【Spring Boot】入门之持久篇（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

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

2.2 配置数据库连接

在 application.properties 中添加：

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spring.datasource.driver-class-name=com.mysql.jdbc.Driver spring.datasource.url=jdbc:mysql://localhost:3306/springboot?useUnicode=true&characterEncoding=utf8&serverTimezone=UTC spring.datasource.username=root 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：

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CREATE TABLE `user` ( `id` INT(11) NOT NULL AUTO_INCREMENT, `username` VARCHAR(50) NOT NULL, `password` VARCHAR(64) NOT NULL, `birthday` DATE NOT NULL, PRIMARY KEY (`id`) ) COLLATE='utf8_general_ci' ENGINE=InnoDB AUTO_INCREMENT=3 ;

2.3.2 建实体类

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public class User implements Serializable{ private static final long serialVersionUID = - 6249397911566315813L; private Integer id; private String username; private String password; private Date birthday; }

setter 和 getter 方法此处省略。

2.3.3 dao 接口

接口和实现类如下：

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public interface UserDao { public int insert(User user); public int deleteById(Integer id); public int update(User user); public User getById(Integer id); } @Repository public class UserDaoImpl implements UserDao { @Autowired private JdbcTemplate jdbcTemplate; @Override public int insert(User user) { String sql = "insert into user(id,username,password,birthday) values(?,?,?,?)"; return this.jdbcTemplate.update( sql, user.getId(), user.getUsername(), user.getPassword(), user.getBirthday() ); } @Override public int deleteById(Integer id) { String sql = "delete from user where id = ?"; return this.jdbcTemplate.update(sql,id); } @Override public int update(User user) { String sql = "update user set password = ? where id = ?"; return this.jdbcTemplate.update( sql, user.getPassword(), user.getId() ); } @Override public User getById(Integer id) { String sql = "select * from user where id = ?"; return this.jdbcTemplate.queryForObject(sql, new RowMapper<User>() { @Override public User mapRow(ResultSet rs, int rowNum) throws SQLException { User user = new User(); user.setId(rs.getInt( "id")); user.setUsername(rs.getString( "username")); user.setPassword(rs.getString( "password")); user.setBirthday(rs.getDate( "birthday")); return user; } },id); } }

2.3.4 测试类：

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@RunWith(SpringRunner.class) @SpringBootTest public class UserDaoTest { @Autowired private UserDao userDao; @Test public void testInsert() { User user = new User(); user.setId( 1); user.setUsername( "张三"); user.setPassword( "zhangsan"); user.setBirthday( new Date()); int result = this.userDao.insert(user); System.out.println(result); } @Test public void testGetById() { User user = this.userDao.getById( 1); System.out.println(user.getUsername()); } @Test public void testUpdate() { User user = new User(); user.setId( 1); user.setPassword( "zhangsan123"); this.userDao.update(user); } @Test public void testDeleteById() { int result = this.userDao.deleteById( 1); System.out.println(result); } }

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

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<!-- jdbc --> <dependency> <groupId>org.springframework.boot </groupId> <artifactId>spring-boot-starter-jdbc </artifactId> </dependency> <!-- springboot,jpa 整合包--> <dependency> <groupId>org.springframework.boot </groupId> <artifactId>spring-boot-starter-data-jpa </artifactId> </dependency> <!-- mysql 驱动包 --> <dependency> <groupId>mysql </groupId> <artifactId>mysql-connector-java </artifactId> </dependency>

3.2 配置数据库连接

在 application.properties 中添加：

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# 数据库连接配置 spring.datasource.driver-class-name=com.mysql.jdbc.Driver spring.datasource.url=jdbc:mysql://localhost:3306/springboot?useUnicode=true&characterEncoding=utf8&serverTimezone=UTC spring.datasource.username=root spring.datasource.password=tiger # JPA 配置 spring.jpa.hibernate.ddl-auto=update 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：

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CREATE TABLE `role` ( `id` INT(11) NOT NULL AUTO_INCREMENT, `name` VARCHAR(10) NOT NULL, `descr` VARCHAR(100) NULL DEFAULT NULL, PRIMARY KEY (`id`) ) COLLATE='utf8_general_ci' ENGINE=InnoDB ;

注意，主键 ID 为 AUTO_INCREMENT 自增。

3.3.2 建实体类

添加相应的注解

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@Entity public class Role implements Serializable{ private static final long serialVersionUID = 3926276668667517847L; @Id @GeneratedValue private Integer id; @Column private String name; @Column private String descr; }

setter 和 getter 方法此处省略。

3.3.3 Repository 接口

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public interface RoleRepository extends JpaRepository<Role, Integer>{ }

