Spring Boot 入门详解教程之基础篇（三）

一、前言

上一篇《Spring Boot 入门之 Web 篇（二）》介绍了 Spring Boot 的 Web 开发相关的内容，项目的开发离不开数据，因此本篇开始介绍持久层相关的知识。

二、整合 JdbcTemplate

2.1 添加依赖

1. <!-- jdbc -->

2. <dependency>

3. <groupId>org.springframework.boot</groupId>

4. <artifactId>spring-boot-starter-jdbc</artifactId>

5. </dependency>

6. 
   

7. <!-- mysql 驱动包 -->

8. <dependency>

9. <groupId>mysql</groupId>

10. <artifactId>mysql-connector-java</artifactId>

11. </dependency>

2.2 配置数据库连接

在 application.properties 中添加：

1. spring.datasource.driver-class-name=com.mysql.jdbc.Driver

2. spring.datasource.url=jdbc:mysql://localhost:3306/springboot?useUnicode=true&characterEncoding=utf8&serverTimezone=UTC

3. spring.datasource.username=root

4. spring.datasource.password=tiger

其中，可以不指定 driver-class-name，因为 spring boot 会自动识别 url。

2.3 测试

2.3.1 建表

在 MySQL 中创建名为 springboot 的数据库，在该库中创建 user 表：

1. CREATE TABLE `user` (

2. `id` INT(11) NOT NULL AUTO_INCREMENT,

3. `username` VARCHAR(50) NOT NULL,

4. `password` VARCHAR(64) NOT NULL,

5. `birthday` DATE NOT NULL,

6. PRIMARY KEY (`id`)

7. )

8. COLLATE='utf8_general_ci'

9. ENGINE=InnoDB

10. AUTO_INCREMENT=3

11. ;

2.3.2 建实体类

1. public class User implements Serializable{

2. 
   

3. private static final long serialVersionUID = -6249397911566315813L;

4. 
   

5. private Integer id;

6. 
   

7. private String username;

8. 
   

9. private String password;

10. 
    

11. private Date birthday;

12. 
    

13. }

14. 
    

setter 和 getter 方法此处省略。

2.3.3 dao 接口

接口和实现类如下：

1. public interface UserDao {

2. 
   

3. public int insert(User user);

4. 
   

5. public int deleteById(Integer id);

6. 
   

7. public int update(User user);

8. 
   

9. public User getById(Integer id);

10. }

11. 
    

12. @Repository

13. public class UserDaoImpl implements UserDao {

14. 
    

15. @Autowired

16. private JdbcTemplate jdbcTemplate;

17. 
    

18. @Override

19. public int insert(User user) {

20. String sql = "insert into user(id,username,password,birthday) values(?,?,?,?)";

21. return this.jdbcTemplate.update(

22. sql,

23. user.getId(),

24. user.getUsername(),

25. user.getPassword(),

26. user.getBirthday()

27. );

28. }

29. 
    

30. @Override

31. public int deleteById(Integer id) {

32. String sql = "delete from user where id = ?";

33. return this.jdbcTemplate.update(sql,id);

34. }

35. 
    

36. @Override

37. public int update(User user) {

38. String sql = "update user set password = ? where id = ?";

39. return this.jdbcTemplate.update(

40. sql,

41. user.getPassword(),

42. user.getId()

43. );

44. }

45. 
    

46. @Override

47. public User getById(Integer id) {

48. String sql = "select * from user where id = ?";

49. return this.jdbcTemplate.queryForObject(sql, new RowMapper<User>() {

50. 
    

51. @Override

52. public User mapRow(ResultSet rs, int rowNum) throws SQLException {

53. User user = new User();

54. user.setId(rs.getInt("id"));

55. user.setUsername(rs.getString("username"));

56. user.setPassword(rs.getString("password"));

57. user.setBirthday(rs.getDate("birthday"));

58. return user;

59. }

60. 
    

61. },id);

62. }

63. 
    

64. }

65. 
    

2.3.4 测试类：

1. @RunWith(SpringRunner.class)

2. @SpringBootTest

3. public class UserDaoTest {

4. 
   

5. @Autowired

6. private UserDao userDao;

7. 
   

8. 
   

9. @Test

10. public void testInsert() {

11. User user = new User();

12. user.setId(1);

13. user.setUsername("张三");

14. user.setPassword("zhangsan");

15. user.setBirthday(new Date());

16. 
    

