SpringBoot整合ORM开发框架MyBatis和JPA

1、在使用Spring整合ORM组件的过程中，为了达到简化的目的，往往会进行大量的配置。利用SpringBoot可以进一步实现配置的简化。SpringBoot整合MyBatis开发框架，MyBatis是一款常用并且配置极为简单的ORM开发框架。其与Spring结合后，可以利用Spring的特征实现DAO接口的自动配置。在SpringBoot中，又对MyBatis框架的整合进行了进一步简化。

修改pom.xml配置文件，在项目中引入mybatis-spring-boot- starter依赖支持库，切记也需要数据库链接池的支持的哦。

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <project xmlns="http://maven.apache.org/POM/4.0.0"
 3     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 4     xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 
 5     https://maven.apache.org/xsd/maven-4.0.0.xsd">
 6 
 7     <modelVersion>4.0.0</modelVersion>
 8     <parent>
 9         <!-- spring-boot-starter-parent就是官方给出的快速构建SpringBoot项目的公共父pom.xml配置文件支持。 -->
10         <groupId>org.springframework.boot</groupId>
11         <artifactId>spring-boot-starter-parent</artifactId>
12         <version>2.3.4.RELEASE</version>
13         <relativePath /> <!-- lookup parent from repository -->
14     </parent>
15 
16     <groupId>com.bie</groupId>
17     <artifactId>springboot-01</artifactId>
18     <version>0.0.1-SNAPSHOT</version>
19     <name>springboot-01</name>
20     <description>Demo project for Spring Boot</description>
21 
22     <properties>
23         <java.version>1.8</java.version>
24         <maven-jar-plugin.version>3.1.1</maven-jar-plugin.version>
25     </properties>
26 
27     <dependencies>
28         <dependency>
29             <groupId>org.springframework.boot</groupId>
30             <artifactId>spring-boot-starter-web</artifactId>
31         </dependency>
32 
33         <dependency>
34             <groupId>org.springframework.boot</groupId>
35             <artifactId>spring-boot-starter-test</artifactId>
36             <scope>test</scope>
37             <exclusions>
38                 <exclusion>
39                     <groupId>org.junit.vintage</groupId>
40                     <artifactId>junit-vintage-engine</artifactId>
41                 </exclusion>
42             </exclusions>
43         </dependency>
44         <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
45         <dependency>
46             <groupId>mysql</groupId>
47             <artifactId>mysql-connector-java</artifactId>
48             <!-- <version>5.1.12</version> -->
49         </dependency>
50         <dependency>
51             <groupId>org.springframework.boot</groupId>
52             <artifactId>spring-boot-configuration-processor</artifactId>
53             <optional>true</optional>
54         </dependency>
55 
56         <!-- 引入 Druid 数据源依赖：https://mvnrepository.com/artifact/com.alibaba/druid -->
57         <dependency>
58             <groupId>com.alibaba</groupId>
59             <artifactId>druid</artifactId>
60             <version>1.1.9</version>
61         </dependency>
62         <!-- 导入MyBatis的ORM开发包。 -->
63         <dependency>
64             <groupId>org.mybatis.spring.boot</groupId>
65             <artifactId>mybatis-spring-boot-starter</artifactId>
66             <version>1.3.1</version>
67         </dependency>
68         <!-- https://mvnrepository.com/artifact/org.mybatis/mybatis -->
69         <dependency>
70             <groupId>org.mybatis</groupId>
71             <artifactId>mybatis</artifactId>
72             <version>3.4.6</version>
73         </dependency>
74         <!-- mybatis的启动器 -->
75         <dependency>
76             <groupId>org.mybatis.spring.boot</groupId>
77             <artifactId>mybatis-spring-boot-starter</artifactId>
78             <version>2.1.1</version>
79         </dependency>
80         <dependency>
81             <groupId>org.springframework.boot</groupId>
82             <artifactId>spring-boot-starter-jdbc</artifactId>
83         </dependency>
84     </dependencies>
85 
86     <build>
87         <plugins>
88             <plugin>
89                 <groupId>org.springframework.boot</groupId>
90                 <artifactId>spring-boot-maven-plugin</artifactId>
91             </plugin>
92         </plugins>
93     </build>
94 
95 </project>

