spring-boot-SpringBoot与数据访问

我会带着你远行 2022-05-11 09:30 230阅读 0赞

### **1.JDBC** ###

**(1).导入依赖**

<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-jdbc</artifactId>
    		 </dependency>
    		 <dependency>
    			<groupId>mysql</groupId>
    			<artifactId>mysql-connector-java</artifactId>
    			<scope>runtime</scope>
    		</dependency>

**(2).application.yml**

spring:
      datasource:
        username: root
        password: 123456
        url: jdbc:mysql://192.168.15.22:3306/jdbc

效果：

默认是org.apache.tomcat.jdbc.pool.DataSource作为数据源

数据源的相关配置都在DataSourceProperties里面

**3).自动配置原理：**

在org.springframework.boot.autoconfigure.jdbc查看

1.参考DataSourceConfiguration,根据配置创建数据源，默认使用Tomcat连接池；可以使用spring.datasource.type指定自定义的数据类型；

@ConditionalOnClass(org.apache.tomcat.jdbc.pool.DataSource.class)
    	@ConditionalOnProperty(name = "spring.datasource.type", havingValue = "org.apache.tomcat.jdbc.pool.DataSource", matchIfMissing = true)
    	static class Tomcat extends DataSourceConfiguration {
    
    		@Bean
    		@ConfigurationProperties(prefix = "spring.datasource.tomcat")

2.SpringBoot默认可以支持

org.apache.tomcat.jdbc.pool.DataSource、HikariDataSource、BasicDataSource

3.自定义数据类型(查看源码)

/**
     * Generic DataSource configuration.
     */
    @ConditionalOnMissingBean(DataSource.class) @ConditionalOnProperty(name="spring.datasource.type") staticclassGeneric{
    @Bean
    public DataSource dataSource(DataSourceProperties properties) { //使用DataSourceBuilder创建数据源，利用反射创建响应type的数据源，并且绑定相关属性
          return properties.initializeDataSourceBuilder().build();
       }
    }

**4)DataSourceInitializer:ApplicationListener;**

作用：

a.run SchemaScripts();运行建表语句

b.run SchemaScripts();运行插入数据的sql语句；

默认只需要将文件命名为：

schema-*.sql、 data-*.sql
    默认规则：schema.sql,schema-all.sql
    可以使用
          schema:
            - classpath:department.sql
           指定位置

### **2.整合Druid数据源** ###

（1）导入依赖

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

2）applicaton.yml

spring:
      datasource:
        username: root
        password: 123456
        url: jdbc:mysql://192.168.15.22:3306/jdbc
        driver-class-name: com.mysql.jdbc.Driver
        type: com.alibaba.druid.pool.DruidDataSource
    
        initialSize: 5
        minIdle: 5
        maxActive: 20
        maxWait: 60000
        timeBetweenEvictionRunsMillis: 60000
        minEvictableIdleTimeMillis: 300000
        validationQuery: SELECT 1 FROM DUAL
        testWhileIdle: true
        testOnBorrow: false
        testOnReturn: false
        poolPreparedStatements: true
    #   配置监控统计拦截的filters，去掉后监控界面sql无法统计，'wall'用于防火墙
        filters: stat,wall,log4j
        maxPoolPreparedStatementPerConnectionSize: 20
        useGlobalDataSourceStat: true
        connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=500
    #    schema:
    #      - classpath:department.sql

3).导入数据源

//读取配置文件中Druid的值
    @Configuration
    public class DruidConfig {
    
        @ConfigurationProperties(prefix = "spring.datasource")
        @Bean
        public DataSource druid(){
           return  new DruidDataSource();
        }
    
        //配置Druid的监控
        //1、配置一个管理后台的Servlet
        @Bean
        public ServletRegistrationBean statViewServlet(){
            ServletRegistrationBean bean = new ServletRegistrationBean(new StatViewServlet(), "/druid/*");
            Map<String,String> initParams = new HashMap<>();
    
            initParams.put("loginUsername","admin");
            initParams.put("loginPassword","123456");
            initParams.put("allow","");//默认就是允许所有访问
            initParams.put("deny","192.168.15.21");
            bean.setInitParameters(initParams);
            return bean;
        }
    
    
        //2、配置一个web监控的filter
        @Bean
        public FilterRegistrationBean webStatFilter(){
            FilterRegistrationBean bean = new FilterRegistrationBean();
            bean.setFilter(new WebStatFilter());
    
            Map<String,String> initParams = new HashMap<>();
            initParams.put("exclusions","*.js,*.css,/druid/*");
    
            bean.setInitParameters(initParams);
    
            bean.setUrlPatterns(Arrays.asList("/*"));
    
            return  bean;
        }
    }

### **3.整合mybatis** ###

**  (1)导入依赖**

<dependency>
        <groupId>org.mybatis.spring.boot</groupId>
        <artifactId>mybatis‐spring‐boot‐starter</artifactId>
        <version>1.3.1</version>
    </dependency

步骤：

a.配置数据源相关属性（见上一节）

b.给数据库建表

c.创建javaBean(此处不添代码了)

**   (2)注解版**

//指定这是一个操作数据库的mapper 2 @Mapper
      
      publicinterfaceDepartmentMapper{
       @Select("select * from department where id=#{id}")
       public Department getDeptById(Integer id);
     
       @Delete("delete from department where id=#{id}")
       public int deleteDeptById(Integer id);
    
      @Options(useGeneratedKeys = true,keyProperty = "id") @Insert("insert into             department(departmentName) values(#{departmentName})")
      public int insertDept(Department department);
    
     @Update("update department set departmentName=#{departmentName} where id=#{id}")
     public int updateDept(Department department);
     }

问题：

自定义Mybatis的配置规则；给容器中添加一个ConfigurationCustomizer(开启驼峰命名 例如 数据库字段是last\_name javaBean

可以是lastName)

@org.springframework.context.annotation.Configuration publicclass
       MyBatisConfig{
        @Bean
        public ConfigurationCustomizer configurationCustomizer(){
            return new ConfigurationCustomizer(){
    @Override
                public void customize(Configuration configuration) {
                    configuration.setMapUnderscoreToCamelCase(true);
    } 
    };
    } 
    }

springbootApplication

package com.atguigu.springboot;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    使用MapperScan扫描所有的mapper接口，可以省去每个mapper接口加@Mapper
    @MapperScan(value="com.hbsi.mapper")
    @SpringBootApplication
    public class SpringBoot06DataJdbcApplication {
    
    	public static void main(String[] args) {
    		SpringApplication.run(SpringBoot06DataJdbcApplication.class, args);
    	}
    }

**(3)配置文件版（此处不做详解，只标明如何扫描配置文件）**

mybatis:
     config‐location: classpath:mybatis/mybatis‐config.xml 指定全局配置文件的位置
     mapper‐locations: classpath:mybatis/mapper/*.xml 指定sql映射文件的位置

更多使用参照

http://www.mybatis.org/spring-boot-starter/mybatis-spring-boot-autoconfigure/