Spring——第一个Spring-Web项目（三层架构实现前后端数据交互）

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文章目录：

1.写在开头

2.项目的大体步骤 

2.1 项目大致结构 

2.2 IDEA中使用Maven创建一个web 

2.3 在pom.xml文件中加入依赖

2.4 创建Student实体类

2.5 创建dao接口和对应的mapper文件

2.5.1 StudentDao接口 

2.5.2 StudentDao.xml 

2.6 创建mybatis主配置文件

2.7 创建service接口和实现类

2.7.1 StudentService接口 

2.7.2 StudentServiceImpl实现类

2.8 创建jdbc外部属性配置文件、spring配置文件

2.9 创建servlet

2.9.1 AddStudentServlet——对应添加学生操作

2.9.2 QueryStudentServlet——对应查询学生操作

2.9.3 在web.xml中注册servlet和监听器 

2.10 创建jsp页面——提交请求参数、显示请求处理结果

2.10.1 提交请求参数 

2.10.2 显示请求处理结果——对应AddStudentServlet

2.10.3 显示请求处理结果——对应QueryStudentServlet

2.11 启动tomcat，测试！！！

2.11.1 AddStudentServlet的测试结果

2.11.2 QueryStudentServlet的测试结果

1.写在开头

在学完了Java Web（Tomcat、Servlet、JSP、MVC）、MyBatis、Spring这些内容之后，大脑里基本有了三层架构的整体框架，所以这里就想着去试着写一个简单的Spring-Web项目，实现一下前端页面和后端数据库的交互。

刚刚开始学，文章中有写的不到位的地方，还希望大佬指出，感谢感谢！！！

2.项目的大体步骤 

2.1 项目大致结构 

  1. controller包：界面层
  2. dao包：数据库访问层
  3. service包：业务逻辑层
  4. entity包：每一个Java类对应于数据库中的一个表
  5. resources目录：mybatis主配置文件、spring配置文件、jdbc外部属性配置文件
  6. webapp：web项目相关内容，注册servlet、监听器、jsp页面

2.2 IDEA中使用Maven创建一个web 

2.3 在pom.xml文件中加入依赖

<dependencies>

    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>4.0.1</version>
      <scope>provided</scope>
    </dependency>

    <dependency>
      <groupId>javax.servlet.jsp</groupId>
      <artifactId>jsp-api</artifactId>
      <version>2.2.1-b03</version>
      <scope>provided</scope>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>5.2.5.RELEASE</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-tx</artifactId>
      <version>5.2.5.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-jdbc</artifactId>
      <version>5.2.5.RELEASE</version>
    </dependency>

    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis-spring</artifactId>
      <version>1.3.1</version>
    </dependency>

    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis</artifactId>
      <version>3.5.1</version>
    </dependency>

    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>5.1.9</version>
    </dependency>

    <dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>druid</artifactId>
      <version>1.1.12</version>
    </dependency>

    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
      <scope>test</scope>
    </dependency>

    <!-- 监听器的依赖 -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-web</artifactId>
      <version>5.2.5.RELEASE</version>
    </dependency>
<build>
    <resources>
      <resource>
        <directory>src/main/java</directory><!--所在的目录-->
        <includes><!--包括目录下的.properties,.xml 文件都会扫描到-->
          <include>**/*.properties</include>
          <include>**/*.xml</include>
        </includes>
        <filtering>false</filtering>
      </resource>
    </resources>
</build>

2.4 创建Student实体类

package com.bjpowernode.entity;

/**
 *
 */
public class Student 

    private Integer id;
    private String name;
    private Integer age;

    public Integer getId() 
        return id;
    

    public void setId(Integer id) 
        this.id = id;
    

    public String getName() 
        return name;
    

    public void setName(String name) 
        this.name = name;
    

    public Integer getAge() 
        return age;
    

    public void setAge(Integer age) 
        this.age = age;
    

    @Override
    public String toString() 
        return "Student" +
                "id=" + id +
                ", name='" + name + '\\'' +
                ", age=" + age +
                '';

2.5 创建dao接口和对应的mapper文件

2.5.1 StudentDao接口 

package com.bjpowernode.dao;

import com.bjpowernode.entity.Student;
import org.apache.ibatis.annotations.Param;

/**
 *
 */
public interface StudentDao 

    int insertStudent(Student student);

    Student selectById(@Param("studentId") Integer id);

2.5.2 StudentDao.xml 

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.bjpowernode.dao.StudentDao">
    <!-- 使用insert、update、delete、select标签编写sql语句 -->
    <insert id="insertStudent">
        insert into student2(name,age) values (#name,#age)
    </insert>

    <select id="selectById" resultType="com.bjpowernode.entity.Student">
        select id,name,age
        from student2
        where id=#studentId
    </select>

</mapper>

2.6 创建mybatis主配置文件

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>

    <!-- 设置日志 -->
    <settings>
        <setting name="logImpl" value="STDOUT_LOGGING"/>
    </settings>

    <mappers>
        <mapper resource="com/bjpowernode/dao/StudentDao.xml"/>
    </mappers>

</configuration>

2.7 创建service接口和实现类

2.7.1 StudentService接口 

package com.bjpowernode.service;

import com.bjpowernode.entity.Student;

/**
 *
 */
public interface StudentService 

    int addStudent(Student student);

    Student findStudent(Integer id);

2.7.2 StudentServiceImpl实现类

package com.bjpowernode.service.impl;

import com.bjpowernode.dao.StudentDao;
import com.bjpowernode.entity.Student;
import com.bjpowernode.service.StudentService;

/**
 *
 */
public class StudentServiceImpl implements StudentService 

    private StudentDao studentDao;

    public void setStudentDao(StudentDao studentDao) 
        this.studentDao = studentDao;
    

