第1章 初始Spring Boot【仿牛客网社区论坛项目】

日星月云2024-05-15 12:17

第1章 初始Spring Boot【仿牛客网社区论坛项目】

前言

2023-4-30 20:42:51

以下内容源自【Java面试项目】
仅供学习交流使用

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仿牛客网项目【面试】

项目总结

第1章初识Spring Boot，开发社区首页

1.课程介绍

2.搭建开发环境

创建项目，完成搭建

添加依赖

  • aspectj aop包
  • Spring Web web开发
  • Thymeleaf 模板引擎
  • Spring Boot DevTools 开发者工具
  • 其他：使用时添加

配置application.properties

#ServerProperties
#端口配置
server.port=8080
#路径配置
server.servlet.context-path=/community

创建一个AlphaController

编写sayHello()

java 复制代码 
@Controller
@RequestMapping("/alpha")
public class AlphaController {
    @RequestMapping("/hello")
    @ResponseBody//返回字符串
    public String sayHello(){
        return "Hello Spring Boot.";
    }
}

访问：http://localhost:8080/community/alpha/hello

3.Spring入门

修改测试代码

体验IOC容器

ApplicationContext，管理Bean

java 复制代码 
package com.jsss.community;


@SpringBootTest
@ContextConfiguration(classes = CommunityApplication.class)
class CommunityApplicationTests implements ApplicationContextAware {

    private ApplicationContext applicationContext;

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        this.applicationContext=applicationContext;
    }

    @Test
    public void testApplicationContext(){
        System.out.println(applicationContext);
    }
}

创建一个Bean

AlphaDAO

java 复制代码 
package com.jsss.community.dao;

public interface AlphaDao {
    String select();

}

两个实现类

AlphaDaoHibernateImpl

java 复制代码 
package com.jsss.community.dao;

import org.springframework.stereotype.Repository;

@Repository("alphaDaoHibernate")//容器管理 指定Bean名字
public class AlphaDaoHibernateImpl implements AlphaDao{

    @Override
    public String select() {
        return "Hibernate";
    }
}

AlphaDaoMybatisImpl

java 复制代码 
package com.jsss.community.dao;

import org.springframework.context.annotation.Primary;
import org.springframework.stereotype.Repository;


@Repository
@Primary//优先装配
public class AlphaDaoMybatisImpl implements AlphaDao{
    @Override
    public String select() {
        return "Mybatis";
    }
}

测试：testApplicationContext()

java 复制代码 
package com.jsss.community;

import com.jsss.community.dao.AlphaDao;
import org.junit.jupiter.api.Test;
import org.springframework.beans.BeansException;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.test.context.ContextConfiguration;


@SpringBootTest
@ContextConfiguration(classes = CommunityApplication.class)
class CommunityApplicationTests implements ApplicationContextAware {//SpringBoot会进行自动配置

    private ApplicationContext applicationContext;

    //配置方法
    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        this.applicationContext=applicationContext;
    }

    //测试容器
    @Test
    public void testApplicationContext(){
        System.out.println(applicationContext);

        AlphaDao alphaDao=applicationContext.getBean(AlphaDao.class);
        System.out.println(alphaDao.select());//Mybatis
        alphaDao= (applicationContext.getBean("alphaDaoHibernate",AlphaDao.class));
        System.out.println(alphaDao.select());//Hibernate
    }
}
体验Bean的生命周期

创建AlphaService

java 复制代码 
package com.jsss.community.service;

import org.springframework.stereotype.Service;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;

@Service//容器管理
//作用域 单例 多态
//@Scope("singleton")
//@Scope("prototype")
public class AlphaService {

    @PostConstruct//IOC容器管理Bean生命周期：初始化
    public void init(){
        System.out.println("初始化AlphaService");
    }

    @PreDestroy//IOC容器管理Bean生命周期：销毁
    public void destroy(){
        System.out.println("销毁AlphaService");
    }
}

