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Java跨域设置

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因浏览器的同源策略限制,在不同域名之间进行数据交互或者资源共享时,会出现跨域请求被拒绝的问题。您可以通过设置允许特定的域名、方法和请求头的跨域访问策略,解决跨域问题。

注意事项

  • 本文以华东1(杭州)外网Endpoint为例。如果您希望通过与OSS同地域的其他阿里云产品访问OSS,请使用内网Endpoint。关于OSS支持的Region与Endpoint的对应关系,请参见访问域名和数据中心

  • 本文以从环境变量读取访问凭证为例。如何配置访问凭证,请参见Java配置访问凭证

  • 本文以OSS域名新建OSSClient为例。如果您希望通过自定义域名、STS等方式新建OSSClient,请参见新建OSSClient

  • 要设置跨域规则,您必须有oss:PutBucketCors权限;要获取跨域规则,您必须有oss:GetBucketCors权限;要删除跨域规则,您必须有oss:DeleteBucketCors权限。具体操作,请参见为RAM用户授权自定义的权限策略

设置跨域规则

以下代码用于设置指定存储空间的跨域规则:

import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.model.SetBucketCORSRequest;
import java.util.ArrayList;

public class Demo {

    public static void main(String[] args) throws Exception {
        // Endpoint以华东1(杭州)为例,其它Region请按实际情况填写。
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // 从环境变量中获取访问凭证。运行本代码示例之前,请确保已设置环境变量OSS_ACCESS_KEY_ID和OSS_ACCESS_KEY_SECRET。
        EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
        // 填写Bucket名称,例如examplebucket。
        String bucketName = "examplebucket";

        // 创建OSSClient实例。
        OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider);

        try {
            SetBucketCORSRequest request = new SetBucketCORSRequest(bucketName);

            // 每个存储空间最多允许设置10条跨域规则。
            ArrayList<SetBucketCORSRequest.CORSRule> putCorsRules = new ArrayList<SetBucketCORSRequest.CORSRule>();

            SetBucketCORSRequest.CORSRule corRule = new SetBucketCORSRequest.CORSRule();

            ArrayList<String> allowedOrigin = new ArrayList<String>();
            // 指定允许跨域请求的来源。
            allowedOrigin.add( "http://example.com");

            ArrayList<String> allowedMethod = new ArrayList<String>();
            // 指定允许的跨域请求方法(GET/PUT/DELETE/POST/HEAD)。
            allowedMethod.add("GET");

            ArrayList<String> allowedHeader = new ArrayList<String>();
            // 是否允许预取指令(OPTIONS)中Access-Control-Request-Headers头中指定的Header。
            allowedHeader.add("x-oss-test");

            ArrayList<String> exposedHeader = new ArrayList<String>();
            // 指定允许用户从应用程序中访问的响应头。
            exposedHeader.add("x-oss-test1");
            // AllowedOrigins和AllowedMethods最多支持一个星号(*)通配符。星号(*)表示允许所有的域来源或者操作。
            corRule.setAllowedMethods(allowedMethod);
            corRule.setAllowedOrigins(allowedOrigin);
            // AllowedHeaders和ExposeHeaders不支持通配符。
            corRule.setAllowedHeaders(allowedHeader);
            corRule.setExposeHeaders(exposedHeader);
            // 指定浏览器对特定资源的预取(OPTIONS)请求返回结果的缓存时间,单位为秒。
            corRule.setMaxAgeSeconds(10);

            // 最多允许10条规则。
            putCorsRules.add(corRule);
            // 已存在的规则将被覆盖。
            request.setCorsRules(putCorsRules);
            // 指定是否返回Vary: Origin头。指定为TRUE,表示不管发送的是否为跨域请求或跨域请求是否成功,均会返回Vary: Origin头。指定为False,表示任何情况下都不会返回Vary: Origin头。
            // request.setResponseVary(Boolean.TRUE);
            ossClient.setBucketCORS(request);
        } catch (OSSException oe) {
            System.out.println("Caught an OSSException, which means your request made it to OSS, "
                    + "but was rejected with an error response for some reason.");
            System.out.println("Error Message:" + oe.getErrorMessage());
            System.out.println("Error Code:" + oe.getErrorCode());
            System.out.println("Request ID:" + oe.getRequestId());
            System.out.println("Host ID:" + oe.getHostId());
        } catch (ClientException ce) {
            System.out.println("Caught an ClientException, which means the client encountered "
                    + "a serious internal problem while trying to communicate with OSS, "
                    + "such as not being able to access the network.");
            System.out.println("Error Message:" + ce.getMessage());
        } finally {
            if (ossClient != null) {
                ossClient.shutdown();
            }
        }
    }
}

