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spring boot ajax跨域 spring boot ajax跨域的两种方式

刘冬 人气:0
想了解spring boot ajax跨域的两种方式的相关内容吗,刘冬在本文为您仔细讲解spring boot ajax跨域的相关知识和一些Code实例,欢迎阅读和指正,我们先划重点:spring,boot,ajax,跨域,springboot,跨域,下面大家一起来学习吧。

前言

 java语言在多数时,会作为一个后端语言,为前端的php,node.js等提供API接口。前端通过ajax请求去调用java的API服务。今天以node.js为例,介绍两种跨域方式:CrossOrigin和反向代理

 一、准备工作

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>com.example</groupId>
 <artifactId>spring-boot-15</artifactId>
 <version>0.0.1-SNAPSHOT</version>
 <packaging>jar</packaging>
 <name>spring-boot-15</name>
 <description>Demo project for Spring Boot</description>
 <parent>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-parent</artifactId>
 <version>1.5.3.RELEASE</version>
 <relativePath/> <!-- lookup parent from repository -->
 </parent>
 <properties>
 <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
 <java.version>1.8</java.version>
 </properties>
 <dependencies>
 <dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-web</artifactId>
 </dependency>
 <dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-devtools</artifactId>
  <scope>runtime</scope>
 </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>

pom.xml

App.java

package com.example;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication
@SpringBootApplication
public class App {
 public static void main(String[] args) {
 SpringApplication.run(App.class, args);
 }
}

User.java

package com.example;
public class User {
 public int id;
 public String name;
 public int age;
}

MainController.java:

package com.example;
import java.util.ArrayList;
import java.util.List;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
/**
 * *
 */
@RestController
public class MainController {
 @GetMapping("findAllUser")
 public List<User> findAllUser() {
 List<User> list = new ArrayList<>();
 for (int i = 0; i < 20; i++) {
  User user = new User();
  list.add(user);
  user.id = i;
  user.name = "name_" + i;
  user.age = 20 + i;
 }
 return list;
 }
}

项目结构如下图所示:

访问http://localhost:8080/findAllUser

使用HBuilder创建node.js express项目:

选择ejs模板引擎:

index.ejs文件代码如下:

<!DOCTYPE html>
<html>
 <head>
 <title>
  <%= title %>
 </title>
 <link rel='stylesheet' href='/stylesheets/style.css' />
 <script src="//cdn.bootcss.com/angular.js/1.5.6/angular.min.js"></script>
 <script type="text/javascript">
  var app = angular.module('app', []);
  app.controller('MainController', function($rootScope, $scope, $http) {
  $http({
   method: 'GET',
   url: 'http://localhost:8080/findAllUser'
  }).then(function successCallback(r) {
   $scope.rows = r.data;
  });
  });
 </script>
 </head>
 <body ng-app="app" ng-controller="MainController">
 <h1><%= title %></h1>
 <p>Welcome to
  <%= title %>
 </p>
 <br />
 <table>
  <tr ng-repeat="row in rows">
  <td>{{row.id}}</td>
  <td>{{row.name}}</td>
  <td>{{row.age}}</td>
  </tr>
 </table>
 </body>
</html>

 通过angular.js的http方法调用api请求

右键运行项目:

运行效果:

发现调用ajax请求时跨域失败。

二、spring boot后台设置允许跨域

这时,修改MainController类,在方法前加@CrossOrigin注解:

/**
 * 
 *
 */
@RestController
public class MainController {
 @CrossOrigin(origins = "http://localhost:3000")
 @GetMapping("findAllUser")
 public List<User> findAllUser() {
 List<User> list = new ArrayList<>();
 for (int i = 0; i < 20; i++) {
  User user = new User();
  list.add(user);
  user.id = i;
  user.name = "name_" + i;
  user.age = 20 + i;
 }
 return list;
 }
}

