NetBeans IDE 向导自动生成JPA代码创建CRUD WEB应用

「爱情、让人受尽委屈。」 2023-09-30 11:44 12阅读 0赞

在数据库中创建表（表名最好为单数英文形式）

CREATE TABLE `book` (
    	`bid` VARCHAR(255) NOT NULL COLLATE 'utf8mb4_unicode_ci',
    	`author` VARCHAR(255) NULL DEFAULT NULL COLLATE 'utf8mb4_unicode_ci',
    	`status` VARCHAR(255) NULL DEFAULT NULL COLLATE 'utf8mb4_unicode_ci',
    	`title` VARCHAR(255) NULL DEFAULT NULL COLLATE 'utf8mb4_unicode_ci',
    	PRIMARY KEY (`bid`) USING BTREE
    )
    COLLATE='utf8mb4_unicode_ci'
    ENGINE=InnoDB
    ;

在NetBeans IDE中创建maven web应用

![watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBAYWxsd2F5Mg_size_20_color_FFFFFF_t_70_g_se_x_16][]

使用向导从数据库表创建实体类：

![watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBAYWxsd2F5Mg_size_20_color_FFFFFF_t_70_g_se_x_16 1][]

![watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBAYWxsd2F5Mg_size_20_color_FFFFFF_t_70_g_se_x_16 2][]

![watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBAYWxsd2F5Mg_size_20_color_FFFFFF_t_70_g_se_x_16 3][]

![watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBAYWxsd2F5Mg_size_20_color_FFFFFF_t_70_g_se_x_16 4][] ![watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBAYWxsd2F5Mg_size_20_color_FFFFFF_t_70_g_se_x_16 5][]

自动生成的实体类代码如下：

使用向导从实体类创建控制器类：

![watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBAYWxsd2F5Mg_size_20_color_FFFFFF_t_70_g_se_x_16 6][]

![watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBAYWxsd2F5Mg_size_20_color_FFFFFF_t_70_g_se_x_16 7][]![watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBAYWxsd2F5Mg_size_20_color_FFFFFF_t_70_g_se_x_16 8][]自动生成的JPA控制器代码如下：

/*
     * Click nbfs://nbhost/SystemFileSystem/Templates/Licenses/license-default.txt to change this license
     * Click nbfs://nbhost/SystemFileSystem/Templates/Classes/Class.java to edit this template
     */
    package com.example.jpawebtomcat;
    
    import com.example.jpawebtomcat.exceptions.NonexistentEntityException;
    import com.example.jpawebtomcat.exceptions.PreexistingEntityException;
    import java.io.Serializable;
    import java.util.List;
    import javax.persistence.EntityManager;
    import javax.persistence.EntityManagerFactory;
    import javax.persistence.Query;
    import javax.persistence.EntityNotFoundException;
    import javax.persistence.criteria.CriteriaQuery;
    import javax.persistence.criteria.Root;
    
    /**
     *
     * @author Administrator
     */
    public class BookJpaController implements Serializable {
    
        public BookJpaController(EntityManagerFactory emf) {
            this.emf = emf;
        }
        private EntityManagerFactory emf = null;
    
        public EntityManager getEntityManager() {
            return emf.createEntityManager();
        }
    
        public void create(Book book) throws PreexistingEntityException, Exception {
            EntityManager em = null;
            try {
                em = getEntityManager();
                em.getTransaction().begin();
                em.persist(book);
                em.getTransaction().commit();
            } catch (Exception ex) {
                if (findBook(book.getBid()) != null) {
                    throw new PreexistingEntityException("Book " + book + " already exists.", ex);
                }
                throw ex;
            } finally {
                if (em != null) {
                    em.close();
                }
            }
        }
    
        public void edit(Book book) throws NonexistentEntityException, Exception {
            EntityManager em = null;
            try {
                em = getEntityManager();
                em.getTransaction().begin();
                book = em.merge(book);
                em.getTransaction().commit();
            } catch (Exception ex) {
                String msg = ex.getLocalizedMessage();
                if (msg == null || msg.length() == 0) {
                    String id = book.getBid();
                    if (findBook(id) == null) {
                        throw new NonexistentEntityException("The book with id " + id + " no longer exists.");
                    }
                }
                throw ex;
            } finally {
                if (em != null) {
                    em.close();
                }
            }
        }
    
