Failed to read schema document

转自：http://eric-yan.iteye.com/blog/1908470

问题描述：

web项目web.xml编译错误：

schema_reference.4: Failed to read schema document ‘http://java.sun.com/xml/ns/j2ee/web-app_2_5.xsd‘, because 1)  could not find the document; 2) the document could not be read; 3) the root element of the document is not <xsd:schema>.

解决方案：

多方查找，终不得解决，最后，format了一下格式，问题得以解决。

compile error format:

<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xmlns="http://java.sun.com/xml/ns/javaee"
         xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
         id="WebApp_ID" version="2.5">

no error format:  

<web-app version="2.5" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
           xmlns="http://java.sun.com/xml/ns/javaee"
           xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
           xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">