<dependencies>    <dependency>        <groupId>org.springframework.boot</groupId>        <artifactId>spring-boot-starter-web</artifactId>    </dependency>
    <dependency>        <groupId>org.projectlombok</groupId>        <artifactId>lombok</artifactId>        <optional>true</optional>    </dependency>    <dependency>        <groupId>org.springframework.boot</groupId>        <artifactId>spring-boot-starter-tomcat</artifactId>        <scope>provided</scope>    </dependency>    <dependency>        <groupId>org.springframework.boot</groupId>        <artifactId>spring-boot-starter-test</artifactId>        <scope>test</scope>    </dependency>
    <dependency>        <groupId>org.apache.httpcomponents</groupId>        <artifactId>httpclient</artifactId>        <version>4.5.7</version>    </dependency>
    <dependency>        <groupId>com.alibaba</groupId>        <artifactId>fastjson</artifactId>        <version>1.2.68</version>    </dependency></dependencies>

server.port=8089spring.servlet.multipart.max-file-size = 100MBspring.servlet.multipart.max-request-size = 1000MB

import lombok.AllArgsConstructor;import lombok.Data;import lombok.NoArgsConstructor;
@Data@AllArgsConstructor@NoArgsConstructorpublic class User {    String name;    int age;
    public User(String name) {        this.name = name;    }
    @Override    public String toString() {        return "User{" +                "name='" + name + '\'' +                ", age=" + age +                '}';    }}

import com.alibaba.fastjson.JSON;import org.springframework.web.bind.annotation.*;import org.springframework.web.multipart.MultipartFile;
import java.util.LinkedHashMap;import java.util.Map;@RestController@RequestMapping("/user")public class UserController {
        @GetMapping("/loginGet")        public String loginGet(String name,Integer age){            System.out.println(name+""+age);            User user=new User(name,age);            return JSON.toJSONString(user);        }
        @PostMapping("/login")        public String login(User user){            System.out.println(user);            return JSON.toJSONString(user);        }
        @PostMapping("/upload")        public Map<String, String> login(User user, @RequestParam("file") MultipartFile file){            System.out.println(user);            System.out.println(file.getName());            Map<String, String> fileMetadata = new LinkedHashMap<>();            fileMetadata.put("文件名", file.getOriginalFilename());            fileMetadata.put("文件类型", file.getContentType());            fileMetadata.put("文件大小(byte)", String.valueOf(file.getSize()));            return fileMetadata;        }

        @PostMapping("/loginJson")        public String loginJson(@RequestBody User user){            System.out.println(user);            return JSON.toJSONString(user);        }}

import lombok.extern.slf4j.Slf4j;import org.apache.http.HttpEntity;import org.apache.http.NameValuePair;import org.apache.http.client.entity.UrlEncodedFormEntity;import org.apache.http.client.methods.CloseableHttpResponse;import org.apache.http.client.methods.HttpPost;import org.apache.http.impl.client.CloseableHttpClient;import org.apache.http.impl.client.HttpClients;import org.apache.http.message.BasicNameValuePair;import org.apache.http.util.EntityUtils;
import java.util.ArrayList;import java.util.List;import java.util.Map;
/** * @ClassName JavaNice * post x-www-form-urlencoded  key-value只能是string **/@Slf4jpublic class PostUtils {    private static final String ENCODING = "UTF-8";
    /**     * post x-www-form-urlencoded  key-value只能是string*     * @param url     * @param paramsMap     * @return     */    public static String sendPost(String url, Map<String, String> paramsMap) {        CloseableHttpClient client = HttpClients.createDefault();        String responseText = "";        CloseableHttpResponse response = null;        try {            HttpPost method = new HttpPost(url);            if (paramsMap != null) {                List<NameValuePair> paramList = new ArrayList<NameValuePair>();                for (Map.Entry<String, String> param : paramsMap.entrySet()) {                    NameValuePair pair = new BasicNameValuePair(param.getKey(), param.getValue());                    paramList.add(pair);                }                method.setEntity(new UrlEncodedFormEntity(paramList, ENCODING));            }            response = client.execute(method);            HttpEntity entity = response.getEntity();            if (entity != null) {                responseText = EntityUtils.toString(entity);            }        } catch (Exception e) {            log.error("http request failed",e);        } finally {            try {                response.close();            } catch (Exception e) {                log.error("",e);            }        }        return responseText;    }}

