httpcomponents.httpclient 使用

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mb5ffd6fed5661e 2021-09-09 22:06:00

文章标签 json java apache spring 返回结果 文章分类 Java 后端开发

1.使用场景

两个Spring Boot 项目DemoA 和 DemoB。DemoA 需要调用DemoB提供的接口，并且传递数据，接收dmeoB的返回数据。

2. Demo B

1.添加依赖

<properties>
  <alibaba.fastjson.version>1.2.75</alibaba.fastjson.version>
  <projecglombok.version>1.18.18</projecglombok.version>
</properties>


  <dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>${alibaba.fastjson.version}</version>
  </dependency>
  <dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <version>${projecglombok.version}</version>
  </dependency>

2. 配置文件application.properties

server.port=8010

3. request 请求实体类

import lombok.Data;

@Data
public class StudentRequest {

  private String name;
  private Integer age;
  private String attachmentFolder;
  private String attachmentName;
  private byte[] attachment;
}

4. response 响应实体类

import lombok.Data;

@Data
public class StudentResponse {

  private String result;
  private String message;
}

5. 这个demo也写到了传递文件，这儿记录一个文件工具类

import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class FileUtil {

  private static Logger logger = LoggerFactory.getLogger(FileUtil.class);

  public static void saveFile(byte[] bfile, String filePath, String fileName) {
    BufferedOutputStream bos = null;
    FileOutputStream fos = null;
    File file = null;
    try {
      File dir = new File(filePath);
      if (!dir.exists()) {// 判断文件目录是否存在
        dir.mkdirs();
      }
      file = new File(filePath + fileName);
      fos = new FileOutputStream(file);
      bos = new BufferedOutputStream(fos);
      bos.write(bfile);
    } catch (Exception e) {
      logger.error(e.getMessage(), e);
    } finally {
      if (bos != null) {
        try {
          bos.close();
        } catch (IOException e1) {
          logger.error(e1.getMessage(), e1);

        }
      }
      if (fos != null) {
        try {
          fos.close();
        } catch (IOException e1) {
          logger.error(e1.getMessage(), e1);
        }
      }
    }
  }
}

6. controller 服务提供

import java.util.List;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import com.alibaba.fastjson.JSONObject;
import com.example.demoB.form.StudentRequest;
import com.example.demoB.form.StudentResponse;
import com.example.demoB.service.utils.FileUtil;

@RestController
@RequestMapping("/api/student")
public class StudentController {

  Logger logger = LoggerFactory.getLogger(StudentController.class);

  @PostMapping("/search")
  public StudentResponse search(@RequestBody StudentRequest request) {
    logger.info("request is {}", JSONObject.toJSONString(request));
    StudentResponse studentResponse = new StudentResponse();
    studentResponse.setResult("success");
    studentResponse.setMessage("wow! success! ");
    return studentResponse;
  }

  @PostMapping(value = "/save")
  public ResponseEntity<StudentResponse> save(@RequestBody StudentRequest studentRequest) {
    StudentResponse studentResponse = new StudentResponse();

    logger.info("student name is {},age is {}", studentRequest.getName(), studentRequest.getAge());
    String filePath = studentRequest.getAttachmentFolder();
    String fileName = studentRequest.getAttachmentName();
    byte[] fileContent = studentRequest.getAttachment();
    FileUtil.saveFile(fileContent, filePath, fileName);

    studentResponse.setResult("success");
    studentResponse.setMessage("wow! success! ");
    return new ResponseEntity<>(studentResponse, HttpStatus.OK);
  }

  @PostMapping(value = "/saveList")
  public ResponseEntity<StudentResponse> save(@RequestBody List<StudentRequest> studentRequests) {
    StudentResponse studentResponse = new StudentResponse();

    for (StudentRequest studentRequest : studentRequests) {
      logger.info("student name is {},age is {}", studentRequest.getName(), studentRequest.getAge());
      String filePath = studentRequest.getAttachmentFolder();
      String fileName = studentRequest.getAttachmentName();
      byte[] fileContent = studentRequest.getAttachment();
      FileUtil.saveFile(fileContent, filePath, fileName);
    }

    studentResponse.setResult("success");
    studentResponse.setMessage("wow! success! ");
    return new ResponseEntity<>(studentResponse, HttpStatus.OK);
  }
}

3. Demo A

1. 添加依赖

<properties>
  <alibaba.fastjson.version>1.2.75</alibaba.fastjson.version>
  <projecglombok.version>1.18.18</projecglombok.version>
  <httpclient.version>4.5.13</httpclient.version>
</properties>


  <dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>${alibaba.fastjson.version}</version>
  </dependency>
  <dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <version>${projecglombok.version}</version>
  </dependency>
  <dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>${httpclient.version}</version>
  </dependency>

2. 配置文件 application.properties

file.folder=C:/test/demoB/

3. request 请求实体类和 response 响应实体类和Demo B 项目保持一致

4. FileUtil 工具类

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class FileUtil {

  private static Logger logger = LoggerFactory.getLogger(FileUtil.class);

  public static byte[] File2byte(File filePath) {
    byte[] buffer = null;

    try {
      FileInputStream fis = new FileInputStream(filePath);

      ByteArrayOutputStream bos = new ByteArrayOutputStream();
      byte[] b = new byte[1024];
      int n;
      while ((n = fis.read(b)) != -1) {
        bos.write(b, 0, n);
      }
      fis.close();
      bos.close();
      buffer = bos.toByteArray();
    } catch (IOException e) {
      logger.error("error message {}", e.getMessage());
    }
    return buffer;
  }
}

5. HttpClient 工具类

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.example.demoA.DemoAApplication;

public class HttpClientUtil {

  static Logger logger = LoggerFactory.getLogger(HttpClientUtil .class);

  public static String doPost(String url, String data) {
    String line = null;

