public abstract class HttpServlet extends GenericServlet
package com.xh.test.api; import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException; /**
* Created by root on 17-11-12.
*/
public class MyHttpServlet extends HttpServlet {
@Override
protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
super.service(req, resp);
System.out.println(">>>MyHttpServlet.service");
resp.getWriter().write("MyHttpServlet.service");
} @Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//super.doGet(req, resp);
System.out.println(">>>MyHttpServlet.doGet");
resp.getWriter().write("MyHttpServlet.doGet");
} @Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//super.doPost(req, resp);
System.out.println(">>>MyHttpServlet.doPost");
resp.getWriter().write("MyHttpServlet.doPost");
}
}
在restclient插件输入：http://localhost:8080/testservlet/1?id=100 ，切换方法GET,POST
输出是：
MyHttpServlet.doGetMyHttpServlet.service
MyHttpServlet.doPostMyHttpServlet.service
控制台：
>>>MyHttpServlet.doGet
>>>MyHttpServlet.service
>>>MyHttpServlet.doPost
>>>MyHttpServlet.service
PS:浏览器的请求过来，都要经过Servlet的service，如果自己不实现则走HttpServlet的。如果自己实现的，没有调用super.service(req, resp)，
则直接返回，如果调用了super.service(req, resp)，则HttpServlet会找当前类的对应的方法，如doGet，doPost，如果没有对应的实现，则抛异常，
如果实现了，就执行当前类的doGet，doPost方法，执行完后又返回到service方法，执行完返回给浏览器。
所以我们一般二者选其一实现（当然建议是doGet，doPost）。
protected void service(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException
{
String method = req.getMethod(); if (method.equals(METHOD_GET)) {
long lastModified = getLastModified(req);
if (lastModified == -1) {
// servlet doesn't support if-modified-since, no reason
// to go through further expensive logic
doGet(req, resp);
} else {
long ifModifiedSince = req.getDateHeader(HEADER_IFMODSINCE);
if (ifModifiedSince < lastModified) {
// If the servlet mod time is later, call doGet()
// Round down to the nearest second for a proper compare
// A ifModifiedSince of -1 will always be less
maybeSetLastModified(resp, lastModified);
doGet(req, resp);
} else {
resp.setStatus(HttpServletResponse.SC_NOT_MODIFIED);
}
} } else if (method.equals(METHOD_HEAD)) {
long lastModified = getLastModified(req);
maybeSetLastModified(resp, lastModified);
doHead(req, resp); } else if (method.equals(METHOD_POST)) {
doPost(req, resp); } else if (method.equals(METHOD_PUT)) {
doPut(req, resp); } else if (method.equals(METHOD_DELETE)) {
doDelete(req, resp); } else if (method.equals(METHOD_OPTIONS)) {
doOptions(req,resp); } else if (method.equals(METHOD_TRACE)) {
doTrace(req,resp); } else {
//
// Note that this means NO servlet supports whatever
// method was requested, anywhere on this server.
// String errMsg = lStrings.getString("http.method_not_implemented");
Object[] errArgs = new Object[1];
errArgs[0] = method;
errMsg = MessageFormat.format(errMsg, errArgs); resp.sendError(HttpServletResponse.SC_NOT_IMPLEMENTED, errMsg);
}
}
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException
{
String protocol = req.getProtocol();
String msg = lStrings.getString("http.method_get_not_supported");
if (protocol.endsWith("1.1")) {
resp.sendError(HttpServletResponse.SC_METHOD_NOT_ALLOWED, msg);
} else {
resp.sendError(HttpServletResponse.SC_BAD_REQUEST, msg);
}
}