How does spring's DispatcherServlet work

In Spring webmvc, there is a specifial servlet which is the portal between Servlet container and Spring webmvc framework. It's the DispatcherServlet. A spring web application usually maps all requst to this DispatcherServlet. A servlet's job is take in a HttpServletRequest, do all the business process...

What are default handlers/resolvers in Spring DispatcherServlet

Spring webmvc's DispatcherServlet rely on several important notions. HandlerMapping  - find which controller's which method to process current http request. HandlerAdapter - use HandlerMapping's result, actually make performe the request handling, return a ModelAndView object ViewResolver - find...

How to use distributed JMeter to test netty server performance

JMeter is good at performance testing. Usually, we often need more than one hosts to send traffic to one server to see how the sever behaves. This Many-To-One test scenario is called distributed testing.  In JMeter's world, the hosts, which generate traffic,  are called 'jmeter server'. You...

Netty tutorial - hello world example

Netty is a NIO client server framework which enables quick and easy development of network applications. In this tutorial the basic concepts of Netty are introduced, as well as  a hello world level example. This hello world example, based on Netty 4, has a server and a client, including heart beat...

Hello world Spark example

In this article, there is 3 hello world level demos.  The difference is where does the spark get its input data. The first one, spark get its input data from external socket server. This method is often used in testing or developing phase. The second demo, spark get its input data from Flume...

How to send message to Flume (avro or thrift) in Java

Apache Flume is mostly used to transfer data from "Out-of-Hadoop" world into Hadoop family.  In Flume, every message transfered is called 'Event', input is call "Source", output is called "Sink". 1. Flume Source & Sink type Flume has many input and output types. Here are some  wildly...

Java-based Spring mvc configuration - with Spring security

This article need you already understand how to config Spring mvc in java-based configuration without Spring security. If not, check this article first on "Java-based Spring mvc configuration - without Spring security" This article is a hello world level spring mvc application with following features:...

Replace jpa persistence.xml with java based configuration in Spring

Jpa 's /META/INF/persistence.xml  with transaction-type set "RESOURCE_LOCAL"  can be replace in spring configuration. The demo persistence.xml looks like below.<?xml version="1.0" encoding="UTF-8"?> <persistence version="2.1" xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence...

Java-based Spring mvc configuration - without Spring security

Spring 3+ supports using java-based configuration in replacement of the tradictional web.xml. You can replace web.xml with any class which implments interface org.springframework.web.WebApplicationInitializer ( which only has one onStartup() method). Usually all you need to provide to a web.xml for...