我要评论目前java实现http请求的方法用的最多的有两种：一种是通过httpclient这种第三方的开源框架去实现。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，httpclient3.1 是 org.apache.commons.httpclient下操作远程 url的工具包，虽然已不再更新，但实现工作中使用httpclient3.1的代码还是很多，httpclient4.5是org.apache.http.client下操作远程 url的工具包，最新的；另一种则是通过httpurlconnection去实现，httpurlconnection是java的标准类，是java比较原生的一种实现方式。
自己在工作中三种方式都用到过，总结一下分享给大家，也方便自己以后使用，话不多说上代码。
第一种方式：java原生httpurlconnection
package com.powerx.httpclient;
import java.io.bufferedreader;
import java.io.ioexception;
import java.io.inputstream;
import java.io.inputstreamreader;
import java.io.outputstream;
import java.net.httpurlconnection;
import java.net.malformedurlexception;
import java.net.url;
public class httpclient {
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
if (connection.getresponsecode() == 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;
}
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);
// 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");
// 设置鉴权信息：authorization: bearer da3efcbf-0845-4fe3-8aba-ee040be542c0
connection.setrequestproperty("authorization", "bearer da3efcbf-0845-4fe3-8aba-ee040be542c0");
// 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
os.write(param.getbytes());
// 通过连接对象获取一个输入流，向远程读取
if (connection.getresponsecode() == 200) {
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();
}
} 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;
}
}
第二种方式：apache httpclient3.1
package com.powerx.httpclient;
import java.io.bufferedreader;
import java.io.ioexception;
import java.io.inputstream;
import java.io.inputstreamreader;
import java.io.unsupportedencodingexception;
import java.util.iterator;
import java.util.map;
import java.util.map.entry;
import java.util.set;
import org.apache.commons.httpclient.defaulthttpmethodretryhandler;
import org.apache.commons.httpclient.httpclient;
import org.apache.commons.httpclient.httpstatus;
import org.apache.commons.httpclient.namevaluepair;
import org.apache.commons.httpclient.methods.getmethod;
import org.apache.commons.httpclient.methods.postmethod;
import org.apache.commons.httpclient.params.httpmethodparams;
public class httpclient3 {
public static string doget(string url) {
// 输入流
inputstream is = null;
bufferedreader br = null;
string result = null;
// 创建httpclient实例
httpclient httpclient = new httpclient();
// 设置http连接主机服务超时时间：15000毫秒
// 先获取连接管理器对象，再获取参数对象,再进行参数的赋值
httpclient.gethttpconnectionmanager().getparams().setconnectiontimeout(15000);
// 创建一个get方法实例对象
getmethod getmethod = new getmethod(url);
// 设置get请求超时为60000毫秒
getmethod.getparams().setparameter(httpmethodparams.so_timeout, 60000);
// 设置请求重试机制，默认重试次数：3次，参数设置为true，重试机制可用，false相反
getmethod.getparams().setparameter(httpmethodparams.retry_handler, new defaulthttpmethodretryhandler(3, true));
try {
// 执行get方法
int statuscode = httpclient.executemethod(getmethod);
// 判断返回码
if (statuscode != httpstatus.sc_ok) {
// 如果状态码返回的不是ok,说明失败了,打印错误信息
system.err.println("method faild: " + getmethod.getstatusline());
} else {
// 通过getmethod实例，获取远程的一个输入流
is = getmethod.getresponsebodyasstream();
// 包装输入流
br = new bufferedreader(new inputstreamreader(is, "utf-8"));
stringbuffer sbf = new stringbuffer();
// 读取封装的输入流
string temp = null;
while ((temp = br.readline()) != null) {
sbf.append(temp).append("\r\n");
}
result = sbf.tostring();
}
} 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();
}
}
// 释放连接
getmethod.releaseconnection();
}
return result;
}
public static string dopost(string url, map<string, object> parammap) {
// 获取输入流
inputstream is = null;
bufferedreader br = null;
string result = null;
// 创建httpclient实例对象
httpclient httpclient = new httpclient();
// 设置httpclient连接主机服务器超时时间：15000毫秒
httpclient.gethttpconnectionmanager().getparams().setconnectiontimeout(15000);
// 创建post请求方法实例对象
postmethod postmethod = new postmethod(url);
// 设置post请求超时时间
postmethod.getparams().setparameter(httpmethodparams.so_timeout, 60000);
namevaluepair[] nvp = null;
// 判断参数map集合parammap是否为空
if (null != parammap && parammap.size() > 0) {// 不为空
// 创建键值参数对象数组，大小为参数的个数
nvp = new namevaluepair[parammap.size()];
// 循环遍历参数集合map
set<entry<string, object>> entryset = parammap.entryset();
// 获取迭代器
iterator<entry<string, object>> iterator = entryset.iterator();
int index = 0;
while (iterator.hasnext()) {
entry<string, object> mapentry = iterator.next();
// 从mapentry中获取key和value创建键值对象存放到数组中
try {
nvp[index] = new namevaluepair(mapentry.getkey(),
new string(mapentry.getvalue().tostring().getbytes("utf-8"), "utf-8"));
} catch (unsupportedencodingexception e) {
e.printstacktrace();
}
index++;
}
}
// 判断nvp数组是否为空
if (null != nvp && nvp.length > 0) {
// 将参数存放到requestbody对象中
postmethod.setrequestbody(nvp);
}
// 执行post方法
try {
int statuscode = httpclient.executemethod(postmethod);
// 判断是否成功
if (statuscode != httpstatus.sc_ok) {
system.err.println("method faild: " + postmethod.getstatusline());
}
// 获取远程返回的数据
is = postmethod.getresponsebodyasstream();
// 封装输入流
br = new bufferedreader(new inputstreamreader(is, "utf-8"));
stringbuffer sbf = new stringbuffer();
string temp = null;
while ((temp = br.readline()) != null) {
sbf.append(temp).append("\r\n");
}
result = sbf.tostring();
} 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();
}
}
// 释放连接
postmethod.releaseconnection();
}
return result;
}
}
第三种方式：apache httpclient4.5
package com.powerx.httpclient;
import java.io.ioexception;
import java.io.unsupportedencodingexception;
import java.util.arraylist;
import java.util.iterator;
import java.util.list;
import java.util.map;
import java.util.map.entry;
import java.util.set;
import org.apache.http.httpentity;
import org.apache.http.namevaluepair;
import org.apache.http.client.clientprotocolexception;
import org.apache.http.client.config.requestconfig;
import org.apache.http.client.entity.urlencodedformentity;
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.impl.client.closeablehttpclient;
import org.apache.http.impl.client.httpclients;
import org.apache.http.message.basicnamevaluepair;
import org.apache.http.util.entityutils;
public class httpclient4 {
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<string, object> 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<namevaluepair> nvps = new arraylist<namevaluepair>();
// 通过map集成entryset方法获取entity
set<entry<string, object>> entryset = parammap.entryset();
// 循环遍历，获取迭代器
iterator<entry<string, object>> iterator = entryset.iterator();
while (iterator.hasnext()) {
entry<string, object> 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;
}
}
有时候我们在使用post请求时，可能传入的参数是json或者其他格式，此时我们则需要更改请求头及参数的设置信息，以httpclient4.5为例，更改下面两列配置：httppost.setentity(new stringentity("你的json串")); httppost.addheader("content-type", "application/json")。
以上所述是小编给大家介绍的java实现http请求的三种方式详解整合，希望对大家有所帮助
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