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Java HttpClient-Restful工具各种请求高度封装提炼及总结

来源:互联网 收集:自由互联 发布时间:2023-01-30
目录 总思路 RestfulService 工具类上一层 文件上传方式 获取文件流 再上一层的业务调用 总思路 总的工具要求底层完全可复用的代码全部提炼,也就是不通类型(GET, POST, DELETE, PUT 等等
目录
  • 总思路
  • RestfulService
    • 工具类上一层
    • 文件上传方式
    • 获取文件流
  • 再上一层的业务调用

    总思路

    总的工具要求底层完全可复用的代码全部提炼,也就是不通类型(GET, POST, DELETE, PUT 等等)请求的决定性公共步骤其实是可以提炼出来的。

    即 一个请求,请求头一定会有,请求路径一定会有,发起请求一定会有,返回处理一定会有。

    但同时由于请求头内容可能会有不同的要求或者加密方式,所以需要将相关加工过程放到基础工具类之外,保证调用基础工具类时只执行所有请求都需要的的步骤,不带有特殊处理。

    这里主要使用的都是 org.apache.http 已包装的 httpClient ,项目中进一步将各种类型的请求做进一步提炼和封装。

    从最底层开始说明

    RestfulService

    基础 RestfulService 工具代码可以参考如下:

    个别说明加入到注释中或示例代码结尾

    ......
    import org.apache.http.HttpEntity;
    import org.apache.http.HttpHeaders;
    import org.apache.http.NameValuePair;
    import org.apache.http.client.methods.CloseableHttpResponse;
    import org.apache.http.client.methods.HttpDelete;
    import org.apache.http.client.methods.HttpGet;
    import org.apache.http.client.methods.HttpPost;
    import org.apache.http.client.methods.HttpPut;
    import org.apache.http.client.methods.HttpRequestBase;
    import org.apache.http.entity.ContentType;
    import org.apache.http.entity.StringEntity;
    import org.apache.http.impl.client.CloseableHttpClient;
    
    import java.io.BufferedReader;
    import java.io.IOException;
    import java.io.InputStreamReader;
    import java.io.OutputStream;
    import java.net.URI;
    import java.nio.charset.StandardCharsets;
    import java.util.Objects;
    
    public class MyRestfulService {
    
        private static xxxLogger = new xxxLog(MyRestfulService .class);
        // 所有请求都由 httpClient.execute()  方式发出
        private CloseableHttpClient httpClient;
        
        // 由于 httpClient 也存在自定义各种属性,所以这里也作为一个定义的参数
        // 通过构造方法传入外侧定义的  CloseableHttpClient
        public MyRestfulService(CloseableHttpClient client) {
            this.httpClient = client;
        }
    
    	// 一般的GET 请求
        public String jsonGet(String url, final NameValuePair[] headerParams) throws IOException, XxxxException {
            URI uri = URI.create(url);
            HttpGet get = new HttpGet(uri);
            this.addHeaders(headerParams, get);
            CloseableHttpResponse response = httpClient.execute(get);
            return this.parseResponseData(response, url);
        }
    
        // Get请求 获取文件某字符串开头的
        public String fileGetLine(String url, final NameValuePair[] headerParams, String head) throws IOException,
                XxxxException {
            URI uri = URI.create(url);
            HttpGet get = new HttpGet(uri);
            this.addHeaders(headerParams, get);
            CloseableHttpResponse response = httpClient.execute(get);
            BufferedReader br = null;
            try {
                br = new BufferedReader(new InputStreamReader(response.getEntity().getContent(), "UTF-8"));
                String output;
                while ((output = br.readLine()) != null) {
                    if (output.contains(head) && Objects.equals(output.split("=")[0], head)) {
                        return output;
                    }
                }
                return null;
            } catch (Exception e) {
                logger.error("Failed to get rest response", e);
                // 为自定义异常类型
                throw new XxxxException(ExceptionType.XXXXXX);
            } finally {
                if (br != null) {
                    br.close();
                }
                response.close();
            }
        }
    
