Spring Boot 入门之持久层篇（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
<!-- 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：
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：
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
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：
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：
@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：
<logger name="org.springframework.jdbc.core.JdbcTemplate" level="debug"/>
三、整合 Spring-data-jpa
3.1 添加依赖
<!-- 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：
# 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：
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
@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
public interface RoleRepository extends JpaRepository<Role, Integer>{
}
3.3.4 测试类
@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：
-
使用 mybatis 官方提供的 Spring Boot 整合包实现。
-
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：
<!-- 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：
# 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：
<!-- 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：
# 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：
@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：
<?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：
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
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
@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 ：
<?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
@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
<!-- 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：
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
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.1.8</version>
</dependency>
5.2.2 添加配置
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
@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：
## 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：
