Spring Boot：控制器什么都不做

【问题标题】：Spring Boot: Controller does nothingSpring Boot：控制器什么都不做
【发布时间】：2016-07-02 00:23:45
【问题描述】：

我正在尝试制作一个 Boot/MVC 项目。当我启动 Tomcat 时，页面显示得非常好，但是当我尝试使用我的 ModelAndView 对象添加任何内容时，页面上什么也没有出现。控制台上甚至不会显示System.out.println("anything")。

这里是 Application.java

package com.markham.main;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

}

IndexController.java：

package com.markham.main;

import java.util.ArrayList;
import java.util.List;

import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.persistence.PersistenceContextType;
import javax.persistence.TypedQuery;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.servlet.ModelAndView;

@RestController
public class IndexController {

    @PersistenceContext(type = PersistenceContextType.TRANSACTION)
    private EntityManager em;

    @RequestMapping(value = "/", method = RequestMethod.GET)
    public ModelAndView index() {
        ModelAndView view = new ModelAndView();
        List<User> users = new ArrayList<User>();

        TypedQuery<User> query1 = em.createNamedQuery("User.getAllUsers", User.class);
        users = query1.getResultList();
        System.out.println("HERE'S THE THING---" + users); //This doesn't even print
        view.addObject("users", users);
        return view;
    }

}

我怎样才能让我的控制器与我的 index.jsp - 默认页面一起工作？

如果您需要更多代码，请询问，我会提供。

编辑：

pom.xml

    <?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>guru.springframework</groupId>
    <artifactId>spring-boot-web</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>Spring Boot Web Application</name>
    <description>Spring Boot Web Application</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.3.3.RELEASE</version>
    </parent>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>

        <dependency>
            <groupId>org.apache.tomcat</groupId>
            <artifactId>tomcat-jsp-api</artifactId>
            <scope>provided</scope>
        </dependency>

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

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-security</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</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-actuator</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-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>

application.properties：

spring.datasource.url = jdbc:mysql://example

spring.datasource.username = example
spring.datasource.password = example

# Keep the connection alive if idle for a long time (needed in production)
spring.datasource.testWhileIdle = true
spring.datasource.validationQuery = SELECT 1

# Show or not log for each sql query
spring.jpa.show-sql = true

spring.jpa.hibernate.ddl-auto = update

spring.jpa.hibernate.naming-strategy = org.hibernate.cfg.ImprovedNamingStrategy

# Allows Hibernate to generate SQL optimized for a particular DBMS
spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQL5Dialect

