阿里云老版人脸识别Java调用示例参考

本文涉及的产品
密钥管理服务KMS,1000个密钥,100个凭据,1个月
简介: 目前阿里云提供了关于人脸识别的调用接口,提供的接口包括人脸检测定位、人脸属性识别及人脸对比三个API,用户可以基于Rest API的调用说明完成调用操作。下面给出使用Java语言分别使用网络图片和本地图片调用人脸属性API的示例。

准备工作

1、拥有阿里云账号并开通了人脸识别服务;
2、获取阿里云账户的AccessKey ID和Access Key Secret;
3、获取服务调用的地址,如果不清楚,可以直接到人脸识别API调试部分获取,也可以使用其完成快速测试。
_API

Java Code Sample

使用网络图片Code
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
import java.security.MessageDigest;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;
import javax.crypto.spec.SecretKeySpec;
import sun.misc.BASE64Encoder;
import javax.crypto.Mac;

//@SuppressWarnings("restriction")
public class FaceDemo1 {
    /*
     * 计算MD5+BASE64
     */
    public static String MD5Base64(String s) {
        if (s == null)
            return null;
        String encodeStr = "";
        byte[] utfBytes = s.getBytes();
        MessageDigest mdTemp;
        try {
            mdTemp = MessageDigest.getInstance("MD5");
            mdTemp.update(utfBytes);
            byte[] md5Bytes = mdTemp.digest();
            BASE64Encoder b64Encoder = new BASE64Encoder();
            encodeStr = b64Encoder.encode(md5Bytes);
        } catch (Exception e) {
            throw new Error("Failed to generate MD5 : " + e.getMessage());
        }
        return encodeStr;
    }
    /*
     * 计算 HMAC-SHA1
     */
    public static String HMACSha1(String data, String key) {
        String result;
        try {
            SecretKeySpec signingKey = new SecretKeySpec(key.getBytes(), "HmacSHA1");
            Mac mac = Mac.getInstance("HmacSHA1");
            mac.init(signingKey);
            byte[] rawHmac = mac.doFinal(data.getBytes());
            result = (new BASE64Encoder()).encode(rawHmac);
        } catch (Exception e) {
            throw new Error("Failed to generate HMAC : " + e.getMessage());
        }
        return result;
    }
    /*
     * 等同于javaScript中的 new Date().toUTCString();
     */
    public static String toGMTString(Date date) {
        SimpleDateFormat df = new SimpleDateFormat("E, dd MMM yyyy HH:mm:ss z", Locale.UK);
        df.setTimeZone(new java.util.SimpleTimeZone(0, "GMT"));
        return df.format(date);
    }
    /*
     * 发送POST请求
     */
    public static String sendPost(String url, String body, String ak_id, String ak_secret) throws Exception {
        PrintWriter out = null;
        BufferedReader in = null;
        String result = "";
        int statusCode = 200;
        try {
            URL realUrl = new URL(url);
            /*
             * http header 参数
             */
            String method = "POST";
            String accept = "application/json";
            String content_type = "application/json";
            String path = realUrl.getFile();
            String date = toGMTString(new Date());
            // 1.对body做MD5+BASE64加密
            String bodyMd5 = MD5Base64(body);
            String stringToSign = method + "\n" + accept + "\n" + bodyMd5 + "\n" + content_type + "\n" + date + "\n"
                    + path;
            // 2.计算 HMAC-SHA1
            String signature = HMACSha1(stringToSign, ak_secret);
            // 3.得到 authorization header
            String authHeader = "Dataplus " + ak_id + ":" + signature;
            // 打开和URL之间的连接
            URLConnection conn = realUrl.openConnection();
            // 设置通用的请求属性
            conn.setRequestProperty("accept", accept);
            conn.setRequestProperty("content-type", content_type);
            conn.setRequestProperty("date", date);
            conn.setRequestProperty("Authorization", authHeader);
            // 发送POST请求必须设置如下两行
            conn.setDoOutput(true);
            conn.setDoInput(true);
            // 获取URLConnection对象对应的输出流
            out = new PrintWriter(conn.getOutputStream());
            // 发送请求参数
            out.print(body);
            // flush输出流的缓冲
            out.flush();
            // 定义BufferedReader输入流来读取URL的响应
            statusCode = ((HttpURLConnection)conn).getResponseCode();
            if(statusCode != 200) {
                in = new BufferedReader(new InputStreamReader(((HttpURLConnection)conn).getErrorStream()));
            } else {
                in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
            }
            String line;
            while ((line = in.readLine()) != null) {
                result += line;
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (out != null) {
                    out.close();
                }
                if (in != null) {
                    in.close();
                }
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }
        if (statusCode != 200) {
            throw new IOException("\nHttp StatusCode: "+ statusCode + "\nErrorMessage: " + result);
        }
        return result;
    }
    /*
     * GET请求
     */
    public static String sendGet(String url, String ak_id, String ak_secret) throws Exception {
        String result = "";
        BufferedReader in = null;
        int statusCode = 200;
        try {
            URL realUrl = new URL(url);
            /*
             * http header 参数
             */
            String method = "GET";
            String accept = "application/json";
            String content_type = "application/json";
            String path = realUrl.getFile();
            String date = toGMTString(new Date());
            // 1.对body做MD5+BASE64加密
            // String bodyMd5 = MD5Base64(body);
            String stringToSign = method + "\n" + accept + "\n" + "" + "\n" + content_type + "\n" + date + "\n" + path;
            // 2.计算 HMAC-SHA1
            String signature = HMACSha1(stringToSign, ak_secret);
            // 3.得到 authorization header
            String authHeader = "Dataplus " + ak_id + ":" + signature;
            // 打开和URL之间的连接
            URLConnection connection = realUrl.openConnection();
            // 设置通用的请求属性
            connection.setRequestProperty("accept", accept);
            connection.setRequestProperty("content-type", content_type);
            connection.setRequestProperty("date", date);
            connection.setRequestProperty("Authorization", authHeader);
            connection.setRequestProperty("Connection", "keep-alive");
            // 建立实际的连接
            connection.connect();
            // 定义 BufferedReader输入流来读取URL的响应
            statusCode = ((HttpURLConnection)connection).getResponseCode();
            if(statusCode != 200) {
                in = new BufferedReader(new InputStreamReader(((HttpURLConnection)connection).getErrorStream()));
            } else {
                in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
            }
            String line;
            while ((line = in.readLine()) != null) {
                result += line;
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (in != null) {
                    in.close();
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        if (statusCode != 200) {
            throw new IOException("\nHttp StatusCode: "+ statusCode + "\nErrorMessage: " + result);
        }
        return result;
    }
    public static void main(String[] args) throws Exception {
        // 发送POST请求示例
            System.out.println(i);
            String ak_id = "******"; //用户ak
            String ak_secret = "******"; // 用户ak_secret
            String url = "https://dtplus-cn-shanghai.data.aliyuncs.com/face/attribute";
            String body = "{\"type\": \"0\", \"image_url\":\"https://ss0.bdstatic.com/94oJfD_bAAcT8t7mm9GUKT-xh_/timg?image&quality=100&size=b4000_4000&sec=1544608444&di=54513735567736d0eaeba7a13aa0421c&src=http://img5q.duitang.com/uploads/item/201411/23/20141123205812_Bircn.jpeg\"}";
            System.out.println("response body:" + sendPost(url, body, ak_id, ak_secret));
    }
}
使用本地图片Code
import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
import java.security.MessageDigest;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;
import javax.crypto.spec.SecretKeySpec;
import sun.misc.BASE64Encoder;
import javax.crypto.Mac;