17. int result = this.userDao.insert(user);

18. System.out.println(result);

19. }

20. 
    

21. @Test

22. public void testGetById() {

23. User user = this.userDao.getById(1);

24. System.out.println(user.getUsername());

25. }

26. 
    

27. @Test

28. public void testUpdate() {

29. User user = new User();

30. user.setId(1);

31. user.setPassword("zhangsan123");

32. this.userDao.update(user);

33. }

34. 
    

35. @Test

36. public void testDeleteById() {

37. int result = this.userDao.deleteById(1);

38. System.out.println(result);

39. }

40. }

41. 
    

测试结果省略...

如需打印日志，在日志配置文件中添加如下配置：

1. <logger name="org.springframework.jdbc.core.JdbcTemplate" level="debug"/>

三、整合 Spring-data-jpa

3.1 添加依赖

1. <!-- jdbc -->

2. <dependency>

3. <groupId>org.springframework.boot</groupId>

4. <artifactId>spring-boot-starter-jdbc</artifactId>

5. </dependency>

6. 
   

7. <!-- springboot,jpa 整合包-->

8. <dependency>

9. <groupId>org.springframework.boot</groupId>

10. <artifactId>spring-boot-starter-data-jpa</artifactId>

11. </dependency>

12. 
    

13. <!-- mysql 驱动包 -->

14. <dependency>

15. <groupId>mysql</groupId>

16. <artifactId>mysql-connector-java</artifactId>

17. </dependency>

3.2 配置数据库连接

在 application.properties 中添加：

1. # 数据库连接配置

2. spring.datasource.driver-class-name=com.mysql.jdbc.Driver

3. spring.datasource.url=jdbc:mysql://localhost:3306/springboot?useUnicode=true&characterEncoding=utf8&serverTimezone=UTC

4. spring.datasource.username=root

5. spring.datasource.password=tiger

6. 
   

7. # JPA 配置

8. spring.jpa.hibernate.ddl-auto=update

9. spring.jpa.show-sql=true

3.3 编码

3.3.1 建表

在 MySQL 中创建名为 springboot 的数据库，在该库中创建 role 表：

1. CREATE TABLE `role` (

2. `id` INT(11) NOT NULL AUTO_INCREMENT,

3. `name` VARCHAR(10) NOT NULL,

4. `descr` VARCHAR(100) NULL DEFAULT NULL,

5. PRIMARY KEY (`id`)

6. )

7. COLLATE='utf8_general_ci'

8. ENGINE=InnoDB

9. ;

注意，主键 ID 为 AUTO_INCREMENT 自增。

3.3.2 建实体类

添加相应的注解

1. @Entity

2. public class Role implements Serializable{

3. 
   

4. private static final long serialVersionUID = 3926276668667517847L;

5. 
   

6. @Id

7. @GeneratedValue

8. private Integer id;

9. 
   

10. @Column

11. private String name;

12. 
    

13. @Column

14. private String descr;

15. }

setter 和 getter 方法此处省略。

3.3.3 Repository 接口

1. public interface RoleRepository extends JpaRepository<Role, Integer>{

2. 
   

3. }

3.3.4 测试类

1. @RunWith(SpringRunner.class)

2. @SpringBootTest

3. public class RoleRepositoryTest {

4. 
   

5. @Autowired

6. private RoleRepository roleRepository;

7. 
   

8. @Test

9. public void testInsert() {

10. Role role = new Role();

11. role.setName("管理员");

12. role.setDescr("测试");

13. Role result = this.roleRepository.save(role);

14. System.out.println(result);

15. }

16. 
    

17. @Test

18. public void testFindOne() {

19. Role role = this.roleRepository.findOne(1);

20. System.out.println(role);

21. }

22. 
    

23. @Test

24. public void testUpdate() {

25. Role role = new Role();

26. role.setId(1);

27. role.setName("管理员");

28. role.setDescr("控制权限");

29. Role result = this.roleRepository.save(role);

30. System.out.println(result);

31. }

32. 
    

33. @Test

34. public void testDelete() {

35. this.roleRepository.delete(1);

36. }

37. }

测试结果省略...