测试：testBean()

java 复制代码 
    //测试Bean的生命周期
    //修改Scope作用域
    @Test
    public void testBean(){
        AlphaService alphaService=applicationContext.getBean(AlphaService.class);
        System.out.println(alphaService);

        alphaService=applicationContext.getBean(AlphaService.class);
        System.out.println(alphaService);
    }
体验配置类

添加AlphaConfig

java 复制代码 
package com.jsss.community.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import java.text.SimpleDateFormat;

@Configuration
public class AlphaConfig {
    //配置类使用Bean注解添加Bean
    //方法名就是Bean名字
    @Bean
    public SimpleDateFormat simpleDateFormat(){
        return new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    }

}

测试：getBeanConfig()

java 复制代码 
    //测试配置类
    @Test
    public void getBeanConfig(){
        SimpleDateFormat simpleDateFormat=applicationContext.getBean(SimpleDateFormat.class);
        System.out.println(simpleDateFormat.format(new Date()));
    }
体验依赖注入

容器的主动getBean

使用注解@AutoWire

测试：testDI()

java 复制代码 
    @Autowired
    @Qualifier("alphaDaoHibernate")//指定Bean名字
    private AlphaDao alphaDao;

    @Autowired
    private AlphaService alphaService;

    @Autowired
    private SimpleDateFormat simpleDateFormat;
    @Test
    public void testDI(){
        System.out.println(alphaDao);
        System.out.println(alphaService);
        System.out.println(simpleDateFormat);
    }
体验三层架构

Controller--Service--Dao

Service调用Dao

java 复制代码 
package com.jsss.community.service;

import com.jsss.community.dao.AlphaDao;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;

@Service//容器管理
//作用域 单例 多态
//@Scope("singleton")
//@Scope("prototype")
public class AlphaService {

    @Autowired
    private AlphaDao alphaDao;

    @PostConstruct//IOC容器管理Bean生命周期：初始化
    public void init(){
        System.out.println("初始化AlphaService");
    }

    @PreDestroy//IOC容器管理Bean生命周期：销毁
    public void destroy(){
        System.out.println("销毁AlphaService");
    }

    public String find(){
        return alphaDao.select();
    }

}

Controller调用Service

java 复制代码 
package com.jsss.community.controller;

@Controller
@RequestMapping("/alpha")
public class AlphaController {

    @Autowired
    private AlphaService alphaService;
    
    @RequestMapping("/data")
    @ResponseBody
    public String getData(){
        return alphaService.find();
    }
}

访问：http://localhost:8080/community/alpha/data

4.SpringMVC入门

配置
properties 复制代码 
# ThymeleafProperties
spring.thymeleaf.cache=false
体验响应数据

AlphaController.http()

java 复制代码 
	@RequestMapping("/http")
    public void http(HttpServletRequest request, HttpServletResponse response){
        //获取请求数据
        System.out.println(request.getMethod());// GET
        System.out.println(request.getServletPath());// /alpha/http
        Enumeration<String> enumeration = request.getHeaderNames();
        while (enumeration.hasMoreElements()){
            String name = enumeration.nextElement();
            String value = request.getHeader(name);
            System.out.println(name+": "+value);
        }
        System.out.println(request.getParameter("code"));//123

        // 返回响应数据
        response.setContentType("text/html;charset=utf-8");
        try (
                PrintWriter writer = response.getWriter();
        ){
            writer.write("<h1>牛客网</h1>");
        } catch (IOException e) {
            e.printStackTrace();
        }

    }

访问：http://localhost:8080/community/alpha/http?code=123

体验响应Get请求
  • 路径拼接
  • Restful风格

AlphaController.getStudents()

AlphaController.getStudent()

java 复制代码 
	// GET 请求

    // /students?current=1&limit=20
    @RequestMapping(path = "/students",method = RequestMethod.GET)
    @ResponseBody
    public String getStudents(
            @RequestParam(name = "current",required = false,defaultValue = "1") int current,
            @RequestParam(name = "limit",required = false,defaultValue = "10") int limit){
        System.out.println(current);
        System.out.println(limit);
        return "some students";
    }