//@SuppressWarnings("restriction")
public class FaceDemo2 {
    /*
     * 计算MD5+BASE64
     */
    public static String MD5Base64(String s) {
        if (s == null)
            return null;
        String encodeStr = "";
        byte[] utfBytes = s.getBytes();
        MessageDigest mdTemp;
        try {
            mdTemp = MessageDigest.getInstance("MD5");
            mdTemp.update(utfBytes);
            byte[] md5Bytes = mdTemp.digest();
            BASE64Encoder b64Encoder = new BASE64Encoder();
            encodeStr = b64Encoder.encode(md5Bytes);
        } catch (Exception e) {
            throw new Error("Failed to generate MD5 : " + e.getMessage());
        }
        return encodeStr;
    }
    /*
     * 计算 HMAC-SHA1
     */
    public static String HMACSha1(String data, String key) {
        String result;
        try {
            SecretKeySpec signingKey = new SecretKeySpec(key.getBytes(), "HmacSHA1");
            Mac mac = Mac.getInstance("HmacSHA1");
            mac.init(signingKey);
            byte[] rawHmac = mac.doFinal(data.getBytes());
            result = (new BASE64Encoder()).encode(rawHmac);
        } catch (Exception e) {
            throw new Error("Failed to generate HMAC : " + e.getMessage());
        }
        return result;
    }
    /*
     * 等同于javaScript中的 new Date().toUTCString();
     */
    public static String toGMTString(Date date) {
        SimpleDateFormat df = new SimpleDateFormat("E, dd MMM yyyy HH:mm:ss z", Locale.UK);
        df.setTimeZone(new java.util.SimpleTimeZone(0, "GMT"));
        return df.format(date);
    }
    /*
     * 发送POST请求
     */
    public static String sendPost(String url, String body, String ak_id, String ak_secret) throws Exception {
        PrintWriter out = null;
        BufferedReader in = null;
        String result = "";
        int statusCode = 200;
        try {
            URL realUrl = new URL(url);
            /*
             * http header 参数
             */
            String method = "POST";
            String accept = "application/json";
            String content_type = "application/json";

