【三种】Java构建HTTP请求的方法
- 在Java开发中，肯定会遇到构建HTTP请求的场景，常遇到的就是 GET 和 POST
- 以下总结三种常用的方法并实践之：①HttpURLConnection ②HttpClient ③Hutool
- demo对应github地址：https://github.com/tyronczt/java-learn/blob/master/Tools/http-request
方法一、HttpURLConnection
HttpURLConnection 是 Java 的标准类，是 Java 比较原生的一种实现方式。
/**
* 发送get请求
*
* @param httpurl url地址
* @return
*/
public static String doGet(String httpurl) {
HttpURLConnection connection = null;
InputStream is = null;
BufferedReader br = null;
String result = null;// 返回结果字符串
try {
// 创建远程url连接对象
URL url = new URL(httpurl);
// 通过远程url连接对象打开一个连接，强转成httpURLConnection类
connection = (HttpURLConnection) url.openConnection();
// 设置连接方式：get
connection.setRequestMethod("GET");
// 设置连接主机服务器的超时时间：15000毫秒
connection.setConnectTimeout(15000);
// 设置读取远程返回的数据时间：60000毫秒
connection.setReadTimeout(60000);
// 发送请求
connection.connect();
// 通过connection连接，获取输入流
int responseCode = connection.getResponseCode();
if (responseCode == 200) {
is = connection.getInputStream();
// 封装输入流is，并指定字符集
br = new BufferedReader(new InputStreamReader(is, "UTF-8"));
// 存放数据
StringBuffer sbf = new StringBuffer();
String temp = null;
while ((temp = br.readLine()) != null) {
sbf.append(temp);
sbf.append("\r\n");
}
result = sbf.toString();
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
// 关闭资源
if (null != br) {
try {
br.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (null != is) {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
connection.disconnect();// 关闭远程连接
}
return result;
}
/**
* Post请求
*
* @param httpUrl url地址
* @param param 参数
* @return 返回
*/
public static String doPost(String httpUrl, String param) {
HttpURLConnection connection = null;
InputStream is = null;
OutputStream os = null;
BufferedReader br = null;
String result = null;
try {
URL url = new URL(httpUrl);
// 通过远程url连接对象打开连接
connection = (HttpURLConnection) url.openConnection();
// 设置连接请求方式
connection.setRequestMethod("POST");
// 设置连接主机服务器超时时间：15000毫秒
connection.setConnectTimeout(15000);
// 设置读取主机服务器返回数据超时时间：60000毫秒
connection.setReadTimeout(60000);
// 默认值为：false，当向远程服务器传送数据/写数据时，需要设置为true
connection.setDoOutput(true);
// 默认值为：true，当前向远程服务读取数据时，设置为true，该参数可有可无
connection.setDoInput(true);
// 请求参数判断,带问号的说明是String拼接，反之则为json
if (param.contains("=")) {
// 设置传入参数的格式:请求参数应该是 name1=value1&name2=value2 的形式。
connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
} else {
//设置参数类型是json格式
connection.setRequestProperty("Content-Type", "application/json;charset=utf-8");
}
// 通过连接对象获取一个输出流
os = connection.getOutputStream();
// 通过输出流对象将参数写出去/传输出去,它是通过字节数组写出的,并设置utf-8,防止中文出错
os.write(param.getBytes("utf-8"));
// 通过连接对象获取一个输入流，向远程读取
if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
is = connection.getInputStream();
// 对输入流对象进行包装:charset根据工作项目组的要求来设置
br = new BufferedReader(new InputStreamReader(is, "UTF-8"));
StringBuffer sbf = new StringBuffer();
String temp = null;
// 循环遍历一行一行读取数据
while ((temp = br.readLine()) != null) {
sbf.append(temp);
sbf.append("\r\n");
}
result = sbf.toString();
} else {
System.out.println("ResponseCode is an error code：" + connection.getResponseCode());
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
// 关闭资源
if (null != br) {
try {
br.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (null != os) {
try {
os.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (null != is) {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