    // (1) 创建HttpGet实例
    HttpPost post = new HttpPost(url);

    // (2) 设置import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.example.demoA.DemoAApplication;

public class HttpClientUtil {

  static Logger logger = LoggerFactory.getLogger(DemoAApplication.class);

  public static String doPost(String url, String data) {
    String line = null;

    // (1) 创建HttpGet实例
    HttpPost post = new HttpPost(url);

    // (2) 设置请求体
    StringEntity myEntity = new StringEntity(data, ContentType.APPLICATION_JSON);
    post.setEntity(myEntity);

    // (3) 使用HttpClient发送get请求，获得返回结果HttpResponse
    CloseableHttpClient client = HttpClients.createDefault();

    try {
      HttpResponse response = client.execute(post);
      // (4) 读取返回结果
      int statusCode = response.getStatusLine().getStatusCode();
      if (statusCode == 200) {
        HttpEntity entity = response.getEntity();
        InputStream in = entity.getContent();

        BufferedReader reader = new BufferedReader(new InputStreamReader(in));
        line = reader.readLine();
        reader.close();
      }
    } catch (IOException e) {
      logger.error(e.getMessage(), e);
    }

    return line;
  }
}请求体
    StringEntity myEntity = new StringEntity(data, ContentType.APPLICATION_JSON);
    post.setEntity(myEntity);

    // (3) 使用HttpClient发送get请求，获得返回结果HttpResponse
    CloseableHttpClient client = HttpClients.createDefault();

    try {
      HttpResponse response = client.execute(post);
      // (4) 读取返回结果
      int statusCode = response.getStatusLine().getStatusCode();
      if (statusCode == 200) {
        HttpEntity entity = response.getEntity();
        InputStream in = entity.getContent();

        BufferedReader reader = new BufferedReader(new InputStreamReader(in));
        line = reader.readLine();
        reader.close();
      }
    } catch (IOException e) {
      logger.error(e.getMessage(), e);
    }

    return line;
  }
}

6. 调用Demo B 提供的服务

package com.example.demoA.controller;

import java.io.File;
import java.util.ArrayList;
import java.util.List;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import com.alibaba.fastjson.JSONObject;
import com.example.demoA.utils.FileUtil;
import com.example.demoA.utils.HttpClientUtil;
import com.example.demoB.form.StudentRequest;
import com.example.demoB.form.StudentResponse;

@RestController
@RequestMapping("/api/student")
public class StudentController {

  @Value("${file.folder}")
  private String fileFolder;

  Logger logger = LoggerFactory.getLogger(StudentController.class);

  @GetMapping("/search")
  public void search() {

    // 请求参数
    StudentRequest request = new StudentRequest();
    request.setName("xiaoming");
    request.setAge(22);
    String requestString = JSONObject.toJSONString(request);
    // 请求url
    String serviceUrl = getUrl() + "/api/student/search";
    // 执行请求
    String responseMessage = HttpClientUtil.doPost(serviceUrl, requestString);
    // 请求返回
    StudentResponse studentResponse = JSONObject.parseObject(responseMessage, StudentResponse.class);
    logger.info("studentResponse is {}", JSONObject.toJSONString(studentResponse));

  }

  @GetMapping("/save")
  public void save() {

    // 请求参数
    StudentRequest request = new StudentRequest();
    request.setName("xiaoming");
    request.setAge(22);
    request.setAttachmentName("test.xls");
    request.setAttachmentFolder(fileFolder);
    byte[] fileByte = FileUtil.File2byte(new File("C:\\test\\demoA\\test.xls"));
    request.setAttachment(fileByte);
    String requestString = JSONObject.toJSONString(request);
    // 请求url
    String serviceUrl = getUrl() + "/api/student/save";
    // 执行请求
    String responseMessage = HttpClientUtil.doPost(serviceUrl, requestString);
    // 请求返回
    StudentResponse studentResponse = JSONObject.parseObject(responseMessage, StudentResponse.class);
    logger.info("studentResponse is {}", JSONObject.toJSONString(studentResponse));

  }

  @GetMapping("/saveList")
  public void saveList() {

    // 请求参数
    List<StudentRequest> studentRequests = new ArrayList<StudentRequest>();

    StudentRequest studentRequest1 = new StudentRequest();
    studentRequest1.setName("Melody");
    studentRequest1.setAge(22);
    studentRequest1.setAttachmentName("test1.xls");
    studentRequest1.setAttachmentFolder(fileFolder);
    byte[] fileByte = FileUtil.File2byte(new File("C:\\test\\demoA\\test1.xls"));
    studentRequest1.setAttachment(fileByte);
    studentRequests.add(studentRequest1);

    StudentRequest studentRequest2 = new StudentRequest();
    studentRequest2.setName("Sara");
    studentRequest2.setAge(21);
    studentRequest2.setAttachmentName("test2.xls");
    studentRequest2.setAttachmentFolder(fileFolder);
    byte[] fileByte2 = FileUtil.File2byte(new File("C:\\test\\demoA\\test2.xls"));
    studentRequest2.setAttachment(fileByte2);
    studentRequests.add(studentRequest2);

    String requestString = JSONObject.toJSONString(studentRequests);
    // 请求url
    String serviceUrl = getUrl() + "/api/student/saveList";
    // 执行请求
    String responseMessage = HttpClientUtil.doPost(serviceUrl, requestString);
    // 请求返回
    StudentResponse studentResponse = JSONObject.parseObject(responseMessage, StudentResponse.class);
    logger.info("studentResponse is {}", JSONObject.toJSONString(studentResponse));

  }

  private String getUrl() {
    return "http://localhost:8010";
  }
}