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背景:
一般情况下都是 后端提供接口,前端调用,解决需求,但是有时需要后端调用后端接口。
几种方式总结:
在Java项目中调用第三方接口的方式有:
①通过JDK网络类Java.net.HttpURLConnection;
②通过common封装好的HttpClient;
③通过Apache封装好的HttpClient;由②发展来的
④通过SpringBoot-RestTemplate;
1. 通过JDK网络类Java.net.HttpURLConnection
比较原始的一种调用做法,这里把get请求和post请求都统一放在一个方法里面
public class HttpUrlConnectionToInterface {
/**
* 以post或get方式调用对方接口方法,
* @param pathUrl
*/
public static void doPostOrGet(String pathUrl, String data){
OutputStreamWriter out = null;
BufferedReader br = null;
String result = "";
try {
URL url = new URL(pathUrl);
//打开和url之间的连接
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
//请求方式
conn.setRequestMethod("POST");
//conn.setRequestMethod("GET");
//设置通用的请求属性
conn.setRequestProperty("accept", "*/*");
conn.setRequestProperty("connection", "Keep-Alive");
conn.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)");
conn.setRequestProperty("Content-Type", "application/json;charset=utf-8");
//DoOutput设置是否向httpUrlConnection输出,DoInput设置是否从httpUrlConnection读入,此外发送post请求必须设置这两个
conn.setDoOutput(true);
conn.setDoInput(true);
/**
* 下面的三句代码,就是调用第三方http接口
*/
//获取URLConnection对象对应的输出流
out = new OutputStreamWriter(conn.getOutputStream(), "UTF-8");
//发送请求参数即数据
out.write(data);
//flush输出流的缓冲
out.flush();
/**
* 下面的代码相当于,获取调用第三方http接口后返回的结果
*/
//获取URLConnection对象对应的输入流
InputStream is = conn.getInputStream();
//构造一个字符流缓存
br = new BufferedReader(new InputStreamReader(is));
String str = "";
while ((str = br.readLine()) != null){
result += str;
}
System.out.println(result);
//关闭流
is.close();
//断开连接,disconnect是在底层tcp socket链接空闲时才切断,如果正在被其他线程使用就不切断。
conn.disconnect();
} catch (Exception e) {
e.printStackTrace();
}finally {
try {
if (out != null){
out.close();
}
if (br != null){
br.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
public static void main(String[] args) {
/**
*手机信息查询接口:http://tcc.taobao.com/cc/json/mobile_tel_segment.htm?tel=手机号
* http://api.showji.com/Locating/www.showji.com.aspx?m=手机号&output=json&callback=querycallback
*/
doPostOrGet("https://tcc.taobao.com/cc/json/mobile_tel_segment.htm?tel=13026194071", "");
}
}
2. 通过apache common封装好的HttpClient
httpClient的get或post请求方式步骤:
- 生成一个HttpClient对象并设置相应的参数
- 生成一个GetMethod对象或PostMethod并设置响应的参数
- 用HttpClient生成的对象来执行GetMethod生成的Get方法
- 处理响应状态码
- 若响应正常,处理HTTP响应内容
- 释放连接
pom文件添加依赖:
<dependency>
<groupId>commons-httpclient</groupId>
<artifactId>commons-httpclient</artifactId>
<version>3.1</version>
</dependency>
生活小提示:
如果有一些jar包找不到,(不是maven管理需要自己下载)有时候有各种问题,或者墙或者找不到之类,可以通过创建一个maven空项目,添加pom依赖,然后下载,在pom仓库里找到即可用。
public class HttpClientToInterface {
/**
* httpClient的get请求方式
* 使用GetMethod来访问一个URL对应的网页实现步骤:
* 1.生成一个HttpClient对象并设置相应的参数;
* 2.生成一个GetMethod对象并设置响应的参数;
* 3.用HttpClient生成的对象来执行GetMethod生成的Get方法;
* 4.处理响应状态码;
* 5.若响应正常,处理HTTP响应内容;
* 6.释放连接。
* @param url
* @param charset
* @return
*/
public static String doGet(String url, String charset){
/**
* 1.生成HttpClient对象并设置参数
*/
HttpClient httpClient = new HttpClient();
//设置Http连接超时为5秒
httpClient.getHttpConnectionManager().getParams().setConnectionTimeout(5000);
/**
* 2.生成GetMethod对象并设置参数
*/
GetMethod getMethod = new GetMethod(url);
//设置get请求超时为5秒
getMethod.getParams().setParameter(HttpMethodParams.SO_TIMEOUT, 5000);
//设置请求重试处理,用的是默认的重试处理:请求三次
getMethod.getParams().setParameter(HttpMethodParams.RETRY_HANDLER, new DefaultHttpMethodRetryHandler());
String response = "";
/**
* 3.执行HTTP GET 请求
*/
try {
int statusCode = httpClient.executeMethod(getMethod);
/**
* 4.判断访问的状态码
*/
if (statusCode != HttpStatus.SC_OK){