    // /student/123
    @RequestMapping(path = "/student/{id}",method = RequestMethod.GET)
    @ResponseBody
    public String getStudent(@PathVariable("id") int id){
        System.out.println(id);
        return "a student";
    }

访问：http://localhost:8080/community/alpha/students?current=1\&limit=20

访问：http://localhost:8080/community/alpha/student/123

体验响应Post请求

新增页面：static/html/student.html

html 复制代码 
<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>增加学生</title>
</head>
<body>
    <form method="post" action="/community/alpha/student">
        <p>
            姓名：<input type="text" name="name">
        </p>
        <p>
            年龄：<input type="text" name="age">
        </p>
        <p>
            <input type="submit" value="保存">
        </p>
    </form>
</body>
</html>

AlphaController.save()

java 复制代码 
    //  POST请求
    @RequestMapping(path = "/student",method = RequestMethod.POST)
    @ResponseBody
    public String save(String name,int age){
        System.out.println(name);
        System.out.println(age);
        return "success";
    }

访问：http://localhost:8080/community/html/student.html

体验响应HTML数据

AlphaController.getTeacher()

java 复制代码 
    //响应HTML数据

    @RequestMapping(path = "/teacher",method = RequestMethod.GET)
    public ModelAndView getTeacher(){
        ModelAndView mav=new ModelAndView();
        mav.addObject("name","张三");
        mav.addObject("age",30);
        mav.setViewName("/demo/view");
        return mav;
    }

新增页面：template/demo/view.html

html 复制代码 
<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>Teacher</title>
</head>
<body>
  <p th:text="${name}"></p>
  <p th:text="${age}"></p>
</body>
</html>

访问：http://localhost:8080/community/alpha/teacher

AlphaController.getSchool()

java 复制代码 
    @RequestMapping(path = "/school",method = RequestMethod.GET)
    public String getSchool(Model model){
        model.addAttribute("name","北京大学");
        model.addAttribute("age","80");
        return "demo/view";
    }

访问：http://localhost:8080/community/alpha/school

体验响应JSON数据

AlphaController.getEmp()

AlphaController.getEmps()

java 复制代码 
	// 响应JSON数据（异步请求）
    // Java对象 -> JSON字符串 -> JS对象

    @RequestMapping(path = "/emp",method = RequestMethod.GET)
    @ResponseBody
    public Map<String,Object> getEmp(){
        Map<String,Object> emp =new HashMap<>();
        emp.put("name","张三");
        emp.put("age",23);
        emp.put("salary",8000.00);
        return emp;
    }

    @RequestMapping(path = "/emps",method = RequestMethod.GET)
    @ResponseBody
    public List<Map<String,Object>> getEmps(){
        List<Map<String,Object>> list=new ArrayList<>();
        Map<String,Object> emp =new HashMap<>();
        emp.put("name","张三");
        emp.put("age",23);
        emp.put("salary",8000.00);
        list.add(emp);

        emp =new HashMap<>();
        emp.put("name","李四");
        emp.put("age",24);
        emp.put("salary",9000.00);
        list.add(emp);

        emp =new HashMap<>();
        emp.put("name","王五");
        emp.put("age",25);
        emp.put("salary",10000.00);
        list.add(emp);

        return list;
    }

访问：http://localhost:8080/community/alpha/emp

访问：http://localhost:8080/community/alpha/emps

5MyBatis入门

配置

添加依赖

xml 复制代码 
        <!--  mysql      -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.22</version>
        </dependency>

        <!--mybatis整合spring-->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.0.1</version>
        </dependency>
xml 复制代码 
        <!--lombok-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.24</version>
        </dependency>

