本身想写一个例子程序的，发现官方的文档比较简单，所以想写一系列的java sdk阅读文章加强对bcs api和参数的认识，然后再写一个例子出来，今天我们先看一下操作的安全部分的代码实现，它位于：com.baidu.inf.iis.bcs.auth包下面，类也很简单，但是之前对java安全和加解密不熟悉，所以还花了点时间，今天将这个阅读过程记录下来。
首先我来看最简单的三个类，即就是BCSCredentials.java、BCSSignCondition.java、SigningAlgorithm.java，这个就不详细讲解了，BCSCredentials里面包含AK和SK是对这连个属性的封装,BCSSignCondition从命名来看，就是Sign生成的条件，里面包含时间、ip、和size，至于这个size，到目前不懂是什么玩意，是什么的大小，从官方给的sdk来看实际上是condition对象整个没使用，最后一个就是加密算法的一个枚举类，里面有两种最常用的消息摘要算法HmacSHA1和HmacSHA256。关于这两种算法我在这里也简单的介绍一下，也是今天刚了解，算是现学现卖。
无论是HmacSHA1还是HmacSHA256均是HMAC算法家族的成员之一，HMAC(Hash Message Authentication Code),散列消息鉴别码，基于密钥的Hash算法的认证协议，它的原理是用公开函数和密钥产生一个固定长度的值作为认证标识，用这个标识鉴别消息的完整性。使用一个密钥生成一个固定大小的小数据块，即MAC，并将其加入到消息中，然后传输。接收方利用与发送方共享的密钥进行鉴别认证等。认证过程如下所示：
如果大家待会还有疑问的，看完代码之后就能彻底的明白，谁是密钥，谁是公共函数，谁是数据等等。
直接上代码吧，这个在网上没找到代码，只能反编译后看，虽然累点，但是还能看出来点东西。
package com.baidu.inf.iis.bcs.auth;
import com.baidu.inf.iis.bcs.http.BCSHttpRequest;
import com.baidu.inf.iis.bcs.http.DefaultBCSHttpRequest;
import com.baidu.inf.iis.bcs.http.HttpMethodName;
import com.baidu.inf.iis.bcs.model.BCSClientException;
import com.baidu.inf.iis.bcs.request.BaiduBCSRequest;
import com.baidu.inf.iis.bcs.utils.ServiceUtils;
import java.io.PrintStream;
import java.net.URISyntaxException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
public class BCSSigner
{
public static void main(String[] paramArrayOfString)
throws URISyntaxException
{
1 local1 = new BaiduBCSRequest("bucket", "object", HttpMethodName.GET)
{
};
BCSSignCondition localBCSSignCondition = new BCSSignCondition();
localBCSSignCondition.setIp("192.168.1.1");
localBCSSignCondition.setSize(Long.valueOf(1234L));
localBCSSignCondition.setTime(Long.valueOf(4321L));
BCSCredentials localBCSCredentials = new BCSCredentials("akakak", "sksksk");
DefaultBCSHttpRequest localDefaultBCSHttpRequest = new DefaultBCSHttpRequest();
localDefaultBCSHttpRequest.setHttpMethod(local1.getHttpMethod());
localDefaultBCSHttpRequest.setEndpoint("10.81.2.114:8685");
sign(local1, localDefaultBCSHttpRequest, localBCSCredentials, localBCSSignCondition);
System.out.println(localDefaultBCSHttpRequest.toString());
}
public static void sign(BaiduBCSRequest paramBaiduBCSRequest, BCSHttpRequest paramBCSHttpRequest, BCSCredentials paramBCSCredentials) {
sign(paramBaiduBCSRequest, paramBCSHttpRequest, paramBCSCredentials, null);
}
public static void sign(BaiduBCSRequest paramBaiduBCSRequest, BCSHttpRequest paramBCSHttpRequest, BCSCredentials paramBCSCredentials, BCSSignCondition paramBCSSignCondition) {
StringBuilder localStringBuilder1 = new StringBuilder();
StringBuilder localStringBuilder2 = new StringBuilder();
if (null == paramBaiduBCSRequest.getHttpMethod()) {
throw new BCSClientException("Sign failed! Param: httpMethod, bucket, object can not be empty!");
}
if (null == paramBaiduBCSRequest.getBucket()) {