System.err.println("请求出错:" + getMethod.getStatusLine());
}
/**
* 5.处理HTTP响应内容
*/
//HTTP响应头部信息,这里简单打印
Header[] headers = getMethod.getResponseHeaders();
for (Header h: headers){
System.out.println(h.getName() + "---------------" + h.getValue());
}
//读取HTTP响应内容,这里简单打印网页内容
//读取为字节数组
byte[] responseBody = getMethod.getResponseBody();
response = new String(responseBody, charset);
System.out.println("-----------response:" + response);
//读取为InputStream,在网页内容数据量大时候推荐使用
//InputStream response = getMethod.getResponseBodyAsStream();
} catch (HttpException e) {
//发生致命的异常,可能是协议不对或者返回的内容有问题
System.out.println("请检查输入的URL!");
e.printStackTrace();
} catch (IOException e){
//发生网络异常
System.out.println("发生网络异常!");
}finally {
/**
* 6.释放连接
*/
getMethod.releaseConnection();
}
return response;
}
/**
* post请求
* @param url
* @param json
* @return
*/
public static String doPost(String url, JSONObject json){
HttpClient httpClient = new HttpClient();
PostMethod postMethod = new PostMethod(url);
postMethod.addRequestHeader("accept", "*/*");
postMethod.addRequestHeader("connection", "Keep-Alive");
//设置json格式传送
postMethod.addRequestHeader("Content-Type", "application/json;charset=utf-8");
//必须设置下面这个Header
postMethod.addRequestHeader("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36");
//添加请求参数
postMethod.addParameter("commentId", json.getString("commentId"));
String res = "";
try {
int code = httpClient.executeMethod(postMethod);
if (code == 200){
res = postMethod.getResponseBodyAsString();
System.out.println(res);
}
} catch (IOException e) {
e.printStackTrace();
}
return res;
}
public static void main(String[] args) {
doGet("http://tcc.taobao.com/cc/json/mobile_tel_segment.htm?tel=13026194071", "UTF-8");
System.out.println("-----------分割线------------");
System.out.println("-----------分割线------------");
System.out.println("-----------分割线------------");
JSONObject jsonObject = new JSONObject();
jsonObject.put("commentId", "13026194071");
doPost("http://tcc.taobao.com/cc/json/mobile_tel_segment.htm?tel=13026194071", jsonObject);
}
}
3 通过Apache封装好的CloseableHttpClient
CloseableHttpClient是在HttpClient的基础上修改更新而来的,这里还涉及到请求头token的设置(请求验证),利用fastjson转换请求或返回结果字符串为json格式,当然上面两种方式也是可以设置请求头token、json的,这里只在下面说明。
<!--CloseableHttpClient-->
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpclient</artifactId>
<version>4.5.2</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.28</version>
</dependency>
public class CloseableHttpClientToInterface {
private static String tokenString = "";
private static String AUTH_TOKEN_EXPIRED = "AUTH_TOKEN_EXPIRED";
private static CloseableHttpClient httpClient = null;
/**
* 以get方式调用第三方接口
* @param url
* @return
*/
public static String doGet(String url, String token){
//创建HttpClient对象
CloseableHttpClient httpClient = HttpClientBuilder.create().build();
HttpGet get = new HttpGet(url);
try {
if (tokenString != null && !tokenString.equals("")){
tokenString = getToken();
}
//api_gateway_auth_token自定义header头,用于token验证使用
get.addHeader("api_gateway_auth_token", tokenString);
get.addHeader("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36");
HttpResponse response = httpClient.execute(get);
if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK){
//返回json格式
String res = EntityUtils.toString(response.getEntity());
return res;
}
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
/**
* 以post方式调用第三方接口
* @param url
* @param json
* @return
*/
public static String doPost(String url, JSONObject json){
try {
if (httpClient == null){