添加配置

bash 复制代码 
# DataSourceProperties
# 驱动
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
# 路径
spring.datasource.url=jdbc:mysql://localhost:3306/community?characterEncoding=utf-8&useSSL=false&serverTimezone=Hongkong

spring.datasource.username=root
spring.datasource.password=root
#spring.datasource.type=com.zaxxer.hikari.HikariDataSource
spring.datasource.type=com.mysql.cj.jdbc.MysqlDataSource
spring.datasource.hikari.maximum-pool-size=15
spring.datasource.hikari.minimum-idle=5
spring.datasource.hikari.idle-timeout=30000

# MybatisProperties
mybatis.mapper-locations=classpath:mapper/*.xml
mybatis.type-aliases-package=com.jsss.community.entity
#启用自动自增主键
mybatis.configuration.useGeneratedKeys=true
#开启驼峰命名自动匹配
mybatis.configuration.mapUnderscoreToCamelCase=true
User

新建：/entity/User.java

java 复制代码 
package com.jsss.community.entity;

import java.util.Date;


import lombok.*;

@AllArgsConstructor
@NoArgsConstructor
@Data
public class User {
    private int id;
    private String username;
    private String password;
    private String salt;
    private String email;
    private int type;
    private int status;
    private String activationCode;
    private String headerUrl;
    private Date createTime;


}
UserMapper

新建：/dao/UserMapper.java

java 复制代码 
package com.jsss.community.dao;

import com.jsss.community.entity.User;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Param;

@Mapper
public interface UserMapper {
    User selectById(int id);

    User selectByName(String name);

    User selectByEmail (String email);

    int insertUser(User user);

    int updateStatus(@Param("id")int id, @Param("status") int status);

    int updateHeader(@Param("id")int id, @Param("headerUrl")String headerUrl);

    int updatePassword(@Param("id")int id, @Param("password")String password);
}
user-mapper.xml

新建：/mapper/user-mapper.xml

java 复制代码 
<?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.jsss.community.dao.UserMapper">

    <sql id="insertFields">
        username, password, salt, email, type, status, activation_code, header_url, create_time
    </sql>

    <sql id="selectFields">
        id, username, password, salt, email, type, status, activation_code, header_url, create_time
    </sql>

    <select id="selectById" resultType="User">
        select <include refid="selectFields"></include>
        from user
        where id = #{id}
    </select>

    <select id="selectByName" resultType="User">
        select <include refid="selectFields"></include>
        from user
        where username = #{username}
    </select>

    <select id="selectByEmail" resultType="User">
        select <include refid="selectFields"></include>
        from user
        where email = #{email}
    </select>

    <insert id="insertUser" parameterType="User" keyProperty="id">
        insert into user (<include refid="insertFields"></include>)
        values(#{username}, #{password}, #{salt}, #{email}, #{type}, #{status}, #{activationCode}, #{headerUrl}, #{createTime})
    </insert>

    <update id="updateStatus">
        update user set status = #{status} where id = #{id}
    </update>

    <update id="updateHeader">
        update user set header_url = #{headerUrl} where id = #{id}
    </update>

    <update id="updatePassword">
        update user set password = #{password} where id = #{id}
    </update>

</mapper>
测试:MapperTest

新建：test:MapperTest.java

java 复制代码 
package com.jsss.community;


import com.jsss.community.dao.UserMapper;

import com.jsss.community.entity.User;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.ContextConfiguration;

import java.util.Date;


@SpringBootTest
@ContextConfiguration(classes = CommunityApplication.class)
public class MapperTest {
    @Autowired
    private UserMapper userMapper;

    @Test
    public void testSelectUser() {
        User user = userMapper.selectById(101);
        System.out.println(user);

        user = userMapper.selectByName("liubei");
        System.out.println(user);

        user = userMapper.selectByEmail("nowcoder101@sina.com");
        System.out.println(user);
    }

    @Test
    public void testInsertUser() {
        User user = new User();
        user.setUsername("test");
        user.setPassword("123456");
        user.setSalt("abc");
        user.setEmail("test@qq.com");
        user.setHeaderUrl("http://www.nowcoder.com/101.png");
        user.setCreateTime(new Date());

        int rows = userMapper.insertUser(user);
        System.out.println(rows);
        System.out.println(user.getId());
    }