获取跨域规则

以下代码用于获取跨域规则:

import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.model.SetBucketCORSRequest;
import java.util.ArrayList;

public class Demo {

    public static void main(String[] args) throws Exception {
        // Endpoint以华东1(杭州)为例,其它Region请按实际情况填写。
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // 从环境变量中获取访问凭证。运行本代码示例之前,请确保已设置环境变量OSS_ACCESS_KEY_ID和OSS_ACCESS_KEY_SECRET。
        EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
        // 填写Bucket名称,例如examplebucket。
        String bucketName = "examplebucket";

        // 创建OSSClient实例。
        OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider);

        try {
            ArrayList<SetBucketCORSRequest.CORSRule> corsRules;
            // 获取跨域规则。
            corsRules =  (ArrayList<SetBucketCORSRequest.CORSRule>) ossClient.getBucketCORSRules(bucketName);
            for (SetBucketCORSRequest.CORSRule rule : corsRules) {
                for (String allowedOrigin1 : rule.getAllowedOrigins()) {
                    // 获取允许的跨域请求源。
                    System.out.println(allowedOrigin1);
                }

                for (String allowedMethod1 : rule.getAllowedMethods()) {
                    // 获取允许的跨域请求方法。
                    System.out.println(allowedMethod1);
                }

                if (rule.getAllowedHeaders().size() > 0){
                    for (String allowedHeader1 : rule.getAllowedHeaders()) {
                        // 获取允许跨域请求的响应头。
                        System.out.println(allowedHeader1);
                    }
                }

                if (rule.getExposeHeaders().size() > 0) {
                    for (String exposeHeader : rule.getExposeHeaders()) {
                        // 获取允许用户从应用程序中访问的响应头。
                        System.out.println(exposeHeader);
                    }
                }

                if ( null != rule.getMaxAgeSeconds()) {
                    System.out.println(rule.getMaxAgeSeconds());
                }
            }
        } catch (OSSException oe) {
            System.out.println("Caught an OSSException, which means your request made it to OSS, "
                    + "but was rejected with an error response for some reason.");
            System.out.println("Error Message:" + oe.getErrorMessage());
            System.out.println("Error Code:" + oe.getErrorCode());
            System.out.println("Request ID:" + oe.getRequestId());
            System.out.println("Host ID:" + oe.getHostId());
        } catch (ClientException ce) {
            System.out.println("Caught an ClientException, which means the client encountered "
                    + "a serious internal problem while trying to communicate with OSS, "
                    + "such as not being able to access the network.");
            System.out.println("Error Message:" + ce.getMessage());
        } finally {
            if (ossClient != null) {
                ossClient.shutdown();
            }
        }
    }
}

删除跨域规则

以下代码用于删除指定存储空间的所有跨域规则:

import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;

public class Demo {

    public static void main(String[] args) throws Exception {
        // Endpoint以华东1(杭州)为例,其它Region请按实际情况填写。
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // 从环境变量中获取访问凭证。运行本代码示例之前,请确保已设置环境变量OSS_ACCESS_KEY_ID和OSS_ACCESS_KEY_SECRET。
        EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
        // 填写Bucket名称,例如examplebucket。
        String bucketName = "examplebucket";

        // 创建OSSClient实例。
        OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider);

        try {
            // 删除存储空间所有跨域规则。
            ossClient.deleteBucketCORSRules(bucketName);
        } catch (OSSException oe) {
            System.out.println("Caught an OSSException, which means your request made it to OSS, "
                    + "but was rejected with an error response for some reason.");
            System.out.println("Error Message:" + oe.getErrorMessage());
            System.out.println("Error Code:" + oe.getErrorCode());
            System.out.println("Request ID:" + oe.getRequestId());
            System.out.println("Host ID:" + oe.getHostId());
        } catch (ClientException ce) {
            System.out.println("Caught an ClientException, which means the client encountered "
                    + "a serious internal problem while trying to communicate with OSS, "
                    + "such as not being able to access the network.");
            System.out.println("Error Message:" + ce.getMessage());
        } finally {
            if (ossClient != null) {
                ossClient.shutdown();
            }
        }
    }
}

相关文档

  • 关于跨域设置的完整示例代码,请参见GitHub示例

  • 关于设置跨域规则的API接口说明,请参见PutBucketCors

  • 关于获取跨域规则的API接口说明,请参见GetBucketCors

  • 关于删除跨域规则的API接口说明,请参见DeleteBucketCors

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