>
        <!-- 自动生成equals方法和hashcode方法 -->
        <plugin type="org.mybatis.generator.plugins.EqualsHashCodePlugin"/>

        <!-- 非官方插件 https://github.com/itfsw/mybatis-generator-plugin -->
        <!-- 查询单条数据插件 -->
        <plugin type="com.itfsw.mybatis.generator.plugins.SelectOneByExamplePlugin"/>
        <!-- 查询结果选择性返回插件 -->
        <plugin type="com.itfsw.mybatis.generator.plugins.SelectSelectivePlugin"/>
        <!-- Example Criteria 增强插件 -->
        <plugin type="com.itfsw.mybatis.generator.plugins.ExampleEnhancedPlugin"/>
        <!-- 数据Model属性对应Column获取插件 -->
        <plugin type="com.itfsw.mybatis.generator.plugins.ModelColumnPlugin"/>
        <!-- 逻辑删除插件 -->
        <plugin type="com.itfsw.mybatis.generator.plugins.LogicalDeletePlugin">
            <!-- 这里配置的是全局逻辑删除列和逻辑删除值，当然在table中配置的值会覆盖该全局配置 -->
            <!-- 逻辑删除列类型只能为数字、字符串或者布尔类型 -->
            <property name="logicalDeleteColumn" value="deleted"/>
            <!-- 逻辑删除-已删除值 -->
            <property name="logicalDeleteValue" value="1"/>
            <!-- 逻辑删除-未删除值 -->
            <property name="logicalUnDeleteValue" value="0"/>
        </plugin>

        <commentGenerator>
            <property name="suppressDate" value="true"/>
            <!--<property name="suppressAllComments" value="true"/>-->
        </commentGenerator>

        <!--数据库连接信息-->
        <jdbcConnection driverClass="com.mysql.jdbc.Driver"
                        connectionURL="jdbc:mysql://127.0.0.1:3306/demo?useUnicode=true&amp;characterEncoding=UTF-8&amp;serverTimezone=UTC&amp;verifyServerCertificate=false&amp;useSSL=false&amp;nullCatalogMeansCurrent=true"
                        userId="root"
                        password="root"/>

        <javaTypeResolver>
            <property name="useJSR310Types" value="true"/>
        </javaTypeResolver>
        <!--代码生成目录-->
        <javaModelGenerator targetPackage="com.zhlab.ssm.demo.web.model" targetProject="src/main/java"/>
        <sqlMapGenerator targetPackage="mapper" targetProject="src/main/resources"/>
        <javaClientGenerator type="XMLMAPPER" targetPackage="com.zhlab.ssm.demo.web.mapper"
                             targetProject="src/main/java"/>
        <!--表名，有多少个写多少个-->
        <table tableName="sys_admin_user" domainObjectName="SysAdminUser">
            <generatedKey column="admin_user_id" sqlStatement="MySql" identity="true"/>
        </table>

    </context>
</generatorConfiguration>

双击生成代码

generator

success

在resources下新建jdbc.properties文件和spring-mybatis.xml
jdbc.properties

jdbc_driverClassName =com.mysql.jdbc.Driver
jdbc_url=jdbc:mysql://127.0.0.1:3306/demo?useUnicode=true&amp;characterEncoding=UTF-8&amp;serverTimezone=UTC&amp;verifyServerCertificate=false&amp;useSSL=false&amp;nullCatalogMeansCurrent=true"
jdbc_username=root
jdbc_password=root

spring-mybatis.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:aop="http://www.springframework.org/schema/aop"
       xmlns:tx="http://www.springframework.org/schema/tx" xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
   http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.2.xsd
   http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.2.xsd
   http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd">

    <!-- 3.配置数据源 ，使用alibaba-druid数据库连接池-->
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource" init-method="init" destroy-method="close">
        <!-- 基本属性 url、user、password -->
        <property name="driverClassName" value="${jdbc_driverClassName}"/>
        <property name="url" value="${jdbc_url}"/>
        <property name="username" value="${jdbc_username}"/>
        <property name="password" value="${jdbc_password}"/>
        <property name="initialSize" value="10"/>
        <property name="minIdle" value="10"/>
        <property name="maxActive" value="50"/>
        <property name="maxWait" value="60000"/>
        <property name="timeBetweenEvictionRunsMillis" value="60000" />
        <property name="minEvictableIdleTimeMillis" value="300000" />
        <property name="validationQuery" value="SELECT 'x'" />
        <property name="testWhileIdle" value="true" />
        <property name="testOnBorrow" value="false" />
        <property name="testOnReturn" value="false" />
        <property name="poolPreparedStatements" value="false" />
        <property name="maxPoolPreparedStatementPerConnectionSize" value="20" />
        <property name="filters" value="wall,stat" />
    </bean>

