在Tomcat 6.0\conf\context.xml中

<?xml version='1.0' encoding='utf-8'?>

<Context>

?? ?<WatchedResource>WEB-INF/web.xml</WatchedResource>

<Resource

?name="jdbc/exam"

?auth="Container"

?type="javax.sql.DataSource"?

driverClassName="com.mysql.jdbc.Driver"

?maxIdle="2"

?maxWait="5000"?

url="jdbc:mysql://localhost:3306/exam?useUnicode=true&amp;characterEncoding=gbk"

?username="root"

?password="root"

?maxActive="20" />?

</Context>

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&amp;??是&?的转义字符

在xml文件中写成：

url="jdbc:mysql://localhost:3306/exam?useUnicode=true&amp;characterEncoding=gbk"

在java类中写成：

url="jdbc:mysql://localhost:3306/exam?useUnicode=true&characterEncoding=gbk"