编辑#2：这是我正在访问的网址http://localhost:8080/BootApp/

这里是日志：

  Mar 16, 2016 6:13:57 PM org.apache.tomcat.util.digester.SetPropertiesRule begin
WARNING: [SetPropertiesRule]{Server/Service/Engine/Host/Context} Setting property 'source' to 'org.eclipse.jst.jee.server:BootApp' did not find a matching property.
Mar 16, 2016 6:13:57 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Server version:        Apache Tomcat/8.0.26
Mar 16, 2016 6:13:57 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Server built:          Aug 18 2015 11:38:37 UTC
Mar 16, 2016 6:13:57 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Server number:         8.0.26.0
Mar 16, 2016 6:13:57 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: OS Name:               Mac OS X
Mar 16, 2016 6:13:57 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: OS Version:            10.11.3
Mar 16, 2016 6:13:57 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Architecture:          x86_64
Mar 16, 2016 6:13:57 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Java Home:             /Library/Java/JavaVirtualMachines/jdk1.8.0_60.jdk/Contents/Home/jre
Mar 16, 2016 6:13:57 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: JVM Version:           1.8.0_60-b27
Mar 16, 2016 6:13:57 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: JVM Vendor:            Oracle Corporation
Mar 16, 2016 6:13:57 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: CATALINA_BASE:         /Users/ben/Documents/workspace/rabbitmq/.metadata/.plugins/org.eclipse.wst.server.core/tmp0
Mar 16, 2016 6:13:57 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: CATALINA_HOME:         /Users/ben/Downloads/apache-tomcat-8.0.26
Mar 16, 2016 6:13:57 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Command line argument: -Dcatalina.base=/Users/ben/Documents/workspace/rabbitmq/.metadata/.plugins/org.eclipse.wst.server.core/tmp0
Mar 16, 2016 6:13:57 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Command line argument: -Dcatalina.home=/Users/ben/Downloads/apache-tomcat-8.0.26
Mar 16, 2016 6:13:57 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Command line argument: -Dwtp.deploy=/Users/ben/Documents/workspace/rabbitmq/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps
Mar 16, 2016 6:13:57 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Command line argument: -Djava.endorsed.dirs=/Users/ben/Downloads/apache-tomcat-8.0.26/endorsed
Mar 16, 2016 6:13:57 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Command line argument: -Dfile.encoding=UTF-8
Mar 16, 2016 6:13:57 PM org.apache.catalina.core.AprLifecycleListener lifecycleEvent
INFO: The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: /Users/ben/Library/Java/Extensions:/Library/Java/Extensions:/Network/Library/Java/Extensions:/System/Library/Java/Extensions:/usr/lib/java:.
Mar 16, 2016 6:13:57 PM org.apache.coyote.AbstractProtocol init
INFO: Initializing ProtocolHandler ["http-nio-8080"]
Mar 16, 2016 6:13:57 PM org.apache.tomcat.util.net.NioSelectorPool getSharedSelector
INFO: Using a shared selector for servlet write/read
Mar 16, 2016 6:13:57 PM org.apache.coyote.AbstractProtocol init
INFO: Initializing ProtocolHandler ["ajp-nio-8009"]
Mar 16, 2016 6:13:57 PM org.apache.tomcat.util.net.NioSelectorPool getSharedSelector
INFO: Using a shared selector for servlet write/read
Mar 16, 2016 6:13:57 PM org.apache.catalina.startup.Catalina load
INFO: Initialization processed in 891 ms
Mar 16, 2016 6:13:57 PM org.apache.catalina.core.StandardService startInternal
INFO: Starting service Catalina
Mar 16, 2016 6:13:57 PM org.apache.catalina.core.StandardEngine startInternal
INFO: Starting Servlet Engine: Apache Tomcat/8.0.26
Mar 16, 2016 6:13:57 PM org.apache.tomcat.dbcp.dbcp2.BasicDataSourceFactory getObjectInstance
WARNING: Name = samsung Property maxActive is not used in DBCP2, use maxTotal instead. maxTotal default value is 8. You have set value of "-1" for "maxActive" property, which is being ignored.
Mar 16, 2016 6:13:57 PM org.apache.tomcat.dbcp.dbcp2.BasicDataSourceFactory getObjectInstance
WARNING: Name = samsung Property maxWait is not used in DBCP2 , use maxWaitMillis instead. maxWaitMillis default value is -1. You have set value of "-1" for "maxWait" property, which is being ignored.
Mar 16, 2016 6:13:57 PM org.apache.tomcat.dbcp.dbcp2.BasicDataSourceFactory getObjectInstance
INFO: Name = samsung Ignoring unknown property: value of "true" for "spring.datasource.testOnBorrow" property
Mar 16, 2016 6:13:57 PM org.apache.tomcat.dbcp.dbcp2.BasicDataSourceFactory getObjectInstance
INFO: Name = samsung Ignoring unknown property: value of "SELECT 1" for "spring.datasource.validationQuery" property
Mar 16, 2016 6:13:57 PM org.apache.tomcat.dbcp.dbcp2.BasicDataSourceFactory getObjectInstance
INFO: Name = samsung Ignoring unknown property: value of "true" for "autoReconnect" property
Mar 16, 2016 6:13:57 PM org.apache.jasper.servlet.TldScanner scanJars
INFO: At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time.
Mar 16, 2016 6:14:00 PM org.apache.tomcat.dbcp.dbcp2.BasicDataSourceFactory getObjectInstance
WARNING: Name = samsung Property maxActive is not used in DBCP2, use maxTotal instead. maxTotal default value is 8. You have set value of "-1" for "maxActive" property, which is being ignored.
Mar 16, 2016 6:14:00 PM org.apache.tomcat.dbcp.dbcp2.BasicDataSourceFactory getObjectInstance
WARNING: Name = samsung Property maxWait is not used in DBCP2 , use maxWaitMillis instead. maxWaitMillis default value is -1. You have set value of "-1" for "maxWait" property, which is being ignored.
Mar 16, 2016 6:14:00 PM org.apache.tomcat.dbcp.dbcp2.BasicDataSourceFactory getObjectInstance
INFO: Name = samsung Ignoring unknown property: value of "true" for "spring.datasource.testOnBorrow" property
Mar 16, 2016 6:14:00 PM org.apache.tomcat.dbcp.dbcp2.BasicDataSourceFactory getObjectInstance
INFO: Name = samsung Ignoring unknown property: value of "SELECT 1" for "spring.datasource.validationQuery" property
Mar 16, 2016 6:14:00 PM org.apache.tomcat.dbcp.dbcp2.BasicDataSourceFactory getObjectInstance
INFO: Name = samsung Ignoring unknown property: value of "true" for "autoReconnect" property
Mar 16, 2016 6:14:01 PM org.apache.jasper.servlet.TldScanner scanJars
INFO: At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time.
Mar 16, 2016 6:14:01 PM org.apache.catalina.core.ApplicationContext log
INFO: Spring WebApplicationInitializers detected on classpath: [org.springframework.boot.autoconfigure.jersey.JerseyAutoConfiguration$JerseyWebApplicationInitializer@60111f5c]
Mar 16, 2016 6:14:01 PM org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["http-nio-8080"]
Mar 16, 2016 6:14:01 PM org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["ajp-nio-8009"]
Mar 16, 2016 6:14:01 PM org.apache.catalina.startup.Catalina start
INFO: Server startup in 3713 ms