数据表结构，如下所示：

注意：如果数据表字段两个英文单词之间是下划线连接的，但是你的实体类是驼峰命名法，此时就需要进行配置，数据库字段是你下划线分隔，但是bean中的字段是驼峰命名的，如user_name和userName，导致无法匹配。如果是通过xml文件来配置的话，只需要开启驼峰命名转换，setting name="mapUnderscoreToCamelCase" value="true"/>，在/src/main/resources/mybatis/mybatis.cfg.xml里面配置即可。

 1 /*
 2  Navicat Premium Data Transfer
 3 
 4  Source Server         : localhost
 5  Source Server Type    : MySQL
 6  Source Server Version : 50724
 7  Source Host           : localhost:3306
 8  Source Schema         : biehl
 9 
10  Target Server Type    : MySQL
11  Target Server Version : 50724
12  File Encoding         : 65001
13 
14  Date: 15/11/2020 13:34:52
15 */
16 
17 SET NAMES utf8mb4;
18 SET FOREIGN_KEY_CHECKS = 0;
19 
20 -- ----------------------------
21 -- Table structure for user_info
22 -- ----------------------------
23 DROP TABLE IF EXISTS `user_info`;
24 CREATE TABLE `user_info`  (
25   `user_id` int(11) NOT NULL AUTO_INCREMENT COMMENT '用户编号',
26   `user_account` varchar(15) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL COMMENT '用户账号',
27   `user_pw` varchar(15) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL COMMENT '用户密码',
28   `user_number` varchar(15) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL COMMENT '用户手机号',
29   `user_name` varchar(10) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL COMMENT '用户姓名',
30   `user_age` int(11) DEFAULT NULL COMMENT '用户年龄',
31   `user_sex` varchar(5) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL COMMENT '用户性别',
32   `user_mark` varchar(5) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL COMMENT '用户标志',
33   `create_time` datetime(0) DEFAULT CURRENT_TIMESTAMP COMMENT '用户创建时间',
34   `is_sync` int(3) DEFAULT 0 COMMENT '用户标识',
35   `is_money` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL COMMENT '是否缴纳押金',
36   PRIMARY KEY (`user_id`) USING BTREE,
37   INDEX `user_id`(`user_id`) USING BTREE
38 ) ENGINE = InnoDB AUTO_INCREMENT = 42 CHARACTER SET = utf8 COLLATE = utf8_general_ci COMMENT = '用户信息表' ROW_FORMAT = Dynamic;
39 
40 SET FOREIGN_KEY_CHECKS = 1;

创建一个po实体类，方便数据传输，如下所示：

 1 package com.bie.po;
 2 
 3 public class UserInfo {
 4 
 5     private Integer userId;// 用户编号
 6     private String userAccount;// 用户账号
 7     private String userPw;// 用户密码
 8     private String userNumber;// 用户学号
 9     private String userName;// 用户姓名
10     private Integer userAge;// 用户年龄
11     private String userSex;// 用户性别
12     private String userMark;// 用户标识，可以使用一张表，完成管理员和用户
13 
14     private String isMoney;
15 
16     public Integer getUserId() {
17         return userId;
18     }
19 
20     public void setUserId(Integer userId) {
21         this.userId = userId;
22     }
23 
24     public String getUserAccount() {
25         return userAccount;
26     }
27 
28     public void setUserAccount(String userAccount) {
29         this.userAccount = userAccount;
30     }
31 
32     public String getUserPw() {
33         return userPw;
34     }
35 
36     public void setUserPw(String userPw) {
37         this.userPw = userPw;
38     }
39 
40     public String getUserNumber() {
41         return userNumber;
42     }
43 
44     public void setUserNumber(String userNumber) {
45         this.userNumber = userNumber;
46     }
47 
48     public String getUserName() {
49         return userName;
50     }
51 
52     public void setUserName(String userName) {
53         this.userName = userName;
54     }
55 
56     public Integer getUserAge() {
57         return userAge;
58     }
59 
60     public void setUserAge(Integer userAge) {
61         this.userAge = userAge;
62     }
63 
64     public String getUserSex() {
65         return userSex;
66     }
67 
68     public void setUserSex(String userSex) {
69         this.userSex = userSex;
70     }
71 
72     public String getUserMark() {
73         return userMark;
74     }
75 
76     public void setUserMark(String userMark) {
77         this.userMark = userMark;
78     }
79 
80     public String getIsMoney() {
81         return isMoney;
82     }
83 
84     public void setIsMoney(String isMoney) {
85         this.isMoney = isMoney;
86     }
87 
88     @Override
89     public String toString() {
90         return "UserInfo [userId=" + userId + ", userAccount=" + userAccount + ", userPw=" + userPw + ", userNumber="
91                 + userNumber + ", userName=" + userName + ", userAge=" + userAge + ", userSex=" + userSex
92                 + ", userMark=" + userMark + ", isMoney=" + isMoney + "]";
93     }
94 
95 }

