[个人笔记]基于SpringBoot的实体设计+用户登录+类别分页展示

新闻系统
各个实体之间的关系的思维导图
新闻实体
（左侧为实体之间的关系 右侧为自己的功能属性）
User实体类
comment类

在pom.xml配置相关的依赖（这里就不截图了）

其中里面的JAVA代码靠JPA的一套规范其实就是Hibernate 叫Spring data.jpa
更侧重与实体类与表的映射关系 一些基本的操作是不需要写sql语句的
侧重于管理实体类，通过实体类创建数据库的表@Entity+@table
User实体类

package com.zr0726.news.po;
import javax.persistence.*;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

@Entity
@Table(name = "t_user")
public class User {

    @Id  //主键标识
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String nickname;
    private String username;
    private String password;
    private String email;
    private String avatar;
    private Integer type;
    @Temporal(TemporalType.TIMESTAMP)//指定类型 时分秒
    private Date createTime;
    @Temporal(TemporalType.TIMESTAMP)
    private Date updateTime;

    @OneToMany(mappedBy = "user")//指定生成中间表 用user管理
    private List<News> newsList = new ArrayList<>();

    public Long getId() {
        return id;
    }

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

    public String getNickname() {
        return nickname;
    }

    public void setNickname(String nickname) {
        this.nickname = nickname;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getAvatar() {
        return avatar;
    }

    public void setAvatar(String avatar) {
        this.avatar = avatar;
    }

    public Integer getType() {
        return type;
    }

    public void setType(Integer type) {
        this.type = type;
    }

    public Date getCreateTime() {
        return createTime;
    }

    public void setCreateTime(Date createTime) {
        this.createTime = createTime;
    }

    public Date getUpdateTime() {
        return updateTime;
    }

    public void setUpdateTime(Date updateTime) {
        this.updateTime = updateTime;
    }

    public List<News> getNewsList() {
        return newsList;
    }

    public void setNewsList(List<News> newsList) {
        this.newsList = newsList;
    }


}

Type实体类

package com.zr0726.news.po;


import javax.persistence.*;
import java.util.ArrayList;
import java.util.List;

@Entity
@Table(name = "t_type")
//分类管理
public class Type {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String name;

    @OneToMany(mappedBy = "type")
    private List<News> news = new ArrayList<>();

    public Type() {
    }

    public Long getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public List<News> getNews() {
        return news;
    }

    public void setNews(List<News> news) {
        this.news = news;
    }

    @Override
    public String toString() {
        return "Type{" +
                "id=" + id +
                ", name='" + name + '\'' +
                '}';
    }
}

News实体类
由于comment加载的数据过多，要用到懒加载
@Basic(fetch = FetchType.LAZY)//懒加载，当数据需要用到才会加载
@Lob//数据存储量大就需要用到

package com.zr0726.news.po;

import javax.persistence.*;
import java.util.Date;


@Entity
@Table(name = "t_news")
public class News {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String title;

    @Basic(fetch = FetchType.LAZY)//懒加载，当数据需要用到才会加载
    @Lob//数据存储量大就需要用到
    private String content;

    private String firstPicture;
    private String flag;
    private String views;
    private boolean appreciation;
    private boolean shareStatement;
    private boolean commentabled;
    private boolean published;
    private boolean recommend;
    @Temporal(TemporalType.TIMESTAMP)//指定类型 时分秒
    private Date createTime;
    @Temporal(TemporalType.TIMESTAMP)
    private Date updateTime;

    @ManyToOne//一对多
    private Type type;

    @ManyToOne//一对多
    private User user;

    public Long getId() {
        return id;
    }

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

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getContent() {
        return content;
    }

    public void setContent(String content) {
        this.content = content;
    }

    public String getFirstPicture() {
        return firstPicture;
    }

    public void setFirstPicture(String firstPicture) {
        this.firstPicture = firstPicture;
    }

    public String getFlag() {
        return flag;
    }

    public void setFlag(String flag) {
        this.flag = flag;
    }

    public String getViews() {
        return views;
    }

    public void setViews(String views) {
        this.views = views;
    }

    public boolean isAppreciation() {
        return appreciation;
    }

    public void setAppreciation(boolean appreciation) {
        this.appreciation = appreciation;
    }

    public boolean isShareStatement() {
        return shareStatement;
    }

    public void setShareStatement(boolean shareStatement) {
        this.shareStatement = shareStatement;
    }

    public boolean isCommentabled() {
        return commentabled;
    }

    public void setCommentabled(boolean commentabled) {
        this.commentabled = commentabled;
    }