@Testvoid postString() {    //post x-www-form-urlencoded  key-value只能是string    Map<String,String> user=new HashMap<>();    user.put("name","javaNice");    String json = JSONObject.toJSONString(user);    Map<String,String> paramsMap = JSONObject.parseObject(json,Map.class);    System.out.println(json);    String resp = PostUtils.sendPost("http://localhost:8089/user/login",paramsMap);    System.out.println(resp);}

import com.alibaba.fastjson.JSONObject;import org.springframework.util.StringUtils;
import java.io.*;import java.net.HttpURLConnection;import java.net.URL;import java.net.URLConnection;import java.net.URLEncoder;import java.util.List;import java.util.Map;
public class HttpRequestUtil {
    public static String sendGet(String url, String param) {        String result = "";        BufferedReader in = null;        try {            if (!url.contains("?")) {                url += "?1=1";            }            if (!param.startsWith("&")) {                url += "&";            }            String urlNameString = url + param;            URL realUrl = new URL(urlNameString);            // 打开和URL之间的连接            URLConnection connection = realUrl.openConnection();            // 设置通用的请求属性            connection.setRequestProperty("accept", "*/*");            connection.setRequestProperty("connection", "Keep-Alive");            connection.setRequestProperty("user-agent",                    "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");            // 建立实际的连接            connection.connect();            // 获取所有响应头字段            Map<String, List<String>> map = connection.getHeaderFields();            // 遍历所有的响应头字段//            for (String key : map.keySet()) {//                System.out.println(key + "--->" + map.get(key));//            }            // 定义 BufferedReader输入流来读取URL的响应            in = new BufferedReader(new InputStreamReader(                    connection.getInputStream()));            String line;            while ((line = in.readLine()) != null) {                result += line;            }        } catch (Exception e) {            System.out.println("发送GET请求出现异常！" + e);            e.printStackTrace();        }        // 使用finally块来关闭输入流        finally {            try {                if (in != null) {                    in.close();                }            } catch (Exception e2) {                e2.printStackTrace();            }        }        return result;    }

    public static String sendPost(String url, String param) {        HttpURLConnection httpURLConnection = null;        OutputStream out = null; //写        InputStream in = null;   //读        int responseCode = 0;    //远程主机响应的HTTP状态码        String result = "";        try {            URL sendUrl = new URL(url);            httpURLConnection = (HttpURLConnection) sendUrl.openConnection();            //post方式请求            httpURLConnection.setRequestMethod("POST");            //一定要设置 Content-Type 要不然服务端接收不到参数            httpURLConnection.setRequestProperty("Content-Type", "application/json");            //指示应用程序要将数据写入URL连接,其值默认为false（是否传参）            httpURLConnection.setDoOutput(true);            //httpURLConnection.setDoInput(true);            httpURLConnection.setUseCaches(false);            httpURLConnection.setConnectTimeout(30000); //30秒连接超时            httpURLConnection.setReadTimeout(30000);    //30秒读取超时            //获取输出流            out = httpURLConnection.getOutputStream();            //输出流里写入POST参数            out.write(param.getBytes());            out.flush();            out.close();            responseCode = httpURLConnection.getResponseCode();            BufferedReader br = new BufferedReader(new InputStreamReader(httpURLConnection.getInputStream(), "UTF-8"));            result = br.readLine();        } catch (Exception e) {            e.printStackTrace();        }        return result;    }
    public static String objectToUrlParam(Object object) {        if (object != null) {            StringBuilder builder = new StringBuilder();//            JSONObject jsonObject = JSON.parseObject(JSON.toJSONString(object));            Map<String, Object> map = JSONObject.parseObject(JSONObject.toJSONString(object), Map.class);            for (Map.Entry<String, Object> entry :                    map.entrySet()) {                if (entry.getValue() != null && !StringUtils.isEmpty(entry.getValue().toString())) {                    builder.append("&").append(entry.getKey()).append("=").append(encode(entry.getValue()));                }            }            return builder.toString();        }        return "";    }
    public static String encode(Object object) {        if (object != null) {            try {                return URLEncoder.encode(object.toString(), "utf-8");            } catch (UnsupportedEncodingException e) {                e.printStackTrace();                throw new RuntimeException("字符串编码失败");            }        }        return "";    }
}

