Java调用http接口（get、post）

1.示例

• get请求，参数可以拼接在url上
• post请求，参数使用json字符串

package org.example;

import org.apache.http.HttpEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.ByteArrayEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.CharArrayBuffer;
import org.apache.http.util.EntityUtils;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.HttpURLConnection;
import java.net.URL;

public class TTest{
	//get请求
    public static String getHttp(String url) {
        PrintWriter out = null;
        BufferedReader in = null;
        String result = "";
        try {
            URL urls = new URL(url);
            HttpURLConnection conn = (HttpURLConnection) urls.openConnection();
            conn.setRequestMethod("GET");
            conn.setRequestProperty("Content-Type", "application/json");
            conn.setDoOutput(true);
            conn.setDoInput(true);
            conn.setReadTimeout(10000);
            conn.setConnectTimeout(10000);
            out = new PrintWriter(conn.getOutputStream());
            out.flush();
            in = new BufferedReader(new InputStreamReader(conn.getInputStream(), "utf-8"));
            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();
            }
        }
        return result;
    }
    //post请求
    public static String postJson(String url, String jsonString) {
        String result = null;
        CloseableHttpClient httpClient = HttpClients.createDefault();
        HttpPost post = new HttpPost(url);
        CloseableHttpResponse response = null;
        try {
            post.setHeader("Content-Type", "application/json");
            if (null!=jsonString) {
                post.setEntity(new ByteArrayEntity(jsonString.getBytes("UTF-8")));
            }
            response = httpClient.execute(post);
            if (response != null && response.getStatusLine().getStatusCode() == 200) {
                HttpEntity entity = response.getEntity();
                result = entityToString(entity);
            }
            return result;
        }  catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                httpClient.close();
                if (response != null) {
                    response.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return null;
    }
    public static String entityToString(HttpEntity entity) throws IOException {
        String result = null;
        if (entity != null) {
            long lenth = entity.getContentLength();
            if (lenth != -1 && lenth < 2048) {
                result = EntityUtils.toString(entity, "UTF-8");
            } else {
                InputStreamReader reader1 = null;
                try {
                    reader1 = new InputStreamReader(entity.getContent(), "UTF-8");
                    CharArrayBuffer buffer = new CharArrayBuffer(2048);
                    char[] tmp = new char[1024];
                    int l;
                    while ((l = reader1.read(tmp)) != -1) {
                        buffer.append(tmp, 0, l);
                    }
                    result = buffer.toString();
                } catch (IOException e) {
                    e.printStackTrace();
                }finally {
                    reader1.close();
                }
            }
        }
        return result;
    }
    public static void main(String[] args) {
        System.out.println(getHttp("https://www.baidu.com"));
        System.out.println("--------------------------------华丽的分割线-----------------------------------");
        System.out.println(postJson("https://www.baidu.com",null));
    }
}

2.打印

<!DOCTYPE html><!--STATUS OK--><html> <head><meta http-equiv=content-type content=text/html;charset=utf-8><meta http-equiv=X-UA-Compatible content=IE=Edge><meta content=always name=referrer><link rel=stylesheet type=text/css href=https://ss1.bdstatic.com/5eN1bjq8AAUYm2zgoY3K/r/www/cache/bdorz/baidu.min.css><title>百度一下，你就知道</title></head> <body link=#0000cc> <div id=wrapper> <div id=head> <div class=head_wrapper> <div class=s_form> <div class=s_form_wrapper> <div id=lg> <img hidefocus=true src=//www.baidu.com/img/bd_logo1.png width=270 height=129> 

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