用java写一个基于spring框架的图书管理系统

好的，下面是一个基于Spring框架的图书管理系统的简单示例：

1. 创建项目并添加依赖

首先，我们需要创建一个Spring项目。在 pom.xml 文件中添加以下依赖：

<dependencies>
    <!-- Spring -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>5.2.0.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-web</artifactId>
        <version>5.2.0.RELEASE</version>
    </dependency>

    <!-- Spring Boot -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
        <version>2.2.0.RELEASE</version>
    </dependency>

    <!-- Thymeleaf -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-thymeleaf</artifactId>
        <version>2.2.0.RELEASE</version>
    </dependency>

    <!-- H2 Database -->
    <dependency>
        <groupId>com.h2database</groupId>
        <artifactId>h2</artifactId>
        <version>1.4.199</version>
    </dependency>

    <!-- JPA -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-jpa</artifactId>
        <version>2.2.0.RELEASE</version>
    </dependency>

    <!-- Validation -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-validation</artifactId>
        <version>2.2.0.RELEASE</version>
    </dependency>
</dependencies>

2. 创建实体类

我们需要创建一个 Book 实体类，可以在 src/main/java/com/example/demo/entity/ 目录下创建 Book.java 文件：

package com.example.demo.entity;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

@Entity
public class Book {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    private String title;

    private String author;

    private String isbn;

    private Integer year;

    // getters and setters
}

3. 创建数据访问对象

我们需要创建一个 BookRepository 接口，可以在 src/main/java/com/example/demo/repository/ 目录下创建 BookRepository.java 文件：

package com.example.demo.repository;

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

public interface BookRepository extends JpaRepository<Book, Long> {
}

4. 创建控制器

我们需要创建一个控制器类，可以在 src/main/java/com/example/demo/controller/ 目录下创建 BookController.java 文件：

package com.example.demo.controller;

import com.example.demo.entity.Book;
import com.example.demo.repository.BookRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.validation.BindingResult;
import org.springframework.web.bind.annotation.*;

import javax.validation.Valid;

@Controller
@RequestMapping("/books")
public class BookController {
    private BookRepository bookRepository;

    @Autowired
    public BookController(BookRepository bookRepository) {
        this.bookRepository = bookRepository;
    }

    @GetMapping
    public String index(Model model) {
        model.addAttribute("books", bookRepository.findAll());
        return "books/index";
    }

    @GetMapping("/new")
    public String newBook(Model model) {
        model.addAttribute("book", new Book());
        return "books/new";
    }

    @PostMapping
    public String create(@ModelAttribute("book") @Valid Book book, BindingResult result) {
        if (result.hasErrors()) {
            return "books/new";
        }

        bookRepository.save(book);
        return "redirect:/books";
    }

    @GetMapping("/{id}/edit")
    public String edit(@PathVariable("id") Long id, Model model) {
        Book book = bookRepository.findById(id)
                .orElseThrow(() -> new IllegalArgumentException("Invalid book id: " + id));

        model.addAttribute("book", book);
        return "books/edit";
    }

    @PutMapping("/{id}")
    public String update(@PathVariable("id") Long id, @ModelAttribute("book") @Valid Book book, BindingResult result) {
        if (result.hasErrors()) {
            book.setId(id);
            return "books/edit";
        }

        bookRepository.save(book);
        return "redirect:/books";
    }

    @DeleteMapping("/{id}")
    public String destroy(@PathVariable("id") Long id) {
        Book book = bookRepository.findById(id)
                .orElseThrow(() -> new IllegalArgumentException("Invalid book id: " + id));

        bookRepository.delete(book);
        return "redirect:/books";
    }
}

5. 创建视图

我们需要创建以下视图文件：

- src/main/resources/templates/books/index.html
- src/main/resources/templates/books/new.html
- src/main/resources/templates/books/edit.html

index.html:

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>Book List</title>
</head>
<body>
    <h1>Book List</h1>