        public void destroy(String id) throws NonexistentEntityException {
            EntityManager em = null;
            try {
                em = getEntityManager();
                em.getTransaction().begin();
                Book book;
                try {
                    book = em.getReference(Book.class, id);
                    book.getBid();
                } catch (EntityNotFoundException enfe) {
                    throw new NonexistentEntityException("The book with id " + id + " no longer exists.", enfe);
                }
                em.remove(book);
                em.getTransaction().commit();
            } finally {
                if (em != null) {
                    em.close();
                }
            }
        }
    
        public List<Book> findBookEntities() {
            return findBookEntities(true, -1, -1);
        }
    
        public List<Book> findBookEntities(int maxResults, int firstResult) {
            return findBookEntities(false, maxResults, firstResult);
        }
    
        private List<Book> findBookEntities(boolean all, int maxResults, int firstResult) {
            EntityManager em = getEntityManager();
            try {
                CriteriaQuery cq = em.getCriteriaBuilder().createQuery();
                cq.select(cq.from(Book.class));
                Query q = em.createQuery(cq);
                if (!all) {
                    q.setMaxResults(maxResults);
                    q.setFirstResult(firstResult);
                }
                return q.getResultList();
            } finally {
                em.close();
            }
        }
    
        public Book findBook(String id) {
            EntityManager em = getEntityManager();
            try {
                return em.find(Book.class, id);
            } finally {
                em.close();
            }
        }
    
        public int getBookCount() {
            EntityManager em = getEntityManager();
            try {
                CriteriaQuery cq = em.getCriteriaBuilder().createQuery();
                Root<Book> rt = cq.from(Book.class);
                cq.select(em.getCriteriaBuilder().count(rt));
                Query q = em.createQuery(cq);
                return ((Long) q.getSingleResult()).intValue();
            } finally {
                em.close();
            }
        }
    
    }

手工编写Servlet调用自动生成的Controller进行CRUD

package com.example.jpawebtomcat;
    
    import com.example.jpawebtomcat.exceptions.NonexistentEntityException;
    import java.io.IOException;
    import java.util.List;
    import java.util.logging.Level;
    import java.util.logging.Logger;
    import javax.persistence.EntityManagerFactory;
    import javax.persistence.Persistence;
    import javax.servlet.RequestDispatcher;
    import javax.servlet.ServletException;
    import javax.servlet.annotation.WebServlet;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    @WebServlet(name = "BookServlet", urlPatterns = {"/BookServlet"})
    public class BookServlet extends HttpServlet {
    
        private static final long serialVersionUID = 1L;
        private static final String PERSISTENCE_UNIT_NAME = "com.example_jpawebtomcat_war_1.0-SNAPSHOTPU";
        private BookJpaController bookDao;
    
        @Override
        public void init() {
            EntityManagerFactory emFactory = Persistence.createEntityManagerFactory(PERSISTENCE_UNIT_NAME);
            bookDao = new BookJpaController(emFactory);
        }
    
        @Override
        protected void doGet(HttpServletRequest request, HttpServletResponse response)
                throws ServletException, IOException {
    
            String action = request.getParameter("action");
            if (action == null) {
                action = "";
            }
    
            switch (action) {
                case "new":
                    showNewForm(request, response);
                    break;
                case "insert":
                    insertBook(request, response);
                    break;
                case "delete":
                    deleteBook(request, response);
                    break;
                case "edit":
                    showEditForm(request, response);
                    break;
                case "update":
                    updateBook(request, response);
                    break;
                default:
                    listBook(request, response);
                    break;
            }
    
        }
    
        private void listBook(HttpServletRequest request, HttpServletResponse response)
                throws IOException, ServletException {
            List<Book> listBook = bookDao.findBookEntities();
            request.setAttribute("listBook", listBook);
            RequestDispatcher dispatcher = request.getRequestDispatcher("book-list.jsp");
            dispatcher.forward(request, response);
        }
    
        private void showNewForm(HttpServletRequest request, HttpServletResponse response)
                throws ServletException, IOException {
            RequestDispatcher dispatcher = request.getRequestDispatcher("book-form.jsp");
            dispatcher.forward(request, response);
        }
    
        private void showEditForm(HttpServletRequest request, HttpServletResponse response)
                throws ServletException, IOException {
    