在src/main/resources目录中创建mybatis/mybatis.cfg.xml配置文件。如果要开启驼峰命名转换，在这里开启即可，如下所示：

如果在application.properties中开启转换的话，使用mybatis.configuration.map-underscore-to-camel-case=true配置即可。

 1 <?xml version="1.0" encoding="UTF-8" ?> 
 2 <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" 
 3 "http://mybatis.org/dtd/mybatis-3-config.dtd">
 4 <!-- 进行Mybatis的相应环境的属性定义 -->
 5 <configuration>
 6 
 7     <settings>
 8         <!-- 通过xml文件来配置的话，只需要开启驼峰命名转换 -->
 9         <setting name="mapUnderscoreToCamelCase" value="true" />
10     </settings>
11 
12 </configuration>

或者搞个配置类，如果数据库表字段Column无法自动映射到相对应的实体类属性上，我们可以在config包下新建一个自动配置类MybatisConfig，开始驼峰命名规则。

MyBatis配置文件开启驼峰命名映射，可参考：https://blog.csdn.net/liu_sisi/article/details/88360155

 1 package com.bie.config;
 2  
 3 import org.apache.ibatis.session.Configuration;
 4 import org.mybatis.spring.boot.autoconfigure.ConfigurationCustomizer;
 5 import org.springframework.context.annotation.Bean;
 6  
 7 
 8 @Configuration
 9 public class MybatisConfig {
10  
11     //注册到容器中
12     @Bean
13     public ConfigurationCustomizer configurationCustomizer(){
14         return new ConfigurationCustomizer(){
15             @Override
16             public void customize(Configuration configuration) {
17                 //开启驼峰命名规则，是否启用下划线与驼峰式命名规则的映射
18                 configuration.setMapUnderscoreToCamelCase(true);
19  
20             }
21         };
22     }
23 }

修改application.yml配置文件，追加MyBatis配置，如下所示：

 1 # 配置当前要使用的数据源的操作类型
 2 spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
 3 # 配置Mysql的驱动程序类
 4 spring.datasource.driver-class-name=com.mysql.jdbc.Driver
 5 # 数据库连接地址
 6 spring.datasource.url=jdbc:mysql://127.0.0.1:3306/biehl?characterEncoding=UTF-8&serverTimezone=UTC
 7 # 数据库用户名称
 8 spring.datasource.username=root
 9 # 数据库密码
10 spring.datasource.password=123456
11 # 进行数据库链接池的配置，数据库最小维持连接数
12 spring.datasource.dbcp2.min-idle=1
13 # 数据库初始化提供的连接数
14 spring.datasource.dbcp2.initial-size=1
15 # 数据库最大维持连接数
16 spring.datasource.dbcp2.max-total=100
17 # 等待连接获取的最大超时时间
18 spring.datasource.dbcp2.max-wait-millis=3000
19 
20 
21 # 后台打印sql语句
22 # mybatis.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl
23 # 指定sql映射文件位置,mapper下的所有.xml文件都是映射文件
24 # mybatis.mapper-locations=classpath:mapper/*Mapper.xml
25 # Mybatis配置文件所在的路径
26 mybatis.config-location=classpath:mybatis/mybatis.cfg.xml
27 # 定义所有操作类的别名所在包
28 mybatis.type-aliases-package=com.bie.po

搞几个Dao层、Service层、Controller层的接口或者类，如下所示：

注意：如果不想每次都在mapper接口上添加@Mapper注解，可以在主启动类上通过添加@MapperScan注解来批量扫描指定包下的所有mapper接口。

 1 package com.bie.dao;
 2 
 3 import java.util.List;
 4 
 5 import org.apache.ibatis.annotations.Mapper;
 6 import org.apache.ibatis.annotations.Select;
 7 
 8 import com.bie.po.UserInfo;
 9 
10 @Mapper // 需要引入Mybatis的依赖包
11 public interface UserInfoDao {
12 
13     /**
14      * 查询全部用户信息
15      * 
16      * @return
17      */
18     @Select(value = " select * from user_info ")
19     public List<UserInfo> findAll(); // 查询全部用户信息
20 
21 }

