Spring：无法访问控制器 404 not found 错误答案

【问题标题】：Spring: can't access controller 404 not found errorSpring：无法访问控制器 404 not found 错误
【发布时间】：2020-08-26 18:23:41
【问题描述】：

我正在尝试访问 http://localhost:8088/test_war_exploded/home/hello，但收到 404 错误。我不知道为什么。

目录结构：

root
  src
    main
      java
         test
           config
              DbConfig.java
              MyAppInitializer.java
              WebConfig.java
          HomeController.java

WebConfig.java：


@Configuration
@ComponentScan("test")
@EnableWebMvc
@EnableTransactionManagement
@EnableGlobalMethodSecurity(prePostEnabled = true)
@EnableJpaRepositories(basePackages = "test",
        entityManagerFactoryRef = "entityManagerFactory",
        transactionManagerRef = "transactionManager")
 public class WebConfig extends WebMvcConfigurerAdapter {
    @Override
    public void configureDefaultServletHandling(
                DefaultServletHandlerConfigurer configurer) {
        configurer.enable();
    }

    @Override
    public void addViewControllers(ViewControllerRegistry registry) {
        registry.addViewController("/").setViewName("index");
    }

    @Bean
    public ViewResolver viewResolver() {
        InternalResourceViewResolver bean = new InternalResourceViewResolver();

        bean.setViewClass(JstlView.class);
        bean.setPrefix("/WEB-INF/view/");
bean.setSuffix(".html");


        return bean;
    }
}

MyAppInitializer.java：

public class MyAppInitializer extends
                AbstractAnnotationConfigDispatcherServletInitializer {
    @Override
    public void onStartup(final ServletContext sc) throws ServletException {
        System.out.println("onStartup!");

        AnnotationConfigWebApplicationContext root =
                new AnnotationConfigWebApplicationContext();

        root.register(WebConfig.class);
        root.setServletContext(sc);

        root.scan("test");
        //sc.addListener(new ContextLoaderListener(root));

        ServletRegistration.Dynamic appServlet =
                sc.addServlet("dispatcher", new DispatcherServlet(new GenericWebApplicationContext()));
        appServlet.setLoadOnStartup(1);
        appServlet.addMapping("/");
    }

        @Override
    protected Class<?>[] getRootConfigClasses() {
        return new Class[] {SecurityConfig.class};
    }

    @Override
    protected Class<?>[] getServletConfigClasses() {
        return new Class[]{WebConfig.class};
    }

    @Override
    protected String[] getServletMappings() {
        return new String[]{"/"};
    }
}

HomeController.java：

@RestController
@RequestMapping("/home")
public class HomeController {

    @GetMapping(value = "/hello")
    public String hello() {
        return "Hello";
    }
}

应用程序已部署，服务器/IDE 日志中没有错误。在部署期间，onStartup 会打印在控制台中，这意味着 MyAppInitializer 中的代码会被执行。

【问题讨论】：

你的 URL 中的“test_war_exploded”来自哪里？请改用localhost:8080/home/hello。如果可行，问题是您需要告诉它相对于 test_war_exploded 服务。
不，它会自动打开那个 url - Idea Intellij，只是 localhost 没有部署！
...您的评论毫无意义。您在哪里告诉 IntelliJ 使用“test_war_exploded”作为基本路径？由于您在共享的代码中没有指定它，那么除非您在其他地方告诉 IntelliJ（例如在运行配置中，您指定端口 8088 的同一位置），否则它只会在 localhost/ 而不是 localhost 提供它/test_war_exploded。
我就像在这个视频中一样 - youtu.be/59D3DmAkxp0?t=38。最后，他访问了 /springblog 的 url，类似于我在 /test_war_exploded 访问它的方式。这不是问题
尝试：用 Controller 替换 RestController 并在方法上添加 ResponseBody 注释。让我知道响应是什么

标签： java spring spring-boot spring-mvc

【解决方案1】：

HomeController 为 /home 提供映射。要访问提到的端点，您可以将第一部分添加到 RequestMapping 注释中：@RequestMapping("test_war_exploded/home")