@Testvoid get() {    //get 方式 传递参数拼接在url上    User user=new User("javaNice",666);    String paramsMap = HttpRequestUtil.objectToUrlParam(user);    String resp = HttpRequestUtil.sendGet("http://localhost:8089/user/loginGet",paramsMap);    System.out.println(resp);}

@Testvoid postUrl() {    //post 方式 传递参数url拼接    User user=new User("javaNice",666);    String paramsMap = HttpRequestUtil.objectToUrlParam(user);    System.out.println("传递参数"+paramsMap);    String url="http://localhost:8089/user/login?1=1"+paramsMap;    String resp = HttpRequestUtil.sendPost(url,"");    System.out.println("返回参数"+resp);}
@Testvoid post() {    //post 方式 传递参数为json    User user=new User("javaNice",666);    String paramsMap = JSON.toJSONString(user);    System.out.println("传递参数"+paramsMap);    String resp = HttpRequestUtil.sendPost("http://localhost:8089/user/loginJson",paramsMap);    System.out.println("返回参数"+resp);}

@Testvoid post() {    //post 方式 传递参数为json    RestTemplate restTemplate = new RestTemplate();    String url = "http://localhost:8089/user/loginJson";    User body = new User("javaNice", 666);    User result = restTemplate.postForObject(url, body, User.class);    System.out.println("返回参数" + result);}

@Testvoid postFormFile() {    //post 方式 传递参数为form-data 并且传递文件    RestTemplate restTemplate = new RestTemplate();    String url = "http://localhost:8089/user/upload";    //①：表单信息，需要放在MultiValueMap中，MultiValueMap相当于Map<String,List<String>>    MultiValueMap<String, Object> body = new LinkedMultiValueMap<>();    //调用add方法放入表单元素(表单名称:值)    //②：文件对应的类型，需要是org.springframework.core.io.Resource类型的，常见的有[FileSystemResource、InputStreamResource、ByteArrayResource]    body.add("file", new FileSystemResource("/java/com/example/springmvc/22c017e48ea445199708dc1d2832dae5.pdf"));    body.add("name", "javaNice");    body.add("age", "666");    //③：头    HttpHeaders headers = new HttpHeaders();    headers.add("header1", "v1");    headers.add("header2", "v2");    //④：请求实体    RequestEntity<MultiValueMap<String, Object>> requestEntity = new RequestEntity<>(body, headers, HttpMethod.POST, URI.create(url));    //⑤：发送请求(请求实体，返回值需要转换的类型)    ResponseEntity<Map<String, String>> responseEntity = restTemplate.exchange(            requestEntity,            new ParameterizedTypeReference<Map<String, String>>() {            });    Map<String, String> result = responseEntity.getBody();    System.out.println(result);}

@Testvoid postFormFileStream() {    RestTemplate restTemplate = new RestTemplate();    String url = "http://localhost:8089/user/upload";    //①：表单信息，需要放在MultiValueMap中，MultiValueMap相当于Map<String,List<String>>    MultiValueMap<String, Object> body = new LinkedMultiValueMap<>();    /**     * ②：通过流的方式上传文件，流的方式需要用到InputStreamResource类，需要重写2个方法     * getFilename：文件名称     * contentLength：长度     */    File file = new File("/java/com/example/springmvc/22c017e48ea445199708dc1d2832dae5.pdf");    //2、建立数据通道    try {        InputStream inputStream = new FileInputStream(file);
        InputStreamResource inputStreamResource = new InputStreamResource(inputStream) {            @Override            public String getFilename() {                return "22c017e48ea445199708dc1d2832dae5.pdf";            }
            @Override            public long contentLength() throws IOException {                return inputStream.available();            }        };        body.add("file", inputStreamResource);        body.add("name", "javaNice");        body.add("age", "666");        //③：头        HttpHeaders headers = new HttpHeaders();        headers.add("header1", "v1");        headers.add("header2", "v2");        //④：请求实体        RequestEntity<MultiValueMap<String, Object>> requestEntity = new RequestEntity<>(body, headers, HttpMethod.POST, URI.create(url));        //⑤：发送请求(请求实体，返回值需要转换的类型)        ResponseEntity<Map<String, String>> responseEntity = restTemplate.exchange(                requestEntity,                new ParameterizedTypeReference<Map<String, String>>() {                });        Map<String, String> result = responseEntity.getBody();        System.out.println(result);    } catch (FileNotFoundException e) {        e.printStackTrace();    }}