为什么GET资源不响应请求

Question

我在Spring开发了一个项目，并创建了GET服务。每当我将来自邮递员的GET请求发送到url localhost：8080 / studentsystem2 / students时，基本上什么都没有发生，并且据说该资源不可用。怎么了？为什么找不到资源？

这是StudentResource类。

package studentsystem2.ikubinfo.resource;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import studentsystem2.ikubinfo.model.StudentModel;
import studentsystem2.ikubinfo.service.StudentService;

@RestController
@RequestMapping(value = "/students", consumes="application/json", produces="application/json")
public class StudentResource {
    @Autowired
    private StudentService studentService;
    public StudentResource () {

    }

    @GetMapping
    public ResponseEntity<List<StudentModel>> getAll() {
        return new ResponseEntity<List<StudentModel>>(studentService.getAll(), HttpStatus.OK);
    }
}

pom.xml

<dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>5.2.0.RELEASE</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/javax.validation/validation-api -->
        <dependency>
            <groupId>javax.validation</groupId>
            <artifactId>validation-api</artifactId>
            <version>2.0.1.Final</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-aop -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aop</artifactId>
            <version>5.2.1.RELEASE</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/commons-logging/commons-logging -->
        <dependency>
            <groupId>commons-logging</groupId>
            <artifactId>commons-logging</artifactId>
            <version>1.2</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-aspects -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aspects</artifactId>
            <version>5.2.1.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>5.2.0.RELEASE</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.2.1.RELEASE</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.2.0.RELEASE</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.springframework.data/spring-data-commons -->
        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-commons</artifactId>
            <version>2.2.0.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.modelmapper</groupId>
            <artifactId>modelmapper</artifactId>
            <version>2.3.2</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.hibernate.javax.persistence/hibernate-jpa-2.1-api -->
        <dependency>
            <groupId>org.hibernate.javax.persistence</groupId>
            <artifactId>hibernate-jpa-2.1-api</artifactId>
            <version>1.0.2.Final</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.postgresql/postgresql -->
        <dependency>
            <groupId>org.postgresql</groupId>
            <artifactId>postgresql</artifactId>
            <version>42.2.8</version>
        </dependency>

这是application.properties

# DATASOURCE (DataSourceAutoConfiguration & DataSourceProperties)

# JDBC URL of the database.
spring.datasource.url=jdbc:postgresql://localhost:5432/postgres
# Login username of the database.
spring.datasource.username=********
# Login password of the database.
spring.datasource.password=*********

# JPA (JpaBaseConfiguration, HibernateJpaAutoConfiguration)

# DDL mode. This is actually a shortcut for the "hibernate.hbm2ddl.auto" property. Defaults to "create-drop" when using an embedded database and no schema manager was detected. Otherwise, defaults to "none".
spring.jpa.hibernate.ddl-auto=update
# Whether to enable logging of SQL statements.
spring.jpa.show-sql=true

# Hibernate additional native properties to set on the JPA provider.
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.PostgreSQLDialect
spring.jpa.properties.hibernate.current_session_context_class=thread
spring.jpa.properties.hibernate.format_sql=true

# Fix Postgres JPA Error (Method org.postgresql.jdbc.PgConnection.createClob() is not yet implemented).
spring.jpa.properties.hibernate.jdbc.lob.non_contextual_creation=true
server.servlet.context-path=/studentsystem2
management.server.servlet.context-path = /studentsystem2

这是web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>studentsystem2</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>


<servlet>
    <servlet-name>rest</servlet-name>
    <servlet-class>
        org.springframework.web.servlet.DispatcherServlet
    </servlet-class>
    <load-on-startup>1</load-on-startup>
</servlet>

<servlet-mapping>
    <servlet-name>rest</servlet-name>
    <url-pattern>/*</url-pattern>
</servlet-mapping>
</web-app>