3.3.4 测试类

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@RunWith(SpringRunner.class) @SpringBootTest public class RoleRepositoryTest { @Autowired private RoleRepository roleRepository; @Test public void testInsert() { Role role = new Role(); role.setName( "管理员"); role.setDescr( "测试"); Role result = this.roleRepository.save(role); System.out.println(result); } @Test public void testFindOne() { Role role = this.roleRepository.findOne( 1); System.out.println(role); } @Test public void testUpdate() { Role role = new Role(); role.setId( 1); role.setName( "管理员"); role.setDescr( "控制权限"); Role result = this.roleRepository.save(role); System.out.println(result); } @Test public void testDelete() { this.roleRepository.delete( 1); } }

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：

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<!-- springboot,mybatis 整合包 --> <dependency> <groupId>org.mybatis.spring.boot </groupId> <artifactId>mybatis-spring-boot-starter </artifactId> <version>1.3.0 </version> </dependency> <!-- mysql 驱动包 --> <dependency> <groupId>mysql </groupId> <artifactId>mysql-connector-java </artifactId> </dependency>

2）配置数据库连接：

在 application.properties 中添加：

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# 数据源配置 spring.datasource.driver-class-name=com.mysql.jdbc.Driver spring.datasource.url=jdbc:mysql://localhost:3306/springboot?useUnicode=true&characterEncoding=utf8&serverTimezone=UTC spring.datasource.username=root spring.datasource.password=tiger # mybatis 配置 mybatis.config-location=classpath:mybatis/mybatis-config.xml mybatis.mapper-locations=classpath:mybatis/mapper/*.xml

方式二：原始 Jar 包 + 手动编程

1）添加依赖：

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<!-- jdbc --> <dependency> <groupId>org.springframework.boot </groupId> <artifactId>spring-boot-starter-jdbc </artifactId> </dependency> <!-- mybatis --> <dependency> <groupId>org.mybatis </groupId> <artifactId>mybatis </artifactId> <version>3.4.4 </version> </dependency> <!-- spring,mybatis整合包 --> <dependency> <groupId>org.mybatis </groupId> <artifactId>mybatis-spring </artifactId> <version>1.3.1 </version> </dependency> <!-- mysql 驱动包 --> <dependency> <groupId>mysql </groupId> <artifactId>mysql-connector-java </artifactId> </dependency>

2）配置数据库连接：

在 application.properties 中添加：

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# 数据源配置 spring.datasource.driver-class-name=com.mysql.jdbc.Driver spring.datasource.url=jdbc:mysql://localhost:3306/springboot?useUnicode=true&characterEncoding=utf8&serverTimezone=UTC spring.datasource.username=root spring.datasource.password=tiger

3）创建配置类：

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@Configuration public class MyBatisConfiguration { @Bean @ConditionalOnMissingBean // 当容器里没有指定的 Bean 的情况下创建该对象 public SqlSessionFactoryBean sqlSessionFactory(DataSource dataSource) { SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean(); // 设置数据源 sqlSessionFactoryBean.setDataSource(dataSource); // 设置mybatis的主配置文件 sqlSessionFactoryBean.setConfigLocation( new ClassPathResource( "mybatis/mybatis-config.xml")); // 设置mapper映射文件 PathMatchingResourcePatternResolver resolver = new PathMatchingResourcePatternResolver(); Resource[] mapperXml; try { mapperXml = resolver.getResources( "classpath:mybatis/mapper/*.xml"); sqlSessionFactoryBean.setMapperLocations(mapperXml); } catch (IOException e) { e.printStackTrace(); } // 设置别名包 sqlSessionFactoryBean.setTypeAliasesPackage( "com.light.springboot.domain"); return sqlSessionFactoryBean; } @Bean @ConditionalOnBean(SqlSessionFactoryBean.class) // 当 SqlSessionFactoryBean 实例存在时创建对象 public MapperScannerConfigurer mapperScannerConfigurer() { MapperScannerConfigurer mapperScannerConfigurer = new MapperScannerConfigurer(); mapperScannerConfigurer.setBasePackage( "com.light.springboot.mapper"); return mapperScannerConfigurer; } }

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：

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<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd"> <configuration> <settings> <!-- 获取数据库自增主键值 --> <setting name="useGeneratedKeys" value="true"/> <!-- 使用列别名替换列名，默认为 true --> <setting name="useColumnLabel" value="true"/> <!-- 开启驼峰命名转换：Table(create_time) => Entity(createTime) --> <setting name="mapUnderscoreToCamelCase" value="true"/> </settings> </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：

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CREATE TABLE `department` ( `id` INT(11) NOT NULL, `name` VARCHAR(10) NOT NULL, `descr` VARCHAR(50) NULL DEFAULT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB ;

