Java Spring JPA必须至少请求两次才能获取数据_Java_Spring_Jpa

Java Spring JPA必须至少请求两次才能获取数据

java spring jpa

Java Spring JPA必须至少请求两次才能获取数据,java,spring,jpa,Java,Spring,Jpa,我接到这个奇怪的案子。所以，无论何时我想得到付款，我都必须用邮递员至少发送两次请求。请看一下我的代码： UserAPI.java @RestController @RequestMapping("/api") public class UserAPI { APISend send = new APISend(); public final APIReceive recv = new APIReceive(); @GetMapping("/

我接到这个奇怪的案子。所以，无论何时我想得到付款，我都必须用邮递员至少发送两次请求。请看一下我的代码：

UserAPI.java

@RestController
@RequestMapping("/api")
public class UserAPI {

    APISend send = new APISend();
    public final APIReceive recv = new APIReceive();

    @GetMapping("/home/{username}")
    public ResponseEntity<?> getData(@PathVariable("username") String username) {
        try {
            send.getPayment(username);
            return new ResponseEntity<>(recv.getPayment(), HttpStatus.OK);
        } catch (Exception e) {
            System.out.println("ERROR GET DATA: " + e);
            return new ResponseEntity<>("Data not found.", HttpStatus.NOT_FOUND);
        }

    }
}

public class APISend {
    public void getPayment(String username) throws IOException, TimeoutException {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        try (Connection con = factory.newConnection();
             Channel channel = con.createChannel()) {
            channel.queueDeclare("getPayment", false, false, false, null);
            channel.basicPublish("", "getPayment", null, username.getBytes(StandardCharsets.UTF_8));
            System.out.println(" [x] SEND GET DATA SALDO '" + username + "'");
        }
    }

}

public void con() {
        this.entityManager = Persistence
                .createEntityManagerFactory("user-unit")
                .createEntityManager();
        naDao = new UserDAO(entityManager);
        try {
            entityManager.getTransaction().begin();
        } catch (IllegalStateException e) {
            entityManager.getTransaction().rollback();
        }
    }

public void com() {
    try {
        entityManager.getTransaction().commit();
        entityManager.close();
    } catch (IllegalStateException e) {
        entityManager.getTransaction().rollback();
    }
}

public void connectRabbitMQ() throws IOException, TimeoutException {
    factory = new ConnectionFactory();
    factory.setHost("localhost");
    connection = factory.newConnection();
}

public void getSaldo() {
        try {
            connectRabbitMQ();
            channel = connection.createChannel();
            channel.queueDeclare("getPayment", false, false, false, null);
            DeliverCallback deliverCallback = (consumerTag, delivery) -> {
                String username = new String(delivery.getBody(), StandardCharsets.UTF_8);
                System.out.println(" [x] Received '" + username + "'");
                con();
                int res = naDao.checkUser(username);
                String payment = "";
                if (res != 0){
                    User nb = new User();
                    nb.setId_user(res);
                    int money = naDao.getPayment(nb);
                    payment = String.valueOf(money);
                } else {
                    payment="0";
                }
                try {
                    send.sendToAPI(payment);
                } catch (Exception e) {
                    System.out.println("ERROR SEND TO API GET PAYMENT: " + e);
                }
                com();
            };
            channel.basicConsume("getPayment", true, deliverCallback, consumerTag -> { });
        } catch (Exception e) {
            System.out.println("ERROR GET PAYMENT = " + e);
        }
    }

public int checkUser(String username) {
        String select = "SELECT id FROM User WHERE username=:username AND loginStatus=:loginStatus";
        Query q = entityManager.createQuery(select);
        q.setParameter("username", username);
        q.setParameter("loginStatus", "true");

        if (q.getResultList().size() != 0) {
            return (int) q.getResultList().get(0);
        } else {
            return q.getResultList().size();
        }
    }

public int getPayment(User nb) {
    String query = "SELECT n.payment FROM User n WHERE n.id=:id";
    Query q = entityManager.createQuery(query);
    q.setParameter("id", nb.getId());
    if (q.getResultList().size()!=0){
        return (int)q.getResultList().get(0);
    } else {
        return q.getResultList().size();
    }
}

public void sendToAPI (String message) throws IOException, TimeoutException {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        try (Connection connection = factory.newConnection();
             Channel channel = connection.createChannel()) {
            channel.queueDeclare("paymentFromDB", false, false, false, null);
            channel.basicPublish("", "paymentFromDB", null, message.getBytes(StandardCharsets.UTF_8));
            System.out.println(" [x] Sent '" + message + "'");
        } catch (Exception e) {
            System.out.println("ERROR SEND TO API" + e);
        }
    }