你尝试通过8088端口访问。默认端口是8080，如果没有在application.properties中设置，否则。

【讨论】：

【解决方案2】：

HomeController bean 未定义且未初始化。

@Component
@RestController
@RequestMapping("/home")
public class HomeController {

    @GetMapping(value = "/hello")
    public String hello() {
        return "Hello";
    }
}

【讨论】：

RestController 是 Component 的特殊形式。两个都加没感觉

【解决方案3】：

我想通了。问题是我没有初始化类。我添加了两个类：SecurityConfig 和 SecurityWebApplicationInitializer：

SecurityConfig.java：

@Configuration
@EnableGlobalMethodSecurity(prePostEnabled=true)
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter  {
    @Override
    protected void configure(HttpSecurity httpSecurity) throws Exception {
        httpSecurity.authorizeRequests().antMatchers("/").permitAll();
    }

    @Bean
    BCryptPasswordEncoder passwordEncoder() {
        return new BCryptPasswordEncoder();
    }
}

SecurityWebApplicationInitializer.java：

public class SecurityWebApplicationInitializer extends
                    AbstractSecurityWebApplicationInitializer {
    public SecurityWebApplicationInitializer() {
        super(SecurityConfig.class, WebConfig.class);
    }
}

这就是我的项目现在的样子：

Main.java 只是用于maven-shade-plugin，没关系，它只包含空的main 方法：

Main.java：

public class Main {
    public static void main(String[] args) {

    }
}

我的其他课程（更新）。为简单起见，我删除了数据库配置类。如果您不需要数据库，您可以从这个答案中复制粘贴类，它应该可以正常工作：

MyAppInitializer.java：

public class MyAppInitializer extends
                AbstractAnnotationConfigDispatcherServletInitializer {
    @Override
    public void onStartup(final ServletContext sc) throws ServletException {
        System.out.println("onStartup!");

        AnnotationConfigWebApplicationContext root =
                new AnnotationConfigWebApplicationContext();

        root.register(WebConfig.class);
        root.setServletContext(sc);

        root.scan("test");
        //sc.addListener(new ContextLoaderListener(root));

        ServletRegistration.Dynamic appServlet =
                sc.addServlet("dispatcher", new DispatcherServlet(new GenericWebApplicationContext()));
        appServlet.setLoadOnStartup(1);
        appServlet.addMapping("/");
    }

        @Override
    protected Class<?>[] getRootConfigClasses() {
        return new Class[] {SecurityConfig.class};
    }

    @Override
    protected Class<?>[] getServletConfigClasses() {
        return new Class[]{WebConfig.class};
    }

    @Override
    protected String[] getServletMappings() {
        return new String[]{"/"};
    }
}

WebConfig.java：

@Configuration
@ComponentScan("test")
@EnableWebMvc
@EnableTransactionManagement
@EnableGlobalMethodSecurity(prePostEnabled = true)
@EnableJpaRepositories(basePackages = "test",
        entityManagerFactoryRef = "entityManagerFactory", transactionManagerRef = "transactionManager")
 public class WebConfig extends WebMvcConfigurerAdapter {
    @Override
    public void addCorsMappings(CorsRegistry registry) {
        registry.addMapping("/**");
    }


    @Override
    public void configureDefaultServletHandling(
                DefaultServletHandlerConfigurer configurer) {
        configurer.enable();
    }
}

HomeController.java：

@RestController
public class HomeController {
    @GetMapping("/")
    public String getHome()  {
        return "home";
    }
}

TestController.java：

@RestController
public class TestController {
    @RequestMapping("/test")
    public String test()  {
        return "test";
    }
}

我从配置类中删除了视图解析器，因为我打算只使用休息控制器作为 API 提供者。感谢您参加我的 TED 演讲。

PS 以下是pom.xml 的外观（这似乎很重要，因为使用不同的 poms，Intellij 不会自动生成战争爆炸的工件）：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>bigpuzzle</artifactId>
    <version>1.0-SNAPSHOT</version>


