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实现图书的增删查改(CRUD)

程序员文章站 2022-06-02 14:19:24
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图书的MySQL数据库创建脚本: CREATE TABLE books ( id int NOT NULL AUTO_INCREMENT, title varchar(255) NOT NULL, description text, image_url varchar(255), price decimal(8, 2) NOT NULL, author varchar(255) NOT NULL, isbn varchar(255) NOT NULL,

图书的MySQL数据库创建脚本:

CREATE TABLE books (
  id int NOT NULL AUTO_INCREMENT,
  title varchar(255) NOT NULL,
  description text,
  image_url varchar(255),
  price decimal(8, 2) NOT NULL,
  author varchar(255) NOT NULL,
  isbn varchar(255) NOT NULL,
  publisher varchar(255) NOT NULL,
  user_id int NOT NULL,
  PRIMARY KEY (id)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

图书实体类文件Book.java主要代码:

public class Book {
    private Long id;
    private String title;
    private String description;
    private String image_url;
    private double price;
    private String author;
    private String isbn;
    private String publisher;
    private User user;
    ...
}

在User类中添加集合变量books:

public class User {
    ...
    private Set books = new HashSet();
    ...
}

在User.hbm.xml中配置和图书的一对多关联:


图书的表映射文件Book.hbm.xml代码:

BookService.java中的代码相对简单,因为没什么复杂的业务逻辑,只是负责把Action和Dao这两层连接起来。

BookDao.java中的代码主要实现图书的读取,更新和删除:

package name.dohkoos.book.dao;
import java.util.List;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import name.dohkoos.book.model.Book;
public class BookDao {
    private SessionFactory sessionFactory;
    public void setSessionFactory(SessionFactory sessionFactory) {
        this.sessionFactory = sessionFactory;
    }
    public List getBookList() {
        Session session = sessionFactory.openSession();
        try {
            Query query = session.createQuery("from Book b");
            List bookList = query.list();
            return bookList;
        } finally {
            session.close();
        }
    }
    public Book getBook(Long bookId) {
        Session session = sessionFactory.openSession();
        try {
            Query query = session.createQuery("from Book b where b.id = :id");
            query.setLong("id", bookId);
            query.setMaxResults(1);
            return (Book)query.uniqueResult();
        } finally {
            session.close();
        }
    }
    public void saveOrUpdateBook(Book book) {
        Session session = sessionFactory.openSession();
        Transaction ts = null;
        try {
            ts = session.beginTransaction();
            session.saveOrUpdate(book);
            ts.commit();
        } finally {
            session.close();
        }
    }
    public void deleteBook(Long bookId) {
        Session session = sessionFactory.openSession();
        Transaction ts = null;
        try {
            ts = session.beginTransaction();
            Book book = (Book)session.get(Book.class, bookId);
            session.delete(book);
            ts.commit();
        } finally {
            session.close();
        }
    }
}

BookAction.java负责协调图书应用程序间的运转。接收访问请求,与模型进行交互,将合适的视图展示给用户:

package name.dohkoos.book.action;
import java.util.List;
import name.dohkoos.account.model.User;
import name.dohkoos.book.model.Book;
import name.dohkoos.book.service.BookService;
import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;
public class BookAction extends ActionSupport {
    private static final long serialVersionUID = 2538923417705852774L;
    private Long bookId;
    private Book book;
    private List bookList;
    private BookService bookService;
    public String list() throws Exception {
        bookList = bookService.getBookList();
        return "list";
    }
    public String show() throws Exception {
        book = bookService.getBook(bookId);
        return "show";
    }
    public String input() throws Exception {
        if (bookId != null) {
            book = bookService.getBook(bookId);
        }
        return INPUT;
    }
    public String saveOrUpdate() throws Exception {
        User user = (User)ActionContext.getContext().getSession().get("user");
        book.setUser(user);
        bookService.saveOrUpdateBook(book);
        return SUCCESS;
    }
    public String delete() throws Exception {
        bookService.deleteBook(bookId);
        return SUCCESS;
    }
    ...
}

在applicationContext.xml中添加Book的相关配置,如下面代码所示:


    ...
    
            ...
            name/dohkoos/book/model/Book.hbm.xml
...

在Struts 2配置文件struts.xml中include文件book.xml。以下是book.xml文件的内容:

/books/list.jsp/books/show.jsp/books/form.jsplistBook

视图文件show.jsp作为显示单本图书的信息,代码很简单,就不放出来了,只把list.jsp和form.jsp的代码列出来。

list.jsp用来显示所有的图书:


Listing books

Title Description Image url Price Author ISBN Publisher Action
Show Edit Destroy
Add

当用户新建或者更新图书时,视图form.jsp就上场了。因为被两个逻辑使用,显示的标题等信息也不相同,所以需要判断图书的id是否存在,如果不存在的话即是新建业务,否则就是更新操作。


Editing book

Add book

Show | Back

最后还要完成图书模型的服务端校验。Struts 2的校验文件有两种格式:ActionName-validation.xml和ActionName-alias-validation.xml。第一种会对该Action中的每个方法进行校验,不符合只对saveOrUpdate校验的要求。在BookAction.java同目录下创建BookAction-saveOrUpdateBook-validation.xml文件:

true
            

当然,还要在Book.java所在的位置创建Book-validation.xml文件:

Price is required
    ...
    Price is required0.01
            Price should be at least 0.01

看着BookAction-saveOrUpdateBook-validation.xml这么长的文件名是不是有点无语:)没关系,BookAction-validation.xml配置文件还是可以用的,只要在BookAction.java中那些不需要进行校验的方法上添加@SkipValidation;也可以在action配置中启用validation.excludeMethods参数:

list,show,input,delete
    
    ...

代码下载:https://github.com/dohkoos/JBookShelf