httpClient = HttpClientBuilder.create().build();
}
HttpPost post = new HttpPost(url);
if (tokenString != null && !tokenString.equals("")){
tokenString = getToken();
}
//api_gateway_auth_token自定义header头,用于token验证使用
post.addHeader("api_gateway_auth_token", tokenString);
post.addHeader("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36");
StringEntity s = new StringEntity(json.toString());
s.setContentEncoding("UTF-8");
//发送json数据需要设置contentType
s.setContentType("application/x-www-form-urlencoded");
//设置请求参数
post.setEntity(s);
HttpResponse response = httpClient.execute(post);
if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK){
//返回json格式
String res = EntityUtils.toString(response.getEntity());
return res;
}
} catch (Exception e) {
e.printStackTrace();
}finally {
if (httpClient != null){
try {
httpClient.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return null;
}
/**
* 获取第三方接口的token
*/
public static String getToken(){
String token = "";
JSONObject object = new JSONObject();
object.put("appid", "appid");
object.put("secretkey", "secretkey");
try {
if (httpClient == null){
httpClient = HttpClientBuilder.create().build();
}
HttpPost post = new HttpPost("http://localhost/login");
post.addHeader("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36");
StringEntity s = new StringEntity(object.toString());
s.setContentEncoding("UTF-8");
//发送json数据需要设置contentType
s.setContentType("application/x-www-form-urlencoded");
//设置请求参数
post.setEntity(s);
HttpResponse response = httpClient.execute(post);
//这里可以把返回的结果按照自定义的返回数据结果,把string转换成自定义类
//ResultTokenBO result = JSONObject.parseObject(response, ResultTokenBO.class);
//把response转为jsonObject
JSONObject result = JSONObject.parseObject(response);
if (result.containsKey("token")){
token = result.getString("token");
}
} catch (Exception e) {
e.printStackTrace();
}
return token;
}
/**
* 测试
*/
public static void test(String telephone){
JSONObject object = new JSONObject();
object.put("telephone", telephone);
try {
//首先获取token
tokenString = getToken();
String response = doPost("http://localhost/searchUrl", object);
//如果返回的结果是list形式的,需要使用JSONObject.parseArray转换
//List<Result> list = JSONObject.parseArray(response, Result.class);
System.out.println(response);
} catch (Exception e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
test("12345678910");
}
}
4 通过SpringBoot-RestTemplate
delete() 在特定的URL上对资源执行HTTP DELETE操作
exchange() 在URL上执行特定的HTTP方法,返回包含对象的ResponseEntity,这个对象是从响应体中映射得到的
execute() 在URL上执行特定的HTTP方法,返回一个从响应体映射得到的对象
getForEntity() 发送一个HTTP GET请求,返回的ResponseEntity包含了响应体所映射成的对象
getForObject() 发送一个HTTP GET请求,返回的请求体将映射为一个对象
postForEntity() POST 数据到一个URL,返回包含一个对象的ResponseEntity,这个对象是从响应体中映射得到的
postForObject() POST 数据到一个URL,返回根据响应体匹配形成的对象
headForHeaders() 发送HTTP HEAD请求,返回包含特定资源URL的HTTP头
optionsForAllow() 发送HTTP OPTIONS请求,返回对特定URL的Allow头信息
postForLocation() POST 数据到一个URL,返回新创建资源的URL
put() PUT 资源到特定的URL
参考:
http://www.cnblogs.com/angusbao/p/7727649.html 纯Java api HttpURLConnection
https://blog.csdn.net/chijiandi/article/details/81388240 纯Java api HttpURLConnection
https://www.cnblogs.com/xuegu/p/8490815.html 封装api HttpClient
https://www.cnblogs.com/unknows/p/8534713.html
https://blog.csdn.net/qq_35860138/article/details/82967727 封装api HttpClient
https://www.cnblogs.com/swordfall/p/10757499.html
https://blog.csdn.net/a1032818891/article/details/81172478 SpringBoot-RestTemplate
发布者:全栈程序员-用户IM,转载请注明出处:https://javaforall.cn/143068.html原文链接:https://javaforall.cn
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