    <p><a href="/books/new">Add Book</a></p>

    <table>
        <thead>
        <tr>
            <th>Title</th>
            <th>Author</th>
            <th>ISBN</th>
            <th>Year</th>
            <th></th>
            <th></th>
        </tr>
        </thead>
        <tbody>
        <tr th:each="book : ${books}">
            <td th:text="${book.title}"></td>
            <td th:text="${book.author}"></td>
            <td th:text="${book.isbn}"></td>
            <td th:text="${book.year}"></td>
            <td><a th:href="@{/books/{id}/edit(id=${book.id})}">Edit</a></td>
            <td>
                <form th:action="@{/books/{id}(id=${book.id})}" method="post">
                    <input type="hidden" name="_method" value="delete"/>
                    <button type="submit">Delete</button>
                </form>
            </td>
        </tr>
        </tbody>
    </table>
</body>
</html>

new.html:

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>Add Book</title>
</head>
<body>
    <h1>Add Book</h1>

    <form th:action="@{/books}" method="post" th:object="${book}">
        <div>
            <label for="title">Title:</label>
            <input type="text" id="title" name="title" th:field="*{title}"/>
            <span th:if="${#fields.hasErrors('title')}" th:errors="*{title}"></span>
        </div>
        <div>
            <label for="author">Author:</label>
            <input type="text" id="author" name="author" th:field="*{author}"/>
            <span th:if="${#fields.hasErrors('author')}" th:errors="*{author}"></span>
        </div>
        <div>
            <label for="isbn">ISBN:</label>
            <input type="text" id="isbn" name="isbn" th:field="*{isbn}"/>
            <span th:if="${#fields.hasErrors('isbn')}" th:errors="*{isbn}"></span>
        </div>
        <div>
            <label for="year">Year:</label>
            <input type="number" id="year" name="year" th:field="*{year}"/>
            <span th:if="${#fields.hasErrors('year')}" th:errors="*{year}"></span>
        </div>
        <div>
            <button type="submit">Save</button>
        </div>
    </form>
</body>
</html>

edit.html:

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>Edit Book</title>
</head>
<body>
    <h1>Edit Book</h1>

    <form th:action="@{/books/{id}(id=${book.id})}" method="post" th:object="${book}">
        <input type="hidden" name="_method" value="put"/>
        <div>
            <label for="title">Title:</label>
            <input type="text" id="title" name="title" th:field="*{title}"/>
            <span th:if="${#fields.hasErrors('title')}" th:errors="*{title}"></span>
        </div>
        <div>
            <label for="author">Author:</label>
            <input type="text" id="author" name="author" th:field="*{author}"/>
            <span th:if="${#fields.hasErrors('author')}" th:errors="*{author}"></span>
        </div>
        <div>
            <label for="isbn">ISBN:</label>
            <input type="text" id="isbn" name="isbn" th:field="*{isbn}"/>
            <span th:if="${#fields.hasErrors('isbn')}" th:errors="*{isbn}"></span>
        </div>
        <div>
            <label for="year">Year:</label>
            <input type="number" id="year" name="year" th:field="*{year}"/>
            <span th:if="${#fields.hasErrors('year')}" th:errors="*{year}"></span>
        </div>
        <div>
            <button type="submit">Save</button>
        </div>
    </form>
</body>
</html>

6. 配置应用程序

最后，我们需要在 src/main/resources/application.properties 文件中添加以下配置：

spring.datasource.url=jdbc:h2:mem:testdb
spring.jpa.hibernate.ddl-auto=update

这将使用 H2 数据库作为我们的数据源，并在启动时自动创建表格。

7. 运行应用程序

现在，我们可以使用以下命令运行应用程序：

mvn spring-boot:run

然后，我们可以在浏览器中访问 http://localhost:8080/books 来查看图书列表，以及 http://localhost:8080/books/new 来添加新图书。

这只是一个简单的示例，实际上，图书管理系统可能需要更多的功能和功能，但是这个示例应该能够帮助你入门。