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深入分析Java中webwork的文件上传机制(1) 点击上传按钮后，webwork的程序流如下：
step 1）进入ServletDispatcher.service
public void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException {
........
request = wrapRequest(request);
.........
}
step2)进入ServletDispatcher.wrapRequest
protected HttpServletRequest wrapRequest(HttpServletRequest request)
throws IOException {
........................
if (MultiPartRequest.isMultiPart(request)) {
request = new MultiPartRequestWrapper(request, getSaveDir(), getMaxSize());
}
return request;
}
step3)进入MultiPartRequestWrapper的构造方法
public MultiPartRequestWrapper(HttpServletRequest request, String saveDir, int maxSize)
throws IOException {
.....................
//step3.1)获取webwork.preperties配置的parser
String parser = "";
parser = Configuration.getString("webwork.multipart.parser");
// If it's not set, use Pell
if (parser.equals("")) {
log.warn("Property webwork.multipart.parser not set." +
" Using com.opensymphony.webwork.dispatcher.multipart.PellMultiPartRequest");
parser = "com.opensymphony.webwork.dispatcher.multipart.PellMultiPartRequest";
}
// legacy support for old style property values
else if (parser.equals("pell")) {
parser = "com.opensymphony.webwork.dispatcher.multipart.PellMultiPartRequest";
} else if (parser.equals("cos")) {
parser = "com.opensymphony.webwork.dispatcher.multipart.CosMultiPartRequest";
} else if (parser.equals("jakarta")) {
parser = "com.opensymphony.webwork.dispatcher.multipart.JakartaMultiPartRequest";
}
//step3.2)获取后通过反射实例化parser
try {
Class baseClazz =
com.opensymphony.webwork.dispatcher.multipart.MultiPartRequest.class;
Class clazz = Class.forName(parser);
// make sure it extends MultiPartRequest
if (!baseClazz.isAssignableFrom(clazz)) {
addError("Class '" + parser + "' does not extend MultiPartRequest");
return;
}
// get the constrUCtor
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