        // 携带请求体即 Body 的GET 请求 其中  HttpGetWithEntity 需要自定义到文件中 稍后给出示例
        public String jsonGetWithBody(String url, final NameValuePair[] headerParams, String requestBody)
                throws IOException, XxxxException {
            URI uri = URI.create(url);
            HttpGetWithEntity get = new HttpGetWithEntity(uri);
            this.addHeaders(headerParams, get);
    
            StringEntity input = new StringEntity(requestBody, ContentType.APPLICATION_JSON);
            get.setEntity(input);
            CloseableHttpResponse response = httpClient.execute(get);
            return this.parseResponseData(response, url);
        }
    	
    	// 普通的POST 请求
        public String jsonPost(String url, final NameValuePair[] headerParams, String requestBody)
                throws IOException, XxxxException {
            HttpPost post = new HttpPost(url);
            this.addHeaders(headerParams, post);
            
            if (requestBody != null) {
                StringEntity input = new StringEntity(requestBody, ContentType.APPLICATION_JSON);
                post.setEntity(input);
            }
            CloseableHttpResponse response = httpClient.execute(post);
            return this.parseResponseData(response, url);
        }
    
    	// 普通 put 请求
        public String jsonPut(String url, final NameValuePair[] headerParams, String requestBody)
                throws IOException, XxxxException {
            HttpPut put = new HttpPut(url);
            this.addHeaders(headerParams, put);
            StringEntity input = new StringEntity(requestBody, ContentType.APPLICATION_JSON);
            put.setEntity(input);
            CloseableHttpResponse response = httpClient.execute(put);
            return this.parseResponseData(response, url);
        }
    
    	// 一般的DELETE 请求
        public String jsonDelete(String url, final NameValuePair[] headerParams) throws IOException, XxxxException {
            HttpDelete delete = new HttpDelete(url);
            this.addHeaders(headerParams, delete);
            CloseableHttpResponse response = null;
            response = httpClient.execute(delete);
            return this.parseResponseData(response, url);
        }
    
    	// 携带请求体的DELETE 请求 HttpDeleteWithBody
        public String jsonDeleteWithBody(String url, final NameValuePair[] headerParams, String requestBody)
                throws IOException, XxxxException {
            HttpDeleteWithBody delete = new HttpDeleteWithBody(url);
            this.addHeaders(headerParams, delete);
            StringEntity input = new StringEntity(requestBody, ContentType.APPLICATION_JSON);
            delete.setEntity(input);
            CloseableHttpResponse response = null;
            response = httpClient.execute(delete);
            return this.parseResponseData(response, url);
        }
    
    	// 文件类传入 上传
        public String uploadFile(String url, final NameValuePair[] headerParams, HttpEntity multipartEntity)
                throws IOException, XxxxException {
            HttpPost post = new HttpPost(url);
            post.setEntity(multipartEntity);
            post.addHeader(HttpHeaders.CONTENT_TYPE, post.getEntity().getContentType().getValue());
            if (headerParams != null) {
                for (NameValuePair nameValuePair : headerParams) {
                    post.addHeader(nameValuePair.getName(), nameValuePair.getValue());
                }
            }
            return this.parseResponseData(httpClient.execute(post), url);
        }
    
    	// 数据结果转换
        private String parseResponseData(CloseableHttpResponse response, String url) throws IOException,
                XxxxException {
            BufferedReader br = null;
            try {
            	// 编码转义结果
                br = new BufferedReader(new InputStreamReader(response.getEntity().getContent(), StandardCharsets.UTF_8));
                StringBuilder sbuilder = new StringBuilder();
                String output;
                while ((output = br.readLine()) != null) {
                    sbuilder.append(output);
                }
                logger.debug("MyRestfulService Request-URL: " + url + "; response: " + response.toString() + "; data:" + sbuilder + "}");
                int statusCode = response.getStatusLine().getStatusCode();
                // 200 可用已有常量替代 HTTP 本身有提供
                if (statusCode != 200) {
                    logger.info("Failed to get restful response, http error code = " + statusCode);
                }
                return sbuilder.toString();
            } catch (Exception e) {
                logger.error("Failed to get rest response", e);
                // 自定义异常
                throw new XxxxException(ExceptionType.XXXXXXX);
            } finally {
                if (br != null) {
                    br.close();
                }
                response.close();
            }
        }
    
