javaWeb学习笔记 13 JSP技术-三层架构-SSM架构初学
JSP快速入门
JSP原理
jsp本质上是一个Servlet，JSP = HTML + Java，用于简化开发
JSP脚本
<%
System.out.println("hello,jsp~");
int i = 3;
%>
<%="hello"%>
<%=i%>
<%!
void show(){}
String name = "zhangsan";
%>练习：使用JSP脚本展示品牌数据
//<% %> 内写java代码 ;<% %> 外写Html 与 Css ;<% %> 俗称 截断
<%
for (int i = 0; i < brands.size(); i++) {
Brand brand = brands.get(i);
%>
<%=brand.getId()%>
<%=brand.getBrandName()%>
<%=brand.getCompanyName()%>
<%=brand.getOrdered()%>
<%=brand.getDescription()%>
<%
if(brand.getStatus() == 1){
//显示启用
%>
<%="启用"%>
<%
}else {
// 显示禁用
%>
<%="禁用"%>
<%
}
%>
修改 删除
<%
}
%>
EL表达式
//1. 准备数据
List brands = new ArrayList();
brands.add(new Brand(1,"三只松鼠","三只松鼠",100,"三只松鼠，好吃不上火",1));
brands.add(new Brand(2,"优衣库","优衣库",200,"优衣库，服适人生",0));
brands.add(new Brand(3,"小米","小米科技有限公司",1000,"为发烧而生",1));
//2. 存储到request域中
request.setAttribute("brands",brands);
request.setAttribute("status",1);
//3. 转发到 el-demo.jsp
//request.getRequestDispatcher("/el-demo.jsp").forward(request,response);
//request.getRequestDispatcher("/jstl-if.jsp").forward(request,response);
request.getRequestDispatcher("/jstl-foreach.jsp").forward(request,response); ${brands}
JSTL标签
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
Title
<%--
c:if：来完成逻辑判断，替换java if else
--%>
<%--
即如果是 true 则 if 成立
true
false
--%>
启用
禁用
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
Title
序号
品牌名称
企业名称
排序
品牌介绍
状态
操作
<%--${brand.id} --%>
${status.count}
${brand.brandName}
${brand.companyName}
${brand.ordered}
${brand.description}
启用
禁用
修改 删除
${i}
MVC模式（编程思想）
三层架构（编程思想）SSM
SpringMVC(表现层) + Spring(业务逻辑层) + MyBatis(数据访问层)
表现层（包名：com.itheima.web/controller）-接收请求，封装数据-调用业务逻辑层封装的方法来响应前端请求的数据
业务逻辑层（包名：com.itheima.service）-对方法进行封装-组合数据访问层中基本的增删改查，实现复杂的业务逻辑功能
数据访问层（包名：com.itheima.dao/mapper）-（持久层）-对数据库增删改查（jdbc和mybatis）
补充：放实体类的pojo.java （品牌实体类）
放工具类的util.java
案例（完成品牌数据的增删改查操作）
jsp（调用html与css等实现前端界面）——web（对用户输入的数据进行验证和对其他jsp的跳转）——service（将mapper实现的sql方法调用，获取sqlsession连接池，获取usermapper文件中的方法，调用方法，释放资源）——mapper（对数据库简单的增删改查定义一些实现方法）——util（工具类，生成动态验证码，定义静态代码块连接池）——pojo（实体类，用户信息实体类，品牌实体类）
//index.html
Title
查询所有
//SelectAllServlet.java
package com.itheima.web;
import com.itheima.pojo.Brand;
import com.itheima.service.BrandService;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.annotation.*;
import java.io.IOException;
import java.util.List;
@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完成查询（将数据获取到数组中）
List brands = service.selectAll();
//2. 存入request域中（转存到域中方便上传至网页）
request.setAttribute("brands",brands);
//3. 转发到brand.jsp（数据上传网页）
request.getRequestDispatcher("/brand.jsp").forward(request,response);
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}
} //brandservice.java
/**
* 查询所有
* @return
*/
public List selectAll(){
//调用BrandMapper.selectAll()
//2. 获取SqlSession（引入连接池）
SqlSession sqlSession = factory.openSession();
//3. 获取BrandMapper（引入BrandMapper类）
BrandMapper mapper = sqlSession.getMapper(BrandMapper.class);
//4. 调用BrandMapper中定义的方法
List brands = mapper.selectAll();
sqlSession.close();
return brands;
} //brandmapper.java
/**
* 查询所有
* 书写sql语句，定义相关的方法
* @return
*/
@Select("select * from tb_brand")
@ResultMap("brandResultMap")
List selectAll(); 
1 中文乱码问题
2 提交事务
//brand.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
Title
序号
品牌名称
企业名称
排序
品牌介绍
状态
操作
<%--${brand.id} --%>
${status.count}
${brand.brandName}
${brand.companyName}
${brand.ordered}
${brand.description}
启用
禁用
修改 删除
//addBrand.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
添加品牌
添加品牌
//AddServlet.java
package com.itheima.web;
import com.itheima.pojo.Brand;
import com.itheima.service.BrandService;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.annotation.*;
import java.io.IOException;
@WebServlet("/addServlet")
public class AddServlet extends HttpServlet {
private BrandService service = new BrandService();
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//处理POST请求的乱码问题
request.setCharacterEncoding("utf-8");