// 断开与远程地址url的连接
connection.disconnect();
}
return result;
}
main方法测试
public static void main(String[] args) {
System.out.println("通过HttpURLConnection的get方式：" + doGet("http://localhost:8080/getReq"));
Map map = new HashMap<>();
map.put("name", "tyron");
map.put("age", 18);
System.out.println("通过HttpURLConnection的POST方式，参数为json形式：" +
doPost("http://localhost:8080/jsonPostReq", parseJson(map)));
String param = "name=tyron";
System.out.println("通过HttpURLConnection的POST方式，参数为String形式：" +
doPost("http://localhost:8080/stringPostReq", param));
}
/**
* map转string
*
* @param map map
* @return
*/
public static String parseJson(Map map) {
return JSONObject.toJSONString(map);
}
控制台输出
通过HttpURLConnection的get方式：hello get
通过HttpURLConnection的POST方式，参数为json形式：用户：tyron,年龄：18
通过HttpURLConnection的POST方式，参数为String形式：hello：tyron
方法二：HttpClient4.5
HTTPClient 对 HTTP 的封装性比较不错，通过它基本上能够满足我们大部分的需求，HttpClient4.5 是 org.apache.http.client 下操作远程 url 的工具包
org.apache.httpcomponents
httpclient
4.5.3
public static String doGet(String url) {
CloseableHttpClient httpClient = null;
CloseableHttpResponse response = null;
String result = "";
try {
// 通过址默认配置创建一个httpClient实例
httpClient = HttpClients.createDefault();
// 创建httpGet远程连接实例
HttpGet httpGet = new HttpGet(url);
// 设置请求头信息，鉴权
// httpGet.setHeader("Authorization", "Bearer da3efcbf-0845-4fe3-8aba-ee040be542c0");
// 设置配置请求参数
RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(35000)// 连接主机服务超时时间
.setConnectionRequestTimeout(35000)// 请求超时时间
.setSocketTimeout(60000)// 数据读取超时时间
.build();
// 为httpGet实例设置配置
httpGet.setConfig(requestConfig);
// 执行get请求得到返回对象
response = httpClient.execute(httpGet);
// 通过返回对象获取返回数据
HttpEntity entity = response.getEntity();
// 通过EntityUtils中的toString方法将结果转换为字符串
result = EntityUtils.toString(entity);
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
// 关闭资源
if (null != response) {
try {
response.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (null != httpClient) {
try {
httpClient.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return result;
}
public static String doPost(String url, Map paramMap) {
CloseableHttpClient httpClient = null;
CloseableHttpResponse httpResponse = null;
String result = "";
// 创建httpClient实例
httpClient = HttpClients.createDefault();
// 创建httpPost远程连接实例
HttpPost httpPost = new HttpPost(url);
// 配置请求参数实例
RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(35000)// 设置连接主机服务超时时间
.setConnectionRequestTimeout(35000)// 设置连接请求超时时间
.setSocketTimeout(60000)// 设置读取数据连接超时时间
.build();
// 为httpPost实例设置配置
httpPost.setConfig(requestConfig);
// 设置请求头
httpPost.addHeader("Content-Type", "application/x-www-form-urlencoded");
// 封装post请求参数
if (null != paramMap && paramMap.size() > 0) {
List nvps = new ArrayList<>();
// 通过map集成entrySet方法获取entity
Set> entrySet = paramMap.entrySet();
// 循环遍历，获取迭代器
Iterator> iterator = entrySet.iterator();
while (iterator.hasNext()) {
Entry mapEntry = iterator.next();
nvps.add(new BasicNameValuePair(mapEntry.getKey(), mapEntry.getValue().toString()));
}
// 为httpPost设置封装好的请求参数
try {
httpPost.setEntity(new UrlEncodedFormEntity(nvps, "UTF-8"));
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
}
try {
// httpClient对象执行post请求,并返回响应参数对象
httpResponse = httpClient.execute(httpPost);
// 从响应对象中获取响应内容
HttpEntity entity = httpResponse.getEntity();