    	// 公用 添加自定义请求头信息
        private void addHeaders(final NameValuePair[] headerParams, HttpRequestBase requestBase) {
            if (headerParams != null) {
                for (int i = 0; i < headerParams.length; i++) {
                    NameValuePair nameValuePair = headerParams[i];
                    requestBase.addHeader(nameValuePair.getName(), nameValuePair.getValue());
                }
            }
            this.addCommonHeader(requestBase);
        }
    
    	// 公用 添加公共请求头或公共操作
        private void addCommonHeader(HttpRequestBase method) {
        	// 去除个别属性
            if (method.containsHeader("Content-Length")) {
                method.removeHeaders("Content-Length");
            }
        	// 没有则添加
            if (!method.containsHeader("Content-Type")) {
                method.addHeader("Content-Type", "application/json;charset=utf-8");
            }
    		
    		// 强制更新或添加
            method.setHeader("accept", "application/json,text/plain,text/html");
        }
        
        // 文件下载
    	public String downloadFile(String url, OutputStream outputStream,NameValuePair[] headerParams)
                throws IOException, DXPException {
            HttpGet httpget = new HttpGet(url);
            this.addHeaders(headerParams, httpget);
            CloseableHttpResponse execute = httpClient.execute(httpget);
            if(null != execute && execute.containsHeader("Content-Disposition")){
                HttpEntity entity = execute.getEntity();
                if (entity != null ) {
                    entity.writeTo(outputStream);
                }
            }else {
                return this.parseResponseData(execute, url);
            }
            return null;
        }
    
    	// httpClient 对应的get set 方法
        public CloseableHttpClient getHttpClient() {
            return this.httpClient;
        }
    
        public void setHttpClient(CloseableHttpClient httpClient) {
            this.httpClient = httpClient;
        }
    }

    上面

    HttpDeleteWithBody 定义:

    import java.net.URI;
    import org.apache.http.client.methods.HttpEntityEnclosingRequestBase;
    
    public class HttpDeleteWithBody extends HttpEntityEnclosingRequestBase {
    
        public static final String METHOD_NAME = "DELETE";
    
        public HttpDeleteWithBody(final String uri) {
            super();
            setURI(URI.create(uri));
        }
    
        public HttpDeleteWithBody(final URI uri) {
            super();
            setURI(uri);
        }
    
        public HttpDeleteWithBody() {
            super();
        }
    
        public String getMethod() {
            return METHOD_NAME;
        }
    }

    上面 HttpGetWithBody:

    import org.apache.http.client.methods.HttpEntityEnclosingRequestBase;
    
    public class HttpGetWithEntity extends HttpEntityEnclosingRequestBase {
    
        private static final String METHOD_NAME = "GET";
    
        public HttpGetWithEntity() {
            super();
        }
    
        public HttpGetWithEntity(final URI uri) {
            super();
            setURI(uri);
        }
    
        HttpGetWithEntity(final String uri) {
            super();
            setURI(URI.create(uri));
        }
    
        @Override
        public String getMethod() {
            return METHOD_NAME;
        }
    }

    具体来源其实就是照抄 源码 httppost POST 的结构

    然后换个名字以及属性名即可完成请求体的携带

    NameValuePair[]

    示例中用到了大量的 NameValuePair[] 其,内部结构类似于 Map 但内部属性为name, value

    实际也可以使用 Map 来替代这种存储结构, NameValuePair 也是 org.apache.http 内部提供的类。

    工具类上一层

    其他调用者。用于处理特殊的请求头信息,拼接请求参数以及请求路径等内容

    并构建使用的 CloseableHttpClient 传入工具类。

    示例:

    某一 上层 Service 的内容示例:

    ......
    ......
    import org.apache.commons.lang.StringUtils;
    import org.apache.http.HttpHeaders;
    import org.apache.http.NameValuePair;
    import org.apache.http.client.config.AuthSchemes;
    import org.apache.http.client.config.CookieSpecs;
    import org.apache.http.client.config.RequestConfig;
    import org.apache.http.client.methods.HttpDelete;
    import org.apache.http.client.methods.HttpGet;
    import org.apache.http.client.methods.HttpPost;
    import org.apache.http.config.ConnectionConfig;
    import org.apache.http.config.SocketConfig;
    import org.apache.http.conn.ssl.NoopHostnameVerifier;
    import org.apache.http.impl.client.CloseableHttpClient;
    import org.apache.http.impl.client.HttpClientBuilder;
    import org.apache.http.message.BasicNameValuePair;
    import org.springframework.stereotype.Service;
    
    import javax.annotation.PostConstruct;
    import javax.annotation.PreDestroy;
    import java.io.IOException;
    import java.io.UnsupportedEncodingException;
    import java.net.URLEncoder;
    import java.nio.charset.StandardCharsets;
    import java.util.ArrayList;
    import java.util.Arrays;
    import java.util.List;
    import java.util.Map;
    
    @Service("XXXRestfulService")
    public class XXXRestfulService implements IXxxRestfulService {
        private static final XXXLog xxxLog = new XXXLog(XXXRestfulService .class);
    
        private static int maxConnPerHost = 20;
        private static int maxTotalConn = 20;
        /**
         * 数据读取超时时间
         */
        private static int soTimeout = 30000;
        /**
         * http连接超时时间
         */
        private static int connectionTimeout = 10000;
        /**
         * 连接管理器超时时间
         */
        private static int connectionManagerTimeout = 10000;
    
    	// 基础工具类对象声明
        private MyRestfulService restService;
    
        private CloseableHttpClient createHttpClient() {
            CloseableHttpClient httpClient = null;
            try {
                @SuppressWarnings("deprecation") ConnectionConfig cConfig =
                        ConnectionConfig.custom().setCharset(StandardCharsets.UTF_8).build();
                SocketConfig config = SocketConfig.custom().setSoTimeout(soTimeout).build();
                RequestConfig defaultRequestConfig =
                        RequestConfig.custom().setExpectContinueEnabled(true).setCookieSpec(CookieSpecs.DEFAULT)
                                .setTargetPreferredAuthSchemes(Arrays.asList(AuthSchemes.NTLM, AuthSchemes.DIGEST))
                                .setProxyPreferredAuthSchemes(Arrays.asList(AuthSchemes.BASIC))
                                .setConnectionRequestTimeout(connectionManagerTimeout).setConnectTimeout(connectionTimeout)
                                .setSocketTimeout(soTimeout).build();
                httpClient = HttpClientBuilder.create().setMaxConnPerRoute(maxConnPerHost).setMaxConnTotal(maxTotalConn)
                        .setSSLHostnameVerifier(new NoopHostnameVerifier())
                        .setDefaultRequestConfig(RequestConfig.copy(defaultRequestConfig).build())
                        .setDefaultConnectionConfig(cConfig).setDefaultSocketConfig(config).build();
            } catch (Exception e) {
                xxxLog.error("Create Http Client Failed", e);
            }
    
            return httpClient;
        }
    
    	// 类初始化时执行的方法
        @PostConstruct
        public void initProperties() {
            try {
                CloseableHttpClient client = this.createHttpClient();
                this.restService = new MyRestfulService(client);
            } catch (Exception e) {
                xxxLog.error("Failed To Init DataFillRestfulService", e);
            }
        }
    