    @Test
    public void updateUser() {
        int rows = userMapper.updateStatus(150, 1);
        System.out.println(rows);

        rows = userMapper.updateHeader(150, "http://www.nowcoder.com/102.png");
        System.out.println(rows);

        rows = userMapper.updatePassword(150, "hello");
        System.out.println(rows);
    }

}
设置日志级别
# logger
logging.level.com.jsss.community=debug

2023-4-30 23:33:09

6开发社区首页

DiscussPost

新增：entity/DiscussPost.java

java 复制代码 
package com.jsss.community.entity;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

import java.util.Date;

@Data
@AllArgsConstructor
@NoArgsConstructor
public class DiscussPost {

    private int id;

    private int userId;

    private String title;

    private String content;

    private int type;

    private int status;

    private Date createTime;

    private int commentCount;

    private double score;

}
DiscussPostMapper

新增：/dao/DiscussPostMapper.java

java 复制代码 
package com.jsss.community.dao;

import com.jsss.community.entity.DiscussPost;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Param;

import java.util.List;

@Mapper
public interface DiscussPostMapper {

    List<DiscussPost> selectDiscussPosts(int userId,int offset,int limit);

    // @Param注解用于给参数取别名,
    // 如果只有一个参数,并且在<if>里使用,则必须加别名.
    int selectDiscussPostRows(@Param("userId") int userId);

}
discusspost-mapper.xml

新增：/mapper/discusspost-mapper.xml

java 复制代码 
<?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.jsss.community.dao.DiscussPostMapper">

    <sql id="selectFields">
        id, user_id, title, content, type, status, create_time, comment_count, score
    </sql>

    <sql id="insertFields">
        user_id, title, content, type, status, create_time, comment_count, score
    </sql>

    <select id="selectDiscussPosts" resultType="DiscussPost">
        select <include refid="selectFields"></include>
        from discuss_post
        where status != 2
        <if test="userId!=0">
            and user_id = #{userId}
        </if>
        order by type desc, create_time desc
        limit #{offset}, #{limit}
    </select>


    <select id="selectDiscussPostRows" resultType="int">
        select count(id)
        from discuss_post
        where status != 2
        <if test="userId!=0">
            and user_id = #{userId}
        </if>
    </select>

</mapper>
测试Dao层

新增：MapperTest.testSelectPosts()

java 复制代码 
    @Test
    public void testSelectPosts() {
        List<DiscussPost> list = discussPostMapper.selectDiscussPosts(149, 0, 10);
        for (DiscussPost post : list) {
            System.out.println(post);
        }

        int rows = discussPostMapper.selectDiscussPostRows(149);
        System.out.println(rows);
    }
DiscussPostService

新增：/service/DiscussPostService.java

java 复制代码 
package com.jsss.community.service;


import com.jsss.community.dao.DiscussPostMapper;


import com.jsss.community.entity.DiscussPost;
import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Service;

import java.util.List;


@Service
public class DiscussPostService {


    @Autowired
    private DiscussPostMapper discussPostMapper;

    public List<DiscussPost> findDiscussPosts(int userId, int offset, int limit) {
        return discussPostMapper.selectDiscussPosts(userId, offset, limit);
    }

    public int findDiscussPostRows(int userId) {
        return discussPostMapper.selectDiscussPostRows(userId);
    }


}

对于帖子：

我们要显示用户名称而不是用户id

有两种解决办法：

  • 关联查询
  • 在高层添加
UserService

新增：/service/UserService.java

java 复制代码 
package com.jsss.community.service;


import com.jsss.community.dao.UserMapper;
import com.jsss.community.entity.User;
import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Service;

@Service
public class UserService{
    @Autowired
    UserMapper userMapper;
    
    public User findUserById(int id){
        return userMapper.selectById(id);
    }

