案例-查询所有

 

 

package com.itheima.mapper;

import com.itheima.pojo.Brand;
import org.apache.ibatis.annotations.ResultMap;
import org.apache.ibatis.annotations.Select;

import java.util.List;

public interface BrandMapper {
    /*
    * 查询所有
    * */
    @Select("select * from tb_brand")
    @ResultMap("brandResultMap")
    List<Brand> selectAll();
}

 

package com.itheima.pojo;

/**
 * 品牌实体类
 */

public class Brand {
    // id 主键
    private Integer id;
    // 品牌名称
    private String brandName;
    // 企业名称
    private String companyName;
    // 排序字段
    private Integer ordered;
    // 描述信息
    private String description;
    // 状态：0：禁用  1：启用
    private Integer status;


    public Brand() {
    }

    public Brand(Integer id, String brandName, String companyName, String description) {
        this.id = id;
        this.brandName = brandName;
        this.companyName = companyName;
        this.description = description;
    }

    public Brand(Integer id, String brandName, String companyName, Integer ordered, String description, Integer status) {
        this.id = id;
        this.brandName = brandName;
        this.companyName = companyName;
        this.ordered = ordered;
        this.description = description;
        this.status = status;
    }

    public Integer getId() {
        return id;
    }

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

    public String getBrandName() {
        return brandName;
    }

    public void setBrandName(String brandName) {
        this.brandName = brandName;
    }

    public String getCompanyName() {
        return companyName;
    }

    public void setCompanyName(String companyName) {
        this.companyName = companyName;
    }

    public Integer getOrdered() {
        return ordered;
    }

    public void setOrdered(Integer ordered) {
        this.ordered = ordered;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    public Integer getStatus() {
        return status;
    }

    public void setStatus(Integer status) {
        this.status = status;
    }

    @Override
    public String toString() {
        return "Brand{" +
                "id=" + id +
                ", brandName='" + brandName + '\'' +
                ", companyName='" + companyName + '\'' +
                ", ordered=" + ordered +
                ", description='" + description + '\'' +
                ", status=" + status +
                '}';
    }
}

 

package com.itheima.service;

import com.itheima.mapper.BrandMapper;
import com.itheima.pojo.Brand;
import com.itheima.util.SqlSessionFactoryUtils;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;

import java.util.List;

public class BrandService {
        //1. 使用工具类获util取到getSqlSessionFactory
        SqlSessionFactory factory = SqlSessionFactoryUtils.getSqlSessionFactory();
    /*
    * 查询所有
    * */
    public List<Brand> selectAll(){
        // 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selectAll()
        List<Brand> brands=mapper.selectAll();

        //返回brand集合，释放资源
        sqlSession.close();
        return brands;
    }
}

 

package com.itheima.util;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

import java.io.IOException;
import java.io.InputStream;

public class SqlSessionFactoryUtils {

    private static SqlSessionFactory sqlSessionFactory;

    static {
        //静态代码块会随着类的加载而自动执行，且只执行一次

        try {
            String resource = "mybatis-config.xml";
            InputStream inputStream = Resources.getResourceAsStream(resource);
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }


    public static SqlSessionFactory getSqlSessionFactory(){
        return sqlSessionFactory;
    }

}

 

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

        //2. 存入request域中
        request.setAttribute("brands",brands);

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

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

}

 

<?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">

    <!-- 为了解决对应实体类的属性名称和数据库的字段名不一致而出现的故障  比如：在网页中某个数据为空其他数据可以正常显示-->
    <!-- 使用resultMap映射可以解决此类问题-->
    <!-- id：为映射(mapper映射接口中)所使用的id type：为实体类类型-->
    <resultMap id="brandResultMap" type="brand">
        <result column="brand_name" property="brandName"></result>
        <result column="company_name" property="companyName"></result>
    </resultMap>

</mapper>

 

<?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="1234"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <!--扫描mapper-->
        <package name="com.itheima.mapper"/>
    </mappers>
</configuration>

 

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<input type="button" value="新增"><br>
<hr>
<table border="1" cellspacing="0" width="80%">
    <tr>
        <th>序号</th>
        <th>品牌名称</th>
        <th>企业名称</th>
        <th>排序</th>
        <th>品牌介绍</th>
        <th>状态</th>
        <th>操作</th>

    </tr>

    <c:forEach items="${brands}" var="brand" varStatus="status">
        <tr align="center">
<%--            <td>${brand.id}</td>--%>
<%--            index 从0开始排序  count 表示用1开始排序 --%>
            <td>${status.count}</td>
            <td>${brand.brandName}</td>
            <td>${brand.companyName}</td>
            <td>${brand.ordered}</td>
            <td>${brand.description}</td>
            <c:if test="${brand.status == 1}">
                <td>启用</td>
            </c:if>
            <c:if test="${brand.status != 1}">
                <td>禁用</td>
            </c:if>
            <td><a href="#">修改</a> <a href="#">删除</a></td>
        </tr>
    </c:forEach>

</table>

</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

    <a href="/brand-demo/selectAllServlet">查询所有</a>
</body>
</html>