EDIT #3（感谢大家的帮助）：做mvn spring-boot:run之后，出现这个错误：

[ERROR] No plugin found for prefix 'spring-boot' in the current project and in the plugin groups [org.apache.maven.plugins, org.codehaus.mojo] available from the repositories [local (/Users/ben/.m2/repository), central (https://repo.maven.apache.org/maven2)] -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/NoPluginFoundForPrefixException

【问题讨论】：

  • 你是如何执行控制器的？你正在形成什么网址来访问它？
  • @BhushanBhangale 默认localhost:8080/BootApp/
  • @bmarkham 您是否将其作为弹簧靴（嵌入式 tomcat）运行？也发布你的 pom.xml 和 application.properties
  • @BalajiKrishnan 编辑了我的帖子
  • 请显示您尝试访问的网址和日志。

标签： java spring spring-mvc spring-boot


【解决方案1】：

您的ModelAndView 没有说明它要访问哪个文件

@RequestMapping(value = "/", method = RequestMethod.GET)
public ModelAndView index() {
    ModelAndView view = new ModelAndView("index"); // This line
    List<User> users = new ArrayList<User>();

    TypedQuery<User> query1 = em.createNamedQuery("User.getAllUsers", User.class);
    users = query1.getResultList();
    System.out.println("HERE'S THE THING---" + users); //This doesn't even print
    view.addObject("users", users);
    return view;
}

您的 application.properties 没有 MVC 视图解析器配置。

spring.mvc.view.prefix=<Path To Jsp>
spring.mvc.view.suffix=.jsp

首先进行这些更改。

【讨论】：

  • 不幸的是，这并没有解决问题:(。我很感激你的回答。
【解决方案2】：

问题：您试图在外部服务器中而不是在嵌入式 tomcat 中运行 SpringBoot 应用程序。

在嵌入式容器中作为 Spring Boot 运行： 要作为 Spring Boot 运行，请在包含 pom.xml 的目录中使用 mvn spring-boot:run 命令。我建议您阅读https://spring.io/guides/gs/serving-web-content/ 入门指南。

部署到外部服务器 如果要部署在外部服务器中，请将打包从 jar 更改为 war 并部署 war 文件。部署到WAS参考https://docs.spring.io/spring-boot/docs/current/reference/html/howto-traditional-deployment.html

【讨论】：

  • 我也从 jar 文件更改为 war 文件，它可以工作......有点.. 我收到一条 404 error 消息，但它现在实际上来自 Spring Boot。这是错误。 There was an unexpected error (type=Not Found, status=404). /src/main/resources/templates/index.jsp这是我的jsp的正确路径
【解决方案3】：

如果您想将您的请求重定向到特定页面。您需要在创建 ModelAndView 对象时将此页面名称作为参数传递。

示例：如果要将请求重定向到 welcome.jsp 页面，则可以创建 ModelAndView，如下所示：

ModelAndView view = new ModelAndView("welcome.jsp");
//code as per your requirement 
return view;

您需要在 pom.xml 文件中遵循以下依赖关系。

<dependency>
        <groupId>org.apache.tomcat.embed</groupId>
        <artifactId>tomcat-embed-jasper</artifactId>
        <scope>provided</scope>
</dependency>

注意：我假设您的 welcome.jsp 页面位于以下包中：

src/main/webapp

您可以找到简单的演示应用程序here。

【讨论】：

  • @bmarkham 我工作正常。你能告诉我你遇到了什么错误吗？
【解决方案4】：

在 IndexController.class 中将 @RestController 更改为 @Controller

并添加wiew页面mame ModelAndView对象

ModelAndView view = new ModelAndView("index.jsp");

和 index.jsp spring boot default location src/main/webapp

【讨论】：

    【解决方案5】：

    好的，多亏了几乎所有提供帮助的人，我终于让它工作了。

    @BalajiKrishnan 在我没有将它作为 Spring Boot 应用程序运行时是正确的。我将它从 jar 更改为 war 并使用 mvn spring-boot:run，现在它作为 Spring Boot 应用程序运行。 BalajiKrishnan's Post

    但是，我仍然收到 404 errors 并使用 @shazin 的答案来更改我的 application.properties 他发布的方式。 here

    仍然收到404 errors，所以我将我的网址从localhost:8080/BootApp/ 更改为localhost:8080，就像在cmets 中建议的@EpicPandaForce 一样。

    我改变了我使用ModelAndView view = new ModelAndView("index");，就像@shazin 建议的那样。

    感谢所有贡献的人！

    【讨论】：

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