//            String content_type = "application/octet-stream";

            String path = realUrl.getFile();
            String date = toGMTString(new Date());
            // 1.对body做MD5+BASE64加密
            String bodyMd5 = MD5Base64(body);
            String stringToSign = method + "\n" + accept + "\n" + bodyMd5 + "\n" + content_type + "\n" + date + "\n"
                    + path;
            // 2.计算 HMAC-SHA1
            String signature = HMACSha1(stringToSign, ak_secret);
            // 3.得到 authorization header
            String authHeader = "Dataplus " + ak_id + ":" + signature;
            // 打开和URL之间的连接
            URLConnection conn = realUrl.openConnection();
            // 设置通用的请求属性
            conn.setRequestProperty("accept", accept);
            conn.setRequestProperty("content-type", content_type);
            conn.setRequestProperty("date", date);
            conn.setRequestProperty("Authorization", authHeader);
            // 发送POST请求必须设置如下两行
            conn.setDoOutput(true);
            conn.setDoInput(true);
            // 获取URLConnection对象对应的输出流
            out = new PrintWriter(conn.getOutputStream());
            // 发送请求参数
            out.print(body);
            // flush输出流的缓冲
            out.flush();
            // 定义BufferedReader输入流来读取URL的响应
            statusCode = ((HttpURLConnection)conn).getResponseCode();
            if(statusCode != 200) {
                in = new BufferedReader(new InputStreamReader(((HttpURLConnection)conn).getErrorStream()));
            } else {
                in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
            }
            String line;
            while ((line = in.readLine()) != null) {
                result += line;
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (out != null) {
                    out.close();
                }
                if (in != null) {
                    in.close();
                }
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }
        if (statusCode != 200) {
            throw new IOException("\nHttp StatusCode: "+ statusCode + "\nErrorMessage: " + result);
        }
        return result;
    }
    /*
     * GET请求
     */
    public static String sendGet(String url, String ak_id, String ak_secret) throws Exception {
        String result = "";
        BufferedReader in = null;
        int statusCode = 200;
        try {
            URL realUrl = new URL(url);
            /*
             * http header 参数
             */
            String method = "GET";
            String accept = "application/json";
            String content_type = "application/json";

//            String content_type = "application/octet-stream";
            String path = realUrl.getFile();
            String date = toGMTString(new Date());
            // 1.对body做MD5+BASE64加密
            // String bodyMd5 = MD5Base64(body);
            String stringToSign = method + "\n" + accept + "\n" + "" + "\n" + content_type + "\n" + date + "\n" + path;
            // 2.计算 HMAC-SHA1
            String signature = HMACSha1(stringToSign, ak_secret);
            // 3.得到 authorization header
            String authHeader = "Dataplus " + ak_id + ":" + signature;
            // 打开和URL之间的连接
            URLConnection connection = realUrl.openConnection();
            // 设置通用的请求属性
            connection.setRequestProperty("accept", accept);
            connection.setRequestProperty("content-type", content_type);
            connection.setRequestProperty("date", date);
            connection.setRequestProperty("Authorization", authHeader);
            connection.setRequestProperty("Connection", "keep-alive");
            // 建立实际的连接
            connection.connect();
            // 定义 BufferedReader输入流来读取URL的响应
            statusCode = ((HttpURLConnection)connection).getResponseCode();
            if(statusCode != 200) {
                in = new BufferedReader(new InputStreamReader(((HttpURLConnection)connection).getErrorStream()));
            } else {
                in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
            }
            String line;
            while ((line = in.readLine()) != null) {
                result += line;
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (in != null) {
                    in.close();
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        if (statusCode != 200) {
            throw new IOException("\nHttp StatusCode: "+ statusCode + "\nErrorMessage: " + result);
        }
        return result;
    }
    public static void main(String[] args) throws Exception {
        // 发送POST请求示例
        String ak_id = "******"; //用户ak
        String ak_secret = "******"; // 用户ak_secret
        String url = "https://dtplus-cn-shanghai.data.aliyuncs.com/face/attribute";

