参考:https://www.cnblogs.com/zs-notes/category/1258467.html。写的很棒的。
项目结构
(红色标注地方,该案例不演示)
一、pom.xml 添加相关依赖
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.3.3.RELEASE</version>
</parent>
<dependencies>
<!-- swagger API 这里可是自己去掉-->
<dependency>
<groupId>io.springfox</groupId>
<artifactId>springfox-swagger2</artifactId>
<version>2.6.1</version>
</dependency>
<dependency>
<groupId>io.springfox</groupId>
<artifactId>springfox-swagger-ui</artifactId>
<version>2.6.1</version>
</dependency>
<!-- SpringBoot 核心组件 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<scope>test</scope>
</dependency>
<!-- 部署tomcat,排除冲突 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
<scope>provided</scope>
</dependency>
<!-- servlet依赖 -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jstl</artifactId>
</dependency>
<dependency>
<groupId>org.apache.taglibs</groupId>
<artifactId>taglibs-standard-impl</artifactId>
<version>1.2.5</version>
</dependency>
<!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
<dependency>
<groupId>jstl</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
<!-- tomcat的支持 -->
<dependency>
<groupId>org.apache.tomcat.embed</groupId>
<artifactId>tomcat-embed-jasper</artifactId>
</dependency>
<!-- mybatis -->
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>1.1.1</version>
</dependency>
<!-- mysql -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.21</version>
</dependency>
<!-- 增加对PageHelper的支持 支持分页的插件-->
<dependency>
<groupId>com.github.pagehelper</groupId>
<artifactId>pagehelper</artifactId>
<version>4.1.6</version>
</dependency>
</dependencies>
<properties>
<java.version>1.8</java.version>
</properties>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
<!-- 打jar需要的插件 -->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
</plugin>
</plugins>
</build>
二、数据库创建表 category_
就两列表格,主键设置自增。自己添点数据进去
三、数据库连接 application.properties 文件配置
spring.mvc.view.prefix=/WEB-INF/jsp/
spring.mvc.view.suffix=.jsp
#这里是文件上传的限制配置(可忽略)
spring.http.multipart.maxFileSize=100Mb
spring.http.multipart.maxRequestSize=100Mb
#数据库连接 注意数据库名
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/springboot?characterEncoding=UTF-8
spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
四、实体类 Category
package com.springboot.pojo;
public class Category {
private int id;
private String name;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
五、创建接口 CategoryMapper
package com.springboot.mapper;
import java.util.List;
import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;
import com.springboot.pojo.Category;
@Mapper
public interface CategoryMapper {
@Select("select * from category_") // 查询所有
List<Category> findAll();
@Insert("insert into category_ (name) values (#{name}) ") // 添加
public int save(Category category);
@Delete("delete from category_ where id=#{id} ") // 删除
public void delete(int id);
@Select("select * from category_ where id=#{id} ") // 查询一个
public Category get(int id);
@Update("update category_ set name = #{name} where id=#{id} ") // 修改
public int update(Category category);
}
关键代码说明:
@Mapper:说明此类是接口类。注意启动类要使用 @MapperScan("com.springboot.mapper")进行扫描
六、创建PagehelperConfig
package com.springboot.config;
import java.util.Properties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import com.github.pagehelper.PageHelper;
@Configuration //配置类
public class PageHelperConfig {
@Bean
public PageHelper pageHelper(){
PageHelper pageHelper = new PageHelper();
Properties p = new Properties();
//1.offsetAsPageNum:设置为true时,会将RowBounds第一个参数offset当成pageNum页码使用.
p.setProperty("offsetAsPageNum", "true");
//2.rowBoundsWithCount:设置为true时,使用RowBounds分页会进行count查询.
p.setProperty("rowBoundsWithCount", "true");
//3.reasonable:启用合理化时,如果pageNum<1会查询第一页,如果pageNum>pages会查询最后一页。
p.setProperty("reasonable", "true");
pageHelper.setProperties(p);
return pageHelper;
}
}
(后面要在启动类扫描这个类@ComponentScan("com.springboot.controller,com.springboot.config"))
之前使用xml配置分页插件方式
<!--
plugins在配置文件中的位置必须符合要求,否则会报错,顺序如下:
properties?, settings?,
typeAliases?, typeHandlers?,
objectFactory?,objectWrapperFactory?,
plugins?,
environments?, databaseIdProvider?, mappers?
