Mybatis学习03
title: Mybatis学习03 date: 2020-01-19 13:03:20 tags:
Mybatis学习的第二天,内容有日志和分页。
<!--more-->
1、日志
1、日志的设置
在mybatis核心配置文件中设置,在<settings></settings>标签中使用<setting></setting>来配置。
Mybatis内置了多个日志,有:
-
SLF4J
-
LOG4J (常用)
-
LOG4J2
-
JDK_LOGGING
-
COMMONS_LOGGING
-
STDOUT_LOGGING (常用,标准日志)
-
NO_LOGGING
例如STDOUT_LOGGING的配置则需在配置文件中加入:
<!-- mybatis的设置--> <settings> <setting name="logImpl" value="STDOUT_LOGGING"/> </settings>
效果如下:
2、LOG4J
log4j的解释:
-
Log4j是Apache的一个开源项目,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,甚至是套接口服务器、NT的事件记录器、UNIX Syslog守护进程等 。
-
我们也可以控制每一条日志的输出格式 。
-
可以通过一个配置文件来灵活地进行配置
开始使用:
-
Maven添加依赖
<!-- https://mvnrepository.com/artifact/log4j/log4j --> <dependency> <groupId>log4j</groupId> <artifactId>log4j</artifactId> <version>1.2.17</version> </dependency>
-
mybatis设置log4j为日志
<settings> <setting name="logImpl" value="LOG4J"/> </settings>
-
编写log4j的配置文件(放在resoures中,名为log4j.properties)
### set log levels ### log4j.rootLogger = INFO , console , debug , error ### console ### log4j.appender.console = org.apache.log4j.ConsoleAppender log4j.appender.console.Target = System.out log4j.appender.console.layout = org.apache.log4j.PatternLayout log4j.appender.console.layout.ConversionPattern = %-d{yyyy-MM-dd HH\:mm\:ss} [%p]-[%c] %m%n ### log file ### log4j.appender.debug = org.apache.log4j.DailyRollingFileAppender log4j.appender.debug.File = ./log/log4j.log log4j.appender.debug.Append = true log4j.appender.debug.Threshold = INFO log4j.appender.debug.layout = org.apache.log4j.PatternLayout log4j.appender.debug.layout.ConversionPattern = %-d{yyyy-MM-dd HH\:mm\:ss} [%p]-[%c] %m%n ### exception ### log4j.appender.error = org.apache.log4j.DailyRollingFileAppender log4j.appender.error.File = ./log/log4j.log log4j.appender.error.Append = true log4j.appender.error.Threshold = ERROR log4j.appender.error.layout = org.apache.log4j.PatternLayout log4j.appender.error.layout.ConversionPattern = %-d{yyyy-MM-dd HH\:mm\:ss} [%p]-[%c] %m%n ###需要声明,然后下方才可以使druid sql输出,否则会抛出log4j.error.key not found log4j.appender.stdout=org.apache.log4j.ConsoleAppender log4j.appender.stdout.Target=System.out log4j.appender.stdout.layout=org.apache.log4j.PatternLayout log4j.appender.stdout.layout.ConversionPattern=%d{ISO8601} %l %c%n%p: %m%n ### druid sql ### log4j.logger.druid.sql=warn,stdout log4j.logger.druid.sql.DataSource=warn,stdout log4j.logger.druid.sql.Connection=warn,stdout log4j.logger.druid.sql.Statement=warn,stdout log4j.logger.druid.sql.ResultSet=warn,stdout
-
java代码中使用log4j
@Test public void TestLog4j(){ Logger logger = Logger.getLogger(UserMapperTest.class); logger.info("info:进入TestLog4j"); logger.debug("debug:进入TestLog4j"); logger.error("error:进入TestLog4j"); }
2、分页
1、limit分页(SQL语句)
-
接口
//通过分页获取用户信息 List<User> getUserByLimit(Map<String,Integer> map);
-
xml的语句
<!-- 获取分页--> <select id="getUserByLimit" parameterType="map" resultType="User"> select * from user limit #{startIndex},#{pageSize} </select>
-
测试
@Test public void getUserByLimit(){ SqlSession sqlSession = MybatisUtils.getSqlSession(); UserMapper mapper = sqlSession.getMapper(UserMapper.class); HashMap<String, Integer> map = new HashMap<String, Integer>(); map.put("startIndex",0); map.put("pageSize",3); List<User> userByLimit = mapper.getUserByLimit(map); for (User user : userByLimit) { System.out.println(user); } sqlSession.close(); }
2、RowBounds实现(JAVA代码层面)
-
接口
//rowbounds实现分页 List<User> getUserByRowBounds();
-
xml文件
<!-- rowbounds实现分页--> <select id="getUserByRowBounds" resultType="User"> select * from user </select>
-
测试代码
@Test public void getUserByRowBounds(){ SqlSession sqlSession = MybatisUtils.getSqlSession(); RowBounds rowBounds = new RowBounds(1, 3); List<User> userList = sqlSession.selectList("com.neversettle.dao.UserMapper.getUserByRowBounds", null, rowBounds); for (User user : userList) { System.out.println(user); } sqlSession.close(); }