教你从头开始用JAVA创建一个自己的简单API并实现第三方调用

spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/my_blog_db?useUnicode=true&characterEncoding=utf8&autoReconnect=true&useSSL=false&serverTimezone=UTC
    username: root
    password: root
 
mybatis-plus:
  mapper-locations: classpath:mapper/*Mapper.xml
  type-aliases-package: com.example.test.pojo
 
server:
  port: 12345

public class Result<T> {
    private Integer code;
    private String msg;
    private T data;
}

public enum ResultEnum {
    ERROR(-1,"ERROR---------"),
    SUCCESS(100,"SUCCESS--------"),
    ;
    //这样就说明我们具有ERROR和SUCCESS两种状态，成功时返回100，SUCCESS
 
    private Integer code;
    private String msg;
 
    ResultEnum(Integer code, String msg) {
        this.code = code;
        this.msg = msg;
    }
 
    public Integer getCode() {
        return code;
    }
 
    public String getMsg() {
        return msg;
    }
}

public class ResultUtil {
    //对应我们在Enum中设置的两种状态
    public static Result success(Object object){
        Result result = new Result();
        result.setCode(ResultEnum.SUCCESS.getCode());
        result.setMsg(ResultEnum.SUCCESS.getMsg());
        result.setData(object);
        return result;
    }
 
    public static Result error(Object object){
        Result result = new Result();
        result.setCode(ResultEnum.ERROR.getCode());
        result.setMsg(ResultEnum.ERROR.getMsg());
        result.setData(object);
        return result;
    }
}

@RestController
@RequestMapping("/api")
public class TestController {
 
    @PostMapping("/postTest")
    public Result postTest(@RequestBody boolean flag) throws Exception{
        /*
        *调用时传入一个参数flag，如果flag值不为true就返回成功数据，否则返回失败数据
        */
        System.out.println("已进入api接口------");
        System.out.println(flag);
        if(flag==true){
            return ResultUtil.success("返回成功数据Congraduations!");
        }
 
        return ResultUtil.error("抱歉sorry!");
    }
 
}

public class HttpClientUtil {
    public static String doPost(String pathUrl, String data){
        OutputStreamWriter out = null;
        BufferedReader br = null;
        String result = "";
        try {
            URL url = new URL(pathUrl);
            //打开和url之间的连接
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            //请求方法为"POST"
            conn.setRequestMethod("POST");
            // 设置是否向httpUrlConnection输出，因为这个是post请求，参数要放在http正文内，因此需要设为true, 默认情况下是false;
            conn.setDoOutput(true);
            // Post请求不能使用缓存
            conn.setUseCaches(false);
            //设置请求属性
            conn.setRequestProperty("accept", "*/*");
            conn.setRequestProperty("connection", "Keep-Alive");  //维持长链接
            conn.setRequestProperty("Content-Type", "application/json;charset=utf-8");
            conn.connect();
            //调用，获取输出流
            out = new OutputStreamWriter(conn.getOutputStream(), "UTF-8");
            //发送请求参数
            out.write(data);
            out.flush();
            //获取URLConnection对象对应的输入流
            InputStream is = conn.getInputStream();
            //构造一个字符流缓存
            br = new BufferedReader(new InputStreamReader(is));
            String str = "";
            while ((str = br.readLine()) != null){
                result += str;
            }
            System.out.println(result);
            //关闭流
            is.close();
            //断开连接，disconnect是在底层tcp socket链接空闲时才切断，如果正在被其他线程使用就不切断。
            conn.disconnect();
 
        } catch (Exception e) {
            e.printStackTrace();
        }
        return result;
    }
 
}

//url需要与我们在api中设置的对应，后一个是传参
String s = HttpClientUtil.doPost("http://localhost:12345/api/postTest","true");
System.out.println(s);