result = EntityUtils.toString(entity);
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
// 关闭资源
if (null != httpResponse) {
try {
httpResponse.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (null != httpClient) {
try {
httpClient.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return result;
}
main方法测试
public static void main(String[] args) {
System.out.println(doGet("http://localhost:8080/getReq"));
Map map = new HashMap<>();
map.put("name", "tyron");
System.out.println(doPost("http://localhost:8080/stringPostReq", map));
}
控制台输出
D:\soft\Java\jdk1.8.0_192\bin\java.exe "-javaagent:H:\Program Files\JetBrains\IntelliJ IDEA 2018.3.1\lib\idea_rt.jar=10427:H:\Program Files\JetBrains\IntelliJ IDEA 2018.3.1\bin" -Dfile.encoding=UTF-8 -classpath D:\soft\Java\jdk1.8.0_192\jre\lib\charsets.jar;D:\soft\Java\jdk1.8.0_192\jre\lib\deploy.jar;D:\soft\Java\jdk1.8.0_192\jre\lib\ext\access-bridge-64.jar;D:\soft\Java\jdk1.8.0_192\jre\lib\ext\cldrdata.jar;D:\soft\Java\jdk1.8.0_192\jre\lib\ext\dnsns.jar;D:\soft\Java\jdk1.8.0_192\jre\lib\ext\jaccess.jar;D:\soft\Java\jdk1.8.0_192\jre\lib\ext\jfxrt.jar;D:\soft\Java\jdk1.8.0_192\jre\lib\ext\localedata.jar;D:\soft\Java\jdk1.8.0_192\jre\lib\ext\nashorn.jar;D:\soft\Java\jdk1.8.0_192\jre\lib\ext\sunec.jar;D:\soft\Java\jdk1.8.0_192\jre\lib\ext\sunjce_provider.jar;D:\soft\Java\jdk1.8.0_192\jre\lib\ext\sunmscapi.jar;D:\soft\Java\jdk1.8.0_192\jre\lib\ext\sunpkcs11.jar;D:\soft\Java\jdk1.8.0_192\jre\lib\ext\zipfs.jar;D:\soft\Java\jdk1.8.0_192\jre\lib\javaws.jar;D:\soft\Java\jdk1.8.0_192\jre\lib\jce.jar;D:\soft\Java\jdk1.8.0_192\jre\lib\jfr.jar;D:\soft\Java\jdk1.8.0_192\jre\lib\jfxswt.jar;D:\soft\Java\jdk1.8.0_192\jre\lib\jsse.jar;D:\soft\Java\jdk1.8.0_192\jre\lib\management-agent.jar;D:\soft\Java\jdk1.8.0_192\jre\lib\plugin.jar;D:\soft\Java\jdk1.8.0_192\jre\lib\resources.jar;D:\soft\Java\jdk1.8.0_192\jre\lib\rt.jar;D:\idea_namespace\demo\target\classes;D:\maven\repository\org\springframework\boot\spring-boot-starter\2.1.4.RELEASE\spring-boot-starter-2.1.4.RELEASE.jar;D:\maven\repository\org\springframework\boot\spring-boot\2.1.4.RELEASE\spring-boot-2.1.4.RELEASE.jar;D:\maven\repository\org\springframework\spring-context\5.1.6.RELEASE\spring-context-5.1.6.RELEASE.jar;D:\maven\repository\org\springframework\boot\spring-boot-autoconfigure\2.1.4.RELEASE\spring-boot-autoconfigure-2.1.4.RELEASE.jar;D:\maven\repository\org\springframework\boot\spring-boot-starter-logging\2.1.4.RELEASE\spring-boot-starter-logging-2.1.4.RELEASE.jar;D:\maven\repository\ch\qos\logback\logback-classic\1.2.3\logback-classic-1.2.3.jar;D:\maven\repository\ch\qos\logback\logback-core\1.2.3\logback-core-1.2.3.jar;D:\maven\repository\org\apache\logging\log4j\log4j-to-slf4j\2.11.2\log4j-to-slf4j-2.11.2.jar;D:\maven\repository\org\apache\logging\log4j\log4j-api\2.11.2\log4j-api-2.11.2.jar;D:\maven\repository\org\slf4j\jul-to-slf4j\1.7.26\jul-to-slf4j-1.7.26.jar;D:\maven\repository\javax\annotation\javax.annotation-api\1.3.2\javax.annotation-api-1.3.2.jar;D:\maven\repository\org\springframework\spring-core\5.1.6.RELEASE\spring-core-5.1.6.RELEASE.jar;D:\maven\repository\org\springframework\spring-jcl\5.1.6.RELEASE\spring-jcl-5.1.6.RELEASE.jar;D:\maven\repository\org\yaml\snakeyaml\1.23\snakeyaml-1.23.jar;D:\maven\repository\org\slf4j\slf4j-api\1.7.26\slf