    <packaging>war</packaging>

    <pluginRepositories>
        <pluginRepository>
            <id>pcentral</id>
            <name>pcentral</name>
            <url>https://repo1.maven.org/maven2</url>
        </pluginRepository>

        <pluginRepository>
            <id>central</id>
            <name>Central Repository</name>
            <url>https://repo.maven.apache.org/maven2</url>
            <layout>default</layout>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </pluginRepository>
    </pluginRepositories>

    <repositories>


        <repository>
            <id>jcenter</id>
            <name>jcenter-bintray</name>
            <url>https://jcenter.bintray.com</url>
        </repository>

    </repositories>


    <dependencies>
        <!-- Jackson to convert Java object to Json -->
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.9.4</version>
        </dependency>

        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-annotations</artifactId>
            <version>2.9.4</version>
        </dependency>




        <dependency>
            <groupId>net.sourceforge</groupId>
            <artifactId>jwbf</artifactId>
            <version>3.1.1</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/com.google.code.gson/gson -->
        <dependency>
            <groupId>com.google.code.gson</groupId>
            <artifactId>gson</artifactId>
            <version>2.8.6</version>
        </dependency>


        <!-- https://mvnrepository.com/artifact/org.springframework.security/spring-security-core -->
        <dependency>
            <groupId>org.springframework.security</groupId>
            <artifactId>spring-security-core</artifactId>
            <version>5.3.1.RELEASE</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.2.5.RELEASE</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework/spring-web -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>5.2.5.RELEASE</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.security/spring-security-core -->
        <dependency>
            <groupId>org.springframework.security</groupId>
            <artifactId>spring-security-core</artifactId>
            <version>5.3.1.RELEASE</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.security/spring-security-config -->
        <dependency>
            <groupId>org.springframework.security</groupId>
            <artifactId>spring-security-config</artifactId>
            <version>5.3.1.RELEASE</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.security/spring-security-web -->
        <dependency>
            <groupId>org.springframework.security</groupId>
            <artifactId>spring-security-web</artifactId>
            <version>5.3.1.RELEASE</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.data/spring-data-jpa -->
        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-jpa</artifactId>
            <version>2.2.6.RELEASE</version>
        </dependency>


        <!-- https://mvnrepository.com/artifact/org.springframework/spring-core -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>5.2.5.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.thymeleaf</groupId>
            <artifactId>thymeleaf</artifactId>
            <version>3.0.7.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.thymeleaf</groupId>
            <artifactId>thymeleaf-spring4</artifactId>
            <version>3.0.7.RELEASE</version>
        </dependency>


        <dependency>
            <groupId>org.apache.opennlp</groupId>
            <artifactId>opennlp-tools</artifactId>
            <version>1.9.1</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/net.dv8tion/JDA -->
        <dependency>
            <groupId>net.dv8tion</groupId>
            <artifactId>JDA</artifactId>
            <version>4.0.0_46</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.hibernate/hibernate-core -->
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>5.4.4.Final</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/com.h2database/h2 -->
        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
            <version>1.4.197</version>
            <scope>test</scope>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework/spring-orm -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-orm</artifactId>
            <version>5.2.5.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.postgresql</groupId>
            <artifactId>postgresql</artifactId>
            <version>9.4-1203-jdbc4</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>4.0.1</version>
            <scope>provided</scope>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.security.oauth/spring-security-oauth2 -->
        <dependency>
            <groupId>org.springframework.security.oauth</groupId>
            <artifactId>spring-security-oauth2</artifactId>
            <version>2.4.1.RELEASE</version>
        </dependency>

        <!--is needed for jwt-->
        <!-- https://mvnrepository.com/artifact/javax.xml/jaxb-api -->
        <dependency>
            <groupId>javax.xml</groupId>
            <artifactId>jaxb-api</artifactId>
            <version>2.1</version>
        </dependency>


