Java实现Http客户端服务端间通信

叁歲伎倆 2022-05-21 03:56 455阅读 0赞

访问Http Post请求的代码示例，项目为spring boot框架，省略不重要的部分。

**1、Post服务端代码**：

样例1：

@RequestMapping(value ="/testDemo1",method = RequestMethod.POST,produces={"application/xml"})
        public @ResponseBody String testDemo1(@RequestBody String body) throws IOException 
        {
        	logger.info(body);    //通过@RequestBody 获取Post 的消息体内容，另外可自行了解@RequestParam、@RequestAttribute
        	return abc;
        }

样例2：

@RequestMapping(value ="/testDemo",method = RequestMethod.POST,produces={"application/xml"})
        public @ResponseBody String flashSingalInterface(HttpServletRequest request, HttpServletResponse response) throws IOException 
        {
        	// 读取请求内容 ----直接从request中获取
            BufferedReader br = new BufferedReader(new InputStreamReader(request.getInputStream(),"utf-8"));  
            String line = null;  
            StringBuilder sb = new StringBuilder();  
            while((line = br.readLine())!=null){  
                sb.append(line);  
            }  
          
            // 将资料解码  
            String reqBody = sb.toString();  
            String result = URLDecoder.decode(reqBody, "utf-8");  //utf-8
            
            logger.info(result);
            
        	Map<String, String> map = new HashMap<String, String>();
        	map.put("resultCode", "200");
        	map.put("resultDesc", "nice try");
        	
        	logger.info(JacksonUtil.bean2Json(map));
        	return JacksonUtil.bean2Json(map);
        }

**2、客户端代码**：（网上很多样例可参考，代码大同小异，依赖的jar包可能略有区别，注意下就行）

**样例1**：使用httpclient-4.5.2.jar 、httpcore-4.4.1.jar里的方法

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.config.Registry;
    import org.apache.http.config.RegistryBuilder;
    import org.apache.http.conn.socket.ConnectionSocketFactory;
    import org.apache.http.conn.socket.PlainConnectionSocketFactory;
    import org.apache.http.entity.StringEntity;
    import org.apache.http.impl.client.CloseableHttpClient;
    import org.apache.http.impl.client.HttpClients;
    import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
    import org.apache.http.util.EntityUtils;

入参为 url地址、json字符串、编码方式。

private static String sendPost(String url, String jsonParams, String encoding) throws ClientProtocolException, IOException
        {
    	int statusCode = 0;
    	String body = "";
    	String resultCode = "";
    
    	// 设置协议http和https对应的处理socket链接工厂的对象
    	Registry<ConnectionSocketFactory> socketFactoryRegistry = RegistryBuilder.<ConnectionSocketFactory> create()
    			.register("http", PlainConnectionSocketFactory.INSTANCE).build();
    
    	PoolingHttpClientConnectionManager connManager = new PoolingHttpClientConnectionManager(socketFactoryRegistry);
    	HttpClients.custom().setConnectionManager(connManager);
    
    	// 创建自定义的httpclient对象
    	CloseableHttpClient client = HttpClients.custom().setConnectionManager(connManager).build();
    	// 创建post方式请求对象
    	HttpPost httpPost = new HttpPost(url);
    	
    	StringEntity uefEntity = new StringEntity(jsonParams, encoding);
    	uefEntity.setContentType("application/json");
    
    	// 设置参数到请求对象中
    	httpPost.setEntity(uefEntity);
    
    	// 执行请求操作，并拿到结果（同步阻塞）
    	CloseableHttpResponse response = client.execute(httpPost);
    
    	statusCode = response.getStatusLine().getStatusCode();
    
    	if (200 != statusCode) 
    	{
    		resultCode = "-1";
    		return resultCode;
    	}
    
    	// 获取结果实体
    	HttpEntity entity = response.getEntity();
    	if (entity != null)
    	{
    		// 按指定编码转换结果实体为String类型
    		body = EntityUtils.toString(entity, encoding);
    		resultCode = getJson(body);
    	}
    	EntityUtils.consume(entity);
    
