Mybatis日志系统

Mybatis也有日志系统，它详细记录了所有的数据库操作等,通过配置xml文件来打开日志系统

"logImpl" value="STDOUT_LOGGING" />

`logImpl`包括很多种配置项，包括 SLF4J | LOG4J | LOG4J2 | JDK_LOGGING | COMMONS_LOGGING | STDOUT_LOGGING | NO_LOGGING，而默认情况下是未配置，也就是说不打印

public class TestMain {
 
    private SqlSessionFactory sqlSessionFactory;
    @Before
    public void before(){
        try {
            sqlSessionFactory = new SqlSessionFactoryBuilder()
                    .build(new FileInputStream("mybatis-config.xml"));
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    }
 
    @Test
    public void test(){
        try(SqlSession sqlSession = sqlSessionFactory.openSession(true)){
            TestMapper mapper = sqlSession.getMapper(TestMapper.class);
            System.out.println(mapper.getStudentBySidAndSex(1, "男"));
            System.out.println(mapper.getStudentBySidAndSex(1, "男"));
        }
    }
}

两次获取学生信息，只有第一次打开了数据库连接，而第二次并没有

将其配置为JDK_LOGGING表示使用JUL进行日志打印，因为Mybatis的日志级别都比较低，因此我们需要设置一下`logging.properties`默认的日志级别

<setting name="logImpl" value="JDK_LOGGING" />

handlers= java.util.logging.ConsoleHandler

.level= ALL

java.util.logging.ConsoleHandler.level = ALL

@Log
public class TestMain {
 
    private SqlSessionFactory sqlSessionFactory;
    @Before
    public void before(){
        try {
            sqlSessionFactory = new SqlSessionFactoryBuilder()
                    .build(new FileInputStream("mybatis-config.xml"));
            LogManager manager = LogManager.getLogManager();
            manager.readConfiguration(new FileInputStream("logging.properties"));
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
 
    @Test
    public void test(){
        try(SqlSession sqlSession = sqlSessionFactory.openSession(true)){
            TestMapper mapper = sqlSession.getMapper(TestMapper.class);
            log.info(mapper.getStudentBySidAndSex(1, "男").toString());
            log.info(mapper.getStudentBySidAndSex(1, "男").toString());
        }
    }
}

可以修改一下日志格式

public class TestFormatter extends Formatter {
    @Override
    public String format(LogRecord record) {
        SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
        String time = format.format(new Date(record.getMillis()));  //格式化日志时间
        return time + " : " + record.getMessage() + "\n";
    }
}

再修改properties文件

handlers= java.util.logging.ConsoleHandler

.level= ALL

java.util.logging.ConsoleHandler.level = ALL

java.util.logging.ConsoleHandler.formatter = com.test.TestFormatter