SpringBoot整合hibernate纯注解版

SpringBoot, hibernate Comments

一、hibernate是什么

hibernate是一款优秀的ORM（Object Relational Mapping ，对象关系映射）框架，是一种面向对象编程的框架，它对JDBC进行了封装，是一个全自动的ORM框架，可以自动生成SQL语句，也可以自定义HQL进行执行脚本。

优点：hibernate在进行对象进行数据库存储时，可以不进行SQL编写，配置好对象与数据库的关系后，自动生成SQL执行，也可自动创建表，在简单的数据库关系项目中，可进行高效率的工作。

缺点：hibernte在项目开发的过程中，由于全自动生成SQL，在使用时会发现，当执行复杂关系的数据库关系的业务时，hibernate略显笨重，执行时间偏长且无法灵活的配置关系较为复杂的业务，所以后期有了mybatis的出现，为了可以更加便捷的写sql，灵活的配置SQL。

二、为什么我还要使用hibernate

刚才也描述了，在进行关系较为简单的项目业务上，hibernate可以自动生成SQL执行，也提供了增删改查的方法，可以很简单直接进行对象存储删除，所以在开发逻辑简单的业务时（例如帮学妹做个毕设，课程设计什么的，你懂的，哈哈），可以利用hibernate进行快速的项目开发。

三、开始整合

1.搭建SpringBoot工程，此处不再多讲，之前已经讲过，可以翻看SpringBoot的搭建的帖子，(点我跳转)，在pom文件加上如下依赖

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

2.在java文件夹下创建自定义包，项目结构如下

3.全局配置文件如下

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#配置数据源
spring.datasource.url=jdbc:mysql://localhost:3306/yang
spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
#服务启动信息
server.port=8088
#jpa配置
#数据库类型为mysql
spring.jpa.database = MYSQL
#是否显示sql
spring.jpa.show-sql = true
#自动创建表
spring.jpa.hibernate.ddl-auto = update
#创建命名策略
spring.jpa.hibernate.naming-strategy = org.hibernate.cfg.ImprovedNamingStrategy
#数据库方言为mysql
spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQL5Dialect

4.创建实体类-用户类，及统一返回对象ResultObject

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package com.yang.bean;

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

/**
 * 用户实体类
 * @author Yang
 *
 */
@Entity
@Table(name="t_user")
public class User {
	/*用户名称*/
	@Id
	@GeneratedValue(strategy = GenerationType.AUTO)
	@Column(name="user_id")
	private int userId;
	/*用户登录名称*/
	@Column(name="user_name")
	private String userName;
	/* 用户登录密码 */
	@Column(name="pass_word")
	private String password;
	public int getUserId() {
		return userId;
	}
	public void setUserId(int userId) {
		this.userId = userId;
	}
	public String getUserName() {
		return userName;
	}
	public void setUserName(String userName) {
		this.userName = userName;
	}
	public String getPassword() {
		return password;
	}
	public void setPassword(String password) {
		this.password = password;
	}
	@Override
	public String toString() {
		return "User [userId=" + userId + ", userName=" + userName + ", password=" + password + "]";
	}
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package com.yang.bean;

public class ResultObject<T> {
	private int code;
	private String msg;
	private T data;
	private Long count;
	
	public Long getCount() {
		return count;
	}
	public void setCount(Long count) {
		this.count = count;
	}
	public int getCode() {
		return code;
	}
	public void setCode(int code) {
		this.code = code;
	}
	public String getMsg() {
		return msg;
	}
	public void setMsg(String msg) {
		this.msg = msg;
	}
	public T getData() {
		return data;
	}
	public void setData(T data) {
		this.data = data;
	}	
}

5.创建数据查询接口，需要继承JpaRepository接口来实现查询

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package com.yang.dao;

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;
import com.yang.bean.User;

@Repository
public interface UserDao extends JpaRepository<User, Long>{

}

6.编写Service接口及实现类，实现类注入数据层接口

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package com.yang.service;

import java.util.List;

import com.yang.bean.User;

/**
 * 
 * @author yzx96
 *
 */
public interface UserService {
	/**
	 * 查询所有用户
	 * @return
	 */
	public List<User> getAllUser();
}
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package com.yang.service.impl;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import com.yang.bean.User;
import com.yang.dao.UserDao;
import com.yang.service.UserService;