四、整合 Mybatis

整合 MyBatis 有两种方式：

1) 使用 mybatis 官方提供的 Spring Boot 整合包实现。

2) 使用 mybatis-spring 整合的方式，也就是传统的方式（推荐，此方式容易控制 MyBatis 的配置）。

4.1 配置依赖

方式一：使用官方整合包

1）添加依赖：

1. <!-- springboot,mybatis 整合包 -->

2. <dependency>

3. <groupId>org.mybatis.spring.boot</groupId>

4. <artifactId>mybatis-spring-boot-starter</artifactId>

5. <version>1.3.0</version>

6. </dependency>

7. 
   

8. <!-- mysql 驱动包 -->

9. <dependency>

10. <groupId>mysql</groupId>

11. <artifactId>mysql-connector-java</artifactId>

12. </dependency>

2）配置数据库连接：

在 application.properties 中添加：

1. # 数据源配置

2. spring.datasource.driver-class-name=com.mysql.jdbc.Driver

3. spring.datasource.url=jdbc:mysql://localhost:3306/springboot?useUnicode=true&characterEncoding=utf8&serverTimezone=UTC

4. spring.datasource.username=root

5. spring.datasource.password=tiger

6. 
   

7. # mybatis 配置

8. mybatis.config-location=classpath:mybatis/mybatis-config.xml

9. mybatis.mapper-locations=classpath:mybatis/mapper/*.xml

方式二：原始 Jar 包 + 手动编程

1）添加依赖：

1. <!-- jdbc -->

2. <dependency>

3. <groupId>org.springframework.boot</groupId>

4. <artifactId>spring-boot-starter-jdbc</artifactId>

5. </dependency>

6. 
   

7. <!-- mybatis -->

8. <dependency>

9. <groupId>org.mybatis</groupId>

10. <artifactId>mybatis</artifactId>

11. <version>3.4.4</version>

12. </dependency>

13. 
    

14. <!-- spring,mybatis整合包 -->

15. <dependency>

16. <groupId>org.mybatis</groupId>

17. <artifactId>mybatis-spring</artifactId>

18. <version>1.3.1</version>

19. </dependency>

20. 
    

21. <!-- mysql 驱动包 -->

22. <dependency>

23. <groupId>mysql</groupId>

24. <artifactId>mysql-connector-java</artifactId>

25. </dependency>

2）配置数据库连接：

在 application.properties 中添加：

1. # 数据源配置

2. spring.datasource.driver-class-name=com.mysql.jdbc.Driver

3. spring.datasource.url=jdbc:mysql://localhost:3306/springboot?useUnicode=true&characterEncoding=utf8&serverTimezone=UTC

4. spring.datasource.username=root

5. spring.datasource.password=tiger

3）创建配置类：

1. @Configuration

2. public class MyBatisConfiguration {

3. 
   

4. @Bean

5. @ConditionalOnMissingBean // 当容器里没有指定的 Bean 的情况下创建该对象

6. public SqlSessionFactoryBean sqlSessionFactory(DataSource dataSource) {

7. SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();

8. // 设置数据源

9. sqlSessionFactoryBean.setDataSource(dataSource);

10. 
    

11. // 设置mybatis的主配置文件

12. sqlSessionFactoryBean.setConfigLocation(new ClassPathResource("mybatis/mybatis-config.xml"));

13. 
    

14. // 设置mapper映射文件

15. PathMatchingResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();

16. Resource[] mapperXml;

17. try {

18. mapperXml = resolver.getResources("classpath:mybatis/mapper/*.xml");

19. sqlSessionFactoryBean.setMapperLocations(mapperXml);

20. } catch (IOException e) {

21. e.printStackTrace();

22. }

23. 
    

24. // 设置别名包

25. sqlSessionFactoryBean.setTypeAliasesPackage("com.light.springboot.domain");

26. 
    

27. return sqlSessionFactoryBean;

28. }

29. 
    

30. @Bean

31. @ConditionalOnBean(SqlSessionFactoryBean.class) // 当 SqlSessionFactoryBean 实例存在时创建对象

32. public MapperScannerConfigurer mapperScannerConfigurer() {

33. MapperScannerConfigurer mapperScannerConfigurer = new MapperScannerConfigurer();

34. mapperScannerConfigurer.setBasePackage("com.light.springboot.mapper");

35. return mapperScannerConfigurer;

36. }

37. }

以上便是两种方式的配置的不同之处，不同之处就在于如何配置 mybatis 配置文件和 mapper 映射文件的路径。

在 src/main/resources 下创建 mybatis 文件夹，并在 mybatis 文件夹中创建 "mybatis-config.xml" 配置文件，内容如下：

