日志

在Settings标签中可以设置logImpl，用于指定 MyBatis 所用日志的具体实现

键为logImpl，值为：

SLF4J
LOG4J
LOG4J2
JDK_LOGGING
COMMONS_LOGGING
STDOUT_LOGGING（标准格式）
NO_LOGGING

1.当值为STDOUT_LOGGING时

<settings>
        <setting name="logImpl" value="STDOUT_LOGGING"/>
    </settings>

结果

PooledDataSource forcefully closed/removed all connections.
PooledDataSource forcefully closed/removed all connections.
PooledDataSource forcefully closed/removed all connections.
PooledDataSource forcefully closed/removed all connections.
Opening JDBC Connection
Created connection 633240419.
Setting autocommit to false on JDBC Connection [com.mysql.jdbc.JDBC4Connection@25be7b63]
==>  Preparing: select * from user where name like "%" ? "%" 
==> Parameters: 李(String)
<==    Columns: id, name, pwd
<==        Row: 3, 李四, 1231233
<==        Row: 4, 李三, 123123
<==      Total: 2
User{id=3, name='李四', password='1231233'}
User{id=4, name='李三', password='123123'}
Resetting autocommit to true on JDBC Connection [com.mysql.jdbc.JDBC4Connection@25be7b63]
Closing JDBC Connection [com.mysql.jdbc.JDBC4Connection@25be7b63]
Returned connection 633240419 to pool.

2.log4j

2.1什么是log4j？

- 通过使用Log4j，我们可以控制日志信息输送的目的地是控制台、文件、GUI组件

- 可以控制每一条日志的输出格式

- 通过定义每一条日志信息的级别，我们能够更加细致地控制日志的生成过程

- 可以通过一个配置文件来灵活地进行配置，而不需要修改应用的代码。

2.2导包

<dependency>
    <groupId>log4j</groupId>
    <artifactId>log4j</artifactId>
    <version>1.2.17</version>
</dependency>

2.3 编写log4j.propertise配置文件（注意名字一定要为log4j，这是要求，要不然会找不到配置文件）

log4j.rootCategory=DEBUG,console,file

log4j.appender.console=org.apache.log4j.ConsoleAppender
log4j.appender.console.Target = System.out
log4j.appender.console.Threshold =DEBUG
#PatternLayout(可以灵活的自定义布局)
log4j.appender.console.layout=org.apache.log4j.PatternLayout
log4j.appender.console.layout.ConversionPattern=[%c]-%m%n

#DailyRollingFileAppender （每天产生一个日志文件）
#FileAppender（文件）
log4j.appender.file=org.apache.log4j.RollingFileAppender
#定义log日记生成的路径
log4j.appender.file.File=./log/luo.log
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=[%p][%d{yy-MM-dd}][%c]%m%n
#指定com.Google包下的所有类的等级为DEBUG。
log4j.logger.org.mybatis=DEBUG
log4j.logger.java.sql=DEBUG
log4j.logger.java.sql.Statement=DEBUG
log4j.logger.java.sql.ResultSet=DEBUG
log4j.logger.java.sql.PreparedStatement=DEBUG

2.4在对应的类中使用该方法

2.4.1 定义一个静态的全局变量（以便后面方法，好用来测试）

static Logger logger = Logger.getLogger(userMapperTest.class);

2.4.2 测试

 public void getUserByID2(){
        logger.debug("欢迎来到Debug的世界");
        logger.info("欢迎来到Info的世界");
        logger.error("欢迎来到error的世界");
        SqlSession sqlSession = sqlSessionFactory.getsqlSession();
        userMapper mapper = sqlSession.getMapper(userMapper.class);
        Map<String, Object> map = new HashMap<>();
        map.put("name","李");
        List<User> userByID2 = mapper.getUserByID2(map);
        for (User user : userByID2) {
            System.out.println(user);
        }
        sqlSession.close();
    }

2.4.3 运行结果

[DEBUG][22-01-19][com.Google.Dao.userMapperTest]欢迎来到Debug的世界
[INFO][22-01-19][com.Google.Dao.userMapperTest]欢迎来到Info的世界
[ERROR][22-01-19][com.Google.Dao.userMapperTest]欢迎来到error的世界
[DEBUG][22-01-19][org.apache.ibatis.logging.LogFactory]Logging initialized using 'class org.apache.ibatis.logging.log4j.Log4jImpl' adapter.
[DEBUG][22-01-19][org.apache.ibatis.datasource.pooled.PooledDataSource]PooledDataSource forcefully closed/removed all connections.
[DEBUG][22-01-19][org.apache.ibatis.datasource.pooled.PooledDataSource]PooledDataSource forcefully closed/removed all connections.
[DEBUG][22-01-19][org.apache.ibatis.datasource.pooled.PooledDataSource]PooledDataSource forcefully closed/removed all connections.
[DEBUG][22-01-19][org.apache.ibatis.datasource.pooled.PooledDataSource]PooledDataSource forcefully closed/removed all connections.
[DEBUG][22-01-19][org.apache.ibatis.transaction.jdbc.JdbcTransaction]Opening JDBC Connection
[DEBUG][22-01-19][org.apache.ibatis.datasource.pooled.PooledDataSource]Created connection 1693226694.
[DEBUG][22-01-19][org.apache.ibatis.transaction.jdbc.JdbcTransaction]Setting autocommit to false on JDBC Connection [com.mysql.jdbc.JDBC4Connection@64ec96c6]
[DEBUG][22-01-19][com.Google.Dao.userMapper.getUserByID2]==>  Preparing: select * from user where name like "%" ? "%" 
[DEBUG][22-01-19][com.Google.Dao.userMapper.getUserByID2]==> Parameters: 李(String)
[DEBUG][22-01-19][com.Google.Dao.userMapper.getUserByID2]<==      Total: 2
[DEBUG][22-01-19][org.apache.ibatis.transaction.jdbc.JdbcTransaction]Resetting autocommit to true on JDBC Connection [com.mysql.jdbc.JDBC4Connection@64ec96c6]
[DEBUG][22-01-19][org.apache.ibatis.transaction.jdbc.JdbcTransaction]Closing JDBC Connection [com.mysql.jdbc.JDBC4Connection@64ec96c6]
[DEBUG][22-01-19][org.apache.ibatis.datasource.pooled.PooledDataSource]Returned connection 1693226694 to pool.