SpringBoot（六）：SpringBoot使用CROS解决跨域问题

系统管理员 2022-06-12 00:24 252阅读 0赞

> 跨域问题其实之前就有说过，不明白的可以参考我之前的文章，这章主要讲解SpringBoot CROS的支持。

这里主要按照官方文档方式讲述。

SpringBoot CROS 参考： [http://docs.spring.io/spring-boot/docs/1.5.4.RELEASE/reference/htmlsingle/\#boot-features-cors][http_docs.spring.io_spring-boot_docs_1.5.4.RELEASE_reference_htmlsingle_boot-features-cors]

Spring CROS 参考： [http://docs.spring.io/spring/docs/4.3.9.RELEASE/spring-framework-reference/htmlsingle/\#cors][http_docs.spring.io_spring_docs_4.3.9.RELEASE_spring-framework-reference_htmlsingle_cors]

### 一、代码准备 ###

![这里写图片描述][SouthEast]

首先是支持Restful的controller，这里就不使用数据库了，简单一点。 UserController.class

package cn.saytime.web;
    
    import cn.saytime.bean.JsonResult;
    import cn.saytime.bean.User;
    import org.springframework.http.ResponseEntity;
    import org.springframework.web.bind.annotation.CrossOrigin;
    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 java.util.ArrayList;
    import java.util.Collections;
    import java.util.Date;
    import java.util.HashMap;
    import java.util.List;
    import java.util.Map;
    
    /** * @author zh * @ClassName cn.saytime.web.UserController * @Description */
    @RestController
    public class UserController {
    
    	// 创建线程安全的Map
    	static Map<Integer, User> users = Collections.synchronizedMap(new HashMap<Integer, User>());
    
    	/** * 根据ID查询用户 * @param id * @return */
    	@RequestMapping(value = "user/{id}", method = RequestMethod.GET)
    	public ResponseEntity<JsonResult> getUserById (@PathVariable(value = "id") Integer id){
    		JsonResult r = new JsonResult();
    		try {
    			User user = users.get(id);
    			r.setResult(user);
    			r.setStatus("ok");
    		} catch (Exception e) {
    			r.setResult(e.getClass().getName() + ":" + e.getMessage());
    			r.setStatus("error");
    			e.printStackTrace();
    		}
    		return ResponseEntity.ok(r);
    	}
    
    	/** * 查询用户列表 * @return */
    	 @CrossOrigin
    	@RequestMapping(value = "users", method = RequestMethod.GET)
    	public ResponseEntity<JsonResult> getUserList (){
    		JsonResult r = new JsonResult();
    		try {
    			List<User> userList = new ArrayList<User>(users.values());
    			r.setResult(userList);
    			r.setStatus("ok");
    		} catch (Exception e) {
    			r.setResult(e.getClass().getName() + ":" + e.getMessage());
    			r.setStatus("error");
    			e.printStackTrace();
    		}
    		return ResponseEntity.ok(r);
    	}
    
    	/** * 添加用户 * @param user * @return */
    	@RequestMapping(value = "user", method = RequestMethod.POST)
    	public ResponseEntity<JsonResult> add (@RequestBody User user){
    		JsonResult r = new JsonResult();
    		try {
    			users.put(user.getId(), user);
    			r.setResult(user.getId());
    			r.setStatus("ok");
    		} catch (Exception e) {
    			r.setResult(e.getClass().getName() + ":" + e.getMessage());
    			r.setStatus("error");
    
    			e.printStackTrace();
    		}
    		return ResponseEntity.ok(r);
    	}
    
    	/** * 根据id删除用户 * @param id * @return */
    	@RequestMapping(value = "user/{id}", method = RequestMethod.DELETE)
    	public ResponseEntity<JsonResult> delete (@PathVariable(value = "id") Integer id){
    		JsonResult r = new JsonResult();
    		try {
    			users.remove(id);
    			r.setResult(id);
    			r.setStatus("ok");
    		} catch (Exception e) {
    			r.setResult(e.getClass().getName() + ":" + e.getMessage());
    			r.setStatus("error");
    
