CREATING SIMPLE SPRING PROJECT[JAVA CONFIGURATION]
STEP1 : ADD DEPENDENCIES
groupId :org.springframework
spring-core
${spring.version}
spring-webmvc
<!-- cglib required for @configuration annotation -->
cglib:cglib\
|
STEP 2 : CREATE BEAN CLASS
PROPERTY + CONSTRUTOR + GETTER /SETTERS
STEP 3 : CREATE CONFIGURTAION CLASS
@Configuration
public class ApplicationConfiguration {
@Bean(name="countryObj")
public Country getCountry()
{
return new Country("India");
}
STEP 4 : CREATE MAIN CLASS
public class SpringJavaConfigMain {
public static void main(String[] args) {
ApplicationContext appContext = new AnnotationConfigApplicationContext(ApplicationConfiguration.class);
Country countryObj = (Country) appContext.getBean("countryObj");
String countryName=countryObj.getCountryName();
System.out.println("Country name: "+ countryName);
}
SCOPES
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public static void main(String[] args) {
ApplicationContext appContext = new ClassPathXmlApplicationContext("ApplicationContext.xml");
Country countryObj1 = (Country) appContext.getBean("country");
countryObj1.setCountryName("India");
System.out.println("Country Name:"+countryObj1.getCountryName());
//getBean called second time
Country countryObj2 = (Country) appContext.getBean("country");
System.out.println("Country Name:"+countryObj2.getCountryName());
}
APPLICATIONCONTEXTAWARE
public static void main(String[] args) {
ApplicationContext appContext = new ClassPathXmlApplicationContext("ApplicationContext.xml");
Country countryObj = (Country) appContext.getBean("country");
System.out.println("Capital Name:"+countryObj.getCapitalName("capital"));
SPRING MVC : JAVA BASED
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Step 1 :Add Dependencies
spring-core |spring-webmvc
javax.servlet-api
jstl junit
Maven plugins
maven-compiler-plugin
maven-war-plugin
Step 3 :Create Configuration
(basePackages = "com.example")
public class SpringConfig extends WebMvcConfigurerAdapter{
public ViewResolver viewResolver() {
InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
viewResolver.setViewClass(JstlView.class);
viewResolver.setPrefix("/WEB-INF/pages/");
viewResolver.setSuffix(".jsp");
return viewResolver;
}
public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
configurer.enable();
}
}
Step 4 :Create Configuration for replacing web.xml
public class WebServletConfiguration implements WebApplicationInitializer{
public void onStartup(ServletContext ctx) throws ServletException {
AnnotationConfigWebApplicationContext webCtx = new AnnotationConfigWebApplicationContext();
webCtx.register(SpringConfig.class);
webCtx.setServletContext(ctx);
ServletRegistration.Dynamic servlet = ctx.addServlet("dispatcher", new DispatcherServlet(webCtx));
servlet.setLoadOnStartup(1);
servlet.addMapping("/");
}
}
Step 5 :Create Controller
7) Create a package named “org.arpit.java2blog.springmvc.controller”
public class GreetController {
(path= "/greet/{name}",method=RequestMethod.GET)
public String greet( String name, ModelMap model){
String greet =" Hello !!!" + name + " How are You?";
model.addAttribute("greet", greet);
System.out.println(greet);
return "greet";
}
}
Step 6 :Create jsp to show message
Step 7: Hit the URL
http://localhost:8080/SpringWebExample/greet/shamik
References
https://dzone.com/articles/spring-mvc-and-java-based-configuration-1
http://websystique.com/springmvc/spring-4-mvc-helloworld-tutorial-annotation-javaconfig-full-example/
MVC Annotations & concepts _______________________________________________________________________
http://localhost:8080/ProjectName/countries
@RequestMapping - Annotations
@RestController
@RequestMapping(value = "/countries")
public class CountryController {
@RequestMapping(method = RequestMethod.POST, headers = "Accept=application/json")
public Country addCountry(@RequestBody Country country) {
return countryService.addCountry(country);
}
@RequestMapping(method = RequestMethod.PUT, headers = "Accept=application/json")
public Country updateCountry(@RequestBody Country country) {
return countryService.updateCountry(country);
}
}
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ModelMap object is used to pass multiple values from Spring MVC controller to JSP .
