httpclient获取digest认证

在使用HttpClient获取Digest认证时，需要进行以下步骤：

1. 创建HttpClient实例

HttpClient httpClient = new DefaultHttpClient();

2. 创建HttpGet请求

HttpGet httpGet = new HttpGet(url);

3. 执行请求并获取响应

HttpResponse response = httpClient.execute(httpGet);

4. 获取响应状态码

int statusCode = response.getStatusLine().getStatusCode();

5. 判断状态码是否为401

if (statusCode == HttpStatus.SC_UNAUTHORIZED) {
    // 获取认证头信息
    Header header = response.getFirstHeader("WWW-Authenticate");
    if (header != null && header.getValue().startsWith("Digest")) {
        // 解析认证头信息
        DigestScheme digestScheme = new DigestScheme();
        digestScheme.processChallenge(header);
        // 构造Digest认证对象
        UsernamePasswordCredentials credentials = new UsernamePasswordCredentials(username, password);
        AuthScope authScope = new AuthScope(targetHost.getHostName(), targetHost.getPort(), digestScheme.getRealm(), AuthSchemes.DIGEST);
        HttpClientContext context = HttpClientContext.create();
        CredentialsProvider credentialsProvider = new BasicCredentialsProvider();
        credentialsProvider.setCredentials(authScope, credentials);
        context.setCredentialsProvider(credentialsProvider);
        // 重新执行请求
        response = httpClient.execute(httpGet, context);
    }
}

6. 获取响应内容

HttpEntity entity = response.getEntity();
String content = EntityUtils.toString(entity);

完整代码示例：

public static void main(String[] args) throws Exception {
    HttpClient httpClient = new DefaultHttpClient();
    HttpGet httpGet = new HttpGet("http://www.example.com");
    HttpResponse response = httpClient.execute(httpGet);
    int statusCode = response.getStatusLine().getStatusCode();
    if (statusCode == HttpStatus.SC_UNAUTHORIZED) {
        Header header = response.getFirstHeader("WWW-Authenticate");
        if (header != null && header.getValue().startsWith("Digest")) {
            DigestScheme digestScheme = new DigestScheme();
            digestScheme.processChallenge(header);
            String username = "your-username";
            String password = "your-password";
            UsernamePasswordCredentials credentials = new UsernamePasswordCredentials(username, password);
            HttpHost targetHost = new HttpHost(httpGet.getURI().getHost(), httpGet.getURI().getPort(), httpGet.getURI().getScheme());
            AuthScope authScope = new AuthScope(targetHost.getHostName(), targetHost.getPort(), digestScheme.getRealm(), AuthSchemes.DIGEST);
            HttpClientContext context = HttpClientContext.create();
            CredentialsProvider credentialsProvider = new BasicCredentialsProvider();
            credentialsProvider.setCredentials(authScope, credentials);
            context.setCredentialsProvider(credentialsProvider);
            response = httpClient.execute(httpGet, context);
        }
    }
    HttpEntity entity = response.getEntity();
    String content = EntityUtils.toString(entity);
    System.out.println(content);
}