4.2.2 实体类

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public class Department implements Serializable{ private static final long serialVersionUID = 6067283535977178571L; private Integer id; private String name; private String descr; }

setet 和 getter 方法省略。

4.2.3 Mapper 接口

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@Mapper public interface DepartmentMapper { public void insert(Department department); public Department getById(Integer id); public void update(Department department); public void deleteById(Integer id); }

mybatis/mapper/departmentMapper.xml ：

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<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <mapper namespace="com.light.springboot.dao.DepartmentMapper"> <insert id="insert" parameterType="com.light.springboot.domain.Department"> insert into department(id,name,descr) values(#{id},#{name},#{descr}) </insert> <select id="getById" parameterType="java.lang.Integer" resultType="com.light.springboot.domain.Department"> select id,name,descr from department where id = #{id} </select> <update id="update" parameterType="com.light.springboot.domain.Department"> update department set descr = #{descr} where id = #{id} </update> <delete id="deleteById" parameterType="java.lang.Integer"> delete from department where id = #{id} </delete> </mapper>

4.2.4 测试类

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@RunWith(SpringRunner.class) @SpringBootTest public class DepartmentTest { @Autowired private DepartmentMapper departmentMapper; @Test public void testInsert() { Department department = new Department(); department.setId( 1); department.setName( "研发部"); department.setDescr( "开发产品"); this.departmentMapper.insert(department); } @Test public void testGetById() { Department department = this.departmentMapper.getById( 1); System.out.println(department); } @Test public void testUpdate() { Department department = new Department(); department.setId( 1); department.setDescr( "开发高级产品"); this.departmentMapper.update(department); } @Test public void testDeleteById() { this.departmentMapper.deleteById( 1); } }

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

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<!-- springboot,druid 整合包 --> <dependency> <groupId>com.alibaba </groupId> <artifactId>druid-spring-boot-starter </artifactId> <version>1.1.8 </version> </dependency>

5.1.2 添加配置

在 application.properties 中添加：

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spring.datasource.driver-class-name=com.mysql.jdbc.Driver spring.datasource.url=jdbc:mysql://localhost:3306/springboot?useUnicode=true&characterEncoding=utf8&serverTimezone=UTC spring.datasource.username=root spring.datasource.password=tiger # 修改数据源 spring.datasource.type=com.alibaba.druid.pool.DruidDataSource spring.datasource.druid.initial-size=5 spring.datasource.druid.min-idle=5 spring.datasource.druid.max-active=20 spring.datasource.druid.max-wait=60000 spring.datasource.druid.time-between-eviction-runs-millis=60000 spring.datasource.druid.min-evictable-idle-time-millis=300000 spring.datasource.druid.validation-query=SELECT 1 FROM DUAL spring.datasource.druid.test-while-idle=true spring.datasource.druid.test-on-borrow=false spring.datasource.druid.test-on-return=false spring.datasource.druid.pool-prepared-statements=true spring.datasource.druid.max-pool-prepared-statement-per-connection-size=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

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<dependency> <groupId>com.alibaba </groupId> <artifactId>druid </artifactId> <version>1.1.8 </version> </dependency>

5.2.2 添加配置

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spring.datasource.druid.driverClassName=com.mysql.jdbc.Driver spring.datasource.druid.url=jdbc:mysql://localhost:3306/springboot?useUnicode=true&characterEncoding=utf8&serverTimezone=UTC spring.datasource.druid.username=root spring.datasource.druid.password=tiger spring.datasource.druid.initialSize=5 spring.datasource.druid.minIdle=5 spring.datasource.druid.maxActive=20 spring.datasource.druid.maxWait=60000 spring.datasource.druid.timeBetweenEvictionRunsMillis=60000 spring.datasource.druid.min-evictableIdleTimeMillis=300000 spring.datasource.druid.validationQuery=SELECT 1 FROM DUAL spring.datasource.druid.testWhileIdle=true spring.datasource.druid.testOnBorrow=false spring.datasource.druid.testOnReturn=false spring.datasource.druid.poolPreparedStatements=true spring.datasource.druid.maxPoolPreparedStatementPerConnectionSize=20 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

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@Configuration public class DruidConfiguration { @ConfigurationProperties(prefix = "spring.datasource.druid") @Bean(initMethod = "init",destroyMethod = "close") public DruidDataSource dataSource() { DruidDataSource ds = new DruidDataSource(); ds.setProxyFilters(Arrays.asList(statFilter())); return ds; } @Bean public Filter statFilter() { StatFilter filter = new StatFilter(); filter.setSlowSqlMillis( 5000); filter.setLogSlowSql( true); filter.setMergeSql( true); return filter; } }

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：

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## druid 监控 spring.datasource.druid.web-stat-filter.enabled=true spring.datasource.druid.web-stat-filter.url-pattern=/* spring.datasource.druid.web-stat-filter.exclusions=*.js,*.gif,*.jpg,*.png,*.css,*.ico,/druid/* ## druid 监控页面 spring.datasource.druid.stat-view-servlet.enabled=true spring.datasource.druid.stat-view-servlet.url-pattern=/druid/* spring.datasource.druid.stat-view-servlet.login-username=druid 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

八、参考资料

• Druid 相关