}
前端资源准备

复制静态文件到static下

复制网页到templates

顺便把mail复制进来

mail：将来学习发邮件的模板

HomeController

新增：/controller/HomeController()

java 复制代码 
package com.jsss.community.controller;

import com.jsss.community.entity.DiscussPost;
import com.jsss.community.entity.User;
import com.jsss.community.service.DiscussPostService;
import com.jsss.community.service.UserService;

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.RequestMethod;


import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

@Controller
public class HomeController {

    @Autowired
    private DiscussPostService discussPostService;

    @Autowired
    private UserService userService;


    @RequestMapping(path = "/", method = RequestMethod.GET)
    public String root() {
        return "forward:/index";

    }

    @RequestMapping(path = "/index", method = RequestMethod.GET)
    public String getIndexPage(Model model) {

        List<DiscussPost> list = discussPostService.findDiscussPosts(0, 0, 10);
        List<Map<String, Object>> discussPosts = new ArrayList<>();
        if (list != null) {
            for (DiscussPost post : list) {
                Map<String, Object> map = new HashMap<>();
                map.put("post", post);
                User user = userService.findUserById(post.getUserId());
                map.put("user", user);
                discussPosts.add(map);
            }
        }
        model.addAttribute("discussPosts", discussPosts);

        return "/index";
    }



}
index.html

修改html标签

html 复制代码 
<html lang="en" xmlns:th="http://www.thymeleaf.org">

修改静态路径

html 复制代码 
	<!--前面-->
	<link rel="stylesheet" th:href="@{/css/global.css}" />
	<!--后面-->
	<script th:src="@{/js/global.js}"></script>
	<script th:src="@{js/index.js}"></script>

主要修改内容main的部分

修改：帖子列表的部分

静态数据改为动态数据

xml 复制代码 
				<!-- 帖子列表 -->
				<ul class="list-unstyled">
					<li class="media pb-3 pt-3 mb-3 border-bottom" th:each="map:${discussPosts}">
						<a href="site/profile.html">
							<img th:src="${map.user.headerUrl}" class="mr-4 rounded-circle" alt="用户头像" style="width:50px;height:50px;">
						</a>
						<div class="media-body">
							<h6 class="mt-0 mb-3">
								<a href="#" th:utext="${map.post.title}">备战春招，面试刷题跟他复习，一个月全搞定！</a>
								<span class="badge badge-secondary bg-primary" th:if="${map.post.type==1}">置顶</span>
								<span class="badge badge-secondary bg-danger" th:if="${map.post.status==1}">精华</span>
							</h6>
							<div class="text-muted font-size-12">
								<u class="mr-3" th:utext="${map.user.username}">寒江雪</u> 发布于 <b th:text="${#dates.format(map.post.createTime,'yyyy-MM-dd HH:mm:ss')}">2019-04-15 15:32:18</b>
								<ul class="d-inline float-right">
									<li class="d-inline ml-2">赞 11</li>
									<li class="d-inline ml-2">|</li>
									<li class="d-inline ml-2">回帖 7</li>
								</ul>
							</div>
						</div>						
					</li>
				</ul>

访问：http://localhost:8080/community/index

Page

分页功能

新增：/entity/Page.java

java 复制代码 
package com.jsss.community.entity;

/**
 * 封装分页相关的信息.
 */
public class Page {

    // 当前页码
    private int current = 1;
    // 显示上限
    private int limit = 10;
    // 数据总数(用于计算总页数)
    private int rows;
    // 查询路径(用于复用分页链接)
    private String path;

    public int getCurrent() {
        return current;
    }

    public void setCurrent(int current) {
        if (current >= 1) {
            this.current = current;
        }
    }

    public int getLimit() {
        return limit;
    }

    public void setLimit(int limit) {
        if (limit >= 1 && limit <= 100) {
            this.limit = limit;
        }
    }

    public int getRows() {
        return rows;
    }

    public void setRows(int rows) {
        if (rows >= 0) {
            this.rows = rows;
        }
    }

    public String getPath() {
        return path;
    }

    public void setPath(String path) {
        this.path = path;
    }

    /**
     * 获取当前页的起始行
     *
     * @return
     */
    public int getOffset() {
        // current * limit - limit
        return (current - 1) * limit;
    }

