使用java发送Http请求
使用java发送Http请求
使用jdk自带HttpUrlRequest发送请求，简单化，轻量化，不集成第三方的框架，不会引入第三方的包，适用于简单场景的第三方远程交互。
发送GET请求
GET请求是最简单的请求，所需要的参数直接拼接到请求URL后面就可以，后端服务器收到请求后就可以解析并处理。
/**
* 发送get请求
* @return 返回请求结果
*/
public String doGet() {
if(params != null && !params.isEmpty()) {
url += "?";
url += createParams();
}
URL u ;
HttpURLConnection connection ;
try {
u = new URL(url);
log.error(url);
connection = (HttpURLConnection) u.openConnection();
connection.setRequestMethod("GET");
connection.setConnectTimeout(connectTimeout);
connection.setReadTimeout(readTimeout);
connection.setRequestProperty("Content-Type",contentType);
if(heads != null){
for (Map.Entry stringStringEntry : heads.entrySet()) {
connection.setRequestProperty(stringStringEntry.getKey(),stringStringEntry.getValue());
}
}
InputStream is = connection.getInputStream();
return getResponse(is);
} catch (MalformedURLException e) {
log.error("the url format is err,check it ! {}",url);
e.printStackTrace();
} catch (IOException e) {
log.error("the I/O operation is error !");
e.printStackTrace();
}
return null;
}
private String createParams() {
if(params != null && !params.isEmpty()) {
StringBuilder sb = new StringBuilder();
for (Map.Entry stringObjectEntry : params.entrySet()) {
try {
sb.append(stringObjectEntry.getKey()).append("=").append(URLEncoder.encode(stringObjectEntry.getValue(),"UTF-8")).append("&");
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
}
sb.delete(sb.length() - 1, sb.length());
return sb.toString();
}
return "";
}
发送POST请求
POST请求分几种情况，根据Content-Type的类型，如下：
- application/json 将请求体使用json格式化为字符串，在请求体里面封闭传输
- application/x-www-form-urlencoded 使用表单提交，将value使用url编码之后，封装成 key=value的格式在请求体里面传输
- multipart/form-data 将参数使用boundary分隔，在服务端解析，可以传输文件
application/json格式请求
/**
* 发送post请求
* @return 请求结果
*/
public String doPost() {
URL u ;
HttpURLConnection connection = null;
OutputStream out ;
try {
connection = getPostConnection();
out = connection.getOutputStream();
if(params != null && !params.isEmpty()) {
out.write(toJSONString(params).getBytes());
}
out.flush();
out.close();
try(InputStream is = connection.getInputStream()) {
return getResponse(is);
}catch (Exception e){
e.printStackTrace();
}
} catch (MalformedURLException e) {
log.error("the url format is err,check it ! {}",url);
e.printStackTrace();
}catch (ProtocolException e) {
assert connection != null;
log.error("the request protocol is error, check it ! {}",connection.getRequestMethod());
e.printStackTrace();
}catch (IOException e) {
log.error("the I/O operation is error !");
e.printStackTrace();
}
return null;
}
实际请求的报文如下:
POST /files/lists HTTP/1.1
Host: localhost:8080
Content-Type: application/json
User-Agent: PostmanRuntime/7.15.2
Accept: */*
Cache-Control: no-cache
Postman-Token: 49cb9315-21f2-44ab-875e-33cfabe58112,fc03e72f-8364-46b5-a81a-c0ee217228f1
Host: localhost:8080
Accept-Encoding: gzip, deflate
Content-Length: 32
Connection: keep-alive
cache-control: no-cache
{
"size": 1,
"start": 1
}
application/x-www-form-urlencoded格式请求
/**
* 发送post表单请求
* @return 请求结果
*/
public String doPostFormUrl() {
URL u ;
HttpURLConnection connection = null;
OutputStream out ;
try {
this.contentType = "application/x-www-form-urlencoded; charset=UTF-8";
this.contentType = "multipart/form-data";
connection = getPostConnection();
out = connection.getOutputStream();
if(params != null && !params.isEmpty()) {
out.write(createParams().getBytes());
}
out.flush();
out.close();
try(InputStream is = connection.getInputStream()) {
return getResponse(is);
}catch (Exception e){
e.printStackTrace();
}
} catch (MalformedURLException e) {
log.error("the url format is err,check it ! {}",url);
e.printStackTrace();
}catch (ProtocolException e) {
assert connection != null;
log.error("the request protocol is error, check it ! {}",connection.getRequestMethod());
e.printStackTrace();
}catch (IOException e) {
log.error("the I/O operation is error !");
e.printStackTrace();
}
return null;
}
实际请求报文如下：
POST /test/formTest HTTP/1.1
Host: localhost:8080
Content-Type: application/x-www-form-urlencoded
User-Agent: PostmanRuntime/7.15.2
