Bootstrap

JSP快速入门（案例:增删改查回显）

目录

一、JSP概述

二、JSP快速入门

​ 三、JSP原理

​四、JSP脚本

五、 JSP缺点

六、EL表达式

七、JSTL标签

 八、MVC模式和三层架构

九、案例练习

9.1 环境准备

9.2 查询所有

 9.3 添加数据

9.4 回显数据

9.5 修改数据

9.6 删除数据

一、JSP概述

二、JSP快速入门

 三、JSP原理

四、JSP脚本

五、 JSP缺点

六、EL表达式

七、JSTL标签

C标签： 

 

 八、MVC模式和三层架构

 MVC模式：

 三层架构：

 两者之间的关系：

九、案例练习

9.1 环境准备

引坐标：

 <packaging>war</packaging>
 

    <!--依赖-->
    <dependencies>
        <!--mybatis-->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.5</version>
        </dependency>

        <!--mysql-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.34</version>
        </dependency>

        <!--servlet-->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.1.0</version>
            <scope>provided</scope>
        </dependency>

        <!--jsp-->
        <dependency>
            <groupId>org.glassfish.web</groupId>
            <artifactId>jsp</artifactId>
            <version>2.2</version>
            <scope>provided</scope>
        </dependency>

        <!--jstl-->
        <dependency>
            <groupId>jstl</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>

        <!--standard库-->
        <dependency>
            <groupId>taglibs</groupId>
            <artifactId>standard</artifactId>
            <version>1.1.2</version>
        </dependency>

    </dependencies>


    <!--插件-->
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.tomcat.maven</groupId>
                <artifactId>tomcat7-maven-plugin</artifactId>
                <version>2.2</version>
            </plugin>
        </plugins>
    </build>

 创建三层架构的包结构：

 Mybatis基础环境：

Mybatis-config.xml

<?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>
    <!--起别名-->
    <typeAliases>
        <package name="com.itheima.pojo"/>
    </typeAliases>

    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql:///db1?useSSL=false&amp;useServerPrepStmts=true"/>
                <property name="username" value="root"/>
                <property name="password" value=""/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <!--扫描mapper-->
        <package name="com.itheima.mapper"/>
    </mappers>
</configuration>

BrandMapper.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.itheima.mapper.BrandMapper">

</mapper>

BrandMapper接口：

package com.itheima.mapper;

public interface BrandMapper {
    
}

9.2 查询所有

Mapper接口(Dao层):

   /**
     * 查询所有
     * @return
     */
    @Select("select * from tb_brand")
//    @ResultMap("brandResultMap")
    List<Brand> selectAll();

Service层: 

        //1.获取SqlSessionFactory对象
        SqlSessionFactory factory = SqlSessionFactoryUtils.getSqlSessionFactory();
        //2.获取SqlSession对象
        SqlSession sqlSession = factory.openSession();

        //3.获取BrandMapper对象
        BrandMapper mapper = sqlSession.getMapper(BrandMapper.class);

        //4.调用方法
        List<Brand> brands = mapper.selectAll();

        //5.关闭资源
        sqlSession.close();

        return brands;

 Web层:

@WebServlet("/selectAllServlet")
public class SelectAllServlet extends HttpServlet {

    private  BrandService service = new BrandService();
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        //1.调用BrandService查询数据,并封装为List对象

        List<Brand> brands = service.selectAll();

        //2.将数据存到request域中
        request.setAttribute("brands",brands);

        //3.转发到brand.jsp
        request.getRequestDispatcher("/brand.jsp").forward(request,response);

    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doGet(request, response);
    }
}

注意:

在BrandMapper.xml里 设置resultMap来解决数据库和java的名称命名不一致,即映射属性名和数据库中的字段名

在mapper接口中记得添加注解使用 

另一种方法:在mybatis-config.xml中设置

    <!--开启驼峰命名自动映射-->
    <settings>
        <setting name="mapUnderscoreToCamelCase" value="true"/>
    </settings>

 9.3 添加数据

Mapper接口(Dao层): 

    @Insert("insert into tb_brand values(null,#{brandName},#{companyName},#{ordered},#{description},#{status})")
//    @ResultMap("brandResultMap")
    void add(Brand brand);