    			e.printStackTrace();
    		}
    		return ResponseEntity.ok(r);
    	}
    
    	/** * 根据id修改用户信息 * @param user * @return */
    	@RequestMapping(value = "user/{id}", method = RequestMethod.PUT)
    	public ResponseEntity<JsonResult> update (@PathVariable("id") Integer id, @RequestBody User user){
    		JsonResult r = new JsonResult();
    		try {
    			User u = users.get(id);
    			u.setUsername(user.getUsername());
    			u.setAge(user.getAge());
    			users.put(id, u);
    			r.setResult(u);
    			r.setStatus("ok");
    		} catch (Exception e) {
    			r.setResult(e.getClass().getName() + ":" + e.getMessage());
    			r.setStatus("error");
    
    			e.printStackTrace();
    		}
    		return ResponseEntity.ok(r);
    	}
    
    }

User.class

package cn.saytime.bean;
    
    import java.util.Date;
    
    /** * @author zh * @ClassName cn.saytime.bean.User * @Description */
    public class User { 
    
    	private int id;
    	private String username;
    	private int age;
    	private Date ctm;
    
    	// Getter Setter
    }

JsonResult.class

package cn.saytime.bean;
    
    public class JsonResult {
    
    	private String status = null;
    
    	private Object result = null;
    
    	// Getter Setter
    }

### 二、测试是否存在跨域问题 ###

我们在static目录新建一个test.html

<!DOCTYPE html>
    <html lang="en">
    <head>
    	<meta charset="UTF-8">
    	<title>Title</title>
    	<script src="https://cdn.bootcss.com/jquery/2.1.0/jquery.min.js"></script>
    	<script type="text/javascript"> function crosRequest(){ $.ajax({ url:'http://localhost:8080/users', type:'get', dataType:'json', success:function(data){ console.log(data); } }); } </script>
    </head>
    <body>
    	<button onclick="crosRequest()">请求跨域资源</button>
    </body>
    </html>

1.  我们使用IDEA的浏览器预览功能，点击谷歌小图标，可以看到打开网址为： [http://localhost:63342/springboot-demo/springboot-cros/static/test.html?\_ijt=ibtt432ffb9rh0vffqkkug3je8][http_localhost_63342_springboot-demo_springboot-cros_static_test.html_ijt_ibtt432ffb9rh0vffqkkug3je8]
2.  启动SpringBoot工程，默认8080

> 不是使用IDEA的用户，自己找个tomcat启动test.html页面，修改端口为其他，然后启动springboot。

![这里写图片描述][SouthEast 1]

![这里写图片描述][SouthEast 2]

所以证明存在跨域问题。

### 一、@CrossOrigin注解方式 Controller method CORS configuration ###

这里我们在users映射的方法getUserList上面加上@CrossOrigin

@CrossOrigin
    	@RequestMapping(value = "users", method = RequestMethod.GET)
    	public ResponseEntity<JsonResult> getUserList ()

然后再次使用上面的方式访问。

![这里写图片描述][SouthEast 3]

> 表示跨域问题解决。 default @CrossOrigin allows all origins and the HTTP methods specified in the @RequestMapping annotation 上面的官方文档说明，也就是默认的@CrossOrigin允许所有跨域请求。

通过查看CrossOrigin源码可以看到， 默认配置为：

"Access-Control-Allow-Origin" : "*"
    "Access-Control-Allow-Methods" : "GET,POST,PUT,OPTIONS"
    "Access-Control-Allow-Credentials" : "true"

@Target({ElementType.METHOD, ElementType.TYPE})
    @Retention(RetentionPolicy.RUNTIME)
    @Documented
    public @interface CrossOrigin {
        /** @deprecated */
        @Deprecated
        String[] DEFAULT_ORIGINS = new String[]{
       "*"};
        /** @deprecated */
        @Deprecated
        String[] DEFAULT_ALLOWED_HEADERS = new String[]{
       "*"};
        /** @deprecated */
        @Deprecated
        boolean DEFAULT_ALLOW_CREDENTIALS = true;
        /** @deprecated */
        @Deprecated
        long DEFAULT_MAX_AGE = 1800L;
    