public class APIReceive {
    protected String message = "";
    private String paymentResponse = "";

    public void setMessage(String message) {
        this.message = message;
    }

    public String getpaymentResponse() {
        return paymentResponse;
    }
    public void setpaymentResponse(String paymentResponse) {
        this.paymentResponse = paymentResponse;
    }
    
        public String getPayment() throws IOException, TimeoutException {
        try {
            ConnectionFactory factory = new ConnectionFactory();
            factory.setHost("localhost");
            Connection connection = factory.newConnection();
            Channel channel = connection.createChannel();

            channel.queueDeclare("paymentFromDB", false, false, false, null);
            System.out.println(" [*] Waiting for messages from database");

            DeliverCallback deliverCallback = (consumerTag, delivery) -> {
                String message = new String(delivery.getBody(), "UTF-8");
                System.out.println(" [x] Payment Received '" + message + "'");
                this.message = message;
            };

            channel.basicConsume("paymentFromDB", true, deliverCallback, consumerTag -> { });
            TimeUnit.SECONDS.sleep(2);
            if (!this.message.equals("0")) {
                JSONObject object = new JSONObject();
                object.put("response", 200);
                object.put("status", "Success");
                object.put("message", "Success Check Payment");
                object.put("Saldo", this.message);
                saldoResponse = object.toJSONString();
            } else {
                JSONObject object = new JSONObject();
                object.put("response", 400);
                object.put("status", "Error");
                object.put("message", "Error Getting Payment!");
                saldoResponse = object.toJSONString();
            }
        } catch (Exception e) {
            System.out.println("ERROR GET SALDO APIRecv: " + e);
        }
        System.out.println("payment response: "+this.getPaymentResponse());
        return this.getPaymentResponse();
    }

    public String getMessage() {
        return message;
    }
}

DatabaseReceiver.java

@RestController
@RequestMapping("/api")
public class UserAPI {

    APISend send = new APISend();
    public final APIReceive recv = new APIReceive();

    @GetMapping("/home/{username}")
    public ResponseEntity<?> getData(@PathVariable("username") String username) {
        try {
            send.getPayment(username);
            return new ResponseEntity<>(recv.getPayment(), HttpStatus.OK);
        } catch (Exception e) {
            System.out.println("ERROR GET DATA: " + e);
            return new ResponseEntity<>("Data not found.", HttpStatus.NOT_FOUND);
        }

    }
}

public class APISend {
    public void getPayment(String username) throws IOException, TimeoutException {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        try (Connection con = factory.newConnection();
             Channel channel = con.createChannel()) {
            channel.queueDeclare("getPayment", false, false, false, null);
            channel.basicPublish("", "getPayment", null, username.getBytes(StandardCharsets.UTF_8));
            System.out.println(" [x] SEND GET DATA SALDO '" + username + "'");
        }
    }

}

public void con() {
        this.entityManager = Persistence
                .createEntityManagerFactory("user-unit")
                .createEntityManager();
        naDao = new UserDAO(entityManager);
        try {
            entityManager.getTransaction().begin();
        } catch (IllegalStateException e) {
            entityManager.getTransaction().rollback();
        }
    }

public void com() {
    try {
        entityManager.getTransaction().commit();
        entityManager.close();
    } catch (IllegalStateException e) {
        entityManager.getTransaction().rollback();
    }
}

public void connectRabbitMQ() throws IOException, TimeoutException {
    factory = new ConnectionFactory();
    factory.setHost("localhost");
    connection = factory.newConnection();
}

public void getSaldo() {
        try {
            connectRabbitMQ();
            channel = connection.createChannel();
            channel.queueDeclare("getPayment", false, false, false, null);
            DeliverCallback deliverCallback = (consumerTag, delivery) -> {
                String username = new String(delivery.getBody(), StandardCharsets.UTF_8);
                System.out.println(" [x] Received '" + username + "'");
                con();
                int res = naDao.checkUser(username);
                String payment = "";
                if (res != 0){
                    User nb = new User();
                    nb.setId_user(res);
                    int money = naDao.getPayment(nb);
                    payment = String.valueOf(money);
                } else {
                    payment="0";
                }
                try {
                    send.sendToAPI(payment);
                } catch (Exception e) {
                    System.out.println("ERROR SEND TO API GET PAYMENT: " + e);
                }
                com();
            };
            channel.basicConsume("getPayment", true, deliverCallback, consumerTag -> { });
        } catch (Exception e) {
            System.out.println("ERROR GET PAYMENT = " + e);
        }
    }