    public boolean isPublished() {
        return published;
    }

    public void setPublished(boolean published) {
        this.published = published;
    }

    public boolean isRecommend() {
        return recommend;
    }

    public void setRecommend(boolean recommend) {
        this.recommend = recommend;
    }

    public Date getCreateTime() {
        return createTime;
    }

    public void setCreateTime(Date createTime) {
        this.createTime = createTime;
    }

    public Date getUpdateTime() {
        return updateTime;
    }

    public void setUpdateTime(Date updateTime) {
        this.updateTime = updateTime;
    }

    public Type getType() {
        return type;
    }

    public void setType(Type type) {
        this.type = type;
    }

    public User getUser() {
        return user;
    }

    public void setUser(User user) {
        this.user = user;
    }

    @Override
    public String toString() {
        return "News{" +
                "id=" + id +
                ", title='" + title + '\'' +
                ", content='" + content + '\'' +
                ", firstPicture='" + firstPicture + '\'' +
                ", flag='" + flag + '\'' +
                ", views='" + views + '\'' +
                ", appreciation=" + appreciation +
                ", shareStatement=" + shareStatement +
                ", commentabled=" + commentabled +
                ", published=" + published +
                ", recommend=" + recommend +
                ", createTime=" + createTime +
                ", updateTime=" + updateTime +
                ", type=" + type +
                ", user=" + user +
                '}';
    }
}

导入相关文件（内容略）
LoginController实现登录注销功能

package com.zr0726.news.web.admin;

import com.zr0726.news.po.User;
import com.zr0726.news.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.servlet.mvc.support.RedirectAttributes;

import javax.servlet.http.HttpSession;

@Controller
@RequestMapping("/admin")//在端口8080才能进入Controller
public class LoginController {
    @Autowired
    private UserService userService;

    @GetMapping//登录跳转后的页面
    public String loginPage(){
        return "admin/login";
    }

    @PostMapping("/login")
    public String login(@RequestParam String username, @RequestParam String password,
                        HttpSession session, RedirectAttributes attributes){
                        //登录成功的用户密码等信息存到session中
        User user = userService.checkUsers(username, password);

        if (user!=null){
            user.setPassword(null);
            session.setAttribute("user", user);
            return "admin/index";
        }else {
            attributes.addFlashAttribute("message", "用户名或密码错误");
            return "redirect:/admin";
        }
    }
    //注销功能 就是对session进行操作 注销的话就是讲session里面的信息清除掉
    @GetMapping("/logout")
    public String logout(HttpSession session){
        session.removeAttribute("user");
        return "redirect:/admin";//返回到主页上
    }
}

数据库的账号密码随便弄一个
在端口8080/admin进行登录操作
登录成功

2.分页功能
创建TypeController

package com.zr0726.news.web.admin;

import com.zr0726.news.service.TypeService;
import net.bytebuddy.TypeCache;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.data.web.PageableDefault;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
@RequestMapping("/admin")
public class TypeController {

    @Autowired
    private TypeService typeService;

    @RequestMapping("/types")
        public String type(@PageableDefault(size = 3,sort = {"id"},direction = Sort.Direction.DESC)Pageable pageable, Model model){


        model.addAttribute("pages", typeService.listType(pageable));
        return "admin/types";

    }
}

创建TypeRepository接口

package com.zr0726.news.dao;

import com.zr0726.news.po.Type;
import org.springframework.data.jpa.repository.JpaRepository;

//指定要使用实体的类型为Type，和主键的类型为Long
public interface TypeRepository extends JpaRepository<Type,Long> {
    
}

创建TypeService接口 利用SpringDate提供的分页接口Page<>

package com.zr0726.news.service;

import com.zr0726.news.po.Type;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;

public interface TypeService {
    //利用SpringDate提供的分页接口Page<> 指定分页的对象为Pageable
    Page<Type> listType(Pageable pageable);
}

创建TypeService类

package com.zr0726.news.service.impl;

import com.zr0726.news.dao.TypeRepository;
import com.zr0726.news.po.Type;
import com.zr0726.news.service.TypeService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import org.springframework.stereotype.Service;

@Service
public class TypeServiceImpl implements TypeService {

    @Autowired
    private TypeRepository typeRepository;


    @Override//找到索要的页面
    public Page<Type> listType(Pageable pageable) {
        return typeRepository.findAll(pageable);
    }
}

在自动创建的数据库添加信息
成功效果图：