SpringBoot使用JPA

叁歲伎倆 2022-06-01 09:27 210阅读 0赞

Spring Data JPA 是 Spring 基于 ORM 框架、JPA 规范的基础上封装的一套JPA应用框架，可使开发者用极简的代码即可实现对数据的访问和操作。它提供了包括增删改查等在内的常用功能，且易于扩展！学习并使用 Spring Data JPA 可以极大提高开发效率！

项目结构：  
![这里写图片描述][SouthEast]

添加依赖：

<dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-jdbc</artifactId>
    </dependency>
    
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
    </dependency>

application.properties

#datasource
    spring.datasource.driver-class-name=com.mysql.jdbc.Driver
    spring.datasource.url=jdbc:mysql:///test?useUnicode=true&characterEncoding=UTF-8
    spring.datasource.username=root
    spring.datasource.password=123456
    spring.datasource.tomcat.max-active=20
    spring.datasource.tomcat.test-while-idle=true
    spring.datasource.tomcat.validation-query=select 1
    spring.datasource.tomcat.default-auto-commit=false
    spring.datasource.tomcat.min-idle=15
    spring.datasource.tomcat.initial-size=15
    #jpa
    spring.jpa.hibernate.ddl-auto=update
    spring.jpa.show-sql=true
    spring.jackson.serialization.indent-output=true

User.java

package com.dx.eintity;
    
    import javax.persistence.Column;
    import javax.persistence.Entity;
    import javax.persistence.GeneratedValue;
    import javax.persistence.GenerationType;
    import javax.persistence.Id;
    import javax.persistence.Table;
    
    /** * * @ClassName: User * @Description:实体User * @author: dongxiang * @date: 2018年1月25日 上午11:30:35 * @version V1.0 */
    @Entity
    @Table(name = "sys_user")
    public class User { 
        public User() {
        }
        public User(String name, String password) {
            this.name = name;
            this.password = password;
        }
        private int id;
        private String name;
        private String password;
        @Id
        @GeneratedValue(strategy = GenerationType.IDENTITY)
        public int getId() {
            return id;
        }
        public void setId(int id) {
            this.id = id;
        }
        @Column(name = "name")
        public String getName() {
            return name;
        }
        public void setName(String name) {
            this.name = name;
        }
        @Column(name = "password")
        public String getPassword() {
            return password;
        }
        public void setPassword(String password) {
            this.password = password;
        }
        @Override
        public String toString() {
            return "User{" + "userId=" + id + ", username='" + name + '\''
                    + ", userpwd='" + password + '\'' + '}';
        }
    }

UserDao.java

package com.dx.dao;
    
    import java.util.List;
    
    import org.springframework.data.domain.Page;
    import org.springframework.data.domain.Pageable;
    import org.springframework.data.jpa.repository.JpaRepository;
    import org.springframework.stereotype.Service;
    
    import com.dx.eintity.User;
    
    @Service
    public interface UserDao extends JpaRepository<User, Integer> {
    
        User findByName(String name);
    
        List<User> findByNameContaining(String name);
    
        Page<User> findByNameNot(String name,Pageable pageable); 
    }

MainController.java

package com.dx.controller;
    
    import java.util.Iterator;
    import java.util.List;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.data.domain.Page;
    import org.springframework.data.domain.PageRequest;
    import org.springframework.data.domain.Pageable;
    import org.springframework.data.domain.Sort;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    import com.dx.dao.UserDao;
    import com.dx.eintity.User;
    
    /** * * @ClassName: MainController * @Description:请求处理 * @author: dongxiang * @date: 2018年1月25日 上午11:37:17 * @version V1.0 */
    @RestController
    public class MainController { 
        @Autowired
        UserDao userDao;
        /** * * @Title: getUser * @Description:获取用户 * @param: @param id * @param: @return * @return: User * @throws */
        @RequestMapping("/getUser")
        public User getUser(String name) {
            return userDao.findByName(name);
        }
        /** * * @Title: getUsersByName * @Description: 根据姓名查询 * @param: @param name * @param: @return * @return: List<User> * @throws */
        @RequestMapping("/getUsersByName")
        public List<User> getUsersByName(String name) {
            return userDao.findByNameContaining(name);
        }
        @RequestMapping("/getPageUser")
        public Page<User> getPageUser(String name) {
            Sort sort = new Sort(Sort.Direction.DESC, "id");// 排序
            int page = 1;// 第几页
            int size = 5;// 每页多少条
            Pageable pageable = new PageRequest(page, size, sort);
            Page<User> pages = userDao.findByNameNot(name, pageable);
            Iterator<User> it = pages.iterator();
            while (it.hasNext()) {
                System.out.println("value:" + ((User) it.next()).getName());
            }
            return userDao.findByNameNot(name, pageable);
        }
        @RequestMapping("/addUser")
        public String addUser() {
            User u = new User("vvv", "vvvvvv");
            userDao.save(u);
            return "添加成功！";
        }
    }

启动项目，测试结果：  
![这里写图片描述][SouthEast 1]

[SouthEast]: /images/20220601/35f7524f090442a58fcc6c31360e569d.png
[SouthEast 1]: /images/20220601/35e2afc801884ba8b68d6908b9e13d80.png