        <!-- https://mvnrepository.com/artifact/com.sun.xml.bind/jaxb-impl -->
        <dependency>
            <groupId>com.sun.xml.bind</groupId>
            <artifactId>jaxb-impl</artifactId>
            <version>3.0.0-M4</version>
        </dependency>


        <!-- https://mvnrepository.com/artifact/com.sun.xml.bind/jaxb-core -->
        <dependency>
            <groupId>com.sun.xml.bind</groupId>
            <artifactId>jaxb-core</artifactId>
            <version>3.0.0-M4</version>
        </dependency>


        <!-- https://mvnrepository.com/artifact/org.springframework.security/spring-security-jwt -->
        <dependency>
            <groupId>org.springframework.security</groupId>
            <artifactId>spring-security-jwt</artifactId>
            <version>1.1.0.RELEASE</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/io.jsonwebtoken/jjwt -->
        <dependency>
            <groupId>io.jsonwebtoken</groupId>
            <artifactId>jjwt</artifactId>
            <version>0.9.1</version>
        </dependency>


        <!-- https://mvnrepository.com/artifact/com.jakewharton.fliptables/fliptables -->
        <dependency>
            <groupId>com.jakewharton.fliptables</groupId>
            <artifactId>fliptables</artifactId>
            <version>1.0.2</version>
        </dependency>




        <dependency>
            <groupId>com.squareup.okhttp3</groupId>
            <artifactId>okhttp</artifactId>
            <version>3.4.2</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.json/json -->
        <dependency>
            <groupId>org.json</groupId>
            <artifactId>json</artifactId>
            <version>20190722</version>
        </dependency>



        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>

        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.9.8</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/commons-codec/commons-codec -->
        <dependency>
            <groupId>commons-codec</groupId>
            <artifactId>commons-codec</artifactId>
            <version>1.14</version>
        </dependency>


        <!-- https://mvnrepository.com/artifact/javax.xml.bind/jaxb-api -->
        <dependency>
            <groupId>javax.xml.bind</groupId>
            <artifactId>jaxb-api</artifactId>
            <version>2.3.1</version>
        </dependency>

    </dependencies>

    <build>
        <finalName>bigpuzzle</finalName>


        <plugins>


            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-shade-plugin</artifactId>
                <version>3.0.0</version>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>shade</goal>
                        </goals>
                        <configuration>
                            <shadedArtifactAttached>true</shadedArtifactAttached>

                            <transformers>
                                <transformer
                                        implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                                    <mainClass>bigpuzzle.Main</mainClass>
                                    <manifestEntries>
                                        <Main-Class>bigpuzzle.Main</Main-Class>
                                    </manifestEntries>
                                </transformer>
                            </transformers>


                            <filters>
                                <filter>
                                    <artifact>*:*</artifact>
                                    <excludes>
                                        <exclude>META-INF/*.SF</exclude>
                                        <exclude>META-INF/*.DSA</exclude>
                                        <exclude>META-INF/*.RSA</exclude>
                                    </excludes>
                                </filter>
                            </filters>
                        </configuration>
                    </execution>
                </executions>
            </plugin>


            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-dependency-plugin</artifactId>
                <version>2.3</version>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals><goal>copy</goal></goals>
                        <configuration>

                            <artifactItems>

                                <artifactItem>
                                    <groupId>com.github.jsimone</groupId>
                                    <artifactId>webapp-runner</artifactId>
                                    <version>8.0.30.2</version>
                                    <destFileName>webapp-runner.jar</destFileName>
                                </artifactItem>

                            </artifactItems>

                        </configuration>
                    </execution>
                </executions>
            </plugin>


            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-war-plugin</artifactId>
                <version>3.2.2</version>

            </plugin>

        </plugins>
    </build>

</project>

配置 Tomcat Local 后，您可以更改此 pom.xml。

如果您还需要数据库支持，请将此文件添加到配置包中：

package bigpuzzle.config;

import org.hibernate.SessionFactory;
import org.hibernate.jpa.HibernatePersistenceProvider;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.jdbc.datasource.DriverManagerDataSource;
import org.springframework.orm.hibernate5.LocalSessionFactoryBean;
import org.springframework.orm.jpa.JpaTransactionManager;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;

import javax.sql.DataSource;
import java.io.IOException;
import java.util.Properties;