        @AliasFor("origins")
        String[] value() default {};
    
        @AliasFor("value")
        String[] origins() default {};
    
        String[] allowedHeaders() default {};
    
        String[] exposedHeaders() default {};
    
        RequestMethod[] methods() default {};
    
        String allowCredentials() default "";
    
        long maxAge() default -1L;
    }

--------------------

> It is also possible to enable CORS for the whole controller 也可以用在整个Controller类上面。即该controller所有映射都支持跨域请求。

@CrossOrigin(origins = "http://domain2.com",
    		maxAge = 3600,
    		methods = {RequestMethod.GET, RequestMethod.POST})
    @RestController
    public class UserController

### 二、全局CORS配置 ###

> Global CORS configuration In addition to fine-grained, annotation-based configuration you’ll probably want to define some global CORS configuration as well. This is similar to using filters but can be declared withing Spring MVC and combined with fine-grained @CrossOrigin configuration. By default all origins and GET, HEAD and POST methods are allowed.

package cn.saytime.config;
    
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.web.servlet.config.annotation.CorsRegistry;
    import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
    import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
    
    /**
     * @author zh
     * @ClassName cn.saytime.config.CORSConfiguration
     * @Description
     */
    @Configuration
    public class CORSConfiguration {
    
    	@Bean
    	public WebMvcConfigurer corsConfigurer() {
    		return new WebMvcConfigurerAdapter() {
    			@Override
    			public void addCorsMappings(CorsRegistry registry) {
    //				registry.addMapping("/api/**");
    				registry.addMapping("/**")
    						.allowedOrigins("http://domain.com", "http://domain2.com")
    						.allowedMethods("GET", "POST", "DELETE", "PUT", "OPTIONS")
    						.allowCredentials(false).maxAge(3600);
    			}
    		};
    	}
    }

### 三、过滤器实现跨域 Filter based CORS support ###

@Configuration
    public class MyConfiguration {
    
    	@Bean
    	public FilterRegistrationBean corsFilter() {
    		UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
    		CorsConfiguration config = new CorsConfiguration();
    		config.setAllowCredentials(false);
    		config.addAllowedOrigin("http://domain.com");
    		config.addAllowedHeader("*");
    		config.addAllowedMethod("*");
    		source.registerCorsConfiguration("/**", config);
    		FilterRegistrationBean bean = new FilterRegistrationBean(new CorsFilter(source));
    		bean.setOrder(0);
    		return bean;
    	}
    }

[http_docs.spring.io_spring-boot_docs_1.5.4.RELEASE_reference_htmlsingle_boot-features-cors]: http://docs.spring.io/spring-boot/docs/1.5.4.RELEASE/reference/htmlsingle/#boot-features-cors
[http_docs.spring.io_spring_docs_4.3.9.RELEASE_spring-framework-reference_htmlsingle_cors]: http://docs.spring.io/spring/docs/4.3.9.RELEASE/spring-framework-reference/htmlsingle/#cors
[SouthEast]: /images/20220612/bbb70af9a2fe470ca4d64e8b2c5db412.png
[http_localhost_63342_springboot-demo_springboot-cros_static_test.html_ijt_ibtt432ffb9rh0vffqkkug3je8]: http://localhost:63342/springboot-demo/springboot-cros/static/test.html?_ijt=ibtt432ffb9rh0vffqkkug3je8
[SouthEast 1]: /images/20220612/ec598ad1923f497e8c9adfd2998070d9.png
[SouthEast 2]: /images/20220612/9f28badd4724436da8843113214d19ee.png
[SouthEast 3]: /images/20220612/54eb75353b4e4903a9770d2ca8e56d7e.png