public int checkUser(String username) {
        String select = "SELECT id FROM User WHERE username=:username AND loginStatus=:loginStatus";
        Query q = entityManager.createQuery(select);
        q.setParameter("username", username);
        q.setParameter("loginStatus", "true");

        if (q.getResultList().size() != 0) {
            return (int) q.getResultList().get(0);
        } else {
            return q.getResultList().size();
        }
    }

public int getPayment(User nb) {
    String query = "SELECT n.payment FROM User n WHERE n.id=:id";
    Query q = entityManager.createQuery(query);
    q.setParameter("id", nb.getId());
    if (q.getResultList().size()!=0){
        return (int)q.getResultList().get(0);
    } else {
        return q.getResultList().size();
    }
}

public void sendToAPI (String message) throws IOException, TimeoutException {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        try (Connection connection = factory.newConnection();
             Channel channel = connection.createChannel()) {
            channel.queueDeclare("paymentFromDB", false, false, false, null);
            channel.basicPublish("", "paymentFromDB", null, message.getBytes(StandardCharsets.UTF_8));
            System.out.println(" [x] Sent '" + message + "'");
        } catch (Exception e) {
            System.out.println("ERROR SEND TO API" + e);
        }
    }

public class APIReceive {
    protected String message = "";
    private String paymentResponse = "";

    public void setMessage(String message) {
        this.message = message;
    }

    public String getpaymentResponse() {
        return paymentResponse;
    }
    public void setpaymentResponse(String paymentResponse) {
        this.paymentResponse = paymentResponse;
    }
    
        public String getPayment() throws IOException, TimeoutException {
        try {
            ConnectionFactory factory = new ConnectionFactory();
            factory.setHost("localhost");
            Connection connection = factory.newConnection();
            Channel channel = connection.createChannel();

            channel.queueDeclare("paymentFromDB", false, false, false, null);
            System.out.println(" [*] Waiting for messages from database");

            DeliverCallback deliverCallback = (consumerTag, delivery) -> {
                String message = new String(delivery.getBody(), "UTF-8");
                System.out.println(" [x] Payment Received '" + message + "'");
                this.message = message;
            };

            channel.basicConsume("paymentFromDB", true, deliverCallback, consumerTag -> { });
            TimeUnit.SECONDS.sleep(2);
            if (!this.message.equals("0")) {
                JSONObject object = new JSONObject();
                object.put("response", 200);
                object.put("status", "Success");
                object.put("message", "Success Check Payment");
                object.put("Saldo", this.message);
                saldoResponse = object.toJSONString();
            } else {
                JSONObject object = new JSONObject();
                object.put("response", 400);
                object.put("status", "Error");
                object.put("message", "Error Getting Payment!");
                saldoResponse = object.toJSONString();
            }
        } catch (Exception e) {
            System.out.println("ERROR GET SALDO APIRecv: " + e);
        }
        System.out.println("payment response: "+this.getPaymentResponse());
        return this.getPaymentResponse();
    }

    public String getMessage() {
        return message;
    }
}

UserDAO.java

@RestController
@RequestMapping("/api")
public class UserAPI {

    APISend send = new APISend();
    public final APIReceive recv = new APIReceive();

    @GetMapping("/home/{username}")
    public ResponseEntity<?> getData(@PathVariable("username") String username) {
        try {
            send.getPayment(username);
            return new ResponseEntity<>(recv.getPayment(), HttpStatus.OK);
        } catch (Exception e) {
            System.out.println("ERROR GET DATA: " + e);
            return new ResponseEntity<>("Data not found.", HttpStatus.NOT_FOUND);
        }

    }
}

public class APISend {
    public void getPayment(String username) throws IOException, TimeoutException {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        try (Connection con = factory.newConnection();
             Channel channel = con.createChannel()) {
            channel.queueDeclare("getPayment", false, false, false, null);
            channel.basicPublish("", "getPayment", null, username.getBytes(StandardCharsets.UTF_8));
            System.out.println(" [x] SEND GET DATA SALDO '" + username + "'");
        }
    }

