springBoot系列教程04：mybatis及druid數據源的集成及查詢緩存的使用

首先說下查詢緩存：查詢緩存就是相同的數據庫查詢請求在設定的時間間隔內僅查詢一次數據庫並保存到redis中，後續的請求只要在時間間隔內都直接從redis中獲取，再也不查詢數據庫，提升查詢效率，下降服務器負荷

 

經過druid數據源和mybatis來操做數據庫

1.pom引入

        <!-- 使用druid配置mysql數據源 -->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.1</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.0.18</version>
        </dependency>

 

2.數據庫連接信息配置

database.type=mysql
spring.datasource.name=test
spring.datasource.url=jdbc:mysql://192.168.032:3306/test?autoReconnect=true&useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull
spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.filters=stat
spring.datasource.maxActive=20
spring.datasource.initialSize=1
spring.datasource.maxWait=60000
spring.datasource.minIdle=1
spring.datasource.timeBetweenEvictionRunsMillis=60000
spring.datasource.minEvictableIdleTimeMillis=300000
spring.datasource.validationQuery=select 'x'
spring.datasource.testWhileIdle=true
spring.datasource.testOnBorrow=false
spring.datasource.testOnReturn=false
spring.datasource.poolPreparedStatements=true
spring.datasource.maxOpenPreparedStatements=20

 

3.數據源配置（部份內容及標籤在後續文章中會說起到）

package com.xiao.config;

import java.sql.SQLException;

import javax.sql.DataSource;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;

import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.support.http.StatViewServlet;
import com.alibaba.druid.support.http.WebStatFilter;

@Configuration
@RefreshScope
public class DruidConfig {
    private Logger logger = LoggerFactory.getLogger(getClass());

    @Value("${spring.datasource.url}")
    private String dbUrl;

    @Value("${spring.datasource.username}")
    private String username;

    @Value("${spring.datasource.password}")
    private String password;

    @Value("${spring.datasource.driver-class-name}")
    private String driverClassName;

    @Value("${spring.datasource.initialSize}")
    private int initialSize;

    @Value("${spring.datasource.minIdle}")
    private int minIdle;

    @Value("${spring.datasource.maxActive}")
    private int maxActive;

    @Value("${spring.datasource.maxWait}")
    private int maxWait;

    @Value("${spring.datasource.timeBetweenEvictionRunsMillis}")
    private int timeBetweenEvictionRunsMillis;

    @Value("${spring.datasource.minEvictableIdleTimeMillis}")
    private int minEvictableIdleTimeMillis;

    @Value("${spring.datasource.validationQuery}")
    private String validationQuery;

    @Value("${spring.datasource.testWhileIdle}")
    private boolean testWhileIdle;

    @Value("${spring.datasource.testOnBorrow}")
    private boolean testOnBorrow;

    @Value("${spring.datasource.testOnReturn}")
    private boolean testOnReturn;

    @Value("${spring.datasource.poolPreparedStatements}")
    private boolean poolPreparedStatements;

    @Value("${spring.datasource.filters}")
    private String filters;

    @Bean
    public ServletRegistrationBean druidServlet() {
        ServletRegistrationBean reg = new ServletRegistrationBean();
        reg.setServlet(new StatViewServlet());
        reg.addUrlMappings("/druid/*");
        reg.addInitParameter("loginUsername", "admin");
        reg.addInitParameter("loginPassword", "123456");
        return reg;
    }

    @Bean
    public FilterRegistrationBean filterRegistrationBean() {
        FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean();
        filterRegistrationBean.setFilter(new WebStatFilter());
        filterRegistrationBean.addUrlPatterns("/*");
        filterRegistrationBean.addInitParameter("exclusions", "*.js,*.gif,*.jpg,*.png,*.css,*.ico,/druid/*");
        filterRegistrationBean.addInitParameter("profileEnable", "true");
        filterRegistrationBean.addInitParameter("principalCookieName", "USER_COOKIE");
        filterRegistrationBean.addInitParameter("principalSessionName", "USER_SESSION");
        return filterRegistrationBean;
    }