Service层的接口和实现类代码，如下所示：

 1 package com.bie.service;
 2 
 3 import java.util.List;
 4 
 5 import com.bie.po.UserInfo;
 6 
 7 public interface UserInfoService {
 8     
 9     public List<UserInfo> findAll();
10 }

 1 package com.bie.service.impl;
 2 
 3 import java.util.List;
 4 
 5 import org.springframework.beans.factory.annotation.Autowired;
 6 import org.springframework.stereotype.Service;
 7 
 8 import com.bie.dao.UserInfoDao;
 9 import com.bie.po.UserInfo;
10 import com.bie.service.UserInfoService;
11 
12 @Service
13 public class UserInfoServiceImpl implements UserInfoService {
14 
15     @Autowired
16     private UserInfoDao userInfoDao;
17 
18     @Override
19     public List<UserInfo> findAll() {
20         return this.userInfoDao.findAll();
21     }
22 
23 }

控制层的代码，如下所示：

 1 package com.bie.controller;
 2 
 3 import java.util.List;
 4 
 5 import org.springframework.beans.factory.annotation.Autowired;
 6 import org.springframework.stereotype.Controller;
 7 import org.springframework.web.bind.annotation.RequestMapping;
 8 import org.springframework.web.bind.annotation.ResponseBody;
 9 
10 import com.bie.po.UserInfo;
11 import com.bie.service.UserInfoService;
12 
13 @Controller
14 public class UserInfoController {
15 
16     @Autowired
17     private UserInfoService userInfoService;
18 
19     @RequestMapping(value = "findAll")
20     @ResponseBody
21     public List<UserInfo> findAll() {
22         List<UserInfo> findAll = this.userInfoService.findAll();
23         return findAll;
24     }
25 
26 }

项目启动类，如下所示：

 1 package com.bie;
 2 
 3 import org.mybatis.spring.annotation.MapperScan;
 4 import org.springframework.boot.SpringApplication;
 5 import org.springframework.boot.autoconfigure.SpringBootApplication;
 6 
 7 @SpringBootApplication
 8 @MapperScan(value = "com.bie.dao")
 9 public class Springboot01Application {
10 
11     public static void main(String[] args) {
12         SpringApplication.run(Springboot01Application.class, args);
13     }
14 
15 }

通过Postman测试一下，自己写的接口，看看好使不，如下所示：

项目结构，如下所示：

2、JPA是官方推出的Java持久层操作标准（现主要使用Hibernate实现），使用SpringData技术和JpaRepository接口技术，也可以达到简化数据层的目的。要在SpringBoot中使用SpringDataJPA，需要spring-boot-starter-data-jpa依赖库的支持。

修改pom.xml配置文件，引入相关依赖包，如下所示：

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <project xmlns="http://maven.apache.org/POM/4.0.0"
 3     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 4     xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 
 5     https://maven.apache.org/xsd/maven-4.0.0.xsd">
 6     <modelVersion>4.0.0</modelVersion>
 7     <parent>
 8         <groupId>org.springframework.boot</groupId>
 9         <artifactId>spring-boot-starter-parent</artifactId>
10         <version>2.3.5.RELEASE</version>
11         <relativePath /> <!-- lookup parent from repository -->
12     </parent>
13     <groupId>com.example</groupId>
14     <artifactId>demo</artifactId>
15     <version>0.0.1-SNAPSHOT</version>
16     <name>demo</name>
17     <description>Demo project for Spring Boot</description>
18 
19     <properties>
20         <java.version>1.8</java.version>
21         <maven-jar-plugin.version>3.1.1</maven-jar-plugin.version>
22     </properties>
23 
24     <dependencies>
25         <dependency>
26             <groupId>org.springframework.boot</groupId>
27             <artifactId>spring-boot-starter-web</artifactId>
28         </dependency>
29 
30         <dependency>
31             <groupId>org.springframework.boot</groupId>
32             <artifactId>spring-boot-starter-test</artifactId>
33             <scope>test</scope>
34             <exclusions>
35                 <exclusion>
36                     <groupId>org.junit.vintage</groupId>
37                     <artifactId>junit-vintage-engine</artifactId>
38                 </exclusion>
39             </exclusions>
40         </dependency>
41 
42         <!-- mysql驱动包 -->
43         <dependency>
44             <groupId>mysql</groupId>
45             <artifactId>mysql-connector-java</artifactId>
46         </dependency>
47 
48         <!-- druid连接池 -->
49         <dependency>
50             <groupId>com.alibaba</groupId>
51             <artifactId>druid</artifactId>
52             <version>1.1.10</version>
53         </dependency>
54 
55         <dependency>
56             <groupId>org.springframework.boot</groupId>
57             <artifactId>spring-boot-starter-data-jpa</artifactId>
58         </dependency>
59         <dependency>
60             <groupId>org.springframework.boot</groupId>
61             <artifactId>spring-boot-starter-cache</artifactId>
62         </dependency>
63         <dependency>
64             <groupId>org.hibernate</groupId>
65             <artifactId>hibernate-ehcache</artifactId>
66         </dependency>
67     </dependencies>
68 
69     <build>
70         <plugins>
71             <plugin>
72                 <groupId>org.springframework.boot</groupId>
73                 <artifactId>spring-boot-maven-plugin</artifactId>
74             </plugin>
75         </plugins>
76         <resources>
77             <resource>
78                 <directory>src/main/resources</directory>
79                 <includes>
80                     <include>**/*.properties</include>
81                     <include>**/*.yml</include>
82                     <include>**/*.xml</include>
83                     <include>**/*.p12</include>
84                     <include>**/*.html</include>
85                     <include>**/*.jpg</include>
86                     <include>**/*.png</include>
87                 </includes>
88             </resource>
89         </resources>
90     </build>
91 
92 </project>