Some basics about Spring MVC ModelMap class:
- ModelMap class subclasses LinkedHashMap. It add some methods for convenience.
- It provides addAttribute method to put key value pair. This method return ModelMap objects that can be used for chaining.
- ModelMap uses
as generics. - ModelMap checks for null values.
@RequestMapping("/helloworld")
public String hello(ModelMap map) {
String helloWorldMessage = "Hello world from java2blog!";
String welcomeMessage = "Welcome to java2blog!";
map.addAttribute("helloMessage", helloWorldMessage);
map.addAttribute("welcomeMessage", welcomeMessage);
return "hello";
}
<body>
${helloMessage}
<br/>
${welcomeMessage}
</body>
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MULTIACTION CONTROLLER
This the expected method struture
public (ModelAndView | Map | String | void) actionName(HttpServletRequest request, HttpServletResponse response, [,HttpSession] [,AnyObject]);
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@Controller
public class PayeeController {
private static final Logger logger = Logger.getLogger(HelloWorldController.class);
@RequestMapping("/payee/add.htm")
public ModelAndView add(HttpServletRequest request,
HttpServletResponse response) throws Exception {
logger.info("This is info message");
logger.error("This is error message");
return new ModelAndView("payee", "message", "Payee Added");
}
@RequestMapping("/payee/delete.htm")
public ModelAndView delete(HttpServletRequest request,
HttpServletResponse response) throws Exception {
return new ModelAndView("payee", "message", "Payee Deleted");
}
_____________________________________________________@MODELATTRIBUTE ANNOTATION'
@ModelAttribute is used to bind request parameters with model object. Lets say you have 10 request parameters , you can wrap them to model object and pass it in the to handler method.
@Controller
public class CountryController {
@ModelAttribute
public Country getCountry(@RequestParam String countryName, @RequestParam long population)
{
Country country=new Country();
country.setCountryName(countryName);
country.setPopulation(population);
return country;
}
@RequestMapping(value = "/addCountry", method = RequestMethod.POST)
public String addCountry(@ModelAttribute Country country,ModelMap model) {
model.addAttribute("countryName", country.getCountryName());
model.addAttribute("population", country.getPopulation());
return "countryDetails";
}
}
<h3>Country Name: ${countryName}</h3>
<h3>Population : ${population}</h3>
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SPRING ANNOTATIONS
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DEPEDNDENCIES
spring-webmvc
@RequestMapping("/helloworld")
return new ModelAndView("hello", "message", helloWorldMessage);
This means populate the ${message} property in help.jsp with value of helloWorldMessage
<body>
${message}
</body>
@Component
public class Country {
//this syntax is used to read a String from the property file
@Value("${countryName}")
private String countryName;
https://java2blog.com/spring-boot-hello-world-standalone-application/
.
@SpringBootApplication = @Configuration+ @EnableAutoConfiguration +@EnableWebMVC+@ComponentScan
Normally you would add @EnableWebMvc for a Spring MVC application, but Spring Boot adds it automatically when it sees spring-webmvc on the classpath.
@ComponentScan: scans
components, configurations, and services in the default package, .
@Autowired
@Qualifier("country")
Country countryBean;
public static void main(String[] args)
{
SpringApplication.run(SpringBootHelloWorldStandaloneApplication.class, args);
}
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Create Restful web services using Spring Boot
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Create Restful web services using Spring Boot
________________________________________________________________________________Spring Security
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@EnableWebSecurity annotation is used to enable spring security for this webapp.
authroizeRequest().addMatchers() method is used
to configure pattern for request.
For example: If http request url has pattern /hello*(hello.jsp,helloworld.html), it will be accessed to ROLE_ADMIN only.
We have hardcoded username(java2blog) and password(java123) using inMemoryAuthentication(), so if user provides correct credential for admin then only he will be able to access helloworld.html.
@Configuration
@EnableWebSecurity
public class WebSecurityConfiguaration extends WebSecurityConfigurerAdapter {
@Override
protected void configure(HttpSecurity http) throws Exception {
http.authorizeRequests()
.antMatchers("/hello*").access("hasRole('ROLE_ADMIN')").and().formLogin();;
}
@Autowired
public void configureGlobal(AuthenticationManagerBuilder auth) throws Exception {
auth.inMemoryAuthentication().withUser("java2blog").password("java123").roles("ADMIN");
}
}
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