java使用RestTemplate封装post请求方式

使用resttemplate封装post请求

之前笔者写过一篇比较实用的文章 java使用httpclient封装post请求和get的请求，其实java中实现http请求还可以用 resttemplate 完成，下面给出示例代码：

import com.alibaba.fastjson.jsonobject;
import org.slf4j.logger;
import org.slf4j.loggerfactory;
import org.springframework.http.*;
import org.springframework.http.converter.stringhttpmessageconverter;
import org.springframework.web.client.resttemplate;
import javax.annotation.postconstruct;
import java.nio.charset.charset;
public class httphelper {
    private static logger logger = loggerfactory.getlogger(httphelper.class);
    private resttemplate resttemplate;
    private httpheaders httpheaders;
    @postconstruct
    public void init() {
        resttemplate = new resttemplate();
        resttemplate.getmessageconverters().add(0, new stringhttpmessageconverter(charset.forname("utf-8")));
        httpheaders = new httpheaders();
        httpheaders.setcontenttype(org.springframework.http.mediatype.application_json);
    }
    /**
     * post - json
     * @param params
     * @return
     */
    public string post(jsonobject params, string url) {
        logger.info("请求参数：{}", params.tojsonstring());
        responseentity<string> response;
        try {
            response = resttemplate.exchange(
                    url,
                    httpmethod.post,
                    new httpentity<>(params, httpheaders),
                    string.class);
        } catch (exception e) {
            logger.error("请求异常", e);
            return "请求异常";
        }
        logger.info("响应结果：{}", jsonobject.tojsonstring(response));
        if (response.getstatuscode().equals(httpstatus.ok)) {
            logger.info("请求成功，返回结果：{}", response.getbody());
            return response.getbody();
        }
        logger.error("请求失败，http状态码：{}，返回结果：{}", response.getstatuscode(), response.getbody());
        return response.getbody();
    }
}

resttemplate 是 spring 提供的用于访问rest服务的客户端，resttemplate 提供了多种便捷访问远程http 服务的方法，能够大大提高客户端的编写效率。

resttemplate使用封装

之前接口调用习惯性使用httpclient，代码复杂，冗余代码多，关心资源回收用起来不是很爽。

resttemplate默认依赖jdk的http连接工具。也可以 通过setrequestfactory属性切换到不同的http源，比如apache httpcomponents、netty、okhttp。

1、springboot使用resttemplate(使用apache的httpclient)

import org.springframework.boot.web.client.resttemplatebuilder;
import org.springframework.context.annotation.bean;
import org.springframework.context.annotation.configuration;
import org.springframework.http.client.clienthttprequestfactory;
import org.springframework.http.client.httpcomponentsclienthttprequestfactory;
import org.springframework.http.converter.bytearrayhttpmessageconverter;
import org.springframework.http.converter.formhttpmessageconverter;
import org.springframework.http.converter.httpmessageconverter;
import org.springframework.http.converter.resourcehttpmessageconverter;
import org.springframework.http.converter.stringhttpmessageconverter;
import org.springframework.http.converter.json.mappingjackson2httpmessageconverter;
import org.springframework.http.converter.support.allencompassingformhttpmessageconverter;
import org.springframework.web.client.resttemplate;
import java.nio.charset.charset;
import java.text.simpledateformat;
import java.util.arraylist;
import java.util.list;
import java.util.concurrent.timeunit;
@configuration
public class resttemplateconfig  {
    @bean
    public resttemplate getresttemplate() {
        //手动指定转换器(httpmessageconverter)
        list<httpmessageconverter<?>> messageconverters = new arraylist<httpmessageconverter<?>>();
        messageconverters.add(new bytearrayhttpmessageconverter());
        messageconverters.add(new stringhttpmessageconverter(charset.forname("utf-8")));//string强制使用utf-8
        messageconverters.add(new resourcehttpmessageconverter());
        messageconverters.add(new allencompassingformhttpmessageconverter());
        messageconverters.add(new formhttpmessageconverter());
        mappingjackson2httpmessageconverter jacksonconverter = new mappingjackson2httpmessageconverter();
        jacksonconverter.getobjectmapper().setdateformat(new simpledateformat("yyyy-mm-dd hh:mm:ss"));
        messageconverters.add(jacksonconverter);
        resttemplate resttemplate = new resttemplatebuilder().additionalmessageconverters(messageconverters).build();
        resttemplate.setrequestfactory(getclienthttprequestfactory());
        return resttemplate;
    }
    @bean
    public clienthttprequestfactory getclienthttprequestfactory() {
        // 保持长连接配置，需要在头添加keep-alive
        final connectionkeepalivestrategy mystrategy = new connectionkeepalivestrategy() {
            @override
            public long getkeepaliveduration(org.apache.http.httpresponse response, httpcontext context) {
                // 设置一个链接的最大存活时间
                return 5 * 1000l;
            }
        };
        poolinghttpclientconnectionmanager pollingconnectionmanager = new poolinghttpclientconnectionmanager(30, timeunit.seconds);
        pollingconnectionmanager.setmaxtotal(2000);//最大连接数
        pollingconnectionmanager.setdefaultmaxperroute(200);//同路由的最大连接数       
        closeablehttpclient closeablehttpclient = httpclientbuilder.create().setconnectionmanager(pollingconnectionmanager).setkeepalivestrategy(mystrategy).build();
        httpcomponentsclienthttprequestfactory factory = new httpcomponentsclienthttprequestfactory(closeablehttpclient);
        factory.setconnecttimeout(3000);
        factory.setreadtimeout(5000);
        return factory;
    }
}

