Spring Boot JPA练习

1.pom.xml

<!-- Web 依赖 -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

<!-- 模板引擎 Thymeleaf 依赖 -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>

<!-- mysql驱动 依赖 -->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
</dependency>

<!-- spring-data-jpa 依赖 -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>

<!-- lombok 依赖 -->
<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
</dependency>

2.application.properties

############################
###数据库配置信息
############################
##基础信息
spring.datasource.url=jdbc:mysql://localhost:3306/springboot_test?useUnicode=true&characterEncoding=utf-8
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
##连接池中最大的活跃连接数
spring.datasource.tomcat.max-active=20  
##连接池中最大、最小的空闲连接数
spring.datasoure.max-idle=8
spring.datasoure.min-idle=8
##初始化连接数
spring.datasoure.initial=10


############################
###Spring Data JPA配置信息
############################
spring.jpa.database=mysql
# 显示SQL语句
spring.jpa.show-sql=true
##指定DDL mode (none, validate, update, create, create-drop)
spring.jpa.properties.hibernate.hbm2ddl.auto=update

spring.thymeleaf.cache=false

3.entity

package com.example.springdatajpa.entity;

import lombok.Data;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import java.io.Serializable;

/**
 * 创建Student持久化类
 * 1.使用@Entity注解实现实体类的持久化，JPA检测到之后，可以在数据库中生成对应的表
 * 2.使用@Id指定主键
 * 3.使用 @GeneratedValue指定主键策略，mysql默认自增
 * 4.使用@Data简化get/set
 */
@Entity
@Data
public class Book implements Serializable {
    @Id
    @GeneratedValue
    private Long id;   //编号
    private String name;  //书名
    private String writer;  //作者
    private String introduction;  //简介

}

4.dao

package com.example.springdatajpa.dao;

import com.example.springdatajpa.entity.Book;
import org.springframework.data.jpa.repository.JpaRepository;

/**
 * Book 数据持久层操作接口
 */
public interface BookRepository extends JpaRepository<Book, Long> {
}

5.service及实现

package com.example.springdatajpa.service;



import com.example.springdatajpa.entity.Book;

import java.util.List;

/**
 * Book 业务接口层
 */
public interface BookService {
    /**
     * 获取所有 Book
     */
    List<Book> findAll();


    /**
     * 获取 Book
     *
     * @param id 编号
     */
    Book findById(Long id);
}

package com.example.springdatajpa.service.impl;

import com.example.springdatajpa.dao.BookRepository;
import com.example.springdatajpa.entity.Book;
import com.example.springdatajpa.service.BookService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

/**
 * Book 业务层实现
 */
@Service
public class BookServiceImpl implements BookService {

    @Autowired
    BookRepository bookRepository;

    @Override
    public List<Book> findAll() {
        return bookRepository.findAll();
    }

    @Override
    public Book findById(Long id) {
        return bookRepository.findById(id).get();
    }
}

6.controller

package com.example.springdatajpa.controller;

import com.example.springdatajpa.entity.Book;
import com.example.springdatajpa.service.BookService;
import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.*;

import javax.annotation.Resource;

/**
 * Book 控制层
 */
@Controller
@RequestMapping(value = "/book")
public class BookController {

    private static final String BOOK_DETAIL_PATH_NAME = "bookDetail";
    private static final String BOOK_LIST_PATH_NAME = "bookList";

    @Resource
    BookService bookService;

    /**
     * 获取 Book 列表
     * 处理 "/book/all" 的 GET 请求，用来获取 Book 列表
     * 数据存入ModelMap，返回Thymeleaf页面
     */
    @GetMapping("/all")
    public String getBookList(ModelMap map) {
        map.addAttribute("bookList", bookService.findAll());
        return BOOK_LIST_PATH_NAME;
    }

    /**
     * 获取 Book
     * 处理 "/book/{id}" 的 GET 请求
     * 返回单个数据的模板页面 
     */
    @GetMapping(value = "/{id}")
    public String getBook(@PathVariable Long id, ModelMap map) {
        map.addAttribute("book", bookService.findById(id));
        return BOOK_DETAIL_PATH_NAME;
    }

}

7.bookList.html页面写法

<html xmlns:th="http://www.thymeleaf.org">
<html lang="zh-CN">
<head>
    <script type="text/javascript" th:src="@{https://cdn.bootcss.com/jquery/3.2.1/jquery.min.js}"></script>
    <link th:href="@{https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css}" rel="stylesheet"/>
    <meta charset="UTF-8"/>
    <title>书籍列表</title>
</head>
<body>
<div class="container">
    <h3>Spring Data JPA练习 </h3>
    <table class="table table-hover table-condensed">
        <legend>
            <strong>书籍列表</strong>
        </legend>
        <thead>
        <tr>
            <th>书籍编号</th>
            <th>书名</th>
            <th>作者</th>
            <th>简介</th>
        </tr>
        </thead>
        <tbody>
        <tr th:each="book : ${bookList}">
            <th scope="row" th:text="${book.id}"></th>
            <td><a th:href="@{/book/{bookId}(bookId=${book.id})}" th:text="${book.name}"></a></td>
            <td th:text="${book.writer}"></td>
            <td th:text="${book.introduction}"></td>
        </tr>
        </tbody>
    </table>
</div>
</body>
</html>

8.bookDetail.html页面写法

<html xmlns:th="http://www.thymeleaf.org">
<html lang="zh-CN">
<head>
    <script type="text/javascript" th:src="@{https://cdn.bootcss.com/jquery/3.2.1/jquery.min.js}"></script>
    <link th:href="@{https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css}" rel="stylesheet"/>
    <meta charset="UTF-8"/>
    <title>书籍详情</title>
</head>
<body>
<div class="container">
    <h3>Spring Data JPA练习 </h3>
    <legend>
        <strong>书籍详情</strong>
    </legend>
    <div class="col-md-4">
        <p th:text="${book.name}"></p>
        <p th:text="${book.writer}"></p>
        <p th:text="${book.introduction}"></p>
    </div>
</div>
</body>
</html>

9.运行效果

图片