不介绍太多,只介绍实用的,像getObject, getEntity我都不介绍,只介绍一个exchange()函数就够了,最后会附上我们公司的代码。
下面对RestTemplate的函数做详细说明及使用技巧:
无论GET请求,还是POST请求,exchange参数位置是一样的。
public <T> ResponseEntity<T> exchange(String url, HttpMethod method, @Nullable HttpEntity<?> requestEntity, Class<T> responseType, Map<String, ?> uriVariables)
参数介绍:
1、url: 该参数是请求的url, 有时请求参数在Param或着在Path里面,这时最好的处理方式是使用占位符处理。注:不要直接把参数值直接写上去,直接写上参数值会请求失败。正确写的法如:
http://localhost:8085/userservice/v1/users/query?queryParam={queryParam}
2、method:是调用的方法,如POST, GET。
3、requestEntity:请求的类名,会放入Body中。
4、responseType:返回的类名,返回后,会自动的转换为该类。
5、uriVariables:指的是参数。很多文章都说默认为PATH,其实不是,他是填充占位符用的。在URL中,哪里有占位符,就会填充哪里。如下所示:
(1)Param位置填充。
http://localhost:8085/userservice/v1/users/query?queryParam={queryParam}
, map为:
Map<String, String> paramMap = new HashMap<String, String>();
paramMap.put("queryParam", "{\"startPage\":1,\"pageSize\":50}");
自动填充占位{queryParam}.
(2)在Path位置
http://localhost:8085/userservice/v1/users/query
/{userId}, 那就会自动填充userId
我的代码如下:
package com.system.http.util; import com.system.http.entity.ErrorCode; import com.system.http.entity.RetEntity; import org.springframework.http.*; import org.springframework.web.client.RestTemplate; import java.util.Map; import java.util.Map.Entry; /** * Http协议的发送类,用于服务之间的调用。 */ public class HttpSendUtils { public static final int MAP_EMPTY_FLAG = 0; public static final int MAP_NOT_EMPTY_FLAG = 1; /** * Http协议的GET请求。 *@param url 请求的URL,包含IP,端口号,还有请求的URI。 *@param sessionId, 服务之间调用的会话id。 *@param authId ,服务之间调用的签名id。 *@param paramsMap,请求参数位置在Param中,以Key,Value的形式保存在HashMap中。 *@return RetEntity, 包含的错误码信息。。 *@exception NA */ public static RetEntity httpGet(String url, String sessionId, String authId, Map<String, String> paramsMap) { return sendMessage(url, sessionId, authId, paramsMap, HttpMethod.GET); } public static RetEntity httpPost(String url, String sessionId, String authId, Map<String, String> paramsMap) { return sendMessage(url, sessionId, authId, paramsMap, HttpMethod.POST); } private static RetEntity sendMessage(String url, String sessionId, String authId, Map<String, String> paramsMap, HttpMethod httpMethod) { String httpUrl = url; //参数标志,标记paramsMap是否为空,0为空。 int flag = MAP_EMPTY_FLAG; if (paramsMap != null && !paramsMap.isEmpty()) { String urlTmp = "?"; for(Entry<String, String> entry : paramsMap.entrySet()) { urlTmp = urlTmp + entry.getKey() + "=" + "{" + entry.getKey() + "}"; urlTmp = urlTmp + "&"; } int endIndex = urlTmp.lastIndexOf("&"); httpUrl = httpUrl + urlTmp.substring(0, endIndex); flag = MAP_NOT_EMPTY_FLAG; } //填充header数据及参数编码格式,防止收到参数为乱码。 HttpHeaders requestHeaders = new HttpHeaders(); MediaType mediaType = MediaType.parseMediaType("application/json;charset=UTF-8"); requestHeaders.setContentType(mediaType); if (sessionId != null) { requestHeaders.add("sessionId", sessionId); requestHeaders.add("authId", authId); } HttpEntity<String> requestEntity = new HttpEntity<String>(null, requestHeaders); RestTemplate restTemplate = new RestTemplate(); ResponseEntity<RetEntity> response = null; if (flag == MAP_NOT_EMPTY_FLAG) { response = restTemplate.exchange(httpUrl, httpMethod,requestEntity, RetEntity.class, paramsMap); } else { response = restTemplate.exchange(httpUrl, httpMethod, requestEntity, RetEntity.class); } RetEntity retValue = response.getBody(); return retValue; } }
返回类定义
package com.system.http.entity;
public class RetEntity <T>
{
private static final long serialVersionUID = 5451109092148890181L;
private int resultCode;
private T resultValue;
private String resultMsg;
public int getResultCode()
{
return resultCode;
}
public void setResultCode(int resultCode)
{
this.resultCode = resultCode;
}
public Object getResultValue()
{
return resultValue;
}
public void setResultValue(T resultValue)
{
this.resultValue = resultValue;
}
public String getResultMsg()
{
return resultMsg;
}
public void setResultMsg(String resultMsg)
{
this.resultMsg = resultMsg;
}
@Override
public String toString()
{
return "{" +
"resultCode=" + resultCode +
", resultValue=" + resultValue +
", resultMsg='" + resultMsg + '\'' +
'}';
}
}
方法调用测试类:
import com.system.http.entity.RetEntity;
import com.system.http.util.HttpSendUtils;
import java.util.HashMap;
import java.util.Map;
public class HttpUtilTmp
{
public static void main(String []args)
{
Map<String, String> paramMap = new HashMap<String, String>();
paramMap.put("queryParam", "{\"startPage\":1,\"pageSize\":50}");
RetEntity retEntity = null;
retEntity = HttpSendUtils.httpGet("http://localhost:8085/userservice/v1/users/query",
"78d5cd86cb9d3caa3adfc7aa2ef221d03e4872dcceb1eb24c0d62be8a6f89366", "6",
paramMap);
}
}