2、使用jdk原生的

// 添加消息转换器
   list messageconverters = new arraylist();
   messageconverters.add(new stringhttpmessageconverter());
   messageconverters.add(new mappingjackson2httpmessageconverter());
   //如果usej2sehttp申明为true,则使用jdk自带的httpurlconnection
   simpleclienthttprequestfactory requestfactory = new simpleclienthttprequestfactory();
   requestfactory.setreadtimeout(3000);
   requestfactory.setconnecttimeout(3000);
   resttemplate = new resttemplate(requestfactory);
   resttemplate.setmessageconverters(messageconverters);
   //这里是添加了拦截器
   list<clienthttprequestinterceptor> interceptorlist = new arraylist<clienthttprequestinterceptor>();
   interceptorlist.add(new requestinteceptor());
   resttemplate.setinterceptors(interceptorlist);

2、拦截器实现clienthttprequestinterceptor

（设置头信息的时候回使用到）

public class requestinteceptor implements clienthttprequestinterceptor {
    @override
    public clienthttpresponse intercept(httprequest request, byte[] body, clienthttprequestexecution execution) throws ioexception {
        request.getheaders().setall(appmetadatautil.getapp_metadata());
        string traceid = uuid.randomuuid().tostring().replaceall("-", "");
        request.getheaders().set("traceid", traceid.tostring());
        return execution.execute(request, body);
    }
}

4、常用的方法

 string url = queryinfo?userid={userid}&pageindex={pageindex}&pagesize={pagesize}";
 hashmap<string,object> parametermap = new hashmap<string,object>();
 parametermap.put("userid", userid);
 parametermap.put("pageindex", pageindex);
 parametermap.put("pagesize", pagesize);
    string str = resttemplate.getforobject(url, string.class, parametermap);    
    string result = resttemp.getforobject(requesturl.tostring(), string.class);
    //post
 string url = "http://www.xxx.com/queryinfo"
 string str = resttemplate.postforobject(url, parametermap, string.class);
   //exchange 设置请求头
    httpheaders headers = new httpheaders();
 headers.setcontenttype(mediatype.parsemediatype("application/json;charset=utf-8"));
 headers.add("accept", "application/json;charset=utf-8");
 httpentity<string> httpentity = new httpentity<string>("", headers);
 resttemplate resttemplate = resttemplateutils.getinstance().getresttemplate();
 responseentity<string> exchange = resttemplate.exchange(retailorderurl, httpmethod.get, httpentity, string.class);
 string forobject = exchange.getbody();
    multivaluemap<string, object> requestentity = new linkedmultivaluemap<>();

以上为个人经验，希望能给大家一个参考，也希望大家多多支持。