    @Override
    public int addStudent(Student student) 
        int rows=studentDao.insertStudent(student);
        return rows;
    

    @Override
    public Student findStudent(Integer id) 
        Student student=studentDao.selectById(id);
        return student;

2.8 创建jdbc外部属性配置文件、spring配置文件

jdbc.driverClassName=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/ssm?useUnicode=true&amp;characterEncoding=UTF-8
jdbc.username=root
jdbc.password=12345678
<?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 https://www.springframework.org/schema/context/spring-context.xsd">

    <context:property-placeholder location="classpath:jdbc.properties" />

    <bean id="myDataSource" class="com.alibaba.druid.pool.DruidDataSource" init-method="init" destroy-method="close">
        <property name="driverClassName" value="$jdbc.driverClassName"/>
        <property name="url" value="$jdbc.url"/>
        <property name="username" value="$jdbc.username"/>
        <property name="password" value="$jdbc.password"/>
    </bean>

    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="myDataSource"/>
        <property name="configLocation" value="classpath:mybatis.xml"/>
    </bean>

    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
        <property name="basePackage" value="com.bjpowernode.dao"/>
    </bean>

    <bean id="studentService" class="com.bjpowernode.service.impl.StudentServiceImpl">
        <property name="studentDao" ref="studentDao"/>
    </bean>

</beans>

2.9 创建servlet

2.9.1 AddStudentServlet——对应添加学生操作

package com.bjpowernode.controller;

import com.bjpowernode.entity.Student;
import com.bjpowernode.service.StudentService;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.IOException;

public class AddStudentServlet extends HttpServlet 
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException 

    

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException 
        request.setCharacterEncoding("utf-8");
        response.setContentType("text/html;charset=utf-8");
        String strName=request.getParameter("name");
        String strAge=request.getParameter("age");

        //获取全局作用域对象，确保spring容器对象只创建一次
        ServletContext servletContext=getServletContext();
        //使用spring提供的工具方法，获取容器对象
        WebApplicationContext ctx= WebApplicationContextUtils.getRequiredWebApplicationContext(servletContext);

        StudentService service= (StudentService) ctx.getBean("studentService");

        Student student=new Student();
        student.setName(strName);
        student.setAge(Integer.valueOf(strAge));

        service.addStudent(student);

        //给用户显示请求的处理结果
        request.getRequestDispatcher("/show.jsp").forward(request,response);

2.9.2 QueryStudentServlet——对应查询学生操作

package com.bjpowernode.controller;

import com.bjpowernode.entity.Student;
import com.bjpowernode.service.StudentService;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 *
 */
public class QueryStudentServlet extends HttpServlet 

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException 
        request.setCharacterEncoding("utf-8");
        response.setContentType("text/html;charset=utf-8");
        String stuId=request.getParameter("stuid");

        //获取全局作用域对象，确保spring容器对象只创建一次
        ServletContext servletContext=getServletContext();
        //使用spring提供的工具方法，获取容器对象
        WebApplicationContext ctx= WebApplicationContextUtils.getRequiredWebApplicationContext(servletContext);

        StudentService service= (StudentService) ctx.getBean("studentService");

        Student student=service.findStudent(Integer.parseInt(stuId));
        System.out.println("student对象===" + student);

        request.setAttribute("stu",student);
        request.getRequestDispatcher("/second.jsp").forward(request,response);
    

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException

2.9.3 在web.xml中注册servlet和监听器 

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
    <servlet>
        <servlet-name>AddStudentServlet</servlet-name>
        <servlet-class>com.bjpowernode.controller.AddStudentServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>AddStudentServlet</servlet-name>
        <url-pattern>/add</url-pattern>
    </servlet-mapping>

    <servlet>
        <servlet-name>QueryStudentServlet</servlet-name>
        <servlet-class>com.bjpowernode.controller.QueryStudentServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>QueryStudentServlet</servlet-name>
        <url-pattern>/query</url-pattern>
    </servlet-mapping>

    <!--
        自定义容器使用的配置文件路径
        context-param: 上下文参数，给监听器提供参数的
    -->
    <context-param>
        <!-- 固定名称，表示自定义spring配置文件的路径 -->
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:spring-beans.xml</param-value>
    </context-param>
    <!-- 声明监听器对象 -->
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
</web-app>

2.10 创建jsp页面——提交请求参数、显示请求处理结果

2.10.1 提交请求参数 

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
    <div align="center">
        <p>添加学生</p>
        <form action="/springWeb/add" method="post">
            姓名：<input type="text" name="name"><br/>
            年龄：<input type="text" name="age"><br/>
            <input type="submit" value="注册学生">
        </form>
        <br/><br/>
        <p>查询学生</p>
        <form action="/springWeb/query" method="get">
            学生id：<input type="text" name="stuid"><br/>
            <input type="submit" value="查询学生">
        </form>
    </div>
</body>
</html>

2.10.2 显示请求处理结果——对应AddStudentServlet

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
    /show.jsp  <p>学生注册成功！！！</p>
</body>
</html>

2.10.3 显示请求处理结果——对应QueryStudentServlet

<%@ page import="com.bjpowernode.entity.Student" %>
<%@ page contentType="text/html;charset=utf-8" language="java" %>
<html>
<head>
    <title>$</title>
</head>
<body>
    <%
        Student student= (Student) request.getAttribute("stu");
    %>
    查询的结果：<%=student%>
</body>
</html>

2.11 启动tomcat，测试！！！

2.11.1 AddStudentServlet的测试结果

2.11.2 QueryStudentServlet的测试结果

以上就是这个很小很小的项目的全部步骤，第一次将Java Web、Spring、MyBatis这些知识综合在了一起学习，感觉还是很不错的！！！😄😄😄

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