/**
 * 服务实现
 * @author yzx96
 *
 */
@Service
public class UserServiceImpl implements UserService {
	/**
	 * 注入数据层接口
	 */
	@Autowired
	UserDao userDao;
	
	@Override
	public List<User> getAllUser() {
		return userDao.findAll();
	}

}

7.编写控制器

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package com.yang.controller;

import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import com.yang.bean.ResultObject;
import com.yang.bean.User;
import com.yang.service.UserService;
@RestController
@RequestMapping("/user")
public class UseController {
	
	@Autowired
    private UserService userService;

	
	@RequestMapping("/getAllUser")
	public ResultObject<List<User>> getAllUser(){
		List<User> list=userService.getAllUser();
		ResultObject<List<User>> rs=new ResultObject<List<User>>();
		rs.setCode(0);
		rs.setData(list);
		return rs;
	}
}

8.编写启动类

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package com.yang.boot;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.domain.EntityScan;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;

@ComponentScan(basePackages={"com.yang"}) // 扫描该包路径下的所有spring组件
@EnableJpaRepositories("com.yang.dao") // JPA扫描该包路径下的Repositorie
@EntityScan("com.yang.bean")
@SpringBootApplication
public class StartAppHibernatelication {
	public static void main(String[] args) {
		SpringApplication.run(StartAppHibernatelication.class, args);
	}
}

9.创建数据库表及插入数据

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CREATE TABLE `t_user` (
  `user_id` int(11) NOT NULL AUTO_INCREMENT,
  `user_name` varchar(50) DEFAULT NULL,
  `pass_word` varchar(50) DEFAULT NULL,
  PRIMARY KEY (`user_id`)
) ENGINE=InnoDB AUTO_INCREMENT=21 DEFAULT CHARSET=utf8;


INSERT INTO `t_user` VALUES ('1', 'zhangsan', '00000');
INSERT INTO `t_user` VALUES ('2', 'lisi2', '123456');
INSERT INTO `t_user` VALUES ('3', 'lisi3', '123456');
INSERT INTO `t_user` VALUES ('4', 'lisi4', '123456');
INSERT INTO `t_user` VALUES ('5', 'lisi5', '123456');
INSERT INTO `t_user` VALUES ('6', 'lisi6', '123456');
INSERT INTO `t_user` VALUES ('7', 'lisi7', '123456');
INSERT INTO `t_user` VALUES ('8', 'lisi8', '123456');
INSERT INTO `t_user` VALUES ('9', 'lisi9', '123456');
INSERT INTO `t_user` VALUES ('10', 'lisi10', '123456');
INSERT INTO `t_user` VALUES ('11', 'lisi11', '123456');
INSERT INTO `t_user` VALUES ('12', 'lisi12', '123456');
INSERT INTO `t_user` VALUES ('13', 'lisi13', '123456');
INSERT INTO `t_user` VALUES ('14', 'lisi14', '123456');
INSERT INTO `t_user` VALUES ('15', 'lisi15', '123456');
INSERT INTO `t_user` VALUES ('16', 'lisi16', '123456');
INSERT INTO `t_user` VALUES ('17', 'lisi17', '123456');
INSERT INTO `t_user` VALUES ('18', 'lisi18', '123456');
INSERT INTO `t_user` VALUES ('19', 'lisi19', '123456');
INSERT INTO `t_user` VALUES ('20', 'lisi20', '123456');

10.启动项目，访问地址：localhost:8088/user/getAllUser ,访问结果如下

四、整合的时候遇到的坑

1.注入数据层接口失败，启动时

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Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2019-01-30 10:57:19.756 ERROR 22892 --- [  restartedMain] o.s.b.d.LoggingFailureAnalysisReporter   : 

***************************
APPLICATION FAILED TO START
***************************

Description:

Field userDao in com.yang.service.impl.UserServiceImpl required a bean of type 'com.yang.dao.UserDao' that could not be found.


Action:

Consider defining a bean of type 'com.yang.dao.UserDao' in your configuration.