Accept: */*
Cache-Control: no-cache
Postman-Token: dcbeee5f-b7f5-45a4-860c-7393514471f5,afdc6811-7655-45ce-8989-cba62c3b434d
Host: localhost:8080
Accept-Encoding: gzip, deflate
Content-Length: 166
Connection: keep-alive
cache-control: no-cache
cname=1&bucketName=22222222222222222222
multipart/form-data格式请求
/**
* 发送post表单请求
* @return 请求结果
*/
public String doPostFormData() {
URL u ;
HttpURLConnection connection = null;
OutputStream out ;
try {
this.contentType = "multipart/form-data; boundary=" + BOUNDARY_STRING;
connection = getPostConnection();
out = connection.getOutputStream();
StringBuilder sb = new StringBuilder();
if(params != null && !params.isEmpty()) {
for (Map.Entry stringStringEntry : params.entrySet()) {
sb.append(BOUNDARY);
sb.append("Content-Disposition:form-data;name=\"");
sb.append(stringStringEntry.getKey());
sb.append("\"\r\n\r\n");
sb.append(stringStringEntry.getValue());
sb.append("\r\n");
}
out.write(sb.toString().getBytes());
}
if(file != null && fileName != null) {
StringBuilder sf = new StringBuilder();
sf.append(BOUNDARY);
sf.append("Content-Disposition:form-data;name=\"");
sf.append(fileName)
.append("\"; filename=\"")
.append(file)
.append("\"\r\n\r\n");
out.write(sf.toString().getBytes());
File f = new File(file);
InputStream is = new FileInputStream(f);
byte[] buffer = new byte[8192];
int count = 0;
while ((count = is.read(buffer)) != -1) {
out.write(buffer, 0, count);
}
out.write("\r\n\r\n".getBytes());
is.close();
}
out.write(("--" + BOUNDARY_STRING + "--\r\n").getBytes());
log.error(sb.toString());
out.flush();
out.close();
try(InputStream is = connection.getInputStream()) {
return getResponse(is);
}catch (Exception e){
e.printStackTrace();
}
} catch (MalformedURLException e) {
log.error("the url format is err,check it ! {}",url);
e.printStackTrace();
}catch (ProtocolException e) {
assert connection != null;
log.error("the request protocol is error, check it ! {}",connection.getRequestMethod());
e.printStackTrace();
}catch (IOException e) {
log.error("the I/O operation is error !");
e.printStackTrace();
}
return null;
}
实际发送的请求报文如下：
POST /test/formTest HTTP/1.1
Host: localhost:8080
Content-Type: multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxkTrZu0gW
User-Agent: PostmanRuntime/7.15.2
Accept: */*
Cache-Control: no-cache
Postman-Token: dcbeee5f-b7f5-45a4-860c-7393514471f5,ad334d00-9477-4eba-a122-cf14be29df11
Host: localhost:8080
Accept-Encoding: gzip, deflate
Content-Length: 166
Connection: keep-alive
cache-control: no-cache
Content-Disposition: form-data; name="bucketName"
2
------WebKitFormBoundary7MA4YWxkTrZu0gW--,
Content-Disposition: form-data; name="bucketName"
2
------WebKitFormBoundary7MA4YWxkTrZu0gW--
Content-Disposition: form-data; name="cname"
1
------WebKitFormBoundary7MA4YWxkTrZu0gW--,
Content-Disposition: form-data; name="bucketName"
2
------WebKitFormBoundary7MA4YWxkTrZu0gW--
Content-Disposition: form-data; name="cname"
1
------WebKitFormBoundary7MA4YWxkTrZu0gW--
Content-Disposition: form-data; name="file"; filename="/C:/Users/zhaoyanjiang-pc/Pictures/59224cf41dd06_610.jpg
------WebKitFormBoundary7MA4YWxkTrZu0gW--
单元测试用例：
@Test
public void getConnection(){
String result = HttpRequests.getInstance("https://service.emmazhang.top/files/db/list")
.addHead("111","111").addParams("size","2").addParams("start","1").doPost();
log.debug(result);
}
@Test
public void getConnection1(){
String result = HttpRequests.getInstance("http://wwww.emmazhang.top/files/get")
.addHead("111","111").addParams("name","1157187738680823810.png").doGet();
log.debug(result);
}
@Test
public void getConnection2(){
HttpRequests requests = HttpRequests.getInstance("http://localhost:8080/test/formTest")
.addHead("111","111").addParams("cname","1157187738680823810.png").addParams("bucketName","11111111111");
requests.setFile("/C:/Users/zhaoyanjiang-pc/Pictures/111.png");
requests.setFileName("file");
String result = requests.doPostFormData();
log.debug(result);
}
完整的实现如下：
package com.zhao.net;
import lombok.Data;
import lombok.extern.slf4j.Slf4j;
import java.io.*;
import java.net.*;