这是声明findAllUser方法允许跨域,

也可以修改App.java,来实现全局跨域:

package com.example;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.web.servlet.config.annotation.CorsRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
@SpringBootApplication
public class App {
 public static void main(String[] args) {
 SpringApplication.run(App.class, args);
 }
 @Bean
 public WebMvcConfigurer corsConfigurer() {
 return new WebMvcConfigurerAdapter() {
  @Override
  public void addCorsMappings(CorsRegistry registry) {
  registry.addMapping("/**").allowedOrigins("http://localhost:3000");
  }
 };
 }
}

registry.addMapping("/**"):为根目录的全部请求,也可以设置为"/user/**",这意味着是user目录下的所有请求。

在访问http://localhost:3000,效果如下:

三、通过node.js的方向代理实现跨域

node.js提供了一些反向代理的中间件,能轻而易举的实现跨域,而不需要spring boot做任何设置。

安装express-http-proxy中间件

npm install --save-dev express-http-proxy

修改app.js文件,使其支持反向代理:

var proxy = require('express-http-proxy');
var apiProxy = proxy('http://localhost:8080', {});
app.use('/api', apiProxy);

以“/api”开头的请求转发为spring boot的API服务。

完整代码如下:

/**
 * Module dependencies.
 */
var express = require('express')
 , routes = require('./routes')
 , user = require('./routes/user')
 , http = require('http')
 , path = require('path');
var app = express();
// all environments
app.set('port', process.env.PORT || 3000);
app.set('views', __dirname + '/views');
app.set('view engine', 'ejs');
app.use(express.favicon());
app.use(express.logger('dev'));
app.use(express.bodyParser());
app.use(express.methodOverride());
app.use(app.router);
app.use(express.static(path.join(__dirname, 'public')));
// development only
if ('development' == app.get('env')) {
 app.use(express.errorHandler());
}
var proxy = require('express-http-proxy');
var apiProxy = proxy('http://localhost:8080', {});
app.use('/api', apiProxy);
app.get('/', routes.index);
app.get('/users', user.list);
http.createServer(app).listen(app.get('port'), function(){
 console.log('Express server listening on port ' + app.get('port'));
});

修改index.ejs文件:

 var app = angular.module('app', []);
  app.controller('MainController', function($rootScope, $scope, $http) {
  $http({
   method: 'GET',
   url: '/api/findAllUser'
  }).then(function successCallback(r) {
   $scope.rows = r.data;
  });
  });

完整的index.ejs文件如下:

<!DOCTYPE html>
<html>
  <head>
    <title>
      <%= title %>
    </title>
    <link rel='stylesheet' href='/stylesheets/style.css' />
    <script src="//cdn.bootcss.com/angular.js/1.5.6/angular.min.js"></script>
    <script type="text/javascript">
      var app = angular.module('app', []);
      app.controller('MainController', function($rootScope, $scope, $http) {
        $http({
          method: 'GET',
          url: '/api/findAllUser'
        }).then(function successCallback(r) {
          $scope.rows = r.data;
        });
      });
    </script>
  </head>
  <body ng-app="app" ng-controller="MainController">
    <h1><%= title %></h1>
    <p>Welcome to
      <%= title %>
    </p>
    <br />
    <table>
      <tr ng-repeat="row in rows">
        <td>{{row.id}}</td>
        <td>{{row.name}}</td>
        <td>{{row.age}}</td>
      </tr>
    </table>
  </body>
</html>

运行效果如下:

总结

  第二种通过反向代理的方式是最佳方案。在正式项目中,可以使用node.js控制web前端渲染与spring boot后端提供API服务的组合。这样,可以控制用户在node.js端登录后才能调用spring boot的API服务。在大型web项目中也可以使用node.js的反向代理,把很多子站点关联起来,这样便发挥出了网站灵活的扩展性。

 以上所述是小编给大家介绍的spring boot ajax跨域的两种方式,希望对大家有所帮助,如果大家有任何疑问请给我留言,小编会及时回复大家的。在此也非常感谢大家对网站的支持!

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