java小白的成长记录之curl的实现

本文主要是介绍java小白的成长记录之curl的实现，对大家解决编程问题具有一定的参考价值，需要的程序猿们随着小编来一起学习吧！

一、背景

一周的忙碌过后又到了愉快的周末，又开始了作为小白的成长之旅。

作为一个资深的中转部门，什么最重要呢，当然是curl了，调用其他地方的接口，获取数据，然后进行处理。

所以今天的目标就是实现curl了！

二、导入核心包

在pom.xml将加入下面内容

        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>4.4</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.51</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>

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配置properties文件

#最大连接数
http.maxTotal = 100
#并发数
http.defaultMaxPerRoute = 20
#创建连接的最长时间
http.connectTimeout=1000
#从连接池中获取到连接的最长时间
http.connectionRequestTimeout=500
#数据传输的最长时间
http.socketTimeout=10000
http.validateAfterInactivity=1000
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三、建立Client实体类

新增HttpClientConfiguration.java

package com.example.demo.controller;

import org.apache.http.client.config.RequestConfig;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class HttpClientConfiguration {
    @Value("${http.maxTotal}")
    private Integer maxTotal;

    @Value("${http.defaultMaxPerRoute}")
    private Integer defaultMaxPerRoute;

    @Value("${http.connectTimeout}")
    private Integer connectTimeout;

    @Value("${http.connectionRequestTimeout}")
    private Integer connectionRequestTimeout;

    @Value("${http.socketTimeout}")
    private Integer socketTimeout;

    @Value("${http.validateAfterInactivity}")
    private Integer validateAfterInactivity;


    @Bean
    public PoolingHttpClientConnectionManager poolingHttpClientConnectionManager(){
        PoolingHttpClientConnectionManager connectionManager = new PoolingHttpClientConnectionManager();
        connectionManager.setMaxTotal(maxTotal);
        connectionManager.setDefaultMaxPerRoute(defaultMaxPerRoute);
        connectionManager.setValidateAfterInactivity(validateAfterInactivity);
        return connectionManager;
    }

    @Bean
    public HttpClientBuilder httpClientBuilder(PoolingHttpClientConnectionManager poolingHttpClientConnectionManager){
        HttpClientBuilder httpClientBuilder = HttpClientBuilder.create();
        httpClientBuilder.setConnectionManager(poolingHttpClientConnectionManager);

        return httpClientBuilder;
    }

    @Bean
    public CloseableHttpClient closeableHttpClient(HttpClientBuilder httpClientBuilder){
        return httpClientBuilder.build();
    }


    @Bean
    public RequestConfig.Builder builder(){
        RequestConfig.Builder builder = RequestConfig.custom();
        return builder.setConnectTimeout(connectTimeout)
                .setConnectionRequestTimeout(connectionRequestTimeout)
                .setSocketTimeout(socketTimeout);
    }

    @Bean
    public RequestConfig requestConfig(RequestConfig.Builder builder){
        return builder.build();
    }
}

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新增HttpClient.java

package com.example.demo.controller;

import com.alibaba.fastjson.JSONObject;
import org.apache.http.HttpHeaders;
import org.apache.http.HttpStatus;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.utils.URIBuilder;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.util.EntityUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

import java.util.Map;

@Component
public class HttpClient {
    public static final String DEFAULT_CHARSET = "UTF-8";

    @Autowired
    private CloseableHttpClient closeableHttpClient;

    @Autowired
    private RequestConfig config;


    /**
     * 用于JSON格式的API调用
     *
     * @param url              url地址
     * @param requestParameter 请求参数
     * @param clazz            接口返回值的类型
     * @return
     * @throws Exception
     */
    public <T> T doGet(String url, Map<String, Object> requestParameter, Class<T> clazz) throws Exception {
        String responseJson = this.doGet(url, requestParameter);
        T response = JSONObject.parseObject(responseJson, clazz);
        return response;
    }

    public String doGet(String url, Map<String, Object> requestParameter) throws Exception {
        URIBuilder uriBuilder = new URIBuilder(url);

        if (requestParameter != null) {
            for (Map.Entry<String, Object> entry : requestParameter.entrySet()) {
                uriBuilder.setParameter(entry.getKey(), entry.getValue().toString());
            }
        }

