传统的Spring项目，配置Servlet需要在web.xml内添加对应的标签以及映射路径规则。
SpringBoot项目中如何创建Servlet以及自动装载到SpringBoot中？
构建项目
访问start.spring.io/
添加WEB依赖、Servlet依赖
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.apache.tomcat.embed</groupId>
<artifactId>tomcat-embed-jasper</artifactId>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
</dependency>
创建Servlet
package com.gala.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class TestServlet extends HttpServlet {
private static final long serialVersionUID = -2646554587718007415L;
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
// 设置返回类型为json
resp.setContentType("application/json");
// 设置返回字符集
resp.setCharacterEncoding("UTF-8");
// 输出对象
PrintWriter writer = resp.getWriter();
// 输出error消息
writer.write("成功执行doGet方法");
writer.close();
}
}
使用Bean注册Servlet（单个Servlet）
新建ServletConfiguration配置类，并且添加一个@Bean的方法返回值为ServletRegistrationBean
package com.gala.servlet.conf;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import com.gala.servlet.TestServlet;
@Configuration
public class ServletConfiguration {
@Bean
public ServletRegistrationBean<TestServlet> servletRegistrationBean() {
return new ServletRegistrationBean<TestServlet>(new TestServlet(), "/test");
}
}
启动项目，访问地址：http://127.0.0.1:8080/test
SpringBoot自动装配Servlet（多个Servlet）
SpringBoot内部提供了注解@ServletComponentScan，这个注解的作用就是自动扫描我们SpringBoot项目内的有关Servlet配置，自动装配到我们的项目中。
TestServlet需要与ServletConfiguration同目录或在其子目录中
- 修改ServletConfiguration，增加@ServletComponentScan
package com.gala.servlet.conf;
import org.springframework.boot.web.servlet.ServletComponentScan;
import org.springframework.context.annotation.Configuration;
@Configuration
@ServletComponentScan
public class ServletConfiguration {
}
- 修改TestServlet，增加@WebServlet(urlPatterns = "/test2")
package com.gala.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@WebServlet(urlPatterns = "/test2")
public class TestServlet extends HttpServlet {
private static final long serialVersionUID = -2646554587718007415L;
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
// 设置返回类型为json
resp.setContentType("application/json");
// 设置返回字符集
resp.setCharacterEncoding("UTF-8");
// 输出对象
PrintWriter writer = resp.getWriter();
// 输出error消息
writer.write("成功执行doGet方法");
writer.close();
}
}
启动项目，访问地址：http://127.0.0.1:8080/test2
