SpringMVC介绍

SpringMVC是属于是spring中web模块的支持一部分
实现的了WEB MVC的设计模式，进行web层的职责解耦
请求驱动类型的web框架:请求-响应的模型

SpringMVC的运行原理

组件：
前端控制器：控制中心，组件间解耦合(无需开发/配置即可)
处理器映射器：匹配URL是否存在(无需开发/配置即可)
处理器适配器：适配查找具体处理器(无需开发/配置即可)
处理器：不同URL处理逻辑不同(需要开发 后端java)
视图解析器：查找View实例对象(无需开发/配置即可)
视图：web页面(jsp、freemark、pdf等类型视图)(需要开发/网页)

SpringMVC的使用

web项目需要放在容器里执行(Tomcat/jetty)本文用的是jetty

1、依赖jar包

springMVC中web依赖：

        <!--web依赖-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>4.1.7.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>4.1.7.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.1.0</version>
        </dependency>
        
    <!--Spring 基本核心jar包-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
            <version>4.1.7.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>4.1.7.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>4.1.7.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-expression</artifactId>
            <version>4.1.7.RELEASE</version>
        </dependency>
        <!--log4j日志-->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
        <!--注解相关jar包-->
        <dependency>
            <groupId>commons-logging</groupId>
            <artifactId>commons-logging</artifactId>
            <version>1.2</version>
        </dependency>        

2、在web.xml中配置前端控制器

<?xml version="1.0" encoding="UTF-8"?>

<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
        http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">

    <!--配置前端控制器-->
    <servlet>
        <servlet-name>springmvc-gysx</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>springmvc-gysx</servlet-name>
        <url-pattern>/</url-pattern>
        <!--http://www.baidu.com/index-->
    </servlet-mapping>
</web-app>

注意：前端控制器需要使用org.springframework.web.servlet.DispatcherServlet会拦截指定格式的URL到DispatcherServlet

3、创建SpringMVC的配置文件

创建一个spring-mvc.xml文件，放在资源文件路径下resource下，配置映射器，适配器和解析器

<?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: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-4.1.xsd

        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.1.xsd">

    <!--配置SpringMVC的需要扫描的包路径-->
    <context:component-scan base-package="com.tulun.gysx.controller"/>
    
    <!--配置映射器、适配器:使用默认的处理器处理，不用显性配置映射器、适配器-->
    <mvc:annotation-driven/>
    
    <!--视图解析器-->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"/>

</beans>

注意：将spring-mvc.xml配置文件加载到web.xml配置文件中，方便加载

        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:spring-mvc.xml</param-value>
        </init-param>

4、编写controller层

@Controller
public class TestController 

    @RequestMapping("/gysx")
    public String gysx() 
        //返回页面
        return "index.jsp";
    

5、编写jsp页面

    <%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
        <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
        <%@ taglib uri="http://java.sun.com/jsp/jstl/fmt"  prefix="fmt"%>
        <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
        <html>
        <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>success</title>
        </head>
        <body>
        <h1>你好，同学们！</h1>
        </body>
        </html>

日志分析

1、日志依赖

        <!--log4j日志文件-->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>

2、日志配置文件

创建log4j.properties文件

## debug 级别  

log4j.rootLogger=DEBUG,Console  

log4j.appender.Console=org.apache.log4j.ConsoleAppender  

log4j.appender.Console.Target=System.out  

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

log4j.appender.Console.layout.ConversionPattern=%dyyyy-MM-dd-HH\\:mm\\:ss,SSS [%t]  [%c] [%p] - %m%n  

log4j.logger.com.mybatis=DEBUG  /  



##输出sql 语句  

log4j.logger.java.sql.Connection=DEBUG  

log4j.logger.java.sql.Statement=DEBUG  

log4j.logger.java.sql.PreparedStatement=DEBUG 

3、日志打印

  2021-07-02-10:31:27,929 [main]  [org.apache.ibatis.transaction.jdbc.JdbcTransaction] [DEBUG] - Setting autocommit to false on JDBC Connection [com.mysql.jdbc.JDBC4Connection@dc24521]
  2021-07-02-10:31:27,931 [main]  [com.tulun.mapper.StudentMapperGY.selectStudentById] [DEBUG] - ==>  Preparing: select * from student where SID = ? 
  2021-07-02-10:31:28,036 [main]  [com.tulun.mapper.StudentMapperGY.selectStudentById] [DEBUG] - ==> Parameters: 3(Integer)
  2021-07-02-10:31:28,196 [main]  [com.tulun.mapper.StudentMapperGY.selectStudentById] [DEBUG] - <==      Total: 1
  "SID":3,"Sname":"sunfen","Ssex":"nan","Sage":21

数据插入示例

insert into student (XXX) values():

mapper.java接口文件

    //插入数据
    int insertStudent(Student student);

mapper.xml文件

    <!--插入数据-->
    <insert id="insertStudent" parameterType="com.tulun.bean.StudentGY">
        insert into student (SID,Sname,Sage,Ssex) values (#SID,#Sname,#Sage,#Ssex)
    </insert>

执行代码：

        //指定mybatis的全局配置文件
        String fileName= "mybatis-config.xml";
        //通过流的形式来读取配置文件
        InputStream inputStream = Resources.getResourceAsStream(fileName);
        //创建会话工厂
        SqlSessionFactory sqlSessionFactory =
                new SqlSessionFactoryBuilder().build(inputStream);
        //获取会话
        SqlSession sqlSession = sqlSessionFactory.openSession();
        //通过动态代理获取一个代理对象
        StudentMapperGY studentMapperGY = sqlSession.getMapper(StudentMapperGY.class);

//        插入操作
        StudentGY studentGY = new StudentGY();
        studentGY.setSID(21);
        studentGY.setSname("GYSX");
        studentGY.setSage(21);
        studentGY.setSsex("nan");
        studentMapperGY.insertStudent(studentGY);
        sqlSession.commit();

删除数据示例

mapper.java接口文件

    //删除数据
    int delStudentById(Integer id);

mapper.xml配置文件

    <!--删除数据-->
    <delete id="delStudentById" parameterType="int">
        delete from student where SID = #id
    </delete>

修改数据示例

mapper.java接口文件

   //修改数据
    int updateNameById(StudentGY studentGY);

mapper.xml配置文件

    <!--修改数据-->
    <update id="updateNameById"  parameterType="com.tulun.bean.StudentGY">
        update student set Sname = #Sname where SID = #SID
    </update>