    @Bean
    @Primary
    @RefreshScope
    public DataSource druidDataSource() {
        DruidDataSource datasource = new DruidDataSource();

        datasource.setUrl(this.dbUrl);
        datasource.setUsername(username);
        datasource.setPassword(password);
        datasource.setDriverClassName(driverClassName);
        datasource.setInitialSize(initialSize);
        datasource.setMinIdle(minIdle);
        datasource.setMaxActive(maxActive);
        datasource.setMaxWait(maxWait);
        datasource.setTimeBetweenEvictionRunsMillis(timeBetweenEvictionRunsMillis);
        datasource.setMinEvictableIdleTimeMillis(minEvictableIdleTimeMillis);
        datasource.setValidationQuery(validationQuery);
        datasource.setTestWhileIdle(testWhileIdle);
        datasource.setTestOnBorrow(testOnBorrow);
        datasource.setTestOnReturn(testOnReturn);
        datasource.setPoolPreparedStatements(poolPreparedStatements);
        try {
            datasource.setFilters(filters);
        } catch (SQLException e) {
            logger.error("druid configuration initialization filter", e);
        }
        return datasource;
    }

}

4.配置sessionFactory及事物

package com.xiao.config;

import javax.sql.DataSource;

import org.apache.ibatis.plugin.Interceptor;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;
import org.springframework.transaction.annotation.TransactionManagementConfigurer;

import com.xiao.interceptor.PageInterceptor;

@Configuration
@EnableTransactionManagement
@MapperScan("com.xiao.mapper")
public class SessionFactoryConfig implements TransactionManagementConfigurer {

    @Autowired
    private DataSource dataSource;

    private String typeAliasPackage = "com.xiao.domain";

    @Bean(name = "sqlSessionFactory")
    public SqlSessionFactoryBean createSqlSessionFactoryBean() throws Exception {
        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        sqlSessionFactoryBean.setDataSource(dataSource);
        sqlSessionFactoryBean.setPlugins(new Interceptor[] { new PageInterceptor() });
        sqlSessionFactoryBean.setTypeAliasesPackage(typeAliasPackage);
        Resource[] resources = new PathMatchingResourcePatternResolver().getResources("classpath:mybatis/*.xml");
        sqlSessionFactoryBean.setMapperLocations(resources);
        return sqlSessionFactoryBean;
    }

    @Bean
    public SqlSessionTemplate sqlSessionTemplate(SqlSessionFactory sqlSessionFactory) {
        return new SqlSessionTemplate(sqlSessionFactory);
    }

    @Bean
    @Override
    public PlatformTransactionManager annotationDrivenTransactionManager() {
        return new DataSourceTransactionManager(dataSource);
    }
}

5.定義mapper

package com.xiao.mapper;

import java.util.List;

import org.springframework.cache.annotation.CacheConfig;
import org.springframework.cache.annotation.Cacheable;

import com.xiao.domain.User;
import com.xiao.domain.UserParamVo;

/**
 * @since 2017年12月7日 下午1:58:46
 * @author 肖昌偉 317409898@qq.com
 * @description
 */

@CacheConfig(cacheNames = "users") 
public interface UserMapper {
    
    @Cacheable(key ="#p0") 
    public int dataCount(String tableName);

    public List<User> getUsers(UserParamVo param);
}

注意上面紅色部分，這部分標記爲對datacount方法進行緩存，緩存時間在redis的配置中

    @Autowired
    UserMapper userMapper;

    @RequestMapping(value = "/dbcache/test")
    public Result cacheTest(@RequestParam(value = "tableName") String tableName) {
        return new Result("數據庫中【" + tableName + "】表的條數爲：" + userMapper.dataCount(tableName) + " [10秒鐘內屢次請求僅訪問一次數據庫]");
    }

執行上面請求後並不斷刷新，發現僅請求一次，超過設置的時間間隔後纔會再次請求

須要注意的是：主方法上面也要開起緩存才生效

package com.xiao;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cache.annotation.EnableCaching;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.netflix.feign.EnableFeignClients;
import org.springframework.transaction.annotation.EnableTransactionManagement;

@EnableDiscoveryClient
@SpringBootApplication
@EnableFeignClients
@EnableTransactionManagement
@EnableCaching
public class SpringBootClient01Application {

    public static void main(String[] args) {
        SpringApplication.run(SpringBootClient01Application.class, args);
    }
}