@Configuration
 @EnableTransactionManagement
@EnableJpaRepositories(basePackages = "bigpuzzle", entityManagerFactoryRef = "entityManagerFactory")
 public class DbConfig {
    @Primary
    @Bean(name = "entityManagerFactory")
    public LocalContainerEntityManagerFactoryBean entityManagerFactory() {
        LocalContainerEntityManagerFactoryBean entityManagerFactoryBean = new LocalContainerEntityManagerFactoryBean();
        entityManagerFactoryBean.setDataSource(getDatasource());
        entityManagerFactoryBean.setPersistenceProviderClass(HibernatePersistenceProvider.class);

        entityManagerFactoryBean.setJpaProperties(getHibernateProperties());

        entityManagerFactoryBean.setPackagesToScan("bigpuzzle");

        return entityManagerFactoryBean;
    }


    @Bean
    public DataSource getDatasource() {
        DriverManagerDataSource dataSource = new DriverManagerDataSource();
        dataSource.setDriverClassName("org.postgresql.Driver");
        dataSource.setUrl("jdbc:postgresql://127.0.0.1:5432/bigpuzzle");
        dataSource.setUsername("postgres");
        dataSource.setPassword("123456");
        return dataSource;
    }

    @Primary
    @Bean
    public SessionFactory getSessionFactory() throws IOException {
        LocalSessionFactoryBean sessionFactoryBean = new LocalSessionFactoryBean();
        sessionFactoryBean.setPackagesToScan("bigpuzzle");
        //getHibernateProperties method is a private method

        sessionFactoryBean.setHibernateProperties(getHibernateProperties());
        sessionFactoryBean.setDataSource(getDatasource());
        sessionFactoryBean.afterPropertiesSet();

        return sessionFactoryBean.getObject();
    }

    @Bean(name = "transactionManager")
     public PlatformTransactionManager transactionManager() throws IOException {
        /*HibernateTransactionManager transactionManager = new HibernateTransactionManager();
        transactionManager.setSessionFactory(getSessionFactory());*/

        JpaTransactionManager transactionManager = new JpaTransactionManager();
        transactionManager.setEntityManagerFactory(entityManagerFactory().getObject());
        return transactionManager;
    }


    @Bean
    private static Properties getHibernateProperties() {
        Properties hibernateProperties = new Properties();  //PostgreSQLDialect
        //hibernateProperties.put("hibernate.dialect", "org.hibernate.dialect.HSQLDialect");
        hibernateProperties.put("hibernate.dialect", "org.hibernate.dialect.PostgreSQLDialect");
        hibernateProperties.put("hibernate.connection.driver_class", "org.postgresql.Driver");
        hibernateProperties.put("hibernate.show_sql", true);
        hibernateProperties.put("hibernate.allow_update_outside_transaction",  false);
    //    hibernateProperties.put("spring.jpa.hibernate.ddl-auto", "create");

        hibernateProperties.put( "hibernate.hbm2ddl.auto", "create-drop");  //create-drop or update
         /*hibernateProperties.setProperty(
                "hibernate.dialect", "org.hibernate.dialect.H2Dialect");
*/
        System.out.println();

        hibernateProperties.put("spring.jpa.properties.hibernate.show_sql", "false");
        hibernateProperties.put("spring.jpa.properties.hibernate.use_sql_comments", "true");
        hibernateProperties.put("spring.jpa.properties.hibernate.format_sql", "true");
        hibernateProperties.put("spring.jpa.properties.hibernate.type", "trace");
        hibernateProperties.put("spring.jpa.show-sql", "true");
        hibernateProperties.put("logging.level.org.hibernate", "TRACE");


        // other properties
        return hibernateProperties;
    }
}

PS 如果您也使用 Idea Intellij，请关注this video 将应用程序部署到 Tomcat 上。

【讨论】：