4j-api-1.7.26.jar;D:\maven\repository\org\springframework\boot\spring-boot-starter-web\2.1.4.RELEASE\spring-boot-starter-web-2.1.4.RELEASE.jar;D:\maven\repository\org\springframework\boot\spring-boot-starter-json\2.1.4.RELEASE\spring-boot-starter-json-2.1.4.RELEASE.jar;D:\maven\repository\com\fasterxml\jackson\core\jackson-databind\2.9.8\jackson-databind-2.9.8.jar;D:\maven\repository\com\fasterxml\jackson\core\jackson-annotations\2.9.0\jackson-annotations-2.9.0.jar;D:\maven\repository\com\fasterxml\jackson\core\jackson-core\2.9.8\jackson-core-2.9.8.jar;D:\maven\repository\com\fasterxml\jackson\datatype\jackson-datatype-jdk8\2.9.8\jackson-datatype-jdk8-2.9.8.jar;D:\maven\repository\com\fasterxml\jackson\datatype\jackson-datatype-jsr310\2.9.8\jackson-datatype-jsr310-2.9.8.jar;D:\maven\repository\com\fasterxml\jackson\module\jackson-module-parameter-names\2.9.8\jackson-module-parameter-names-2.9.8.jar;D:\maven\repository\org\springframework\boot\spring-boot-starter-tomcat\2.1.4.RELEASE\spring-boot-starter-tomcat-2.1.4.RELEASE.jar;D:\maven\repository\org\apache\tomcat\embed\tomcat-embed-core\9.0.17\tomcat-embed-core-9.0.17.jar;D:\maven\repository\org\apache\tomcat\embed\tomcat-embed-el\9.0.17\tomcat-embed-el-9.0.17.jar;D:\maven\repository\org\apache\tomcat\embed\tomcat-embed-websocket\9.0.17\tomcat-embed-websocket-9.0.17.jar;D:\maven\repository\org\hibernate\validator\hibernate-validator\6.0.16.Final\hibernate-validator-6.0.16.Final.jar;D:\maven\repository\javax\validation\validation-api\2.0.1.Final\validation-api-2.0.1.Final.jar;D:\maven\repository\org\jboss\logging\jboss-logging\3.3.2.Final\jboss-logging-3.3.2.Final.jar;D:\maven\repository\com\fasterxml\classmate\1.4.0\classmate-1.4.0.jar;D:\maven\repository\org\springframework\spring-web\5.1.6.RELEASE\spring-web-5.1.6.RELEASE.jar;D:\maven\repository\org\springframework\spring-beans\5.1.6.RELEASE\spring-beans-5.1.6.RELEASE.jar;D:\maven\repository\org\springframework\spring-webmvc\5.1.6.RELEASE\spring-webmvc-5.1.6.RELEASE.jar;D:\maven\repository\org\springframework\spring-aop\5.1.6.RELEASE\spring-aop-5.1.6.RELEASE.jar;D:\maven\repository\org\springframework\spring-expression\5.1.6.RELEASE\spring-expression-5.1.6.RELEASE.jar;D:\maven\repository\com\alibaba\fastjson\1.2.39\fastjson-1.2.39.jar;D:\maven\repository\org\apache\httpcomponents\httpclient\4.5.3\httpclient-4.5.3.jar;D:\maven\repository\org\apache\httpcomponents\httpcore\4.4.11\httpcore-4.4.11.jar;D:\maven\repository\commons-codec\commons-codec\1.11\commons-codec-1.11.jar;D:\maven\repository\cn\hutool\hutool-all\4.5.10\hutool-all-4.5.10.jar com.tyron.demo.http_client.Client_HttpClient4
DEBUG org.apache.http.client.protocol.RequestAddCookies - CookieSpec selected: default
DEBUG org.apache.http.client.protocol.RequestAuthCache - Auth cache not set in the context
DEBUG org.apache.http.impl.conn.PoolingHttpClientConnectionManager - Connection request: [route: {}->http://localhost:8080][total kept alive: 0; route allocated: 0 of 2; total allocated: 0 of 20]
DEBUG org.apache.http.impl.conn.PoolingHttpClientConnectionManager - Connection leased: [id: 0][route: {}->http://localhost:8080][total kept alive: 0; route allocated: 1 of 2; total allocated: 1 of 20]
DEBUG org.apache.http.impl.execchain.MainClientExec - Opening connection {}->http://localhost:8080
