springboot使用httpclient(PostMethod，RequestEntity等)需要导入哪些jar包

所需jar包如下：

commons-codec-1.7.jar
commons-logging-1.1.1.jar

commons-httpclient.jar
httpclient-4.2.2.jar
httpcore-4.2.2.jar

如果有​​spring-boot-starter-parent​​ ，下面2个默认会带：

commons-codec-1.7.jar
commons-logging-1.1.1.jar

所以pom.xml只需要引入如下：

<dependency>
  <groupId>commons-httpclient</groupId>
  <artifactId>commons-httpclient</artifactId>
  <version>3.1</version>
</dependency>
<dependency>
  <groupId>org.apache.httpcomponents</groupId>
  <artifactId>httpclient</artifactId>
  <version>4.3.1</version>
</dependency>

<dependency>
  <groupId>org.apache.httpcomponents</groupId>
  <artifactId>httpcore</artifactId>
  <version>4.3.1</version>
</dependency>

httpClient设置header

注：setHeader()或者setRequestHeader() 都是会累加的，不用专门弄个header体。

写法一：

HttpPost httpPost = new HttpPost(url);
StringEntity stringEntity = new StringEntity(req, StandardCharsets.UTF_8);
httpPost.setEntity(stringEntity);
httpPost.setHeader("appID", appID);
httpPost.setHeader("customKey", "customValue"); 
response = httpClient.execute(httpPost);

写法二：

PostMethod postMethod = new PostMethod(url);
byte[] b = req.getBytes("utf-8");
InputStream is = new ByteArrayInputStream(b, 0, b.length);
RequestEntity re = new InputStreamRequestEntity(is, b.length,
        "text/xml; charset=utf-8");
postMethod.setRequestHeader("customKey","customValue");
postMethod.setRequestEntity(re);
org.apache.commons.httpclient.HttpClient httpClient = new org.apache.commons.httpclient.HttpClient();
int statusCode = httpClient.executeMethod(postMethod);