Question

我正在尝试Java EE servlet教程代码示例 https://javaee.github.io/tutorial/servlets013.html（Servlet 4.0）

首先，它可以与Spring Boot + Tomcat ，Spring boot + Jetty 和 GlassFish 一起使用。但是，当我尝试使用Spring Boot + Undertow 时，它失败并显示错误：

“处于异步模式的流尚未准备好进行IO操作”

这是我的gradle设置：

buildscript {
    ext {
        springBootVersion = '2.0.3.RELEASE'
    }
    // ext ['undertow.version'] = '2.0.10.Final'  the latest version, does not work either

    dependencies {
        classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
    }
}
apply plugin: 'java'
apply plugin: 'org.springframework.boot'
apply plugin: 'io.spring.dependency-management'

sourceCompatibility = 1.8
targetCompatibility = 1.8 

configurations {
    // not to use tomcat from spring boot
    compile.exclude module: "spring-boot-starter-tomcat"
}

dependencies {
    compile group: 'javax.servlet', name: 'javax.servlet-api', version: '4.0.1'
    compile('org.springframework.boot:spring-boot-starter-web')
    // explicitly choose undertow 
    compile("org.springframework.boot:spring-boot-starter-undertow")
}

这是我的春季靴子主班

@SpringBootApplication
@ServletComponentScan // scan and load all servlets with @WebServlet annotation
public class HelloWorldApplication {
  public static void main(String[] args) {
    SpringApplication.run(HelloWorldApplication.class, args);
  }
}

这是教程示例代码（https://javaee.github.io/tutorial/servlets013.html）

@WebServlet(urlPatterns={"/asyncioservlet"}, asyncSupported=true)
public class AsyncIOServlet extends HttpServlet {
  @Override
  public void doPost(HttpServletRequest request,
      HttpServletResponse response)
      throws IOException {
    final AsyncContext acontext = request.startAsync();
    final ServletInputStream input = request.getInputStream();

    input.setReadListener(new ReadListener() {
      byte buffer[] = new byte[4*1024];
      StringBuilder sbuilder = new StringBuilder();
      @Override
      public void onDataAvailable() {
        try {
          do {
            int length = input.read(buffer);
            sbuilder.append(new String(buffer, 0, length));
          } while(input.isReady());
        } catch (IOException ex) {  }
      }
      @Override
      public void onAllDataRead() {
        try {
          acontext.getResponse().getWriter()
              .write("...the response...");
        } catch (IOException ex) { }
        acontext.complete();
      }
      @Override
      public void onError(Throwable t) {  }
    });
  }
}

Java EE servlet教程示例不适用于Undertow + Spring Boot

0 个答案: