java调用Restful接口的三种方法

• 2，httpurlconnection实现
  
• 3.httpclient实现
  
• 4.spring的resttemplate
  

1,基本介绍

restful接口的调用，前端一般使用ajax调用，后端可以使用的方法比较多，

　　本次介绍三种：

　　　　1.httpurlconnection实现

　　　　2.httpclient实现

　　　　3.spring的resttemplate 　　　　

2，httpurlconnection实现

@controller
public class restfulaction {

    @autowired
    private userservice userservice;
    // 修改
    @requestmapping(value = "put/{param}", method = requestmethod.put)
    public @responsebody string put(@pathvariable string param) {
        return "put:" + param;
    }
    // 新增
    @requestmapping(value = "post/{param}", method = requestmethod.post)
    public @responsebody string post(@pathvariable string param,string id,string name) {
        system.out.println("id:"+id);
        system.out.println("name:"+name);
        return "post:" + param;
    }
    // 删除
    @requestmapping(value = "delete/{param}", method = requestmethod.delete)
    public @responsebody string delete(@pathvariable string param) {
        return "delete:" + param;
    }
    // 查找
    @requestmapping(value = "get/{param}", method = requestmethod.get)
    public @responsebody string get(@pathvariable string param) {
        return "get:" + param;
    }
    // httpurlconnection 方式调用restful接口
    // 调用接口
    @requestmapping(value = "dealcon/{param}")
    public @responsebody string dealcon(@pathvariable string param) {
        try {
            string url = "http://localhost:8080/tao-manager-web/";
            url+=(param+"/xxx");
            url restserviceurl = new url(url);
            httpurlconnection httpconnection = (httpurlconnection) restserviceurl
                    .openconnection();
            //param 输入小写，转换成 get post delete put 
            httpconnection.setrequestmethod(param.touppercase());
//            httpconnection.setrequestproperty("accept", "application/json");
            if("post".equals(param)){
                //打开输出开关
                httpconnection.setdooutput(true);
//                httpconnection.setdoinput(true);

                //传递参数
                string input = "&id="+ urlencoder.encode("abc", "utf-8");
                input+="&name="+ urlencoder.encode("啊啊啊", "utf-8");
                outputstream outputstream = httpconnection.getoutputstream();
                outputstream.write(input.getbytes());
                outputstream.flush();
            }
            if (httpconnection.getresponsecode() != 200) {
                throw new runtimeexception(
                        "http get request failed with error code : "
                                + httpconnection.getresponsecode());
            }
            bufferedreader responsebuffer = new bufferedreader(
                    new inputstreamreader((httpconnection.getinputstream())));
            string output;
            system.out.println("output from server:  \n");
            while ((output = responsebuffer.readline()) != null) {
                system.out.println(output);
            }
            httpconnection.disconnect();
        } catch (malformedurlexception e) {
            e.printstacktrace();
        } catch (ioexception e) {
            e.printstacktrace();
        }
        return "success";
    }
}

3.httpclient实现

package com.taozhiye.controller;
import org.apache.http.httpentity;
import org.apache.http.httpresponse;
import org.apache.http.namevaluepair;
import org.apache.http.client.httpclient;
import org.apache.http.client.entity.urlencodedformentity;
import org.apache.http.client.methods.httpdelete;
import org.apache.http.client.methods.httpget;
import org.apache.http.client.methods.httppost;
import org.apache.http.client.methods.httpput;
import org.apache.http.impl.client.httpclients;
import org.apache.http.message.basicnamevaluepair;
import org.springframework.beans.factory.annotation.autowired;
import org.springframework.stereotype.controller;
import org.springframework.web.bind.annotation.pathvariable;
import org.springframework.web.bind.annotation.requestmapping;
import org.springframework.web.bind.annotation.requestmethod;
import org.springframework.web.bind.annotation.responsebody;
import com.fasterxml.jackson.databind.objectmapper;
import com.taozhiye.entity.user;
import com.taozhiye.service.userservice;
import java.io.bufferedreader;
import java.io.ioexception;
import java.io.inputstreamreader;
import java.io.outputstream;
import java.net.httpurlconnection;
import java.net.malformedurlexception;
import java.net.url;
import java.net.urlencoder;
import java.util.arraylist;
import java.util.list;

