Spring 4 RestController服务未从Web应用程序中的jsp调用答案

【问题标题】：Spring 4 RestController services not getting called from jsp in web applicationSpring 4 RestController服务未从Web应用程序中的jsp调用
【发布时间】：2017-03-23 17:41:54
【问题描述】：

我使用 Spring4、maven、jquery、tomcat 开发了一个 web 应用程序。我正在使用 java config 类而不是 web.xml 和 spring applicationContext.xml。在控制器类中使用 @RestController 而不是 @Controller 来解耦应用程序。不想使用@Controller，因为在这种情况下我必须返回我不想返回的视图名称和模型。

问题：- 我的 Web 应用程序启动良好，并且从 dashboard.jsp 调用了 dashboard.js。但是当我尝试调用 DashboardController.java 服务 '/dashboard/getDashboardDetails' 时，它会给出 404 page not found 错误。 eclipse或tomcat控制台没有错误。

过滤器类：-

package com.me.configuration;

import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletResponse;

public class CORSFilter implements Filter {

public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
    System.out.println("Filtering on...........................................................");
    HttpServletResponse response = (HttpServletResponse) res;
    response.setHeader("Access-Control-Allow-Origin", "*");
    response.setHeader("Access-Control-Allow-Methods", "POST, GET, PUT, OPTIONS, DELETE");
    response.setHeader("Access-Control-Max-Age", "3600");
    response.setHeader("Access-Control-Allow-Headers", "x-requested-with");
    chain.doFilter(req, res);
}

public void init(FilterConfig filterConfig) {}

public void destroy() {}

}

配置类 包 com.me.configuration;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.view.InternalResourceViewResolver;
import org.springframework.web.servlet.view.JstlView;

@Configuration
@EnableWebMvc
@ComponentScan(basePackages = "com.me")
public class ManageBudgetConfiguration {

@Bean
public ViewResolver viewResolver() {
    InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
    viewResolver.setViewClass(JstlView.class);
    viewResolver.setPrefix("/pages/");
    viewResolver.setSuffix(".jsp");

    return viewResolver;
}

}

初始化器类

package com.me.configuration;

import javax.servlet.Filter;

import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;

public class ManageBudgetInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {


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

@Override
protected Class<?>[] getServletConfigClasses() {
    return null;
}

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

@Override
protected Filter[] getServletFilters() {
    Filter [] singleton = { new CORSFilter()};
    return singleton;
}

}

控制器类

package com.me.controller;

import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestBody;
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.util.UriComponentsBuilder;

import com.me.model.DashboardBean;
import com.me.model.User;
import com.me.service.DashboardServiceInf;
import com.me.service.UserService;


@RestController
@RequestMapping("/dashboard")
public class DashboardController {


@Autowired
UserService userService;  //Service which will do all data retrieval/manipulation work

@Autowired
DashboardServiceInf dashboardService; 


/**
 * This service returns Dashboard data details
 * @return String
 */
@RequestMapping(value = "/getDashboardDetails", method = RequestMethod.GET)
public ResponseEntity<List<DashboardBean>> getDashBoardDetails() {
    System.out.println("Dashboardcontroller : getDashBoardDetails");
    String userId ="rahil";
    List<DashboardBean> dashboardBeanList = dashboardService.getDashBoardDetails(userId);
    if(dashboardBeanList.isEmpty()){
        return new ResponseEntity<List<DashboardBean>>(HttpStatus.NO_CONTENT);//You many decide to return HttpStatus.NOT_FOUND
    }

    return new ResponseEntity<List<DashboardBean>>(dashboardBeanList, HttpStatus.OK);
}

}

dashboard.jsp

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
<meta name="description" content="">
<meta name="author" content="">

<title>Manage Expense</title>

<!-- jQuery -->
<script type ="text/javascript" src="./resources/javascript/vendor/jquery/jquery.min.js"></script>

<!-- Dashboard Charts -->
<script src="resources/javascript/js/dashboardCharts.js"></script>

</head>
<body>

<script type ="text/javascript">

$(document).ready(function() {
    console.log("\tdashboard.jsp");

    $.ajax({ 
        url : "resources/javascript/system/dashboard.js",
        dataType : "script",
        cache : true        
    }).done(function(){ 
        console.log("inside done....");
        me.dashboard.onload();
    });

});


</script>

</body>
</html>

dashboard.js

me = new Object();

if (typeof me.dashboard == 'undefined') {
me.dashboard = function() {
    return {

        msgArray:[], // variable for  checking same message

        /**
         * @author rahikhan
         * @description Function to be called once the dashboard loaded.
         */
        onload : function(){
            console.log("dashboard.js : onload..called without error");
            me.dashboard.getDashboardDetails();
        },

        getDashboardDetails : function(){
            console.log("dashboard.js : getDashboardDetails...");
            var promise = $.ajax({
                async: true,
                url: "dashboard/getDashboardDetails.htm",
                type: "GET",
                datatype: "json",
                accept: "application/json",
            }).done(function(result) {
                result = JSON.parse(result);
                console.log("\tresult : " + result);
            }).fail(function(jqXHR, textStatus) {
                console.log("\tgetDashboardDetails : Application Exception Occured " );
            });
            return promise;
        },