原因：在启动类上，只是用了@EnableJpaRepositories注解，但未将该注解指定数据层接口包名，需要指定数据层接口的包名，上面代码是已经修复过的，错误代码如下

2.启动时，无法创建userDao,原因为无法创建bean

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Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'userDao': Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: Not a managed type: class com.yang.bean.User
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1706) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:579) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:501) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:317) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:315) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
	at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:251) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1138) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1065) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:584) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
	... 37 common frames omitted
Caused by: java.lang.IllegalArgumentException: Not a managed type: class com.yang.bean.User
	at org.hibernate.metamodel.internal.MetamodelImpl.managedType(MetamodelImpl.java:473) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
	at org.springframework.data.jpa.repository.support.JpaMetamodelEntityInformation.<init>(JpaMetamodelEntityInformation.java:73) ~[spring-data-jpa-2.0.7.RELEASE.jar:2.0.7.RELEASE]
	at org.springframework.data.jpa.repository.support.JpaEntityInformationSupport.getEntityInformation(JpaEntityInformationSupport.java:66) ~[spring-data-jpa-2.0.7.RELEASE.jar:2.0.7.RELEASE]
	at org.springframework.data.jpa.repository.support.JpaRepositoryFactory.getEntityInformation(JpaRepositoryFactory.java:181) ~[spring-data-jpa-2.0.7.RELEASE.jar:2.0.7.RELEASE]
	at org.springframework.data.jpa.repository.support.JpaRepositoryFactory.getTargetRepository(JpaRepositoryFactory.java:119) ~[spring-data-jpa-2.0.7.RELEASE.jar:2.0.7.RELEASE]
	at org.springframework.data.jpa.repository.support.JpaRepositoryFactory.getTargetRepository(JpaRepositoryFactory.java:102) ~[spring-data-jpa-2.0.7.RELEASE.jar:2.0.7.RELEASE]
	at org.springframework.data.repository.core.support.RepositoryFactorySupport.getRepository(RepositoryFactorySupport.java:298) ~[spring-data-commons-2.0.7.RELEASE.jar:2.0.7.RELEASE]
	at org.springframework.data.repository.core.support.RepositoryFactoryBeanSupport.lambda$afterPropertiesSet$3(RepositoryFactoryBeanSupport.java:287) ~[spring-data-commons-2.0.7.RELEASE.jar:2.0.7.RELEASE]
	at org.springframework.data.util.Lazy.getNullable(Lazy.java:141) ~[spring-data-commons-2.0.7.RELEASE.jar:2.0.7.RELEASE]
	at org.springframework.data.util.Lazy.get(Lazy.java:63) ~[spring-data-commons-2.0.7.RELEASE.jar:2.0.7.RELEASE]
	at org.springframework.data.repository.core.support.RepositoryFactoryBeanSupport.afterPropertiesSet(RepositoryFactoryBeanSupport.java:290) ~[spring-data-commons-2.0.7.RELEASE.jar:2.0.7.RELEASE]
	at org.springframework.data.jpa.repository.support.JpaRepositoryFactoryBean.afterPropertiesSet(JpaRepositoryFactoryBean.java:102) ~[spring-data-jpa-2.0.7.RELEASE.jar:2.0.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1765) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1702) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
	... 47 common frames omitted

解决方案：使用@EntityScan注解指定实体类的地址

3.注解的顺序导致的项目无法启动@SpringBootApplication注解需要放到扫描包指定配置之后，否则数据层也无法依赖，实体类指向也不能生效（这个问题困扰了我两个小时）

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Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2019-01-30 11:07:22.925 ERROR 21064 --- [  restartedMain] o.s.boot.SpringApplication               : Application run failed

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'useController': Unsatisfied dependency expressed through field 'userService'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userServiceImpl': Unsatisfied dependency expressed through field 'userDao'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'userDao': Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: Not a managed type: class com.yang.bean.User
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:587) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
	at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:91) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:373) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1348) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:578) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:501) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:317) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:315) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:760) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:869) ~[spring-context-5.0.6.RELEASE.jar:5.0.6.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:550) ~[spring-context-5.0.6.RELEASE.jar:5.0.6.RELEASE]
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:140) ~[spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:759) [spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:395) [spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:327) [spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1255) [spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1243) [spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
	at com.yang.boot.StartAppHibernatelication.main(StartAppHibernatelication.java:15) [classes/:na]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_91]
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_91]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_91]
	at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_91]
	at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) [spring-boot-devtools-2.0.2.RELEASE.jar:2.0.2.RELEASE]

五、项目下载地址如下

点击我下载，小心你的鼠标

Java小白_Mr.YangJava 开发工程师

个人简介。