    /**
     * 获取总页数
     *
     * @return
     */
    public int getTotal() {
        // rows / limit [+1]
        if (rows % limit == 0) {
            return rows / limit;
        } else {
            return rows / limit + 1;
        }
    }

    /**
     * 获取起始页码
     *
     * @return
     */
    public int getFrom() {
        int from = current - 2;
        return from < 1 ? 1 : from;//低的时候，就按最大页算
    }

    /**
     * 获取结束页码
     *
     * @return
     */
    public int getTo() {
        int to = current + 2;
        int total = getTotal();
        return to > total ? total : to;//超的时候，就按最大页算
    }

}

修改：HomeController.getIndexPage()

java 复制代码 
    @RequestMapping(path = "/index", method = RequestMethod.GET)
    public String getIndexPage(Model model, Page page) {
        // 方法调用栈,SpringMVC会自动实例化Model和Page,并将Page注入Model.
        // 所以,在thymeleaf中可以直接访问Page对象中的数据.
        page.setRows(discussPostService.findDiscussPostRows(0));
        page.setPath("/index");

        List<DiscussPost> list = discussPostService.findDiscussPosts(0, page.getOffset(), page.getLimit());
        List<Map<String, Object>> discussPosts = new ArrayList<>();
        if (list != null) {
            for (DiscussPost post : list) {
                Map<String, Object> map = new HashMap<>();
                map.put("post", post);
                User user = userService.findUserById(post.getUserId());
                map.put("user", user);
                discussPosts.add(map);
            }
        }
        model.addAttribute("discussPosts", discussPosts);

        return "/index";
    }

修改：index.html:分页

html 复制代码 
				<!-- 分页 -->
				<nav class="mt-5" th:if="${page.rows>0}">
					<ul class="pagination justify-content-center">
						<li class="page-item">
							<a class="page-link" th:href="@{${page.path}(current=1)}">首页</a>
						</li>
						<li th:class="|page-item ${page.current==1?'disabled':''}|">
							<a class="page-link" th:href="@{${page.path}(current=${page.current-1})}">上一页</a></li>
						<li th:class="|page-item ${i==page.current?'active':''}|" th:each="i:${#numbers.sequence(page.from,page.to)}">
							<a class="page-link" th:href="@{${page.path}(current=${i})}" th:text="${i}">1</a>
						</li>
						<li th:class="|page-item ${page.current==page.total?'disabled':''}|">
							<a class="page-link" th:href="@{${page.path}(current=${page.current+1})}">下一页</a>
						</li>
						<li class="page-item">
							<a class="page-link" th:href="@{${page.path}(current=${page.total})}">末页</a>
						</li>
					</ul>
				</nav>
			</div>
		</div>

访问：http://localhost:8080/community/index?current=1

7项目调试技巧

测试：日志功能

新增：test:LoggerTests.java

java 复制代码 
package com.jsss.community;

import org.junit.jupiter.api.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.ContextConfiguration;

@SpringBootTest
@ContextConfiguration(classes = CommunityApplication.class)
public class LoggerTests {

    private static final Logger logger= LoggerFactory.getLogger(LoggerTests.class);

    @Test
    public void testLogger(){
        System.out.println(logger.getName());
        
        logger.debug("debug log");
        logger.info("info log");
        logger.warn("warn log");
        logger.error("error log");
    }
}

配置：

java 复制代码 
# logger
logging.level.com.jsss.community=debug
logging.file.name=E:/work/data/jsss/community.log

添加：/logback-spring.xml

8版本控制

git的使用

java 复制代码 
git add .
git commit -m "消息"
git push
git status
git reset HEAD

最后

这篇博客能写好的原因是：站在巨人的肩膀上

这篇博客要写好的目的是：做别人的肩膀

开源：为爱发电

学习：为我而行

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