            Book existingBook = bookDao.findBook(request.getParameter("bid"));
            RequestDispatcher dispatcher = request.getRequestDispatcher("book-form.jsp");
            request.setAttribute("book", existingBook);
            dispatcher.forward(request, response);
    
        }
    
        private void insertBook(HttpServletRequest request, HttpServletResponse response)
                throws IOException {
            Book newBook = new Book();
            newBook.setAuthor(request.getParameter("author"));
            newBook.setBid(request.getParameter("bid"));
            newBook.setTitle(request.getParameter("title"));
            newBook.setStatus(request.getParameter("status"));
    
            try {
                bookDao.create(newBook);
            } catch (Exception ex) {
                Logger.getLogger(BookServlet.class.getName()).log(Level.SEVERE, null, ex);
            }
            response.sendRedirect("?action=list");
        }
    
        private void updateBook(HttpServletRequest request, HttpServletResponse response)
                throws IOException {
            Book book = new Book();
            book.setAuthor(request.getParameter("author"));
            book.setBid(request.getParameter("bid"));
            book.setTitle(request.getParameter("title"));
            book.setStatus(request.getParameter("status"));
            try {
                bookDao.edit(book);
            } catch (Exception ex) {
                Logger.getLogger(BookServlet.class.getName()).log(Level.SEVERE, null, ex);
            }
            response.sendRedirect("?action=list");
        }
    
        private void deleteBook(HttpServletRequest request, HttpServletResponse response)
                throws IOException {
    
            try {
                bookDao.destroy(request.getParameter("bid"));
            } catch (NonexistentEntityException ex) {
                Logger.getLogger(BookServlet.class.getName()).log(Level.SEVERE, null, ex);
            }
            response.sendRedirect("?action=list");
        }
    
        @Override
        protected void doPost(HttpServletRequest request, HttpServletResponse response)
                throws ServletException, IOException {
            doGet(request, response);
        }
    }

手工编写html和jsp页面

book-list.jsp

book-form.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
             pageEncoding="UTF-8"%>
    <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
    <html>
        <head>
            <title>Book Management Application</title>
        </head>
        <body>
        <center>
            <h1>Book Management</h1>
            <h2>
                <a href="?action=new">Add New Book</a>
                   
                <a href="?action=list">List All Books</a>
    
            </h2>
        </center>
        <div align="center">
            <c:if test="${book != null}">
                <form action="?action=update" method="post">
                </c:if>
                <c:if test="${book == null}">
                    <form action="?action=insert" method="post">
                    </c:if>
                    <table border="1" cellpadding="5">
                        <caption>
                            <h2>
                                <c:if test="${book != null}">
                                    Edit Book
                                </c:if>
                                <c:if test="${book == null}">
                                    Add New Book
                                </c:if>
                            </h2>
                        </caption>
                        <tr>
                            <th>Book ID: </th>
                            <td>
                                <input type="text" name="bid" size="45"
                                       value="<c:out value='${book.bid}' />"
                                       />
                            </td>
                        </tr>
                        <tr>
                            <th>Book Author: </th>
                            <td>
                                <input type="text" name="author" size="45"
                                       value="<c:out value='${book.author}' />"
                                       />
                            </td>
                        </tr>
                        <tr>
                            <th>Book Status: </th>
                            <td>
                                <input type="text" name="status" size="45"
                                       value="<c:out value='${book.status}' />"
                                       />
                            </td>
                        </tr>
                        <tr>
                            <th>Book Title: </th>
                            <td>
                                <input type="text" name="title" size="15"
                                       value="<c:out value='${book.title}' />"
                                       />
                            </td>
                        </tr>
                        <tr>
                            <td colspan="2" align="center">
                                <input type="submit" value="Save" />
                            </td>
                        </tr>
                    </table>
                </form>
        </div>
    </body>
    </html>

在pom.xml中增加数据库驱动包

<?xml version="1.0" encoding="UTF-8"?>
    <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>
    
        <groupId>com.example</groupId>
        <artifactId>jpawebtomcat</artifactId>
        <version>1.0-SNAPSHOT</version>
        <packaging>war</packaging>
    