 Service层:

     /**
     * 添加
     * @param brand
     */
    public  void add(Brand brand){
        //1.获取SqlSessionFactory对象
        SqlSessionFactory factory = SqlSessionFactoryUtils.getSqlSessionFactory();

        //2.获取sqlSession对象
        SqlSession sqlSession = factory.openSession();

        //3.获取BrandMapper对象
        BrandMapper mapper = sqlSession.getMapper(BrandMapper.class);

        //4.调用方法
        mapper.add(brand);

        //5.增删改需要提交事务
        sqlSession.commit();

        //6.释放资源
        sqlSession.close();

Web层:

@WebServlet("/addServlet")
public class AddServlet extends HttpServlet {

    private BrandService service = new BrandService();

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //解决Post中文乱码问题
        request.setCharacterEncoding("utf-8");
        //1.接受表单提交的数据并将其封装为一个Brand对象
        String brandName = request.getParameter("brandName");
        String companyName = request.getParameter("companyName");
        String ordered = request.getParameter("ordered");
        String description = request.getParameter("description");
        String status = request.getParameter("status");

        //封装为Brand对象
        Brand brand = new Brand();
        brand.setBrandName(brandName);
        brand.setCompanyName(companyName);
        brand.setOrdered(Integer.parseInt(ordered));//将字符类型转为Int类型
        brand.setDescription(description);
        brand.setStatus(Integer.parseInt(status));

        //2.调用service完成添加操作
        service.add(brand);

        //3.转发到查询所有Servlet
        request.getRequestDispatcher("/selectAllServlet").forward(request,response);


    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doGet(request, response);
    }
}

注意:

中文乱码问题:post请求只需要在AddServlet中添加一行代码

  //解决Post中文乱码问题
  request.setCharacterEncoding("utf-8");

MySQL中增删改操作需要提交事务

可以在获取sqlSession对象设置为自动提交:

//2.获取sqlSession对象
SqlSession sqlSession = factory.openSession(true);

也可以手动提交:

     //5.增删改需要提交事务
        sqlSession.commit();

9.4 回显数据

Mapper接口(Dao层):

    /**
     * 根据id查询
     * @param id
     * @return
     */
    @Select("select * from tb_brand where id = #{id}")
    Brand selectById(int id);

Service层:

    /**
     * 根据id查询
     * @param id
     * @return
     */
    public Brand selectById(int id){
        //调用BrandselectAll()

        //1.获取SqlSessionFactory对象
        SqlSessionFactory factory = SqlSessionFactoryUtils.getSqlSessionFactory();

        //2.获取SqlSession对象
        SqlSession sqlSession = factory.openSession();

        //3.获取BrandMapper对象
        BrandMapper mapper = sqlSession.getMapper(BrandMapper.class);

        //4.调用方法
        Brand brand = mapper.selectById(id);

        //5.关闭资源
        sqlSession.close();

        return brand;

    }

Web层:

@WebServlet("/selectByIdServlet")
public class SelectByIdServlet extends HttpServlet {

    private  BrandService service = new BrandService();
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        //1.接受id
        String id = request.getParameter("id");

        //2.调用Service查询
        Brand brand = service.selectById(Integer.parseInt(id));

        //3.存储到request域中
        request.setAttribute("brand", brand);

        //4.转发到update.jsp中
        request.getRequestDispatcher("/update.jsp").forward(request, response);



    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doGet(request, response);
    }
}

9.5 修改数据

Mapper接口(Dao层):

     /**
     * 修改操作
     * @param brand
     */
    @Update("update tb_brand set brand_name = #{brandName}," +
            "                    company_name = #{companyName}," +
            "                    ordered = #{ordered}," +
            "                    description = #{description}," +
            "                    status = #{status} " +
            "                    where id = #{id}")
    void update(Brand brand);

 Service层:

     /**
     * 修改
     * @param brand
     */
    public  void update(Brand brand){

        //1.获取SqlSessionFactory对象
        SqlSessionFactory factory = SqlSessionFactoryUtils.getSqlSessionFactory();

        //2.获取sqlSession对象
        SqlSession sqlSession = factory.openSession();