@controller
public class restfulaction {  
    @autowired
    private userservice userservice;
    // 修改
    @requestmapping(value = "put/{param}", method = requestmethod.put)
    public @responsebody string put(@pathvariable string param) {
        return "put:" + param;
    }
    // 新增
    @requestmapping(value = "post/{param}", method = requestmethod.post)
    public @responsebody user post(@pathvariable string param,string id,string name) {
        user u = new user();
        system.out.println(id);
        system.out.println(name);
        u.setname(id);
        u.setpassword(name);
        u.setemail(id);
        u.setusername(name);
        return u;
    }    
    // 删除
    @requestmapping(value = "delete/{param}", method = requestmethod.delete)
    public @responsebody string delete(@pathvariable string param) {
        return "delete:" + param;
    }
    // 查找
    @requestmapping(value = "get/{param}", method = requestmethod.get)
    public @responsebody user get(@pathvariable string param) {
        user u = new user();
        u.setname(param);
        u.setpassword(param);
        u.setemail(param);
        u.setusername("爱爱啊");
        return u;
    }
    @requestmapping(value = "dealcon2/{param}")
    public @responsebody user dealcon2(@pathvariable string param) {
        user user = null;
        try {
            httpclient client = httpclients.createdefault();
            if("get".equals(param)){
                httpget request = new httpget("http://localhost:8080/tao-manager-web/get/"
                        +"啊啊啊");
                request.setheader("accept", "application/json");
                httpresponse response = client.execute(request);
                httpentity entity = response.getentity();
                objectmapper mapper = new objectmapper();
                user = mapper.readvalue(entity.getcontent(), user.class);
            }else if("post".equals(param)){
                httppost request2 = new httppost("http://localhost:8080/tao-manager-web/post/xxx");
                list<namevaluepair> nvps = new arraylist<namevaluepair>();  
                nvps.add(new basicnamevaluepair("id", "啊啊啊"));  
                nvps.add(new basicnamevaluepair("name", "secret"));
                urlencodedformentity formentity = new urlencodedformentity(nvps, "gbk");
                request2.setentity(formentity);
                httpresponse response2 = client.execute(request2);
                httpentity entity = response2.getentity();
                objectmapper mapper = new objectmapper();
                user = mapper.readvalue(entity.getcontent(), user.class);
            }else if("delete".equals(param)){

            }else if("put".equals(param)){

            }
        } catch (exception e) {
            e.printstacktrace();
        }
        return user;
    } 
}

4.spring的resttemplate

springmvc.xml增加

<!-- 配置resttemplate -->
    <!--http client factory -->
    <bean id="httpclientfactory"
        class="org.springframework.http.client.simpleclienthttprequestfactory">
        <property name="connecttimeout" value="10000" />
        <property name="readtimeout" value="10000" />
    </bean>

    <!--resttemplate -->
    <bean id="resttemplate" class="org.springframework.web.client.resttemplate">
        <constructor-arg ref="httpclientfactory" />
    </bean>

controller

@controller
public class resttemplateaction {

    @autowired
    private resttemplate template;

    @requestmapping("resttem")
    public @responsebody user resttem(string method) {
        user user = null;
        //查找
        if ("get".equals(method)) {
            user = template.getforobject(
                    "http://localhost:8080/tao-manager-web/get/{id}",
                    user.class, "呜呜呜呜");

            //getforentity与getforobject的区别是可以获取返回值和状态、头等信息
            responseentity<user> re = template.
                    getforentity("http://localhost:8080/tao-manager-web/get/{id}",
                    user.class, "呜呜呜呜");
            system.out.println(re.getstatuscode());
            system.out.println(re.getbody().getusername());

        //新增
        } else if ("post".equals(method)) {
            httpheaders headers = new httpheaders();
            headers.add("x-auth-token", uuid.randomuuid().tostring());
            multivaluemap<string, string> postparameters = new linkedmultivaluemap<string, string>();
            postparameters.add("id", "啊啊啊");
            postparameters.add("name", "部版本");
            httpentity<multivaluemap<string, string>> requestentity = new httpentity<multivaluemap<string, string>>(
                    postparameters, headers);
            user = template.postforobject(
                    "http://localhost:8080/tao-manager-web/post/aaa", requestentity,
                    user.class);
        //删除
        } else if ("delete".equals(method)) {
            template.delete("http://localhost:8080/tao-manager-web/delete/{id}","aaa");
        //修改
        } else if ("put".equals(method)) {
            template.put("http://localhost:8080/tao-manager-web/put/{id}",null,"bbb");
        }
        return user;

    }
}

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