    	// 关闭资源,如果每次都重新请求则也可以放到工具类内每次请求完成都关闭
        @PreDestroy   // @PreDestroy 实际 Servlet 被销毁前调用的方法
        public void destroy() {
            try {
                CloseableHttpClient httpclient = restService.getHttpClient();
                httpclient.close();
            } catch (IOException e) {
                xxxLog.error("Failed To Destroy HttpClient", e);
            }
        }
    
    	// 对请求头内容的特殊处理
        private NameValuePair[] getBaseHeaders(String methodName, String urlStr) {
        // 对请求头内容的特殊处理  若没有则直接添加到 返回值 NameValuePair[] 数组即可
            ............
        }
    
    	// 如果需要URL编码则可以使用该方法
        private String encodeHeader(String value) throws UnsupportedEncodingException {
            if (StringUtils.isEmpty(value)) {
                return value;
            }
            return URLEncoder.encode(value, "UTF-8");
        }
    
    	// 拼接实际请求路径
    	// XXXXConfig 可以作为一个类专门加载配置文件中的一些有关的地址信息等
        public String getRequestUrl(String actionUrl) {
            return XXXXConfig.getXxxxServer() + actionUrl;
        }
    
    
        @Override
        public String get(final String actionUrl, Map<String, String> map) {
        	String requestUrl = getRequestUrl(actionUrl);
            // 传入实际地址等 调用基础工具类请求
            .....
        }
    
        @Override
        public String post(final String actionUrl, final String jsonBody) {
        	String requestUrl = getRequestUrl(actionUrl);
            // 传入实际地址等 调用基础工具类请求
            .....
        }
    
        @Override
        public String delete(final String actionUrl) {
        	String requestUrl = getRequestUrl(actionUrl);
            // 传入实际地址等 调用基础工具类请求
            .....
        }
    }
    

    可以看的出,上层工具类先声明了 工具类对象 然后在当前类初始化时完成了对当前Service请求自己 httpClient 的相关创建以及配置的赋值,并将该对象 传递给工具类,使得调用工具类时依旧使用的是自己创建的那一个对象。

    并通过一般的工具类将需要的配置文件的信息加载后,直接在该类中引用。完成请求信息的拼接。

    由于不同的产品间的请求头要求信息可能不同,所以需要自己额外处理请求头相关信息。

    这里其实还是在封装部分内容,使得业务请求调用时进一步简化。

    一些工具类特殊的传入如下示例:

    文件上传方式

    public String uploadFile(String url, final NameValuePair[] headerParams, HttpEntity multipartEntity)

    中 HttpEntity 中加入文件的方式

    		MultipartEntityBuilder builder = MultipartEntityBuilder.create();
            builder.setMode(HttpMultipartMode.BROWSER_COMPATIBLE);
            builder.setCharset(StandardCharsets.UTF_8);
            builder.addBinaryBody("file", inputStream, ContentType.DEFAULT_BINARY, fileName);
    
    		builder.build();   // 最终可以到的 想要的 HttpEntity 携带文件内容

    其中 inputStreamInputStream 类型的文件输入流, fileName 为 String 文件名;

    获取文件流

    public String downloadFile(String url, OutputStream outputStream,NameValuePair[] headerParams)

    获得请求中的文件流,则需要传入 OutputStream 类型的 输出流对象 outputStream。

    再上一层的业务调用

    业务层处则通过直接定义指定的方法和入参,在内部直接写入请求映射路径,并要求传入指定参数完成业务封装,类似于:

    	@Override
        public XxxxxxxDTO<XXX> getXxxxList(XxxxxListRequest request,
                                                   String xxx, String xxxx) throws XXXException {
            String url = "/xxxx/api/xxxx/xxxx/list";
            String result = XxxxxRestfulService.post(url, JsonUtil.getJsonStr(request), xxx, xxxx);
            // 对 result 进行转化 转为自定义类或者Map 等返回
            return ......;
        }

    这样在外部调用该业务方法时需要感知的只有入参,其他几乎感知不到,与一般的方法差别几乎没有

    以上为个人经验,希望能给大家一个参考,也希望大家多多支持自由互联。

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