    	// 释放链接
    	response.close();
    	return resultCode;
    }
    
        //解析json串,获取resultCode值
        private static String getJson(String body)
        {
    	JSONObject obj = JSONObject.fromObject(body);	
    	String resultCode = obj.getString("resultCode");
    	return resultCode;
        }

PS：使用Jackson，注意依赖包要导全了，参考：https://blog.csdn.net/zengdeqing2012/article/details/52053832

主函数：

public static void main(String[] args)
        {
        	String postUrl = "http://localhost:8080/testDemo";
        	String reqJson = "{'name':'zhnagsan','age':'你好'}";
        	try 
        	{
    	    sendPost(postUrl, reqJson, "UTF-8");
    	}
        	catch (IOException e) 
        	{
    	    e.printStackTrace();
    	}
        }

**样例2**：使用com.springsource.org.apache.commons.httpclient-3.1.0.3510.jar 里的方法

import org.apache.commons.httpclient.HttpClient;
    import org.apache.commons.httpclient.URI;
    import org.apache.commons.httpclient.methods.PostMethod;
    import org.apache.commons.httpclient.methods.StringRequestEntity;

入参为url、Map类型的消息体（代码里进行json封装）

private static void send2(String url, Map<String, String> contentPara) throws IOException
    {
    	HttpClient client = new HttpClient();
    	PostMethod httpPost = new PostMethod(url);	
    	httpPost.setRequestHeader("Content-type", "text/xml; charset=utf-8");
    //	httpPost.setRequestHeader("Content-Length", String.valueOf(reqHead.length()));
    	
    	BufferedReader br = null;	
    	String content = JacksonUtil.bean2Json(contentPara);
    	
    	httpPost.setRequestEntity(new StringRequestEntity(content, "text/xml", "utf-8"));
    	int returnCode = client.executeMethod(httpPost);
    	// 请求成功
    	if (returnCode == 200)
    	{
    		br = new BufferedReader(new InputStreamReader(httpPost.getResponseBodyAsStream(), "utf-8"));
    		StringBuffer stb = new StringBuffer();
    		String str = null;
    		// 拼接json字符串 后续处理
    		while ((str = br.readLine()) != null)
    		{
    		    stb.append(str);
    		}
    		System.out.println(stb);
    	} 
    	br.close();	
    	return;
    }

主函数：

public static void main(String[] args){
        	String postUrl = "xxx";
        	Map<String, String> map = new HashMap<String, String>();
        	map.put("name", "zhangsan");
        	map.put("age", "你好");
        	try{
        	    send2(postUrl, map);
    	} catch (IOException e) {
                e.printStackTrace();
    	}
    }

**3、自定义Jackson 工具类**

依赖 jackson-annotations-2.8.0.jar、jackson-core-2.8.6.jar、jackson-databind-2.8.6.jar 包

package xxx;
    import java.io.IOException;
    
    import com.fasterxml.jackson.core.JsonParseException;
    import com.fasterxml.jackson.core.JsonProcessingException;
    import com.fasterxml.jackson.databind.JsonMappingException;
    import com.fasterxml.jackson.databind.ObjectMapper;  
    public class JacksonUtil
    {
    	private static ObjectMapper objectMapper = null;
    
    	private static void init()
    	{
    		objectMapper = new ObjectMapper();
    	}
            //对象转成Json字符串
    	public static String bean2Json(Object obj) throws JsonProcessingException 
    	{
    		if (objectMapper == null)
    		{
    			init();
    		}
    		return objectMapper.writeValueAsString(obj);
    	}
    	//字符串转成对象
    	public static <T> T json2Bean(String str, Class<T> type) throws JsonParseException, JsonMappingException, IOException 
    	{
    		if (objectMapper == null)
    		{
    			init();
    		}
    		return objectMapper.readValue(str, type);
    	}
    	
    }

调用方式在前面的代码里有，自己测下就明白了。