        //上传本地图片
        // Request body
        String pic_path = "C:\\Users\\****\\Desktop\\timg.jpg";//本地图片的路径

        File picBase64 = new File(pic_path);
        String pic = encodeImageToBase64(picBase64);
        //提出base64编码的换行符问题
        String data = pic.replaceAll("[\\s*\t\n\r]", "");
        data = "'" + data + "'";
        String body = "{\"type\": "+1+", \"content\": "+data+"}";
        System.out.println("response body:" + sendPost(url, body, ak_id, ak_secret));
    }

    /**
     * 将本地图片编码为base64
     *
     * @param file
     * @return
     * @throws Exception
     */
    public static String encodeImageToBase64(File file) throws Exception {
        //将图片文件转化为字节数组字符串,并对其进行Base64编码处理
//        loggerger.info("图片的路径为:" + file.getAbsolutePath());
        InputStream in = null;
        byte[] data = null;
        //读取图片字节数组
        try {
            in = new FileInputStream(file);
            data = new byte[in.available()];
            in.read(data);
            in.close();
        } catch (IOException e) {
            e.printStackTrace();
            throw new Exception("图片上传失败,请联系客服!");
        }
        //对字节数组Base64编码
        BASE64Encoder encoder = new BASE64Encoder();
        String base64 = encoder.encode(data);
        return base64;//返回Base64编码过的字节数组字符串
    }
}
人脸比对示例使用本地图片Code
import sun.misc.BASE64Encoder;

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
import java.security.MessageDigest;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;

//@SuppressWarnings("restriction")
public class FaceDemoVerify {
    /*
     * 计算MD5+BASE64
     */
    public static String MD5Base64(String s) {
        if (s == null)
            return null;
        String encodeStr = "";
        byte[] utfBytes = s.getBytes();
        MessageDigest mdTemp;
        try {
            mdTemp = MessageDigest.getInstance("MD5");
            mdTemp.update(utfBytes);
            byte[] md5Bytes = mdTemp.digest();
            BASE64Encoder b64Encoder = new BASE64Encoder();
            encodeStr = b64Encoder.encode(md5Bytes);
        } catch (Exception e) {
            throw new Error("Failed to generate MD5 : " + e.getMessage());
        }
        return encodeStr;
    }
    /*
     * 计算 HMAC-SHA1
     */
    public static String HMACSha1(String data, String key) {
        String result;
        try {
            SecretKeySpec signingKey = new SecretKeySpec(key.getBytes(), "HmacSHA1");
            Mac mac = Mac.getInstance("HmacSHA1");
            mac.init(signingKey);
            byte[] rawHmac = mac.doFinal(data.getBytes());
            result = (new BASE64Encoder()).encode(rawHmac);
        } catch (Exception e) {
            throw new Error("Failed to generate HMAC : " + e.getMessage());
        }
        return result;
    }
    /*
     * 等同于javaScript中的 new Date().toUTCString();
     */
    public static String toGMTString(Date date) {
        SimpleDateFormat df = new SimpleDateFormat("E, dd MMM yyyy HH:mm:ss z", Locale.UK);
        df.setTimeZone(new java.util.SimpleTimeZone(0, "GMT"));
        return df.format(date);
    }
    /*
     * 发送POST请求
     */
    public static String sendPost(String url, String body, String ak_id, String ak_secret) throws Exception {
        PrintWriter out = null;
        BufferedReader in = null;
        String result = "";
        int statusCode = 200;
        try {
            URL realUrl = new URL(url);
            /*
             * http header 参数
             */
            String method = "POST";
            String accept = "application/json";
            String content_type = "application/json";

//            String content_type = "application/octet-stream";

