java实现类似python requests的session功能

Posted 2020-11-30 lwb444

怎么在java中实现类似于python的requests模块的session功能呢。java也是可以实现的，用java的okhttp包可以实现。

在pom.xml中加入相关依赖

<!-- https://mvnrepository.com/artifact/com.squareup.okhttp3/okhttp -->
<dependency>
    <groupId>com.squareup.okhttp3</groupId>
    <artifactId>okhttp</artifactId>
    <version>4.2.2</version>
</dependency>

　　后面是相关的java代码：

package com.puple.atto.datastructure;



import java.text.MessageFormat;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Set;
import java.util.regex.*;

import okhttp3.Cookie;
import okhttp3.CookieJar;
import okhttp3.FormBody;
import okhttp3.HttpUrl;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;





public class Session {

    private final OkHttpClient mOkHttpClient = new OkHttpClient.Builder().cookieJar(new CookieJarManager()).build();
//　　 //如果直接写个类，里面写saveFromResponse和loadForRequest，而不实现CookieJar接口，运行可以正常通过，但ide会显红，因为Bulider类的cookieJsr方法需要接受CookieJar类型的实例。鸭子类除了能节约代码行数，在可理解性 可读性 多人合作性上面都不如接口规范，谁知道鸭子类里面要写什么方法，除了写代码得人自己。
    private class CookieJarManager implements CookieJar{
        private final HashMap<String, List<Cookie>> cookieStore = new HashMap<>();

        @Override
        public void saveFromResponse(HttpUrl url, List<Cookie> cookies) {
            cookieStore.put(url.host(), cookies);
        }

        @Override
        public List<Cookie> loadForRequest(HttpUrl url) {
            List<Cookie> cookies = cookieStore.get(url.host());
            return cookies != null ? cookies : new ArrayList<Cookie>(){};
        }
    }

    /**
     * @param url  要请求的url
     * @param  paramsMap post的请求参数
     * @return  post的返回结果
     */
    public String post(String url, HashMap<String, String > paramsMap){

        FormBody.Builder formBodyBuilder = new FormBody.Builder();
        Set<String> keySet = paramsMap.keySet();
        for(String key:keySet) {
            String value = paramsMap.get(key);
            formBodyBuilder.add(key,value);
        }
        FormBody formBody = formBodyBuilder.build();
        Request request = new Request
                .Builder()
                .post(formBody)
                .url(url)
                .build();
        try (Response response = mOkHttpClient.newCall(request).execute()) {
            String  respStr = response.body().string();

            return respStr;
        }catch (Exception e){

            e.printStackTrace();
            return "";
        }
    }

    public String get(String url)  {
        final Request.Builder builder = new Request.Builder();
        builder.url(url);
        final Request request = builder.build();
        try (Response response = mOkHttpClient.newCall(request).execute()) {
            return response.body().string();
        }catch (Exception e){
            e.printStackTrace();
            return "";
        }
    }

    public static void test(){
        Session ss=new Session();
        String loginUrl="http://192.168.9.244:8080/RDCJWeb/login";
        HashMap<String,String> paramsMap = new HashMap<>() ;
        paramsMap.put("username","soft1");
        paramsMap.put("password","soft1");
        String respStr = ss.post(loginUrl,paramsMap);

        String res=ss.get("http://192.168.9.244:8080/RDCJWeb/static/dist/html/deviceWarn.html");
        System.out.println(res);


    }



    public static void main(String[] args) {
        test();
    }

}