生成一个给HTTP GET请求用的presigned URL。浏览器/移动端的客户端可以用这个URL进行下载，即使其所在的存储桶是私有的。这个presigned URL可以设置一个失效时间，默认值是7天。方法声明如下：
public String presignedGetObject(String bucketName, String objectName) public String presignedGetObject(String bucketName, String objectName, Integer expires)
其中：
bucketName：存储桶名称
objectName：存储桶里的对象名称
expiry：失效时间（以秒为单位），默认是7天，不得大于七天
实例：生成 files 存储桶下面 308608.jpg 图片对象的临时访问 URL 地址，默认该地址有效期为7天。使用该地址可以在浏览器中查看该图片对象，不用输入 accessKey 和 securetKey。代码如下：
package com.hxstrive.minio.demos.presigned;
import io.minio.MinioClient;
import io.minio.errors.MinioException;
/**
* 获取指定存储桶下对象的临时访问 URL 地址
* @author Administrator 2021/8/5 22:43
* @version 1.0
*/
public class PresignedGetObject {
/** MinioClient.presignedGetObject() example. */
public static void main(String[] args) throws Exception {
try {
MinioClient minioClient = new MinioClient(
"http://127.0.0.1:9000",
"root", "mypassword");
// 生成 files 存储桶下面 308608.jpg 图片对象的临时访问地址
// 默认该地址有效期为7天
String url = minioClient.presignedGetObject(
"files", "308608.jpg");
System.out.println(url);
// 生成 files 存储桶下面 308608.jpg 图片对象的临时访问地址
// 手动指定过期时间为 30 秒
String url2 = minioClient.presignedGetObject(
"files", "308608.jpg", 30);
System.out.println(url2);
} catch (MinioException e) {
e.printStackTrace();
}
}
}生成一个给HTTP PUT请求用的presigned URL。浏览器/移动端的客户端可以用这个URL进行上传，即使其所在的存储桶是私有的。这个presigned URL可以设置一个失效时间，默认值是7天。方法声明如下：
public String presignedPutObject(String bucketName, String objectName) public String presignedPutObject(String bucketName, String objectName, Integer expires)
其中：
bucketName：存储桶名称
objectName：存储桶里的对象名称
expiry：失效时间（以秒为单位），默认是7天，不得大于七天
实例：获取一个 PUT 地址，然后使用 HttpComponent 库发起一个 PUT 请求，将一段文本保存到对象中；再次获取对象的 GET 地址，获取对象内容且输出到控制台。代码如下：
package com.hxstrive.minio.demos.presigned;
import io.minio.MinioClient;
import io.minio.errors.MinioException;
import org.apache.http.HttpEntity;
import org.apache.http.HttpStatus;
import org.apache.http.StatusLine;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPut;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import java.io.InputStream;
/**
* 生成一个给 HTTP PUT 请求用的 presigned URL
* @author Administrator 2021/8/5 22:50
* @version 1.0
*/
public class PresignedPutObject {
/** MinioClient.presignedPutObject() example. */
public static void main(String[] args) throws Exception {
try {
MinioClient minioClient = new MinioClient(
"http://127.0.0.1:9000",
"root", "mypassword");
// 获取指定存储桶下对象的 PUT URL 地址
String putUrl = minioClient.presignedPutObject(
"files", "myObject.txt");
System.out.println("put url = " + putUrl);
// 模拟一个 HTTP PUT 请求
CloseableHttpClient httpclient = HttpClients.createDefault();
HttpPut httpPut = new HttpPut(putUrl);
httpPut.setEntity(new StringEntity("Hello, World"));
CloseableHttpResponse responsePut = httpclient.execute(httpPut);
StatusLine statusLinePut = responsePut.getStatusLine();
System.out.println("status code = " + statusLinePut.getStatusCode());
System.out.println("reason phrase = " + statusLinePut.getReasonPhrase());
// 获取刚刚上传文件内容
String getUrl = minioClient.presignedGetObject(
"files", "myObject.txt");
System.out.println("get url = " + getUrl);
HttpGet httpGet = new HttpGet(getUrl);
CloseableHttpResponse responseGet = httpclient.execute(httpGet);
StatusLine statusLineGet = responseGet.getStatusLine();
System.out.println("status code = " + statusLineGet.getStatusCode());
System.out.println("reason phrase = " + statusLineGet.getReasonPhrase());
if(statusLineGet.getStatusCode() == HttpStatus.SC_OK) {
HttpEntity httpEntity = responseGet.getEntity();
InputStream inputStream = httpEntity.getContent();
byte[] bytes = new byte[(int)(httpEntity.getContentLength())];
inputStream.read(bytes);
inputStream.close();
System.out.println("content = " + new String(bytes));
}
} catch (MinioException e) {
e.printStackTrace();
}
}
}允许给POST请求的presigned URL设置策略，比如接收对象上传的存储桶名称的策略，key名称前缀，过期策略。方法声明如下：
public Map<String, String> presignedPostPolicy(PostPolicy policy)
其中：
policy：对象的post策略
实例：获取存储桶 files 中 myObject.txt 对象的策略信息，代码如下：
package com.hxstrive.minio.demos.presigned;
import io.minio.MinioClient;
import io.minio.PostPolicy;
import io.minio.errors.MinioException;
import java.time.ZonedDateTime;
import java.util.Map;
/**
* 给POST请求的presigned URL设置策略，比如接收对象上传的存储桶名称的策略，key名称前缀，过期策略
* @author Administrator 2021/8/6 8:50
* @version 1.0
*/
public class PresignedPostPolicy {
/** MinioClient.presignedGetObject() example. */
public static void main(String[] args) throws Exception {
try {
MinioClient minioClient = new MinioClient(
"http://127.0.0.1:9000",
"root", "mypassword");
// ZonedDateTime 需要JDK1.8+
ZonedDateTime expirationDate = ZonedDateTime.now();
PostPolicy postPolicy = new PostPolicy(
"files", "myObject.txt", expirationDate);
Map<String,String> map = minioClient.presignedPostPolicy(postPolicy);
for(Map.Entry<String,String> entry : map.entrySet()) {
System.out.println(entry.getKey() + " = " + entry.getValue());
}
} catch (MinioException e) {
e.printStackTrace();
}
}
}输出如下：
bucket = files x-amz-date = 20210806T042936Z x-amz-signature = 04dacf1fcb35e572634519a5383f370366185110350bc9bf5a66c54dcff1c0cd key = myObject.txt x-amz-algorithm = AWS4-HMAC-SHA256 x-amz-credential = root/20210806/zh-east-1/s3/aws4_request policy = eyJleHBpcmF0aW9uIjoiMjAyMS0wOC0wNlQwNDoyOTozNS4zODBaIiwiY29uZGl0aW9ucyI6W1siZXEiLCIkYnVja2V0IiwiZmlsZXMiXSxbImVxIiwiJGtleSIsIm15T2JqZWN0LnR4dCJdLFsiZXEiLCIkeC1hbXotYWxnb3JpdGhtIiwiQVdTNC1ITUFDLVNIQTI1NiJdLFsiZXEiLCIkeC1hbXotY3JlZGVudGlhbCIsInJvb3QvMjAyMTA4MDYvemgtZWFzdC0xL3MzL2F3czRfcmVxdWVzdCJdLFsiZXEiLCIkeC1hbXotZGF0ZSIsIjIwMjEwODA2VDA0MjkzNloiXV19
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