    <!-- spring和MyBatis完美整合，不需要mybatis的配置映射文件 -->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <!-- 自动扫描mapping.xml文件 -->
        <property name="mapperLocations" value="classpath:/mapper/*.xml"></property>
    </bean>


    <!-- DAO接口所在包名，Spring会自动查找其下的类 ,自动扫描了所有的XxxxMapper.xml对应的mapper接口文件,只要Mapper接口类和Mapper映射文件对应起来就可以了-->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.zhlab.ssm.demo.web.mapper" />
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"></property>
    </bean>

    <!-- (事务管理)transaction manager, use JtaTransactionManager for global tx -->
    <!-- 配置事务管理器 -->
    <bean id="transactionManager"
          class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource" />
    </bean>

    <!-- 配置基于注解的声明式事务 -->
    <!-- enables scanning for @Transactional annotations -->
    <tx:annotation-driven transaction-manager="transactionManager" />

</beans>

在resources下新建applicationContext.xml配置文件,加入上面创建的两个文件路径

<?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:aop="http://www.springframework.org/schema/aop"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
">
    <!-- 1.配置jdbc文件 -->
    <bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
        <property name="locations" value="classpath:jdbc.properties"/>
    </bean>

    <!-- 2.扫描的包路径，这里不扫描被@Controller注解的类 --><!--使用<context:component-scan/> 可以不在配置<context:annotation-config/> -->
    <context:component-scan base-package="com.zhlab.ssm.demo">
        <context:exclude-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
    </context:component-scan>

    <import resource="classpath:spring-mybatis.xml" />

</beans>

web.xml中引入spring相关配置,加入上面创建的applicationContext.xml路径:

    <!-- 读取spring配置文件 -->
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:applicationContext.xml</param-value>
    </context-param>

弄完以上配置,开始写service接口,写一个SysAdminUserService接口和实现类

public interface SysAdminUserService {

    List<SysAdminUser> selectAll(SysAdminUser user);


}

SysAdminUserServiceImpl.java

/**
 * @ClassName SysAdminUserServiceImpl
 * @Description //SysAdminUserServiceImpl
 * @Author singleZhang
 * @Email 405780096@qq.com
 * @Date 2021/1/19 0019 上午 10:57
 **/
@Service
public class SysAdminUserServiceImpl implements SysAdminUserService {


    @Autowired
    SysAdminUserMapper sysAdminUserMapper;

    @Override
    public List<SysAdminUser> selectAll(SysAdminUser user){
        return sysAdminUserMapper.selectAll(user);
    }

}

7.写一个测试接口,在之前的TestController里添加

   @Autowired
    SysAdminUserService sysAdminUserService;

    @GetMapping("/userList")
    @ResponseBody
    public List<SysAdminUser> list(){

        return sysAdminUserService.selectAll(new SysAdminUser());
    }

打开postman,访问http://localhost:8080/ssmDemo_war_exploded/userList,结果如下:

测试结果

也可以直接写一个main方法来调用bean,如下App.java:

/**
 * @ClassName App
 * @Description //App
 * @Author singleZhang
 * @Email 405780096@qq.com
 * @Date 2021/1/19 0019 下午 3:02
 **/
public class App {

    public static void main(String[] args) throws ClassNotFoundException {
        //XmlBeanFactory因为已经被废弃,这里使用了ClassPathXmlApplicationContext
        ClassPathXmlApplicationContext context =
                new ClassPathXmlApplicationContext("applicationContext.xml");

        SysAdminUserService s = (SysAdminUserService)context.getBean(SysAdminUserService.class);

        List<SysAdminUser> list = s.selectAll(new SysAdminUser());
        list.stream().forEach(System.out::println);
    }

}

运行main方法，结果如下:

Spring中Bean的使用

好了,SSM的demo示例就已经完成了。

demo代码已传gitee:
https://gitee.com/kaixinshow/my-batis-note

总结

Spring常用模块

在用SpringBoot做项目熟悉了之后，回过来弄SSM框架的项目应该是比较简单的，搭建方面的工作不再过多描述，我们的目的主要是聚焦在对Spring常用模块的原理以及源码进行分析。

Spring源码阅读----从SSM开始熟悉Spring

概述

用IDEA搭建SSM项目----整合Spirng、SpringMVC

用IDEA搭建SSM项目----整合MyBatis

总结

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