1. <?xml version="1.0" encoding="UTF-8"?>

2. <!DOCTYPE configuration

3. PUBLIC "-//mybatis.org//DTD Config 3.0//EN"

4. "http://mybatis.org/dtd/mybatis-3-config.dtd">

5. <configuration>

6. <settings>

7. <!-- 获取数据库自增主键值 -->

8. <setting name="useGeneratedKeys" value="true"/>

9. <!-- 使用列别名替换列名，默认为 true -->

10. <setting name="useColumnLabel" value="true"/>

11. <!-- 开启驼峰命名转换：Table(create_time) => Entity(createTime) -->

12. <setting name="mapUnderscoreToCamelCase" value="true"/>

13. </settings>

14. </configuration>

mybatis 文件夹下再创建一个 "mapper" 文件夹，里边存放 Mpper 接口对应的 mapper 映射文件。

4.2 测试

4.2.1 建表

在 MySQL 中创建名为 springboot 的数据库，在该库中创建 role 表：

1. CREATE TABLE `department` (

2. `id` INT(11) NOT NULL,

3. `name` VARCHAR(10) NOT NULL,

4. `descr` VARCHAR(50) NULL DEFAULT NULL,

5. PRIMARY KEY (`id`)

6. )

7. ENGINE=InnoDB

8. ;

9. 
   

4.2.2 实体类

1. public class Department implements Serializable{

2. 
   

3. private static final long serialVersionUID = 6067283535977178571L;

4. 
   

5. private Integer id;

6. 
   

7. private String name;

8. 
   

9. private String descr;

10. }

setet 和 getter 方法省略。

4.2.3 Mapper 接口

1. @Mapper

2. public interface DepartmentMapper {

3. 
   

4. public void insert(Department department);

5. 
   

6. public Department getById(Integer id);

7. 
   

8. public void update(Department department);

9. 
   

10. public void deleteById(Integer id);

11. }

mybatis/mapper/departmentMapper.xml ：

1. <?xml version="1.0" encoding="UTF-8"?>

2. <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"

3. "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

4. <mapper namespace="com.light.springboot.dao.DepartmentMapper">

5. 
   

6. <insert id="insert" parameterType="com.light.springboot.domain.Department">

7. insert into department(id,name,descr) values(#{id},#{name},#{descr})

8. </insert>

9. 
   

10. <select id="getById" parameterType="java.lang.Integer" resultType="com.light.springboot.domain.Department">

11. select id,name,descr from department where id = #{id}

12. </select>

13. 
    

14. <update id="update" parameterType="com.light.springboot.domain.Department">

15. update department set descr = #{descr} where id = #{id}

16. </update>

17. 
    

18. <delete id="deleteById" parameterType="java.lang.Integer">

19. delete from department where id = #{id}

20. </delete>

21. </mapper>

4.2.4 测试类

1. @RunWith(SpringRunner.class)

2. @SpringBootTest

3. public class DepartmentTest {

4. 
   

5. @Autowired

6. private DepartmentMapper departmentMapper;

7. 
   

8. @Test

9. public void testInsert() {

10. Department department = new Department();

11. department.setId(1);

12. department.setName("研发部");

13. department.setDescr("开发产品");

14. this.departmentMapper.insert(department);

15. }

16. 
    

17. @Test

18. public void testGetById() {

19. Department department = this.departmentMapper.getById(1);

20. System.out.println(department);

21. }

22. 
    

23. @Test

24. public void testUpdate() {

25. Department department = new Department();

26. department.setId(1);

27. department.setDescr("开发高级产品");

28. this.departmentMapper.update(department);

29. }

30. 
    

31. @Test

32. public void testDeleteById() {

33. this.departmentMapper.deleteById(1);

34. }

35. }

测试结果省略...

五、配置 Druid 数据源

同样地，有两种方式配置：

1）Spring boot，Druid 整合包

2）原始 jar 包 + 手动编程

5.1 Spring boot，Druid 整合包方式

5.1.1 添加依赖

1. <!-- springboot,druid 整合包 -->

2. <dependency>

3. <groupId>com.alibaba</groupId>

4. <artifactId>druid-spring-boot-starter</artifactId>

5. <version>1.1.8</version>

6. </dependency>

5.1.2 添加配置

在 application.properties 中添加：

1. spring.datasource.driver-class-name=com.mysql.jdbc.Driver

2. spring.datasource.url=jdbc:mysql://localhost:3306/springboot?useUnicode=true&characterEncoding=utf8&serverTimezone=UTC

3. spring.datasource.username=root

4. spring.datasource.password=tiger

5. 
   

