RestTemplate中使用ParameterizedType

在使用http请求时，往往会封装一个统一的结果类

package com.plateno.booking.sync.ebk.process.http.response;  
  
public class  InternalDataServiceResult <T> {  
  
    private String resultCode;  
    private String resultMsg;  
    private T data;  
    public String getResultCode() {  
        return resultCode;  
    }  
    public void setResultCode(String resultCode) {  
        this.resultCode = resultCode;  
    }  
    public String getResultMsg() {  
        return resultMsg;  
    }  
    public void setResultMsg(String resultMsg) {  
        this.resultMsg = resultMsg;  
    }  
    public T getData() {  
        return data;  
    }  
    public void setData(T data) {  
        this.data = data;  
    }  
      
    @Override  
    public String toString() {  
        return "InternalDataServiceResult [resultCode=" + resultCode + ", resultMsg=" + resultMsg + ", data=" + data  
                + "]";  
    }  
    /** 
     * 是否操作成功 
     * @return 
     */  
    public boolean isSuccess(){  
        return "0".equals(this.resultCode);  
    }  
      
      
}  

data是实际返回的数据（程序需要的），这里是个T泛型，当T是类似List<OrderInnDay>时，使用普通的RestTemplate.postForObject是无法知道OrderInnDay的类型的，最终T会是List<LinkedHashMap>，这不是我们想要的结果，恰好RestTemplate有其它的方法可以代替，比较麻烦（怪spring没有很好的封装上层方法）

package com.plateno.booking.util;

import java.util.List;
import java.util.Map;

import javax.annotation.PostConstruct;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Lazy;
import org.springframework.core.ParameterizedTypeReference;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpMethod;
import org.springframework.stereotype.Component;
import org.springframework.web.client.RestTemplate;

import com.plateno.booking.bean.InternalDataServiceResult;

@Component
@Lazy(false)
public class RestTemplateUtil {
    
    @Autowired
    private RestTemplate xRestTemplate;
    
    private static RestTemplate restTemplate;
    
    public static <T> InternalDataServiceResult<List<T>> exchangeAsList(HttpMethod method,String url, Map<String,Object> params, ParameterizedTypeReference<InternalDataServiceResult<List<T>>> responseType) {
        HttpEntity requestEntity = new HttpEntity(params);
        return restTemplate.exchange(url, method, requestEntity, responseType).getBody();
    }
    
    public static <T> InternalDataServiceResult<List<T>> postForList(String url, Map<String,Object> params, ParameterizedTypeReference<InternalDataServiceResult<List<T>>> responseType){
        return exchangeAsList(HttpMethod.POST, url, params, responseType);
    }
    
    
    @PostConstruct
    public void init(){
        restTemplate = this.xRestTemplate;
    }

    public static RestTemplate getRestTemplate() {
        return restTemplate;
    }

    public static void setRestTemplate(RestTemplate restTemplate) {
        RestTemplateUtil.restTemplate = restTemplate;
    }

    public RestTemplate getxRestTemplate() {
        return xRestTemplate;
    }

    public void setxRestTemplate(RestTemplate xRestTemplate) {
        this.xRestTemplate = xRestTemplate;
    }
    
    
}

当需要使用post请求，返回List<OrderInnDay>时，即可这样使用：

public List<OrderInnDay> getOrderInnDayList(String orderCode,Integer memberId){  
    Map<String, Object> params = new HashMap<>();  
    params.put("orderCode", orderCode);  
    params.put("memberId", memberId);  
    String url = apiProperties.getInternalDataService().getGetOrderInnDayList();  
    log.info("query orderInnDayList,url：{},params:{}", url ,JsonUtil.toJson(params));  
               //use postForList  
    InternalDataServiceResult<List<OrderInnDay>> result = RestTemplateUtil.postForList(  
            url, params, new ParameterizedTypeReference<InternalDataServiceResult<List<OrderInnDay>>>(){});  
    if (!result.isSuccess()) {  
        log.warn("query orderInnDayList failed：url:{},params：{},response：{}", url,JsonUtil.toJson(params), JsonUtil.toJson(result));  
    }  
    return result.getData();  
}