            String path = realUrl.getFile();
            String date = toGMTString(new Date());
            // 1.对body做MD5+BASE64加密
            String bodyMd5 = MD5Base64(body);
            String stringToSign = method + "\n" + accept + "\n" + bodyMd5 + "\n" + content_type + "\n" + date + "\n"
                    + path;
            // 2.计算 HMAC-SHA1
            String signature = HMACSha1(stringToSign, ak_secret);
            // 3.得到 authorization header
            String authHeader = "Dataplus " + ak_id + ":" + signature;
            // 打开和URL之间的连接
            URLConnection conn = realUrl.openConnection();
            // 设置通用的请求属性
            conn.setRequestProperty("accept", accept);
            conn.setRequestProperty("content-type", content_type);
            conn.setRequestProperty("date", date);
            conn.setRequestProperty("Authorization", authHeader);
            // 发送POST请求必须设置如下两行
            conn.setDoOutput(true);
            conn.setDoInput(true);
            // 获取URLConnection对象对应的输出流
            out = new PrintWriter(conn.getOutputStream());
            // 发送请求参数
            out.print(body);
            // flush输出流的缓冲
            out.flush();
            // 定义BufferedReader输入流来读取URL的响应
            statusCode = ((HttpURLConnection)conn).getResponseCode();
            if(statusCode != 200) {
                in = new BufferedReader(new InputStreamReader(((HttpURLConnection)conn).getErrorStream()));
            } else {
                in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
            }
            String line;
            while ((line = in.readLine()) != null) {
                result += line;
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (out != null) {
                    out.close();
                }
                if (in != null) {
                    in.close();
                }
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }
        if (statusCode != 200) {
            throw new IOException("\nHttp StatusCode: "+ statusCode + "\nErrorMessage: " + result);
        }
        return result;
    }
    /*
     * GET请求
     */
    public static String sendGet(String url, String ak_id, String ak_secret) throws Exception {
        String result = "";
        BufferedReader in = null;
        int statusCode = 200;
        try {
            URL realUrl = new URL(url);
            /*
             * http header 参数
             */
            String method = "GET";
            String accept = "application/json";
            String content_type = "application/json";

//            String content_type = "application/octet-stream";
            String path = realUrl.getFile();
            String date = toGMTString(new Date());
            // 1.对body做MD5+BASE64加密
            // String bodyMd5 = MD5Base64(body);
            String stringToSign = method + "\n" + accept + "\n" + "" + "\n" + content_type + "\n" + date + "\n" + path;
            // 2.计算 HMAC-SHA1
            String signature = HMACSha1(stringToSign, ak_secret);
            // 3.得到 authorization header
            String authHeader = "Dataplus " + ak_id + ":" + signature;
            // 打开和URL之间的连接
            URLConnection connection = realUrl.openConnection();
            // 设置通用的请求属性
            connection.setRequestProperty("accept", accept);
            connection.setRequestProperty("content-type", content_type);
            connection.setRequestProperty("date", date);
            connection.setRequestProperty("Authorization", authHeader);
            connection.setRequestProperty("Connection", "keep-alive");
            // 建立实际的连接
            connection.connect();
            // 定义 BufferedReader输入流来读取URL的响应
            statusCode = ((HttpURLConnection)connection).getResponseCode();
            if(statusCode != 200) {
                in = new BufferedReader(new InputStreamReader(((HttpURLConnection)connection).getErrorStream()));
            } else {
                in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
            }
            String line;
            while ((line = in.readLine()) != null) {
                result += line;
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (in != null) {
                    in.close();
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        if (statusCode != 200) {
            throw new IOException("\nHttp StatusCode: "+ statusCode + "\nErrorMessage: " + result);
        }
        return result;
    }
    public static void main(String[] args) throws Exception {
        // 发送POST请求示例
        String ak_id = "********"; //用户ak
        String ak_secret = "********"; // 用户ak_secret
        String url = "https://dtplus-cn-shanghai.data.aliyuncs.com/face/verify";

        //上传本地图片
        // Request body
        String pic_path = "D:\\picturetest\\timg.jpg";//本地图片的路径

        File picBase64 = new File(pic_path);
        String pic = encodeImageToBase64(picBase64);
        //提出base64编码的换行符问题
        String data = pic.replaceAll("[\\s*\t\n\r]", "");
        data = "'" + data + "'";
        String body = "{\"type\":1,\n" +
                "\"content_1\":"+data+",\n" +
                "\"content_2\":"+data+"\n" +
                "}";
        System.out.println("response body:" + sendPost(url, body, ak_id, ak_secret));
    }