        <name>jpawebtomcat</name>
    
        <properties>
            <endorsed.dir>${project.build.directory}/endorsed</endorsed.dir>
            <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        </properties>
    
        <dependencies>
            <dependency>
                <groupId>jstl</groupId>
                <artifactId>jstl</artifactId>
                <version>1.2</version>
            </dependency>
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>8.0.28</version>
            </dependency>
            <dependency>
                <groupId>org.eclipse.persistence</groupId>
                <artifactId>org.eclipse.persistence.core</artifactId>
                <version>2.7.9</version>
            </dependency>
            <dependency>
                <groupId>org.eclipse.persistence</groupId>
                <artifactId>org.eclipse.persistence.asm</artifactId>
                <version>9.1.0</version>
            </dependency>
            <dependency>
                <groupId>org.eclipse.persistence</groupId>
                <artifactId>org.eclipse.persistence.antlr</artifactId>
                <version>2.7.9</version>
            </dependency>
            <dependency>
                <groupId>org.eclipse.persistence</groupId>
                <artifactId>org.eclipse.persistence.jpa</artifactId>
                <version>2.7.9</version>
            </dependency>
            <dependency>
                <groupId>org.eclipse.persistence</groupId>
                <artifactId>org.eclipse.persistence.jpa.jpql</artifactId>
                <version>2.7.9</version>
            </dependency>
            <dependency>
                <groupId>org.eclipse.persistence</groupId>
                <artifactId>org.eclipse.persistence.moxy</artifactId>
                <version>2.7.9</version>
            </dependency>
            <dependency>
                <groupId>org.eclipse.persistence</groupId>
                <artifactId>javax.persistence</artifactId>
                <version>2.2.1</version>
            </dependency>
            <dependency>
                <groupId>org.eclipse.persistence</groupId>
                <artifactId>org.eclipse.persistence.jpa.modelgen.processor</artifactId>
                <version>2.7.9</version>
                <scope>provided</scope>
            </dependency>
            <dependency>
                <groupId>javax</groupId>
                <artifactId>javaee-web-api</artifactId>
                <version>7.0</version>
                <scope>provided</scope>
            </dependency>
        </dependencies>
    
        <build>
            <plugins>
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <version>3.1</version>
                    <configuration>
                        <source>1.7</source>
                        <target>1.7</target>
                        <compilerArguments>
                            <endorseddirs>${endorsed.dir}</endorseddirs>
                        </compilerArguments>
                    </configuration>
                </plugin>
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-war-plugin</artifactId>
                    <version>2.3</version>
                    <configuration>
                        <failOnMissingWebXml>false</failOnMissingWebXml>
                    </configuration>
                </plugin>
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-dependency-plugin</artifactId>
                    <version>2.6</version>
                    <executions>
                        <execution>
                            <phase>validate</phase>
                            <goals>
                                <goal>copy</goal>
                            </goals>
                            <configuration>
                                <outputDirectory>${endorsed.dir}</outputDirectory>
                                <silent>true</silent>
                                <artifactItems>
                                    <artifactItem>
                                        <groupId>javax</groupId>
                                        <artifactId>javaee-endorsed-api</artifactId>
                                        <version>7.0</version>
                                        <type>jar</type>
                                    </artifactItem>
                                </artifactItems>
                            </configuration>
                        </execution>
                    </executions>
                </plugin>
            </plugins>
        </build>
    
    </project>

向导使用的JPA实现是**EclipseLink****：**

<?xml version="1.0" encoding="UTF-8"?>
    <persistence version="2.1" xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd">
        <persistence-unit name="com.example_jpawebtomcat_war_1.0-SNAPSHOTPU" transaction-type="RESOURCE_LOCAL">
            <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
            <class>com.example.jpawebtomcat.Book</class>
            <exclude-unlisted-classes>false</exclude-unlisted-classes>
            <shared-cache-mode>NONE</shared-cache-mode>
            <properties>
                <property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/db?autoReconnect=true&useSSL=false&useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai"/>
                <property name="javax.persistence.jdbc.user" value="root"/>
                <property name="javax.persistence.jdbc.driver" value="com.mysql.cj.jdbc.Driver"/>
                <property name="javax.persistence.jdbc.password" value="root"/>
            </properties>
        </persistence-unit>
    </persistence>