DEBUG org.apache.http.impl.conn.DefaultHttpClientConnectionOperator - Connecting to localhost/127.0.0.1:8080
DEBUG org.apache.http.impl.conn.DefaultHttpClientConnectionOperator - Connection established 127.0.0.1:10432<->127.0.0.1:8080
DEBUG org.apache.http.impl.conn.DefaultManagedHttpClientConnection - http-outgoing-0: set socket timeout to 60000
DEBUG org.apache.http.impl.execchain.MainClientExec - Executing request GET /getReq HTTP/1.1
。。。省略
DEBUG org.apache.http.impl.execchain.MainClientExec - Connection can be kept alive indefinitely
DEBUG org.apache.http.impl.conn.PoolingHttpClientConnectionManager - Connection [id: 0][route: {}->http://localhost:8080] can be kept alive indefinitely
DEBUG org.apache.http.impl.conn.PoolingHttpClientConnectionManager - Connection released: [id: 0][route: {}->http://localhost:8080][total kept alive: 1; route allocated: 1 of 2; total allocated: 1 of 20]
DEBUG org.apache.http.impl.conn.PoolingHttpClientConnectionManager - Connection manager is shutting down
DEBUG org.apache.http.impl.conn.DefaultManagedHttpClientConnection - http-outgoing-0: Close connection
DEBUG org.apache.http.impl.conn.PoolingHttpClientConnectionManager - Connection manager shut down
hello get
DEBUG org.apache.http.impl.conn.PoolingHttpClientConnectionManager - Connection request: [route: {}->http://localhost:8080][total kept alive: 0; route allocated: 0 of 2; total allocated: 0 of 20]
DEBUG org.apache.http.impl.conn.PoolingHttpClientConnectionManager - Connection leased: [id: 1][route: {}->http://localhost:8080][total kept alive: 0; route allocated: 1 of 2; total allocated: 1 of 20]
DEBUG org.apache.http.impl.execchain.MainClientExec - Opening connection {}->http://localhost:8080
DEBUG org.apache.http.impl.conn.DefaultHttpClientConnectionOperator - Connecting to localhost/127.0.0.1:8080
DEBUG org.apache.http.impl.conn.DefaultHttpClientConnectionOperator - Connection established 127.0.0.1:10433<->127.0.0.1:8080
DEBUG org.apache.http.impl.conn.DefaultManagedHttpClientConnection - http-outgoing-1: set socket timeout to 60000
DEBUG org.apache.http.impl.execchain.MainClientExec - Executing request POST /stringPostReq HTTP/1.1
。。。省略
DEBUG org.apache.http.impl.conn.PoolingHttpClientConnectionManager - Connection manager shut down
hello：tyron
方法三、Hutool - HttpUtil
- A set of tools that keep Java sweet。Hutool是一个Java工具包，也只是一个工具包，它帮助我们简化每一行代码，减少每一个方法，让Java语言也可以“甜甜的”。Hutool最初是我项目中“util”包的一个整理，后来慢慢积累并加入更多非业务相关功能，并广泛学习其它开源项目精髓，经过自己整理修改，最终形成丰富的开源工具集。
- 此处使用的是 Http客户端工具类 - HttpUtil
main方法测试
public static void main(String[] args) {
// 最简单的HTTP请求，可以自动通过header等信息判断编码，不区分HTTP和HTTPS
String result1 = HttpUtil.get("http://localhost:8080/getReq");
System.out.println(result1);
// 当无法识别页面编码的时候，可以自定义请求页面的编码
String result2 = HttpUtil.get("http://localhost:8080/getReq", CharsetUtil.CHARSET_UTF_8);
System.out.println(result2);
HashMap paramMap = new HashMap<>();
paramMap.put("name", "tyron");
String result = HttpUtil.post("http://localhost:8080/stringPostReq", paramMap);
System.out.println(result);
Map map = new HashMap<>();
map.put("name", "tyron");
map.put("age", 18);
System.out.println(HttpUtil.post("http://localhost:8080/jsonPostReq", JSONUtil.parseFromMap(map).toString()));
}
控制台输出
[main] DEBUG cn.hutool.log.LogFactory - Use [Slf4j] Logger As Default.
hello get
hello get
hello：tyron
用户：tyron,年龄：18