    }
}();

}

pom.xml

<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/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.me</groupId>
    <artifactId>manageBudget</artifactId>
    <packaging>war</packaging>
    <version>0.0.1-SNAPSHOT</version>
    <name>manageBudget</name>
    <url>http://maven.apache.org</url>

    <properties>
        <springframework.version>4.2.0.RELEASE</springframework.version>
        <jackson.version>2.5.3</jackson.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${springframework.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-tx</artifactId>
            <version>${springframework.version}</version>
        </dependency>

        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>${jackson.version}</version>
        </dependency>

    <!-- System Related dependencies -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.1.0</version>
        </dependency>
    <dependency>
        <groupId>javax.servlet.jsp</groupId>
        <artifactId>javax.servlet.jsp-api</artifactId>
        <version>2.3.1</version>
    </dependency>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>jstl</artifactId>
        <version>1.2</version>
    </dependency>

    </dependencies>

    <build>
        <pluginManagement>
            <plugins>
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <version>3.2</version>
                    <configuration>
                        <source>1.8</source>
                        <target>1.8</target>
                    </configuration>
                </plugin>

                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-war-plugin</artifactId>
                    <version>2.4</version>
                    <configuration>
                        <warSourceDirectory>${basedir}/src/main/webapp</warSourceDirectory>
                        <warName>manageBudgetWar</warName>
                        <failOnMissingWebXml>false</failOnMissingWebXml> 
                    </configuration>
                </plugin>

            </plugins>
        </pluginManagement>
        <finalName>manageBudget</finalName>
    </build>

</project>

【问题讨论】：

为什么你有 3 个 jquery 脚本？为什么要动态加载js文件而不是静态加载？为什么你的控制器被映射到dashboard/getDashboardDetails，并且不返回html，而是json，为什么还要请求dashboard/getDashboardDetails.htm？
@JB Nizet 3 jquery 脚本输入错误。更正了。
@JB Nizet 1. 3 jquery 脚本输入错误。纠正它。 2. 静态添加脚本会有所不同。我应该改变它吗？ 3. DashboardController.java 路径是“/dashboard”，getDashBoardDetails() 方法的路径是“/getDashboardDetails”，我试图将此服务称为/dashboard/getDashboardDetails.htm。此服务返回 json，它将动态填充 dashbard.jsp 上的字段。我在这里做错了什么吗？
再次：您的控制器映射到/dashboard//getDashboardDetails。您的请求已发送至/dashboard/getDashboardDetails.htm。你没看出区别吗？ .htm 后缀不应该在那里。而且它甚至没有意义，因为.htm 通常用于引用返回 HTML 的资源。但是您的资源返回 JSON。删除该后缀。
你能解释一下 url 'dashboard//getDashboardDetails' 是如何用 // 形成的吗？

标签： spring-mvc web-applications spring-4 spring-restcontroller

【解决方案1】：

自从我在这个论坛上发布（大约一个月前）以来，我一直在研究上述问题。最后，我能够解决这个问题。这是我最初遗漏的内容并对其进行了更正以解决问题：-

1. ManageBudgetConfiguration.java：我错过了在 ManageBudgetConfiguration 类中扩展 WebMvcConfigurerAdapter。

public class ManageBudgetConfiguration **extends WebMvcConfigurerAdapter**{ ... }

2. 覆盖 ManageBudgetConfiguration.java 类中的 addResourceHandlers(...) 方法包含静态 ui 资源，例如 js、css 等。我的 javascript 和 css 文件位于 <basedir>/webapp/resources/ 文件夹中

@Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/resources/**").addResourceLocations("/resources/");
    }

上面的方法是应用-上下文映射的等效代码：-

<mvc:resources mapping="/resources/**" location="/resources/theme-new/" />

3a. 在 pom 中包含 Gson。 Gson 是 google lib，用于将 Java 对象转换为 JSON，反之亦然。

<dependency>
        <groupId>com.google.code.gson</groupId>
        <artifactId>gson</artifactId>
        <version>2.8.0</version>
    </dependency>

3b 更改 rest-endpoints 方法的返回类型：-

return new ResponseEntity<List<DashboardBean>>(dashboardBeanList, HttpStatus.OK)
    to
return response;
where response is json string
eg


@RequestMapping(value = "/getDashboardDetails", method = RequestMethod.GET)
    public @ResponseBody
    String getDashBoardDetails(HttpServletRequest request) {
        System.out.println("Dashboardcontroller : getDashBoardDetails1");
        String response = null;
        String userId ="rahil";

        List<DashboardBean> dashboardBeanList = dashboardService.getDashBoardDetails(userId);
        response = new Gson().toJson(dashboardBeanList);
        return response;
    }

【讨论】：