P6Spy是一个框架，它可以无缝地拦截和记录数据库活动，而无需更改现有应用程序的代码。一般我们使用的比较多的是使用p6spy打印我们最后执行的sql语句

P6Spy简介

P6Spy是一个可以用来在应用程序中拦截和修改数据操作语句的开源框架。

通过P6Spy可以对SQL语句进行拦截，相当于一个SQL语句的记录器，这样我们可以用它来作相关的分析，比如性能分析。

应用场景

pom

<dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.20</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.1.1</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
        <dependency>
            <groupId>p6spy</groupId>
            <artifactId>p6spy</artifactId>
            <version>3.8.2</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.83</version>
        </dependency>
    </dependencies>

application.yml

spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    #driver-class-name: com.p6spy.engine.spy.P6SpyDriver
    type: com.alibaba.druid.pool.DruidDataSource
    url: jdbc:mysql://localhost:3306/course_db?serverTimezone=GMT%2B8
    # url: jdbc:p6spy:mysql://localhost:3306/course_db?serverTimezone=GMT%2B8
    username: root
    password: root
# 打开mybatis-plus的sql日志输出
mybatis-plus:
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

entity

@Data
@NoArgsConstructor
@AllArgsConstructor
@TableName("course_1")
public class Course {
    @TableField("cid")
    private Long cId;
    private String cName;
    private Integer userId;
    private String cStatus;
}

Mapper

public interface CourseMapper extends BaseMapper<Course> {
}

启动类

@SpringBootApplication
@MapperScan(basePackages = "cn.zysheep.mapper")
public class ShardingjdbcdemoApplication {
    public static void main(String[] args) {
        SpringApplication.run(ShardingjdbcdemoApplication.class, args);
    }
}

测试类

@SpringBootTest
@Slf4j
class ShardingjdbcdemoApplicationTests {
    @Autowired
    private CourseMapper courseMapper;
    @SneakyThrows
    @Test
    void findCourse() {
        courseMapper.selectList(null).forEach(System.out::println);
    }
}

mybatis-plus也可以打印输出的sql日志，但是不是我们想要的效果，如何来控制想要的sql日志输出，可以使用P6Spy开源产品。

P6Spy入门使用

spy.properties

resources目录添加配置文件，类似log4j.xml，记录配置信息

module.log=com.p6spy.engine.logging.P6LogFactory,com.p6spy.engine.outage.P6OutageFactory
# sql日志打印输出
# 1、logMessageFormat=com.p6spy.engine.spy.appender.SingleLineFormat
# 2、logMessageFormat=com.p6spy.engine.spy.appender.CustomLineFormat
# customLogMessageFormat=%(currentTime) | SQL use time: %(executionTime) ms | connect info: %(category)-%(connectionId) | execute sql: %(sql)
# 3、自定义日志打印(全限定类名)
logMessageFormat=cn.zysheep.config.P6SPYConfig
# 使用日志系统记录sql
appender=com.p6spy.engine.spy.appender.Slf4JLogger
## 配置记录Log例外
excludecategories=info,debug,result,batc,resultset
# 设置使用p6spy driver来做代理
deregisterdrivers=true
# 日期格式
dateformat=yyyy-MM-dd HH:mm:ss
# 实际驱动
driverlist=com.mysql.cj.jdbc.Driver
# 是否开启慢SQL记录
outagedetection=true
# 慢SQL记录标准 秒
outagedetectioninterval=2

P6Spy有内置的SQL输出格式，如上配置文件。这里我们使用自定义SQL日志打印

P6SPYConfig

public class P6SPYConfig  implements MessageFormattingStrategy {
    @Override
    public String formatMessage(int connectionId, String now, long elapsed, String category,
     String prepared, String sql, String url) {
        Map<String, Object> message = new LinkedHashMap<>(8);
        String newPrepared = prepared.replace("   ", "").replace("\n", " ");
        message.put("prepared", newPrepared);
        String newSql = sql.replace("   ", "").replace("\n", " ");
        message.put("sql", newSql);
        return JSONObject.toJSONString(message, true);
    }
}

application.yml

spring:
  datasource:
    # driver-class-name: com.mysql.cj.jdbc.Driver
    driver-class-name: com.p6spy.engine.spy.P6SpyDriver
    type: com.alibaba.druid.pool.DruidDataSource
    #  url: jdbc:mysql://localhost:3306/course_db?serverTimezone=GMT%2B8
    url: jdbc:p6spy:mysql://localhost:3306/course_db?serverTimezone=GMT%2B8
    username: root
    password: root
# 打开mybatis-plus的sql日志输出
mybatis-plus:
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

测试类不变