import java.util.*;
/**
* @program: test
* @description:
* @author: zhaoyj
* @create: 2019-08-26 15:10
*/
@Slf4j
@Data
public class HttpRequests {
public static HttpRequests getInstance(String url) {
HttpRequests httpRequests = new HttpRequests();
httpRequests.setUrl(url);
return httpRequests;
}
private String file;
private String fileName;
private String url;
private Map params;
private String contentType = "application/json";
private Map heads;
private Integer connectTimeout = 15000;
private Integer readTimeout = 60000;
private static final String BOUNDARY_STRING = "7MA4YWxkTrZu0gW";
public static final String BOUNDARY = "--" + BOUNDARY_STRING + "\r\n";
public HttpRequests addHead(String key, String value) {
heads = Optional.ofNullable(heads).orElseGet(HashMap::new);
heads.put(key,value);
return this;
}
public HttpRequests addParams(String key,String value){
params = Optional.ofNullable(params).orElseGet(HashMap::new);
params.put(key,value);
return this;
}
private String getResponse(InputStream in) throws IOException {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
// 封装输入流is，并指定字符集
int i;
while ((i = in.read()) != -1){
baos.write(i);
}
String result = baos.toString();
return result;
}
private String toJSONString(Map map){
Iterator> i = map.entrySet().iterator();
if (! i.hasNext()) {
return "{}";
}
StringBuilder sb = new StringBuilder();
sb.append('{');
for (;;) {
Map.Entry e = i.next();
String key = e.getKey();
String value = e.getValue();
sb.append("\"");
sb.append(key);
sb.append("\"");
sb.append(':');
sb.append("\"");
sb.append(value);
sb.append("\"");
if (! i.hasNext()) {
return sb.append('}').toString();
}
sb.append(',').append(' ');
}
}
private String createParams() {
if(params != null && !params.isEmpty()) {
StringBuilder sb = new StringBuilder();
for (Map.Entry stringObjectEntry : params.entrySet()) {
try {
sb.append(stringObjectEntry.getKey()).append("=").append(URLEncoder.encode(stringObjectEntry.getValue(),"UTF-8")).append("&");
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
}
sb.delete(sb.length() - 1, sb.length());
return sb.toString();
}
return "";
}
/**
* 发送get请求
* @return 返回请求结果
*/
public String doGet() {
if(params != null && !params.isEmpty()) {
url += "?";
url += createParams();
}
URL u ;
HttpURLConnection connection ;
try {
u = new URL(url);
log.error(url);
connection = (HttpURLConnection) u.openConnection();
connection.setRequestMethod("GET");
connection.setConnectTimeout(connectTimeout);
connection.setReadTimeout(readTimeout);
connection.setRequestProperty("Content-Type",contentType);
if(heads != null){
for (Map.Entry stringStringEntry : heads.entrySet()) {
connection.setRequestProperty(stringStringEntry.getKey(),stringStringEntry.getValue());
}
}
InputStream is = connection.getInputStream();
return getResponse(is);
} catch (MalformedURLException e) {
log.error("the url format is err,check it ! {}",url);
e.printStackTrace();
} catch (IOException e) {
log.error("the I/O operation is error !");
e.printStackTrace();
}
return null;
}
/**
* 发送post请求
* @return 请求结果
*/
public String doPost() {
URL u ;
HttpURLConnection connection = null;
OutputStream out ;
try {
connection = getPostConnection();
out = connection.getOutputStream();
if(params != null && !params.isEmpty()) {
out.write(toJSONString(params).getBytes());
}
out.flush();
out.close();
try(InputStream is = connection.getInputStream()) {
return getResponse(is);
}catch (Exception e){
e.printStackTrace();
}
} catch (MalformedURLException e) {
log.error("the url format is err,check it ! {}",url);
e.printStackTrace();
}catch (ProtocolException e) {
assert connection != null;
log.error("the request protocol is error, check it ! {}",connection.getRequestMethod());
e.printStackTrace();
}catch (IOException e) {
log.error("the I/O operation is error !");
e.printStackTrace();
}
return null;
}
/**
* 发送post表单请求
* @return 请求结果
*/
public String doPostFormUrl() {
URL u ;
HttpURLConnection connection = null;
OutputStream out ;
try {
this.contentType = "application/x-www-form-urlencoded; charset=UTF-8";