    /**
     * 将本地图片编码为base64
     *
     * @param file
     * @return
     * @throws Exception
     */
    public static String encodeImageToBase64(File file) throws Exception {
        //将图片文件转化为字节数组字符串,并对其进行Base64编码处理
//        loggerger.info("图片的路径为:" + file.getAbsolutePath());
        InputStream in = null;
        byte[] data = null;
        //读取图片字节数组
        try {
            in = new FileInputStream(file);
            data = new byte[in.available()];
            in.read(data);
            in.close();
        } catch (IOException e) {
            e.printStackTrace();
            throw new Exception("图片上传失败,请联系客服!");
        }
        //对字节数组Base64编码
        BASE64Encoder encoder = new BASE64Encoder();
        String base64 = encoder.encode(data);
        return base64;//返回Base64编码过的字节数组字符串
    }
}

注意事项

关于调用本地图片的问题,特别需要注意关于base64编码默认添加了换行符的问题,需要剔除,请求body的具体格式也需要注意,具体参考示例代码。

参考链接

API校验规范

人脸识别错误码

相关文章
|
12天前
|
Java
在 Java 中捕获和处理自定义异常的代码示例
本文提供了一个 Java 代码示例,展示了如何捕获和处理自定义异常。通过创建自定义异常类并使用 try-catch 语句,可以更灵活地处理程序中的错误情况。
|
1月前
|
存储 Java
Java中的HashMap和TreeMap,通过具体示例展示了它们在处理复杂数据结构问题时的应用。
【10月更文挑战第19天】本文详细介绍了Java中的HashMap和TreeMap,通过具体示例展示了它们在处理复杂数据结构问题时的应用。HashMap以其高效的插入、查找和删除操作著称,而TreeMap则擅长于保持元素的自然排序或自定义排序,两者各具优势,适用于不同的开发场景。
44 1
|
1月前
|
存储 缓存 Java
java基础:IO流 理论与代码示例(详解、idea设置统一utf-8编码问题)
这篇文章详细介绍了Java中的IO流,包括字符与字节的概念、编码格式、File类的使用、IO流的分类和原理,以及通过代码示例展示了各种流的应用,如节点流、处理流、缓存流、转换流、对象流和随机访问文件流。同时,还探讨了IDEA中设置项目编码格式的方法,以及如何处理序列化和反序列化问题。
70 1
java基础:IO流 理论与代码示例(详解、idea设置统一utf-8编码问题)
|
1月前
|
存储 Java
什么是带有示例的 Java 中的交错数组?
什么是带有示例的 Java 中的交错数组?
46 9
|
1月前
|
Java
让星星⭐月亮告诉你,jdk1.8 Java函数式编程示例:Lambda函数/方法引用/4种内建函数式接口(功能性-/消费型/供给型/断言型)
本示例展示了Java中函数式接口的使用,包括自定义和内置的函数式接口。通过方法引用,实现对字符串操作如转换大写、数值转换等,并演示了Function、Consumer、Supplier及Predicate四种主要内置函数式接口的应用。
27 1
|
1月前
|
Java API 网络安全
Java 发送邮件示例
本示例展示了如何使用Java编程语言发送电子邮件。通过利用JavaMail API,这段代码实现了从配置SMTP服务器,设置邮件属性,到发送邮件的全过程,为开发者提供了实用的参考。
|
2月前
|
JavaScript 前端开发 Java
Java 8 新特性详解及应用示例
Java 8 新特性详解及应用示例
|
1月前
|
XML Java 数据格式
Java正则表达式大全(参考)
Java正则表达式大全(参考)
|
2月前
|
存储 SQL 分布式计算
Java连接阿里云MaxCompute例
要使用Java连接阿里云MaxCompute数据库,首先需在项目中添加MaxCompute JDBC驱动依赖,推荐通过Maven管理。避免在代码中直接写入AccessKey,应使用环境变量或配置文件安全存储。示例代码展示了如何注册驱动、建立连接及执行SQL查询。建议使用RAM用户提升安全性,并根据需要配置时区和公网访问权限。具体步骤和注意事项请参考阿里云官方文档。
|
3月前
|
Java 开发工具
通过Java SDK调用阿里云模型服务
在阿里云平台上,可以通过创建应用并使用模型服务完成特定任务,如生成文章内容。本示例展示了一段简化的Java代码,演示了如何调用阿里云模型服务生成关于“春秋战国经济与文化”的简短文章。示例代码通过设置系统角色为历史学家,并提出文章生成需求,最终处理并输出生成的文章内容。在实际部署前,请确保正确配置环境变量中的密钥和ID,并根据需要调整SDK导入语句及类名。更多详情和示例,请参考相关链接。
下一篇
无影云桌面