使用Maven和Mybatis开发时，遇到“java.sql.SQLException: No suitable driver found for http://maven.apache.org”...

今天使用Maven和Mybatis，在Eclipse上开发j2ee的程序。本人刚学Mybatis，对Maven还算熟悉，看过书，用的时间不长。本想试下Mybatis的selectList，结果程序编译通过，运行时报错：

org.apache.ibatis.exceptions.PersistenceException: ### Error opening session. Cause: java.sql.SQLException: No suitable driver found for http://maven. apache.org ### Cause: java.sql.SQLException: No suitable driver found for http://maven.apache.org at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:8) at org.apache.ibatis.session.defaults.DefaultSqlSessionFactory.openSessionFromDataSource(DefaultSql SessionFactory.java:83) at org.apache.ibatis.session.defaults.DefaultSqlSessionFactory.openSession(DefaultSqlSessionFactory .java:32) at databaseAdapter.CollegeAdapter.selectCollege(CollegeAdapter.java:28) at temp.RunSqlSession.main(RunSqlSession.java:30) Caused by: java.sql.SQLException: No suitable driver found for http://maven.apache.org at java.sql.DriverManager.getConnection(DriverManager.java:602) at java.sql.DriverManager.getConnection(DriverManager.java:185) at org.apache.ibatis.datasource.unpooled.UnpooledDataSource.getConnection(UnpooledDataSource.java:6 4) at org.apache.ibatis.datasource.pooled.PooledDataSource.popConnection(PooledDataSource.java:349) at org.apache.ibatis.datasource.pooled.PooledDataSource.getConnection(PooledDataSource.java:55) at org.apache.ibatis.session.defaults.DefaultSqlSessionFactory.openSessionFromDataSource(DefaultSql SessionFactory.java:73) ... 3 more
郁闷！

之前见过SQLException报错，说ClassNotFound的或者链接打不开的，可就是没见过

java.sql.SQLException: No suitable driver found for http://maven.apache.org

的，我重新把java代码看了一遍，并没有在java代码中发现http://maven.apache.org，使用Maven的mvn clean compile一遍，发现问题依旧，猛然心想，去target里看看Mybatis的configuration配置文件吧，结果找到原因了！

我的Mybatis的配置文件源码如下：

<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd"> <configuration> <properties> <property name="url" value="jdbc:postgresql://localhost/mydb3"/> <property name="driver" value="org.postgresql.Driver"/> <property name="username" value="1234"/> <property name="password" value="1234"/> </properties> <typeAliases> <typeAlias alias="College" type="pojo.College"/> </typeAliases> <environments default="development"> <environment id="development"> <transactionManager type="JDBC"/> <dataSource type="POOLED"> <property name="driver" value="${driver}"/> <property name="url" value="${url}"/> <property name="username" value="${username}"/> <property name="password" value="${password}"/> </dataSource> </environment> </environments> <mappers> <mapper resource="mybatis/mapper/CollegeMapper.xml"/> </mappers> </configuration>
可经过Maven的mvn compile之后，变成了：

<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd"> <configuration> <properties> <property name="url" value="jdbc:postgresql://localhost/mydb3"/> <property name="driver" value="org.postgresql.Driver"/> <property name="username" value="1234"/> <property name="password" value="1234"/> </properties> <typeAliases> <typeAlias alias="College" type="pojo.College"/> </typeAliases> <environments default="development"> <environment id="development"> <transactionManager type="JDBC"/> <dataSource type="POOLED"> <property name="driver" value="${driver}"/> <property name="url" value="http://maven.apache.org"/> <property name="username" value="${username}"/> <property name="password" value="${password}"/> </dataSource> </environment> </environments> <mappers> <mapper resource="mybatis/mapper/CollegeMapper.xml"/> </mappers> </configuration>
发现问题了吧？

是的，maven把Mybatis的${url}替换成http://maven.apache.org了！

为什么呢？

在maven的compile之前，有一个阶段（phase）是process-resources，这时resources插件会把src/main/resources里的xml用到的${XXX}变量替换成设定的值，而url值碰巧在项目pom文件中定义了：

<modelVersion>4.0.0</modelVersion> <groupId>cn.edu.sdu.ise.leesonlog.lms4g</groupId> <artifactId>lms4g-website</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>war</packaging> <name>lms4g-website Maven Webapp</name> <url>http://maven.apache.org</url>
又碰巧，我把Mybatis的配置文件放到src/main/resouces目录底下了……然后悲剧就发生了。

如何解决：

不让maven过滤resources目录下的Mybatis配置文件，及其mapper文件！

修改工程的POM文件：

<resources> <!-- 对resources目录进行过滤，主要是设置bin目录里的内容 --> <resource> <directory>${project.basedir}/src/main/resources</directory> <filtering>true</filtering> <excludes> <exclude>mybatis/**/*</exclude> </excludes> </resource> <!-- 不过滤resources/mybatis目录，否则容易破坏mybatis的一些xml配置 --> <resource> <directory>${project.basedir}/src/main/resources</directory> <filtering>false</filtering> <includes> <include>mybatis/**/*</include> </includes> </resource> </resources>
让maven不过滤mybatis文件夹下的东西就可以了。

注意：我的mybatis的配置文件被我放到src/main/resouces/mybatis文件夹下了。