        //3.获取BrandMapper对象
        BrandMapper mapper = sqlSession.getMapper(BrandMapper.class);

        //4.调用方法
        mapper.update(brand);

        //5.增删改需要提交事务
        sqlSession.commit();

        //6.释放资源
        sqlSession.close();
    }

 Web层:

@WebServlet("/updateServlet")
public class UpdateServlet extends HttpServlet {

    private BrandService service = new BrandService();

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //解决Post中文乱码问题
        request.setCharacterEncoding("utf-8");
        //1.接受表单提交的数据并将其封装为一个Brand对象
        String id = request.getParameter("id");
        String brandName = request.getParameter("brandName");
        String companyName = request.getParameter("companyName");
        String ordered = request.getParameter("ordered");
        String description = request.getParameter("description");
        String status = request.getParameter("status");


        //封装为Brand对象
        Brand brand = new Brand();
        brand.setId(Integer.parseInt(id));
        brand.setBrandName(brandName);
        brand.setCompanyName(companyName);
        brand.setOrdered(Integer.parseInt(ordered));//将字符类型转为Int类型
        brand.setDescription(description);
        brand.setStatus(Integer.parseInt(status));

        //2.调用service完成修改操作
        service.update(brand);

        //3.转发到查询所有Servlet
        request.getRequestDispatcher("/selectAllServlet").forward(request,response);


    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doGet(request, response);
    }
}

brand.jsp: 

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<html lang="en">


<head>
    <meta charset="UTF-8">
    <title>修改品牌</title>

</head>
<body>
<h3>修改品牌</h3>
<form action="/brand-demo/updateServlet" method="post">

    <%--隐藏域提交id--%>
    <input type="hidden" name="id" value="${brand.id}">

    品牌名称：<input name="brandName" value="${brand.brandName}"><br>
    企业名称：<input name="companyName" value="${brand.companyName}"><br>
    排序：<input name="ordered" value="${brand.ordered}"><br>
    描述信息：<textarea rows="5" cols="20" name="description" >${brand.description}</textarea><br>
    状态：
    <c:if test="${brand.status == 0}">
        <input type="radio" name="status" value="0" checked>禁用
        <input type="radio" name="status" value="1">启用<br>
    </c:if>
    <c:if test="${brand.status == 1}">
        <input type="radio" name="status" value="0" >禁用
        <input type="radio" name="status" value="1" checked>启用<br>
    </c:if>


    <input type="submit" value="提交">
</form>
</body>
</html>

注意:

处理"启用/禁用"状态时使用<c>标签,需要在头部引入

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

通过隐藏域将id传到Servlet中

 <%--隐藏域提交id--%>
 <input type="hidden" name="id" value="${brand.id}">

9.6 删除数据

Mapper接口(Dao层):

    /**
     * 删除
     * @param id
     */
    @Delete("delete from tb_brand where id = #{id}")
    void deleteById(int id);

Service层:

 /**
     * 根据id删除
     * @param id
     */
    public void deleteById(int id){
        //调用BrandselectAll()

        //2.获取SqlSession对象
        SqlSession sqlSession = factory.openSession();

        //3.获取BrandMapper对象
        BrandMapper mapper = sqlSession.getMapper(BrandMapper.class);

        //4.调用方法
        mapper.deleteById(id);

        //5.提交事务
        sqlSession.commit();

        //6.关闭资源
        sqlSession.close();

    }

Web层:

@WebServlet("/deleteByIdServlet")
public class DeleteByIdServlet extends HttpServlet {

    private BrandService service = new BrandService();

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //解决Post中文乱码问题
        request.setCharacterEncoding("utf-8");
        //1.接受表单提交的数据获取id
        String id = request.getParameter("id");

        //2.调用service完成修改操作
        service.deleteById(Integer.parseInt(id));

        //3.转发到查询所有Servlet
        request.getRequestDispatcher("/selectAllServlet").forward(request,response);


    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doGet(request, response);
    }
}

悦读

道可道，非常道；名可名，非常名。 无名，天地之始，有名，万物之母。 故常无欲，以观其妙，常有欲，以观其徼。 此两者，同出而异名，同谓之玄，玄之又玄，众妙之门。

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