创建UserInfo实体类，如下所示：

  1 package com.demo.po;
  2 
  3 import javax.persistence.Cacheable;
  4 import javax.persistence.Column;
  5 import javax.persistence.Entity;
  6 import javax.persistence.GeneratedValue;
  7 import javax.persistence.GenerationType;
  8 import javax.persistence.Id;
  9 
 10 @Cacheable()
 11 @Entity(name = "user_info")
 12 public class UserInfo {
 13 
 14     @Id()
 15     @Column(name = "user_id")
 16     @GeneratedValue(strategy = GenerationType.IDENTITY) // 根据名称引用配置的主键生成器
 17     private Integer userId;// 用户编号
 18 
 19     @Column(name = "user_account")
 20     private String userAccount;// 用户账号
 21 
 22     @Column(name = "user_pw")
 23     private String userPw;// 用户密码
 24 
 25     @Column(name = "user_number")
 26     private String userNumber;// 用户学号
 27 
 28     @Column(name = "user_name")
 29     private String userName;// 用户姓名
 30 
 31     @Column(name = "user_age")
 32     private Integer userAge;// 用户年龄
 33 
 34     @Column(name = "user_sex")
 35     private String userSex;// 用户性别
 36 
 37     @Column(name = "user_mark")
 38     private String userMark;// 用户标识，可以使用一张表，完成管理员和用户
 39 
 40     @Column(name = "is_money")
 41     private String isMoney;
 42 
 43     public Integer getUserId() {
 44         return userId;
 45     }
 46 
 47     public void setUserId(Integer userId) {
 48         this.userId = userId;
 49     }
 50 
 51     public String getUserAccount() {
 52         return userAccount;
 53     }
 54 
 55     public void setUserAccount(String userAccount) {
 56         this.userAccount = userAccount;
 57     }
 58 
 59     public String getUserPw() {
 60         return userPw;
 61     }
 62 
 63     public void setUserPw(String userPw) {
 64         this.userPw = userPw;
 65     }
 66 
 67     public String getUserNumber() {
 68         return userNumber;
 69     }
 70 
 71     public void setUserNumber(String userNumber) {
 72         this.userNumber = userNumber;
 73     }
 74 
 75     public String getUserName() {
 76         return userName;
 77     }
 78 
 79     public void setUserName(String userName) {
 80         this.userName = userName;
 81     }
 82 
 83     public Integer getUserAge() {
 84         return userAge;
 85     }
 86 
 87     public void setUserAge(Integer userAge) {
 88         this.userAge = userAge;
 89     }
 90 
 91     public String getUserSex() {
 92         return userSex;
 93     }
 94 
 95     public void setUserSex(String userSex) {
 96         this.userSex = userSex;
 97     }
 98 
 99     public String getUserMark() {
100         return userMark;
101     }
102 
103     public void setUserMark(String userMark) {
104         this.userMark = userMark;
105     }
106 
107     public String getIsMoney() {
108         return isMoney;
109     }
110 
111     public void setIsMoney(String isMoney) {
112         this.isMoney = isMoney;
113     }
114 
115     @Override
116     public String toString() {
117         return "UserInfo [userId=" + userId + ", userAccount=" + userAccount + ", userPw=" + userPw + ", userNumber="
118                 + userNumber + ", userName=" + userName + ", userAge=" + userAge + ", userSex=" + userSex
119                 + ", userMark=" + userMark + ", isMoney=" + isMoney + "]";
120     }
121 
122 }