this.contentType = "multipart/form-data";
connection = getPostConnection();
out = connection.getOutputStream();
if(params != null && !params.isEmpty()) {
out.write(createParams().getBytes());
}
out.flush();
out.close();
try(InputStream is = connection.getInputStream()) {
return getResponse(is);
}catch (Exception e){
e.printStackTrace();
}
} catch (MalformedURLException e) {
log.error("the url format is err,check it ! {}",url);
e.printStackTrace();
}catch (ProtocolException e) {
assert connection != null;
log.error("the request protocol is error, check it ! {}",connection.getRequestMethod());
e.printStackTrace();
}catch (IOException e) {
log.error("the I/O operation is error !");
e.printStackTrace();
}
return null;
}
/**
* 发送post表单请求
* @return 请求结果
*/
public String doPostFormData() {
URL u ;
HttpURLConnection connection = null;
OutputStream out ;
try {
this.contentType = "multipart/form-data; boundary=" + BOUNDARY_STRING;
connection = getPostConnection();
out = connection.getOutputStream();
StringBuilder sb = new StringBuilder();
if(params != null && !params.isEmpty()) {
for (Map.Entry stringStringEntry : params.entrySet()) {
sb.append(BOUNDARY);
sb.append("Content-Disposition:form-data;name=\"");
sb.append(stringStringEntry.getKey());
sb.append("\"\r\n\r\n");
sb.append(stringStringEntry.getValue());
sb.append("\r\n");
}
out.write(sb.toString().getBytes());
}
if(file != null && fileName != null) {
StringBuilder sf = new StringBuilder();
sf.append(BOUNDARY);
sf.append("Content-Disposition:form-data;name=\"");
sf.append(fileName)
.append("\"; filename=\"")
.append(file)
.append("\"\r\n\r\n");
out.write(sf.toString().getBytes());
File f = new File(file);
InputStream is = new FileInputStream(f);
byte[] buffer = new byte[8192];
int count = 0;
while ((count = is.read(buffer)) != -1) {
out.write(buffer, 0, count);
}
out.write("\r\n\r\n".getBytes());
is.close();
}
out.write(("--" + BOUNDARY_STRING + "--\r\n").getBytes());
log.error(sb.toString());
out.flush();
out.close();
try(InputStream is = connection.getInputStream()) {
return getResponse(is);
}catch (Exception e){
e.printStackTrace();
}
} catch (MalformedURLException e) {
log.error("the url format is err,check it ! {}",url);
e.printStackTrace();
}catch (ProtocolException e) {
assert connection != null;
log.error("the request protocol is error, check it ! {}",connection.getRequestMethod());
e.printStackTrace();
}catch (IOException e) {
log.error("the I/O operation is error !");
e.printStackTrace();
}
return null;
}
/**
* 发送post表单请求
* @return 请求结果
*/
private HttpURLConnection getPostConnection() throws IOException {
URL u ;
HttpURLConnection connection = null;
OutputStream out ;
u = new URL(url);
connection = (HttpURLConnection) u.openConnection();
connection.setRequestMethod("POST");
connection.setConnectTimeout(connectTimeout);
connection.setReadTimeout(readTimeout);
connection.setRequestProperty("Content-Type",contentType);
connection.setDoOutput(true);
connection.setDoInput(true);
if(heads != null){
for (Map.Entry stringStringEntry : heads.entrySet()) {
connection.setRequestProperty(stringStringEntry.getKey(),stringStringEntry.getValue());
}
}
return connection;
}
}
后端接收时，带文件的需要实体接收，如下：
package com.zhao.aliyun.controller;
import com.baomidou.mybatisplus.core.toolkit.IdWorker;
import com.zhao.aliyun.entity.FileEntity;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;
import java.io.File;
/**
* @program: aliyun
* @description:
* @author: zhaoyj
* @create: 2019-08-27 10:35
*/
@RestController
@RequestMapping("/test")
@Slf4j
public class TestController {
@RequestMapping(value = "/formTest",method = RequestMethod.POST)
public Object formTest(@ModelAttribute FileEntity multipartFile){
MultipartFile multipartFile1 = multipartFile.getFile();
File f = new File("d:\\test\\" + IdWorker.getIdStr() + "." + multipartFile1.getOriginalFilename().split("[.]")[multipartFile1.getOriginalFilename().split("[.]").length - 1]);
try{
log.error(multipartFile.getFile().getContentType());
multipartFile.getFile().transferTo(f);
}catch (Exception e){
e.printStackTrace();
}
return null;
}
}
转存后的文件
