Struts request param 去除空格 TrimInterceptor

package com.ehi.struts.interceptor.servicemanagement;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import com.opensymphony.xwork2.interceptor.MethodFilterInterceptor;
import com.opensymphony.xwork2.ActionInvocation;
import org.apache.commons.lang.StringUtils;

/**
* An interceptor to trim all the parameters. <br>
* It's bascially adapted from the book, <br/>
* 'Apache Struts 2 Web Application Development'
*
* @author candicew
*
*/
@SuppressWarnings("serial")
public class TrimInterceptor extends MethodFilterInterceptor {

private List<String> excluded = new ArrayList<String>();

protected String doIntercept(ActionInvocation invocation) throws Exception {
Map<String, Object> parameters = invocation.getInvocationContext().getParameters();

for (String param : parameters.keySet()) {
if (shouldTrim(param)) {
doTrim(parameters, param);
}
}

return invocation.invoke();
}

void doTrim(Map<String, Object> parameters, String param) {
Object val = parameters.get(param);
if(val == null){
return;
}
if (val instanceof String) {
trimString(parameters, param, val);
} else {
trimStringArray(parameters, param, val);
}
}

private void trimString(Map<String, Object> parameters, String param, Object val) {

String value = (String) val;
value = StringUtils.trimToNull(value);
parameters.put(param, value);

}

private void trimStringArray(Map<String, Object> parameters, String param, Object val) {

String[] vals = (String[]) val;
boolean allNull = true;
for (int i = 0; i < vals.length; i++) {
vals[i] = StringUtils.trimToNull(vals[i]);
allNull = allNull && (vals[i] == null);
}
if (allNull) {
parameters.put(param, null);
}

}

private boolean shouldTrim(String param) {
for (String exclude : excluded) {
if (param.equalsIgnoreCase(exclude)) {
return false;
}
}

return true;
}

public void setExcludedParams(String excludedParams) {
for (String s : StringUtils.split(excludedParams, ",")) {
excluded.add(s.trim());
}
}

}