创建UserDao，然后继承JpaRepository<UserInfo, Integer>，此时就可以使用写好的方法了，不用自己再额外写接口和实现，如下所示：

 1 package com.demo.dao;
 2 
 3 import org.springframework.data.jpa.repository.JpaRepository;
 4 
 5 import com.demo.po.UserInfo;
 6 
 7 /**
 8  * 
 9  * @author 继承JpaRepository包含全部的基础CURD操作
10  *
11  */
12 public interface UserDao extends JpaRepository<UserInfo, Integer> {
13 
14 }

然后定义Service接口和Service接口实现，如下所示：

 1 package com.demo.service;
 2 
 3 import java.util.List;
 4 
 5 import com.demo.po.UserInfo;
 6 
 7 public interface UserService {
 8 
 9     public List<UserInfo> findAll();
10 }

 1 package com.demo.service.impl;
 2 
 3 import java.util.List;
 4 
 5 import org.springframework.beans.factory.annotation.Autowired;
 6 import org.springframework.stereotype.Service;
 7 
 8 import com.demo.dao.UserDao;
 9 import com.demo.po.UserInfo;
10 import com.demo.service.UserService;
11 
12 @Service
13 public class UserServiceImpl implements UserService {
14 
15     @Autowired
16     private UserDao userDao;
17 
18     @Override
19     public List<UserInfo> findAll() {
20 
21         return userDao.findAll();
22     }
23 
24 }

然后搞一个Controller，作为接口访问的入口，如下所示：

 1 package com.demo.controller;
 2 
 3 import java.util.List;
 4 
 5 import org.springframework.beans.factory.annotation.Autowired;
 6 import org.springframework.stereotype.Controller;
 7 import org.springframework.web.bind.annotation.RequestMapping;
 8 import org.springframework.web.bind.annotation.ResponseBody;
 9 
10 import com.demo.po.UserInfo;
11 import com.demo.service.UserService;
12 
13 @Controller
14 public class SpringBootController {
15 
16     @Autowired
17     private UserService userService;
18 
19     @RequestMapping(value = "/findAll")
20     @ResponseBody
21     public List<UserInfo> findAll() {
22         List<UserInfo> findAll = userService.findAll();
23         return findAll;
24     }
25 
26 }

修改程序启动主类，追加Repository扫描配置。如果使用JpaRepository实现了DAO接口的自动实现。需要注意的是，如果想启用Repository配置，则需要在程序启动主类时使用@EnableJpaRepositories注解配置扫描包，而后才可以正常使用。

 1 package com.demo;
 2 
 3 import org.springframework.boot.SpringApplication;
 4 import org.springframework.boot.autoconfigure.SpringBootApplication;
 5 import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
 6 
 7 @SpringBootApplication // 启动Springboot程序，而后自带子包扫描
 8 @EnableJpaRepositories(basePackages = "com.demo.dao")
 9 public class DemoApplication {
10 
11     public static void main(String[] args) {
12         // 启动Springboot程序
13         SpringApplication.run(DemoApplication.class, args);
14     }
15 
16 }

修改application.properties，使用Druid作为数据源连接池，如下所示：

 1 # mysql的数据库驱动
 2 spring.datasource.driver-class-name=com.mysql.jdbc.Driver
 3 # mysql的链接
 4 spring.datasource.url=jdbc:mysql://localhost:3306/biehl
 5 # mysql的账号
 6 spring.datasource.username=root
 7 # mysql的密码
 8 spring.datasource.password=123456
 9 
10 # druid连接池的配置
11 spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
12 
13 # Spring Data JPA,此配置可以在实体类中使用注解来创建数据表，开启正向工程
14 spring.jpa.hibernate.ddl-auto=update
15 # 在控制台打印sql语句
16 spring.jpa.show-sql=true

使用postman进行接口调用，如下所示：

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原文地址：https://www.cnblogs.com/biehongli/p/13976518.html