//1. 接收表单提交的数据，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");
//封装为一个Brand对象
Brand brand = new Brand();
brand.setBrandName(brandName);
brand.setCompanyName(companyName);
brand.setOrdered(Integer.parseInt(ordered));
brand.setDescription(description);
brand.setStatus(Integer.parseInt(status));
//2. 调用service 完成添加
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);
}
}//BrandService.java
/**
* 添加
* @param brand
*/
public void add(Brand brand){
//2. 获取SqlSession（引入连接池）
SqlSession sqlSession = factory.openSession();
//3. 获取BrandMapper（引入BrandMapper类）
BrandMapper mapper = sqlSession.getMapper(BrandMapper.class);
//4. 调用方法
mapper.add(brand);
//提交事务（mysql更新数据需要提交事务）
sqlSession.commit();
//释放资源
sqlSession.close();
}//BrandMapper.java
/**
* 添加数据
* @param brand
*/
@Insert("insert into tb_brand values(null,#{brandName},#{companyName},#{ordered},#{description},#{status})")
void add(Brand brand);
//brand.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
Title
序号
品牌名称
企业名称
排序
品牌介绍
状态
操作
<%--${brand.id} --%>
${status.count}
${brand.brandName}
${brand.companyName}
${brand.ordered}
${brand.description}
启用
禁用
修改 删除
//Updata.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
修改品牌
修改品牌
//SelectByIdServlet
package com.itheima.web;
import com.itheima.pojo.Brand;
import com.itheima.service.BrandService;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.List;
@WebServlet("/selectByIdServlet")
public class SelectByIdServlet extends HttpServlet {
private BrandService service = new BrandService();
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//1. 接收id
String id = request.getParameter("id");
//2. 调用service查询
Brand brand = service.selectById(Integer.parseInt(id));
//3. 存储到request中
request.setAttribute("brand",brand);
//4. 转发到update.jsp
request.getRequestDispatcher("/update.jsp").forward(request,response);
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}
}//BrandService
/**
* 根据id查询
* @return
*/
public Brand selectById(int id){
//调用BrandMapper.selectAll()
//2. 获取SqlSession
SqlSession sqlSession = factory.openSession();
//3. 获取BrandMapper
BrandMapper mapper = sqlSession.getMapper(BrandMapper.class);
//4. 调用方法
Brand brand = mapper.selectById(id);
sqlSession.close();
return brand;
}//BrandMapper
/**
* 根据id查询
* 本来应该在BrandMapper.xml中创建映射，写SQL语句 但由于只有一句话，所以不创建了 直接写在这
* @param id
* @return
*/
@Select("select * from tb_brand where id = #{id}")
@ResultMap("brandResultMap")
Brand selectById(int id);
//brand.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
Title
序号
品牌名称
企业名称
排序
品牌介绍
状态
操作
<%--${brand.id} --%>
${status.count}
${brand.brandName}
${brand.companyName}
${brand.ordered}
${brand.description}
启用
禁用
修改 删除
//Updata.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
修改品牌
修改品牌
//UpdateServlet.java
package com.itheima.web;
import com.itheima.pojo.Brand;
import com.itheima.service.BrandService;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
@WebServlet("/updateServlet")
public class UpdateServlet extends HttpServlet {
private BrandService service = new BrandService();
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//处理POST请求的乱码问题
request.setCharacterEncoding("utf-8");
//1. 接收表单提交的数据，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");
//封装为一个Brand对象
Brand brand = new Brand();
brand.setId(Integer.parseInt(id));
brand.setBrandName(brandName);
brand.setCompanyName(companyName);
brand.setOrdered(Integer.parseInt(ordered));
brand.setDescription(description);
brand.setStatus(Integer.parseInt(status));
//2. 调用service 完成修改
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);
}
}//BrandService.java
/**
* 修改
* @param brand
*/
public void update(Brand brand){
//2. 获取SqlSession
SqlSession sqlSession = factory.openSession();
//3. 获取BrandMapper
BrandMapper mapper = sqlSession.getMapper(BrandMapper.class);
//4. 调用方法
mapper.update(brand);
//提交事务
sqlSession.commit();
//释放资源
sqlSession.close();
}//BrandMapper.java
/**
* 修改
* @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);