6. # 修改数据源

7. spring.datasource.type=com.alibaba.druid.pool.DruidDataSource

8. spring.datasource.druid.initial-size=5

9. spring.datasource.druid.min-idle=5

10. spring.datasource.druid.max-active=20

11. spring.datasource.druid.max-wait=60000

12. spring.datasource.druid.time-between-eviction-runs-millis=60000

13. spring.datasource.druid.min-evictable-idle-time-millis=300000

14. spring.datasource.druid.validation-query=SELECT 1 FROM DUAL

15. spring.datasource.druid.test-while-idle=true

16. spring.datasource.druid.test-on-borrow=false

17. spring.datasource.druid.test-on-return=false

18. spring.datasource.druid.pool-prepared-statements=true

19. spring.datasource.druid.max-pool-prepared-statement-per-connection-size=20

20. spring.datasource.druid.filters=stat,wall,log4j

5.2 原始 jar 包 + 手动编程方式

5.2.1 添加依赖

1. <dependency>

2. <groupId>com.alibaba</groupId>

3. <artifactId>druid</artifactId>

4. <version>1.1.8</version>

5. </dependency>

5.2.2 添加配置

1. spring.datasource.druid.driverClassName=com.mysql.jdbc.Driver

2. spring.datasource.druid.url=jdbc:mysql://localhost:3306/springboot?useUnicode=true&characterEncoding=utf8&serverTimezone=UTC

3. spring.datasource.druid.username=root

4. spring.datasource.druid.password=tiger

5. 
   

6. spring.datasource.druid.initialSize=5

7. spring.datasource.druid.minIdle=5

8. spring.datasource.druid.maxActive=20

9. spring.datasource.druid.maxWait=60000

10. spring.datasource.druid.timeBetweenEvictionRunsMillis=60000

11. spring.datasource.druid.min-evictableIdleTimeMillis=300000

12. spring.datasource.druid.validationQuery=SELECT 1 FROM DUAL

13. spring.datasource.druid.testWhileIdle=true

14. spring.datasource.druid.testOnBorrow=false

15. spring.datasource.druid.testOnReturn=false

16. spring.datasource.druid.poolPreparedStatements=true

17. spring.datasource.druid.maxPoolPreparedStatementPerConnectionSize=20

18. spring.datasource.druid.filters=stat,wall

注意：配置中都是以 spring.datasource.druid 开头，使用驼峰命名

5.2.3 手动编程

1. @Configuration

2. public class DruidConfiguration {

3. 
   

4. @ConfigurationProperties(prefix = "spring.datasource.druid")

5. @Bean(initMethod = "init",destroyMethod = "close")

6. public DruidDataSource dataSource() {

7. DruidDataSource ds = new DruidDataSource();

8. ds.setProxyFilters(Arrays.asList(statFilter()));

9. return ds;

10. }

11. 
    

12. @Bean

13. public Filter statFilter() {

14. StatFilter filter = new StatFilter();

15. filter.setSlowSqlMillis(5000);

16. filter.setLogSlowSql(true);

17. filter.setMergeSql(true);

18. return filter;

19. }

20. }

通过上文 MyBatis 的测试代码，运行结果如下：

项目已经使用了 Druid 数据源了。

六、配置 Druid 监控

默认情况下，Druid 的监控统计功能和页面是开启的。

我们启动项目，访问 http://localhost:8080/druid/index.html，如下图：

为了保证访问的安全性，我们可以如下配置：

在 application.properties 中添加：

1. ## druid 监控

2. spring.datasource.druid.web-stat-filter.enabled=true

3. spring.datasource.druid.web-stat-filter.url-pattern=/*

4. spring.datasource.druid.web-stat-filter.exclusions=*.js,*.gif,*.jpg,*.png,*.css,*.ico,/druid/*

5. 
   

6. ## druid 监控页面

7. spring.datasource.druid.stat-view-servlet.enabled=true

8. spring.datasource.druid.stat-view-servlet.url-pattern=/druid/*

9. spring.datasource.druid.stat-view-servlet.login-username=druid

10. spring.datasource.druid.stat-view-servlet.login-password=druid123

重启项目，再次访问 http://localhost:8080/druid/index.html 地址时需要身份验证：

七、源码下载

• Spring Boot 入门之持久层篇测试源码