本文主要介绍在SpringBoot2.0中如何使用Servlet和Jsp，如图所示，对于Servlet的创建主要使用了注解方式和API注册方式，分别讲解了Servlet, Filter和Listener的创建。对于Jsp的使用，由于SpringBoot更提倡使用模板引擎，所以对于Jsp的自动配置 并不多，主要还是手动配置，本文对其步骤进行梳理。
项目结构:
1. SprinbBoot中使用Servlet
1.1 注解方式
a. 首先添加组件扫描注解
@ServletComponentScan(basePackages="com.hebaohua.springbootservletjsp.anotationServlet")
b.配置Servlet
@WebServlet(
name = "myServlet",
urlPatterns = "/myservlet",
initParams = @WebInitParam(name = "paramName", value = "paramValue")
)
public class MyServlet extends HttpServlet {
String value;
@Override
public void init(ServletConfig config) throws ServletException {
super.init(config);
ServletContext context = getServletContext();
context.log("init has been executed...");
value = config.getInitParameter("paramName");
}
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
Writer writer = resp.getWriter();
ServletContext context = getServletContext();
context.log("doGet has been executed...");
writer.write("<html><body>Hello, " + value + "</body></html>");
}
@Override
public void destroy() {
ServletContext context = getServletContext();
context.log("destroy has been executed...");
}
}
c.配置Filter
@WebFilter(urlPatterns = "/myservlet")
public class MyFilter extends OncePerRequestFilter {
@Override
protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException {
ServletContext context = request.getServletContext();
context.log("myservlet is filterd...");
filterChain.doFilter(request, response);
}
}
d. 配置Listener
@WebListener
public class MyServletRequestListener implements ServletRequestListener {
@Override
public void requestInitialized(ServletRequestEvent sre) {
HttpServletRequest request = (HttpServletRequest) sre.getServletRequest();
ServletContext context = request.getServletContext();
context.log("requestInitialized in Listener...");
}
@Override
public void requestDestroyed(ServletRequestEvent sre) {
HttpServletRequest request = (HttpServletRequest) sre.getServletRequest();
ServletContext context = request.getServletContext();
context.log("requestDestroyed in Listener...");
}
}
1.2 API注册
a.配置Servlet
public class MyServlet2 extends HttpServlet {
String value;
@Override
public void init(ServletConfig config) throws ServletException {
super.init(config);
ServletContext context = getServletContext();
context.log("init2 has been executed...");
value = config.getInitParameter("paramName2");
}
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
Writer writer = resp.getWriter();
ServletContext context = getServletContext();
context.log("doGet2 has been executed...");
writer.write("<html><body>Hello, " + value + "</body></html>");
}
@Override
public void destroy() {
ServletContext context = getServletContext();
context.log("destroy2 has been executed...");
}
}
b.配置Filter
public class MyFilter2 extends OncePerRequestFilter {
@Override
protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException {
ServletContext context = request.getServletContext();
context.log("myservlet2 is filterd...");
filterChain.doFilter(request, response);
}
}
c. 配置Listener
public class MyServletRequestListener2 implements ServletRequestListener {
@Override
public void requestInitialized(ServletRequestEvent sre) {
HttpServletRequest request = (HttpServletRequest) sre.getServletRequest();
ServletContext context = request.getServletContext();
context.log("requestInitialized2 in Listener...");
}
@Override
public void requestDestroyed(ServletRequestEvent sre) {
HttpServletRequest request = (HttpServletRequest) sre.getServletRequest();
ServletContext context = request.getServletContext();
context.log("requestDestroyed2 in Listener...");
}
}
d.注册
在主类中增加以下代码：
@Bean
public static ServletRegistrationBean servletRegistrationBean(){
ServletRegistrationBean servletRegistrationBean = new ServletRegistrationBean();
servletRegistrationBean.setServlet(new MyServlet2());
servletRegistrationBean.addUrlMappings("/myservlet2");
servletRegistrationBean.addInitParameter("paramName2", "myvalue2");
return servletRegistrationBean;
}
@Bean
public static FilterRegistrationBean filterRegistrationBean(){
FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean();
filterRegistrationBean.setFilter(new MyFilter2());
filterRegistrationBean.addUrlPatterns("/myservlet2");
return filterRegistrationBean;
}
@Bean
public static ServletListenerRegistrationBean servletListenerRegistrationBean(){
ServletListenerRegistrationBean servletListenerRegistrationBean = new ServletListenerRegistrationBean();
servletListenerRegistrationBean.setListener(new MyServletRequestListener2());
return servletListenerRegistrationBean;
}
运行日志:
上面部分为注解方式，下面为API注册方式
2. SprinbBoot中使用Jsp
2.1 添加依赖
<!-- JSP 渲染引擎 -->
<dependency>
<groupId>org.apache.tomcat.embed</groupId>
<artifactId>tomcat-embed-jasper</artifactId>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jstl</artifactId>
</dependency>
2.2 激活传统Servle部署
让主类继承SpringBootServletInitializer
public class SpringbootServletJspApplication extends SpringBootServletInitializer
2.3 组装
在主类中增加以下代码：
protected SpringApplicationBuilder configure(SpringApplicationBuilder builder){
builder.sources(SpringbootServletJspApplication.class);
return builder;
}
2.4 编写.jsp文件
创建src\main\webapp\WEB-INF\jsp文件夹并添加index.jsp文件:
<html>
<body>
Hello, ${name}
</body>
</html>
2.5 配置JSP视图
在application.properties文件中增加以下内容:
spring.mvc.view.prefix=/WEB-INF/jsp/
spring.mvc.view.suffix=.jsp
2.6 编写Controller
@Controller
public class JspControllerDemo {
@GetMapping("/jsp")
String jspTest(Model model) {
model.addAttribute("name", "Acamy");
return "index";
}
}
运行测试:
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