throw new BCSClientException("Sign failed! Param: httpMethod, bucket, object can not be empty!");
}
if ((null == paramBaiduBCSRequest.getObject()) || (0 == paramBaiduBCSRequest.getObject().length())) {
throw new BCSClientException("Sign failed! Param: httpMethod, bucket, object can not be empty!");
}
localStringBuilder1.append("MBO");
localStringBuilder2.append("Method=").append(paramBaiduBCSRequest.getHttpMethod().toString()).append("\n");
localStringBuilder2.append("Bucket=").append(paramBaiduBCSRequest.getBucket()).append("\n");
localStringBuilder2.append("Object=").append(paramBaiduBCSRequest.getObject()).append("\n");
if (paramBCSSignCondition != null) {
if (0 != paramBCSSignCondition.getIp().length()) {
localStringBuilder1.append("I");
localStringBuilder2.append("Ip=").append(paramBCSSignCondition.getIp()).append("\n");
}
if (paramBCSSignCondition.getTime().longValue() > 0L) {
localStringBuilder1.append("T");
localStringBuilder2.append("Time=").append(paramBCSSignCondition.getTime()).append("\n");
paramBCSHttpRequest.addParameter("time", String.valueOf(paramBCSSignCondition.getTime()));
}
if (paramBCSSignCondition.getSize().longValue() > 0L) {
localStringBuilder1.append("S");
localStringBuilder2.append("Size=").append(paramBCSSignCondition.getSize()).append("\n");
paramBCSHttpRequest.addParameter("size", String.valueOf(paramBCSSignCondition.getSize()));
}
}
localStringBuilder2.insert(0, "\n");
localStringBuilder2.insert(0, localStringBuilder1.toString());
byte[] arrayOfByte = new byte[0];
try {
SecretKeySpec localSecretKeySpec = new SecretKeySpec(paramBCSCredentials.getSecretKey().getBytes(), SigningAlgorithm.HmacSHA1.toString());
Mac localMac = Mac.getInstance(localSecretKeySpec.getAlgorithm());
localMac.init(localSecretKeySpec);
arrayOfByte = localMac.doFinal(ServiceUtils.toByteArray(localStringBuilder2.toString()));
paramBCSHttpRequest.addParameter("sign", ":" + paramBCSCredentials.getAccessKey() + ":" + ServiceUtils.toBase64(arrayOfByte));
}
catch (NoSuchAlgorithmException localNoSuchAlgorithmException) {
throw new BCSClientException("NoSuchAlgorithmException. Sign bcs failed!", localNoSuchAlgorithmException);
} catch (InvalidKeyException localInvalidKeyException) {
throw new BCSClientException("InvalidKeyException. Sign bcs failed!", localInvalidKeyException);
} catch (RuntimeException localRuntimeException) {
throw new BCSClientException("Sign bcs failed!", localRuntimeException);
}
}
}
从代码结构来看就sign函数在做事，我们来看，首先构造了两个StringBuffer用于盛放后来生成的东西，从意图上来看，第一个buffer放的是一些标志位，第一个buffer放的是签名的内容。 从代码来看每次操作的三个参数是必须的，bucket、object、httpMethod,从代码来看httpMethod就是标准的HTTP方法。
package com.baidu.inf.iis.bcs.http;
public enum HttpMethodName
{
GET, POST, PUT, DELETE, HEAD;
}
我们继续来看，这个是比较简单的，首先会放一个标志MBO，我们终于知道MBO是什么东西，Method、Object、Bucket。即就是