好久没有写java了，昨天学了下maven，不用手动的下载和添加jar包，实在是太方便。
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搭了下ssm。spring和mybatis集成时遇到太多bug:
bug1. 找不到dao对应的xml
Caused by: java.lang.IllegalArgumentException: Could not resolve resource location pattern [classpath:xin/redips/urls/mapper/*.xml]:
class path resource [xin/redips/urls/mapper/] cannot be resolved to URL because it does not exist
去target/classes文件夹下看了下还真是没有，maven没有把xml拷贝到classpath下，需要加上：
<build>
...
<resources>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*.xml</include>
</includes>
<filtering>true</filtering>
</resource> <resource>
<directory>src/main/resources</directory>
<includes>
<include>**/*.xml</include>
<include>**/*.properties</include>
</includes>
<filtering>true</filtering>
</resource> </resources>
</build>
bug2. Cannot load JDBC driver class 'com.mysql.jdbc.Driver '
原因是配置文件多加了个空格。。
bug3. No suitable driver
网上说：Java.sql.SQLException: No suitable driver found for这个异常的发生，原因有二：
一，在可寻的路径下没有合适的数据库驱动。
二，数据库连接时提供的url不正确。
maven已经下好了jar包，所以不是原因一。而倒数第二个异常是：
我url明明写的是：
原来是pom.xml中定义的url覆盖了properties中定义的url.