-->
<plugins>
<!-- com.github.pagehelper为PageHelper类所在包名 -->
<plugin interceptor="com.github.pagehelper.PageHelper">
<property name="dialect" value="mysql"/>
<!-- 该参数默认为false -->
<!-- 设置为true时,会将RowBounds第一个参数offset当成pageNum页码使用 -->
<!-- 和startPage中的pageNum效果一样-->
<property name="offsetAsPageNum" value="true"/>
<!-- 该参数默认为false -->
<!-- 设置为true时,使用RowBounds分页会进行count查询 -->
<property name="rowBoundsWithCount" value="true"/>
<!-- 设置为true时,如果pageSize=0或者RowBounds.limit = 0就会查询出全部的结果 -->
<!-- (相当于没有执行分页查询,但是返回结果仍然是Page类型)-->
<property name="pageSizeZero" value="true"/>
<!-- 3.3.0版本可用 - 分页参数合理化,默认false禁用 -->
<!-- 启用合理化时,如果pageNum<1会查询第一页,如果pageNum>pages会查询最后一页 -->
<!-- 禁用合理化时,如果pageNum<1或pageNum>pages会返回空数据 -->
<property name="reasonable" value="true"/>
<!-- 3.5.0版本可用 - 为了支持startPage(Object params)方法 -->
<!-- 增加了一个`params`参数来配置参数映射,用于从Map或ServletRequest中取值 -->
<!-- 可以配置pageNum,pageSize,count,pageSizeZero,reasonable,不配置映射的用默认值 -->
<property name="params" value="pageNum=start;pageSize=limit;pageSizeZero=zero;reasonable=heli;count=contsql"/>
</plugin>
</plugins>
对比看看,就知道差距多大了。springboot 很贴心了。
七、创建controller
package com.springboot.controller;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import com.github.pagehelper.PageHelper;
import com.github.pagehelper.PageInfo;
import com.springboot.mapper.CategoryMapper;
import com.springboot.pojo.Category;
@Controller
public class CategoryController {
@Autowired
CategoryMapper categoryMapper;
// @RequestMapping("/listCategory")
// public String listCategory(Model m) throws Exception {
// List<Category> cs = categoryMapper.findAll();
// m.addAttribute("cs", cs);
// return "listCategory";
// }
@RequestMapping("/listCategory")
public String listCategory(Model m,@RequestParam(value="start",defaultValue="0")int start,@RequestParam(value = "size", defaultValue = "5") int size) throws Exception {
//1. 在参数里接受当前是第几页 start ,以及每页显示多少条数据 size。 默认值分别是0和5。
//2. 根据start,size进行分页,并且设置id 倒排序
PageHelper.startPage(start,size,"id desc");
//3. 因为PageHelper的作用,这里就会返回当前分页的集合了
List<Category> cs = categoryMapper.findAll();
//4. 根据返回的集合,创建PageInfo对象
PageInfo<Category> page = new PageInfo<>(cs);
//5. 把PageInfo对象扔进model,以供后续显示
m.addAttribute("page", page);
//6. 跳转到listCategory.jsp
return "listCategory";
}
@RequestMapping("/addCategory")
public String addCategory(Category c)throws Exception{
categoryMapper.save(c);
return "redirect:listCategory"; //添加成功,重定向到分类查询页面
}
@RequestMapping("/deleteCategory")
public String deleteCategory(int id)throws Exception{
categoryMapper.delete(id);
return "redirect:listCategory"; //删除成功,重定向到分类查询页面
}
@RequestMapping("/updateCategory") //修改方法
public String updateCategory(Category c)throws Exception{
categoryMapper.update(c);
return "redirect:listCategory"; //修改成功,重定向到分类查询页面
}
@RequestMapping("/editCategory")
public String editCategory(int id ,Model m)throws Exception{
Category c = categoryMapper.get(id); //根据id查询
m.addAttribute("c", c); //查到展示到修改页面
return "editCategory"; //跳转到修改页面
}
}
八、创建相关jsp 页面
(1)展示页面 listCategory.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<!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>分类展示列表</title>
</head>
<body>
<!-- <table align="center" border="1" > -->
<!-- <tr> -->
<!-- <td>id</td> -->
<!-- <td>name</td> -->
<!-- </tr> -->
<%-- <c:forEach items="${cs}" var="c" varStatus="st"> --%>
<!-- <tr> -->
<%-- <td>${c.id}</td> --%>
<%-- <td>${c.name}</td> --%>
<!-- </tr> -->
<%-- </c:forEach> --%>
<!-- </table> -->
<div style="width:500px;margin:20px auto;text-align: center">
<table align='center' border='1' cellspacing='0'>
<tr>
<td>id</td>
<td>name</td>
<td>编辑</td>
<td>删除</td>
</tr>
<c:forEach items="${page.list}" var="c" varStatus="st">
<tr>
<td>${c.id}</td>
<td>${c.name}</td>
<td><a href="editCategory?id=${c.id}">编辑</a></td>
<td><a href="deleteCategory?id=${c.id}">删除</a></td>
</tr>
</c:forEach>
</table>
<br>
<div>
<a href="?start=1">[首 页]</a> <!-- 这是相对路径的写法。 前面没有斜线就是相对当前路径加上这个地址。 -->
<c:if test="${page.pageNum-1>0}">
<a href="?start=${page.pageNum-1}">[上一页]</a>
</c:if>
<c:if test="${page.pageNum+1<page.pages+1}">
<a href="?start=${page.pageNum+1}">[下一页]</a>
</c:if>
<a href="?start=${page.pages}">[末 页]</a>
</div>
<br>
<div>当前页/总页数:<a href="?start=${page.pageNum}">${page.pageNum}</a>/<a href="?start=${page.pages}">${page.pages}</a> </div>
<br>
<form action="addCategory" method="post">
添加分类:
name: <input name="name"> <br>
<button type="submit">提交</button>
</form>
</div>
</body>
</html>
(2)提交页面 editCategory.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<div style="margin:0px auto; width:500px">
<form action="update" method="post">
name: <input name="name" value="${c.name}"> <br>
<input name="id" type="hidden" value="${c.id}">
<button type="submit">提交</button>
</form>
</div>
</body>
</html>
九、启动类
package com.springboot.application;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ComponentScan;
//
//@EnableAutoConfiguration
@SpringBootApplication
@ComponentScan("com.springboot.controller,com.springboot.config")
@MapperScan("com.springboot.mapper")
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
十、测试
输入:http://127.0.0.1:8080/listCategory
测试彩蛋:
这里由于自己的疏忽,留下了一个小bug。
有问题,请留言。