HttpClient以json形式的参数调用http接口并对返回的json数据进行处理（可以带文件）

1、参数的url就是被调用的地址，map是你要传的参数。参数转成json我使用的是gson方式转换的。
    主要使用的jar包有httpclient-4.5.3.jar、httpcore-4.4.6.jar、commons-codec-1.9.jar、gson-2.2.4.jar和commons-logging-1.2.jar。

　 如果发送的post请求想传送文件，需添加httpmime-4.5.3.jar包，并设置如下代码：

    HttpEntity multipartEntityBuilder = MultipartEntityBuilder.create().addBinaryBody("file", new File("D:\\workspace\\programm\\WebContent\\programm\\1991.zip")).build();

    第一个参数表示请求字段名，第二个参数就是文件。

    还想添加参数则

    HttpEntity multipartEntityBuilder = MultipartEntityBuilder.create().addTextBody("name", "张三").addBinaryBody("file", new File("D:\\workspace\\programm\\WebContent\\programm\\1991.zip")).build();

    httpPost.setEntity(multipartEntityBuilder);

import java.io.IOException;
import java.util.Map;

import org.apache.http.HttpEntity;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

import com.google.gson.Gson;

public class HttpClientUtil {

private final static String CONTENT_TYPE_TEXT_JSON = "text/json";

public static String postRequest(String url, Map<String, Object> param) throws ClientProtocolException, IOException{

CloseableHttpClient client = HttpClients.createDefault();

HttpPost httpPost = new HttpPost(url);
httpPost.setHeader("Content-Type", "application/json;charset=UTF-8");

Gson gson = new Gson();
String parameter = gson.toJson(param);

StringEntity se = new StringEntity(parameter);
se.setContentType(CONTENT_TYPE_TEXT_JSON);
httpPost.setEntity(se);

CloseableHttpResponse response = client.execute(httpPost);
HttpEntity entity = response.getEntity();
String result = EntityUtils.toString(entity, "UTF-8");

return result;
}

}

 2、返回的结果也可以使用gson转换成对象进行下一步操作。

import com.google.gson.Gson;

public class GsonUtil {

public static <T> T jsonToObject(String jsonData, Class<T> type) {
Gson gson = new Gson();
T result = gson.fromJson(jsonData, type);
return result;
}

public static void main(String[] args) {
String json = "{'id':'1','name':'zhang','address':'Hubei'}";
jsonToObject(json, Person.class);
Person person = jsonToObject(json, Person.class);
System.out.println(person);
}

}

建立要转成的对象的类。

import java.util.Date;

public class Person {

private int id;

private String name;

private int age;

private String address;public int getId() {
return id;
}

public void setId(int id) {
this.id = id;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public int getAge() {
return age;
}

public void setAge(int age) {
this.age = age;
}

public String getAddress() {
return address;
}

public void setAddress(String address) {
this.address = address;
}

@Override
public String toString() {
return "Person [id=" + id + ", name=" + name + ", age=" + age + ", address=" + address + "]";
}

}

 3、发送以键值对形式的参数的post请求

package com.avatarmind.httpclient;

import java.util.ArrayList;
import java.util.List;

import org.apache.http.HttpEntity;
import org.apache.http.NameValuePair;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;

9df6
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;

public class HttpClient3 {

public static void main(String[] args) throws Exception {
CloseableHttpClient client = HttpClients.createDefault();

String url = "http://yuntuapi.amap.com/datamanage/table/create";

HttpPost httpPost = new HttpPost(url);

// 参数形式为key=value&key=value
List<NameValuePair> formparams = new ArrayList<NameValuePair>();
formparams.add(new BasicNameValuePair("key", "060212638b94290e3dd0648c15753b64"));
formparams.add(new BasicNameValuePair("name", "火狐"));

// 加utf-8进行编码
UrlEncodedFormEntity uefEntity = new UrlEncodedFormEntity(formparams, "UTF-8");
httpPost.setEntity(uefEntity);

CloseableHttpResponse response = client.execute(httpPost);
HttpEntity entity = response.getEntity();
String result = EntityUtils.toString(entity, "UTF-8");
System.out.println(result);
}

}