TOMCAT下运行输出：

![watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBAYWxsd2F5Mg_size_20_color_FFFFFF_t_70_g_se_x_16 9][]

源码下载：

[https://github.com/allwaysoft/netbean-auto-jpa-web-mysql-tomcat![icon-default.png?t=M276][icon-default.png_t_M276]https://github.com/allwaysoft/netbean-auto-jpa-web-mysql-tomcat][https_github.com_allwaysoft_netbean-auto-jpa-web-mysql-tomcat_icon-default.png_t_M276_icon-default.png_t_M276_https_github.com_allwaysoft_netbean-auto-jpa-web-mysql-tomcat]

[watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBAYWxsd2F5Mg_size_20_color_FFFFFF_t_70_g_se_x_16]: https://img-blog.csdnimg.cn/022e48465003433e869e07a7888f9b64.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBAYWxsd2F5Mg==,size_20,color_FFFFFF,t_70,g_se,x_16
[watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBAYWxsd2F5Mg_size_20_color_FFFFFF_t_70_g_se_x_16 1]: https://img-blog.csdnimg.cn/60e2f1a1018c4236a929e4ae94b3c297.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBAYWxsd2F5Mg==,size_20,color_FFFFFF,t_70,g_se,x_16
[watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBAYWxsd2F5Mg_size_20_color_FFFFFF_t_70_g_se_x_16 2]: https://img-blog.csdnimg.cn/720ffc37c2314c5c83583dd54129d824.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBAYWxsd2F5Mg==,size_20,color_FFFFFF,t_70,g_se,x_16
[watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBAYWxsd2F5Mg_size_20_color_FFFFFF_t_70_g_se_x_16 3]: https://img-blog.csdnimg.cn/cb687841f8f848dc9546f3ea4aef7614.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBAYWxsd2F5Mg==,size_20,color_FFFFFF,t_70,g_se,x_16
[watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBAYWxsd2F5Mg_size_20_color_FFFFFF_t_70_g_se_x_16 4]: https://img-blog.csdnimg.cn/da1f070361914a9d93155182cb73d172.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBAYWxsd2F5Mg==,size_20,color_FFFFFF,t_70,g_se,x_16
[watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBAYWxsd2F5Mg_size_20_color_FFFFFF_t_70_g_se_x_16 5]: https://img-blog.csdnimg.cn/7fd46fd03d02415d822563db71d84e2d.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBAYWxsd2F5Mg==,size_20,color_FFFFFF,t_70,g_se,x_16
[watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBAYWxsd2F5Mg_size_20_color_FFFFFF_t_70_g_se_x_16 6]: https://img-blog.csdnimg.cn/6d67118534c0456a8768493632bb0745.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBAYWxsd2F5Mg==,size_20,color_FFFFFF,t_70,g_se,x_16
[watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBAYWxsd2F5Mg_size_20_color_FFFFFF_t_70_g_se_x_16 7]: https://img-blog.csdnimg.cn/c34782ee6f6a45e8be7a3029537b9679.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBAYWxsd2F5Mg==,size_20,color_FFFFFF,t_70,g_se,x_16
[watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBAYWxsd2F5Mg_size_20_color_FFFFFF_t_70_g_se_x_16 8]: https://img-blog.csdnimg.cn/0a364e21845e4e11822fb4addbaa7c06.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBAYWxsd2F5Mg==,size_20,color_FFFFFF,t_70,g_se,x_16
[watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBAYWxsd2F5Mg_size_20_color_FFFFFF_t_70_g_se_x_16 9]: https://img-blog.csdnimg.cn/709c67aad1824b3cb304ca821c32f8dc.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBAYWxsd2F5Mg==,size_20,color_FFFFFF,t_70,g_se,x_16
[icon-default.png_t_M276]: https://csdnimg.cn/release/blog_editor_html/release2.0.8/ckeditor/plugins/CsdnLink/icons/icon-default.png?t=M276
[https_github.com_allwaysoft_netbean-auto-jpa-web-mysql-tomcat_icon-default.png_t_M276_icon-default.png_t_M276_https_github.com_allwaysoft_netbean-auto-jpa-web-mysql-tomcat]: https://github.com/allwaysoft/netbean-auto-jpa-web-mysql-tomcat