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java后端解決跨域的幾種問(wèn)題解決

更新時(shí)間：2021年03月23日 10:59:55 作者：曉宇碼匠

這篇文章主要介紹了java后端解決跨域的幾種問(wèn)題解決，文中通過(guò)示例代碼介紹的非常詳細(xì)，對(duì)大家的學(xué)習(xí)或者工作具有一定的參考學(xué)習(xí)價(jià)值，需要的朋友們下面隨著小編來(lái)一起學(xué)習(xí)學(xué)習(xí)吧

1.java過(guò)濾器過(guò)濾

允許整個(gè)項(xiàng)目跨域訪問(wèn)，可通過(guò)filter來(lái)進(jìn)行過(guò)慮：

public class SimpleCORSFilter implements Filter{ 
 
  @Override 
  public void destroy() { 
     
  } 
 
  @Override 
  public void doFilter(ServletRequest req, ServletResponse res, 
      FilterChain chain) throws IOException, ServletException { 
      HttpServletResponse response = (HttpServletResponse) res; 
      response.setHeader("Access-Control-Allow-Origin", "*"); 
      response.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE"); 
      response.setHeader("Access-Control-Max-Age", "3600"); 
      response.setHeader("Access-Control-Allow-Headers", "x-requested-with"); 
      chain.doFilter(req, res); 
     
  } 
 
  @Override 
  public void init(FilterConfig arg0) throws ServletException { 
     
  }  
}

在web.xml中需要添加如下配置：

<filter> 
   <filter-name>cors</filter-name> 
   <filter-class>com.ssm.web.filter.SimpleCORSFilter</filter-class> 
  </filter> 
  <filter-mapping> 
   <filter-name>cors</filter-name> 
   <url-pattern>/*</url-pattern> 
  </filter-mapping>
</filter>

為單個(gè)方法提供跨域訪問(wèn)，直接添加請(qǐng)求頭：

    response.setHeader("Access-Control-Allow-Origin", "*"); 
      response.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE"); 
      response.setHeader("Access-Control-Max-Age", "3600"); 
      response.setHeader("Access-Control-Allow-Headers", "x-requested-with");

2.后臺(tái)Http請(qǐng)求轉(zhuǎn)發(fā)

使用HttpClinet轉(zhuǎn)發(fā)進(jìn)行轉(zhuǎn)發(fā)(簡(jiǎn)單的例子不推薦使用這種方式)

try {
  HttpClient client = HttpClients.createDefault();      //client對(duì)象
  HttpGet get = new HttpGet("http://localhost:8080/test");  //創(chuàng)建get請(qǐng)求
  CloseableHttpResponse response = httpClient.execute(get);  //執(zhí)行g(shù)et請(qǐng)求
  String mes = EntityUtils.toString(response.getEntity());  //將返回體的信息轉(zhuǎn)換為字符串
  System.out.println(mes);
} catch (ClientProtocolException e) {
  e.printStackTrace();
} catch (IOException e) {
  e.printStackTrace();
}

3、后臺(tái)配置同源Cors （推薦）

在SpringBoot2.0 上的跨域用以下代碼配置即可完美解決你的前后端跨域請(qǐng)求問(wèn)題

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.cors.CorsConfiguration;
import org.springframework.web.cors.UrlBasedCorsConfigurationSource;
import org.springframework.web.filter.CorsFilter;
/**
 * 實(shí)現(xiàn)基本的跨域請(qǐng)求
 * @author linhongcun
 *
 */
@Configuration
public class CorsConfig {
  @Bean
  public CorsFilter corsFilter() {
    final UrlBasedCorsConfigurationSource urlBasedCorsConfigurationSource = new UrlBasedCorsConfigurationSource();
    final CorsConfiguration corsConfiguration = new CorsConfiguration();
    /*是否允許請(qǐng)求帶有驗(yàn)證信息*/
    corsConfiguration.setAllowCredentials(true);
    /*允許訪問(wèn)的客戶端域名*/
    corsConfiguration.addAllowedOrigin("*");
    /*允許服務(wù)端訪問(wèn)的客戶端請(qǐng)求頭*/
    corsConfiguration.addAllowedHeader("*");
    /*允許訪問(wèn)的方法名,GET POST等*/
    corsConfiguration.addAllowedMethod("*");
    urlBasedCorsConfigurationSource.registerCorsConfiguration("/**", corsConfiguration);
    return new CorsFilter(urlBasedCorsConfigurationSource);
  }
}

4、使用SpringCloud網(wǎng)關(guān)

服務(wù)網(wǎng)關(guān)(zuul)又稱路由中心，用來(lái)統(tǒng)一訪問(wèn)所有api接口，維護(hù)服務(wù)。
Spring Cloud Zuul通過(guò)與Spring Cloud Eureka的整合，實(shí)現(xiàn)了對(duì)服務(wù)實(shí)例的自動(dòng)化維護(hù)，所以在使用服務(wù)路由配置的時(shí)候，我們不需要向傳統(tǒng)路由配置方式那樣去指定具體的服務(wù)實(shí)例地址，只需要通過(guò)Ant模式配置文件參數(shù)即可

5、使用nginx做轉(zhuǎn)發(fā)

現(xiàn)在有兩個(gè)網(wǎng)站想互相訪問(wèn)接口在http://a.a.com:81/A中想訪問(wèn) http://b.b.com:81/B 那么進(jìn)行如下配置即可
然后通過(guò)訪問(wèn) www.my.com/A 里面即可訪問(wèn) www.my.com/B

server {
    listen    80;
    server_name www.my.com;
    location /A {
      proxy_pass http://a.a.com:81/A;
      index index.html index.htm;
    }
    location /B {
      proxy_pass http://b.b.com:81/B;
      index index.html index.htm;
    }
  }

如果是兩個(gè)端口想互相訪問(wèn)接口在http://b.b.com:80/Api中想訪問(wèn) http://b.b.com:81/Api 那么進(jìn)行如下配置即可
使用nginx轉(zhuǎn)發(fā)機(jī)制就可以完成跨域問(wèn)題

server {
    listen    80;
    server_name b.b.com;
    location /Api {
      proxy_pass http://b.b.com:81/Api;
      index index.html index.htm;
    }
  }

到此這篇關(guān)于java后端解決跨域的幾種問(wèn)題解決的文章就介紹到這了,更多相關(guān)java 跨域內(nèi)容請(qǐng)搜索腳本之家以前的文章或繼續(xù)瀏覽下面的相關(guān)文章希望大家以后多多支持腳本之家！

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