如何解决无论我做什么，Java控制器始终会返回404
我遵循的是Spring Boot文档中的一个示例，由于某种原因，java控制器总是返回404
这是我尝试过的
package com.example.accessingdatamysql;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;
@Controller // This means that this class is a Controller
@RequestMapping(path="/demo") // This means URL's start with /demo (after Application path)
public class MainController {
@Autowired // This means to get the bean called userRepository
// Which is auto-generated by Spring,we will use it to handle the data
private UserRepository userRepository;
@PostMapping(path="/add") // Map ONLY POST Requests
public @ResponseBody String addNewUser (@RequestParam String name,@RequestParam String email) {
// @ResponseBody means the returned String is the response,not a view name
// @RequestParam means it is a parameter from the GET or POST request
User n = new User();
n.setName(name);
n.setEmail(email);
userRepository.save(n);
return "Saved";
}
@GetMapping(path="/all")
public @ResponseBody Iterable<User> getAllUsers() {
// This returns a JSON or XML with the users
return userRepository.findAll();
}
}
这是spring boot https://spring.io/guides/gs/accessing-data-mysql/
给出的示例然后我也尝试过
@RestController
@RequestMapping("/demo")
public class GreetingClass {
@GetMapping("/greeting")
public String getGreeting() {
return "hello";
}
}
.pom文件：
<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.3.2.RELEASE</version>
<relativePath /> <!-- lookup parent from repository -->
</parent>
<groupId>com.braintobytes</groupId>
<artifactId>Finance_microservice</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>Finance_microservice</name>
<description>Finance service</description>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-rest</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-mail</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-webflux</artifactId>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<!-- https://mvnrepository.com/artifact/javax.persistence/javax.persistence-api -->
<dependency>
<groupId>javax.persistence</groupId>
<artifactId>javax.persistence-api</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>io.projectreactor</groupId>
<artifactId>reactor-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
我知道这很奇怪，我按照页面上的指示进行了所有设置，但显然没有任何效果，并且我还检查了类似的其他问题，但没有一个回答我的问题。
tomcat服务器似乎被命中了，因为它表示我拨打电话时
o.s.web.servlet.DispatcherServlet : Completed initialization in 9 ms
但是随后我得到这个调用curl'http：// localhost：8080 / demo / greeting'和'http：// localhost：8080 / demo / all'
curl：远程服务器返回错误：（404）找不到。
日志（在第一行中删除了文件路径）：
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__,| / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v2.3.2.RELEASE)
2020-08-31 08:19:16.508 INFO 20708 --- [ main] c.b.f.FinanceMicroserviceApplication : Starting FinanceMicroserviceApplication on DESKTOP-A65224I with PID 20708 ()
2020-08-31 08:19:16.510 INFO 20708 --- [ main] c.b.f.FinanceMicroserviceApplication : No active profile set,falling back to default profiles: default
2020-08-31 08:19:17.096 INFO 20708 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8080 (http)
2020-08-31 08:19:17.101 INFO 20708 --- [ main] o.apache.catalina.core.StandardService : Starting service [Tomcat]
2020-08-31 08:19:17.101 INFO 20708 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet engine: [Apache Tomcat/9.0.37]
2020-08-31 08:19:17.150 INFO 20708 --- [ main] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2020-08-31 08:19:17.150 INFO 20708 --- [ main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 618 ms
2020-08-31 08:19:17.465 INFO 20708 --- [ main] o.s.s.concurrent.ThreadPoolTaskExecutor : Initializing ExecutorService 'applicationTaskExecutor'
2020-08-31 08:19:17.675 INFO 20708 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path ''
2020-08-31 08:19:17.681 INFO 20708 --- [ main] c.b.f.FinanceMicroserviceApplication : Started FinanceMicroserviceApplication in 1.328 seconds (JVM running for 1.835)
2020-08-31 08:20:21.893 INFO 20708 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring DispatcherServlet 'dispatcherServlet'
2020-08-31 08:20:21.893 INFO 20708 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet : Initializing Servlet 'dispatcherServlet'
2020-08-31 08:20:21.905 INFO 20708 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet : Completed initialization in 12 ms
响应：
{
"timestamp": "2020-08-31T13:20:21.930+00:00","status": 404,"error": "Not Found","message": "","path": "/demo/greeting"
}
如果我这样做，这会起作用：
https://github.com/BraintoByte/Test_App_Stack/tree/master/demo
不同的示例：
我附上了一个不同的示例，其中的层次结构完全相同，但是省略了业务逻辑：
控制器中的代码
package com.braintobytes.controllers;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;
import com.braintobytes.data.Currency;
import com.braintobytes.data.repository.CurrencyRepository;
@RestController
@RequestMapping("/demo")
public class CurrencyController {
@Autowired
private CurrencyRepository currencyRepository;
@GetMapping("/currency")
public String getCurrency() {
return "currency";
}
}
项目层次结构：
与pom相同，并且在application.properties中：
spring.jpa.hibernate.ddl-auto=update
spring.datasource.url=jdbc:mydatabase
spring.datasource.username=myusername
spring.datasource.password=mypassword
解决方法
您的控制器在软件包中-com.example.accessingdatamysql
Spring启动启动日志显示您的主要应用程序类c.b.f.FinanceMicroserviceApplication在另一个不相关的程序包层次结构中。
Spring boot建议将主应用程序类放在其他类之上的根包中，以便组件扫描可以立即使用。
如果将com.example软件包保留为根软件包，并将主应用程序类FinanceMicroserviceApplication移至该软件包，那么一切都会按预期进行。
如果您不遵循Spring推荐的软件包层次结构建议，则需要显式指定要使用@SpringBootApplication批注进行扫描的软件包。
,好的，因此以上建议均无用，尽管我们走在正确的道路上。
按如下方式更改结构：
application.properties中也存在路径问题，因此我进行了如下更改：
spring.datasource.url = jdbc：mysql：// $ {MYSQL_HOST：localhost}
收件人：
jdbc：mysql：// localhost
最后：
package com.braintobytes.finance.data.repository;
import org.springframework.data.repository.CrudRepository;
import com.braintobytes.finance.data.Currency;
public interface CurrencyRepository extends CrudRepository<Currency,Integer> {
}
哇！
版权声明：本文内容由互联网用户自发贡献，该文观点与技术仅代表作者本人。本站仅提供信息存储空间服务，不拥有所有权，不承担相关法律责任。如发现本站有涉嫌侵权/违法违规的内容， 请发送邮件至 dio@foxmail.com 举报，一经查实，本站将立刻删除。