        return this.doGet(uriBuilder.build().toString());
    }

    public String doGet(String url) throws Exception {
        HttpGet httpGet = new HttpGet(url);
        httpGet.setConfig(config);
        httpGet.addHeader(HttpHeaders.CONTENT_TYPE, ContentType.APPLICATION_JSON.getMimeType());
        CloseableHttpResponse response = this.closeableHttpClient.execute(httpGet);

        int statusCode = response.getStatusLine().getStatusCode();
        if (statusCode != HttpStatus.SC_OK) {
            throw new Exception("api request exception, http reponse code:" + statusCode);
        }

        return EntityUtils.toString(response.getEntity(), DEFAULT_CHARSET);
    }

    public <T> T doPost(String url, Map<String, Object> requestParameter, Class<T> clazz) throws Exception {
        HttpResponse httpResponse = this.doPost(url, requestParameter);
        int statusCode = httpResponse.getCode();
        if (statusCode != HttpStatus.SC_OK) {
            throw new Exception("api request exception, http reponse code:" + statusCode);
        }

        T response = JSONObject.parseObject(httpResponse.getBody(), clazz);
        return response;
    }

    public HttpResponse doPost(String url, Map<String, Object> requestParameter) throws Exception {
        HttpPost httpPost = new HttpPost(url);
        httpPost.setConfig(config);
        httpPost.addHeader(HttpHeaders.CONTENT_TYPE, ContentType.APPLICATION_JSON.getMimeType());

        if (requestParameter != null) {
            String requestBody = JSONObject.toJSONString(requestParameter);
            StringEntity postEntity = new StringEntity(requestBody, "UTF-8");
            httpPost.setEntity(postEntity);
        }

        CloseableHttpResponse response = this.closeableHttpClient.execute(httpPost);
        // 对请求的响应进行简单的包装成自定义的类型
        return new HttpResponse(response.getStatusLine().getStatusCode(), EntityUtils.toString(
                response.getEntity(), DEFAULT_CHARSET));
    }


    public HttpResponse doPost(String url) throws Exception {
        return this.doPost(url, null);
    }


    /**
     * 封住请求的响应码和响应的内容
     */
    public class HttpResponse {
        /**
         * http status
         */
        private Integer code;
        /**
         * http response content
         */
        private String body;

        public HttpResponse() {
        }

        public HttpResponse(Integer code, String body) {
            this.code = code;
            this.body = body;
        }

        public Integer getCode() {
            return code;
        }

        public void setCode(Integer code) {
            this.code = code;
        }

        public String getBody() {
            return body;
        }

        public void setBody(String body) {
            this.body = body;
        }
    }

}


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四、curl实现

CurlController.java 里面实现两个接口，一个是get方式的，一个是post方式的。

package com.example.demo.controller;

import com.alibaba.fastjson.JSONObject;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.HashMap;
import java.util.Map;

@RestController
public class CurlController {

    @Autowired
    private HttpClient httpClient;

    @RequestMapping("/curlBaidu")
    public String curlBaidu() throws Exception {
        return httpClient.doGet("http://www.baidu.com");
    }

    @RequestMapping("/curlLocation")
    public String curlLocation() throws Exception {

        Map<String, Object> name = new HashMap<>();
        name.put("name", "caohaoyu");
        name.put("name2", "chy");

        HttpClient.HttpResponse httpResult = httpClient.doPost("http://localhost:8080/helloByParam", name);
        String body = httpResult.getBody();
        JSONObject jsonObject = JSONObject.parseObject(body);

        return jsonObject.getString("data");
    }
}

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在原有的HelloController.java修改helloByParam接口,接收post传输过来的数据并直接返回。

@RequestMapping("/helloByParam")
    public String helloByParam(@RequestBody JSONObject jsonObject) {
        JSONObject result = new JSONObject();
        result.put("msg", "ok");
        result.put("code", "0");
        result.put("data", jsonObject);
        return result.toJSONString();
    }
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五、实现结果

get实现结果：

post实现结果：

圆满完成简单版curl的实现！

六、感受

java是强类型的，这点对于写惯了php这种弱类型的人来说一开始确实还是有点别扭的。不过编辑器还是挺好用的，以后慢慢适应吧。

还有就是java对调用方式也比较严格，需要注意。不能像php简单的$_REQUEST来同时支持post和get。

成长记录传送门：

输出hello word！

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