}

public void con() {
        this.entityManager = Persistence
                .createEntityManagerFactory("user-unit")
                .createEntityManager();
        naDao = new UserDAO(entityManager);
        try {
            entityManager.getTransaction().begin();
        } catch (IllegalStateException e) {
            entityManager.getTransaction().rollback();
        }
    }

public void com() {
    try {
        entityManager.getTransaction().commit();
        entityManager.close();
    } catch (IllegalStateException e) {
        entityManager.getTransaction().rollback();
    }
}

public void connectRabbitMQ() throws IOException, TimeoutException {
    factory = new ConnectionFactory();
    factory.setHost("localhost");
    connection = factory.newConnection();
}

public void getSaldo() {
        try {
            connectRabbitMQ();
            channel = connection.createChannel();
            channel.queueDeclare("getPayment", false, false, false, null);
            DeliverCallback deliverCallback = (consumerTag, delivery) -> {
                String username = new String(delivery.getBody(), StandardCharsets.UTF_8);
                System.out.println(" [x] Received '" + username + "'");
                con();
                int res = naDao.checkUser(username);
                String payment = "";
                if (res != 0){
                    User nb = new User();
                    nb.setId_user(res);
                    int money = naDao.getPayment(nb);
                    payment = String.valueOf(money);
                } else {
                    payment="0";
                }
                try {
                    send.sendToAPI(payment);
                } catch (Exception e) {
                    System.out.println("ERROR SEND TO API GET PAYMENT: " + e);
                }
                com();
            };
            channel.basicConsume("getPayment", true, deliverCallback, consumerTag -> { });
        } catch (Exception e) {
            System.out.println("ERROR GET PAYMENT = " + e);
        }
    }

public int checkUser(String username) {
        String select = "SELECT id FROM User WHERE username=:username AND loginStatus=:loginStatus";
        Query q = entityManager.createQuery(select);
        q.setParameter("username", username);
        q.setParameter("loginStatus", "true");

        if (q.getResultList().size() != 0) {
            return (int) q.getResultList().get(0);
        } else {
            return q.getResultList().size();
        }
    }

public int getPayment(User nb) {
    String query = "SELECT n.payment FROM User n WHERE n.id=:id";
    Query q = entityManager.createQuery(query);
    q.setParameter("id", nb.getId());
    if (q.getResultList().size()!=0){
        return (int)q.getResultList().get(0);
    } else {
        return q.getResultList().size();
    }
}

public void sendToAPI (String message) throws IOException, TimeoutException {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        try (Connection connection = factory.newConnection();
             Channel channel = connection.createChannel()) {
            channel.queueDeclare("paymentFromDB", false, false, false, null);
            channel.basicPublish("", "paymentFromDB", null, message.getBytes(StandardCharsets.UTF_8));
            System.out.println(" [x] Sent '" + message + "'");
        } catch (Exception e) {
            System.out.println("ERROR SEND TO API" + e);
        }
    }

public class APIReceive {
    protected String message = "";
    private String paymentResponse = "";

    public void setMessage(String message) {
        this.message = message;
    }

    public String getpaymentResponse() {
        return paymentResponse;
    }
    public void setpaymentResponse(String paymentResponse) {
        this.paymentResponse = paymentResponse;
    }
    
        public String getPayment() throws IOException, TimeoutException {
        try {
            ConnectionFactory factory = new ConnectionFactory();
            factory.setHost("localhost");
            Connection connection = factory.newConnection();
            Channel channel = connection.createChannel();

            channel.queueDeclare("paymentFromDB", false, false, false, null);
            System.out.println(" [*] Waiting for messages from database");

            DeliverCallback deliverCallback = (consumerTag, delivery) -> {
                String message = new String(delivery.getBody(), "UTF-8");
                System.out.println(" [x] Payment Received '" + message + "'");
                this.message = message;
            };

            channel.basicConsume("paymentFromDB", true, deliverCallback, consumerTag -> { });
            TimeUnit.SECONDS.sleep(2);
            if (!this.message.equals("0")) {
                JSONObject object = new JSONObject();
                object.put("response", 200);
                object.put("status", "Success");
                object.put("message", "Success Check Payment");
                object.put("Saldo", this.message);
                saldoResponse = object.toJSONString();
            } else {
                JSONObject object = new JSONObject();
                object.put("response", 400);
                object.put("status", "Error");
                object.put("message", "Error Getting Payment!");
                saldoResponse = object.toJSONString();
            }
        } catch (Exception e) {
            System.out.println("ERROR GET SALDO APIRecv: " + e);
        }
        System.out.println("payment response: "+this.getPaymentResponse());
        return this.getPaymentResponse();
    }

    public String getMessage() {
        return message;
    }
}

DatabaseSender.java

@RestController
@RequestMapping("/api")
public class UserAPI {

    APISend send = new APISend();
    public final APIReceive recv = new APIReceive();

    @GetMapping("/home/{username}")
    public ResponseEntity<?> getData(@PathVariable("username") String username) {
        try {
            send.getPayment(username);
            return new ResponseEntity<>(recv.getPayment(), HttpStatus.OK);
        } catch (Exception e) {
            System.out.println("ERROR GET DATA: " + e);
            return new ResponseEntity<>("Data not found.", HttpStatus.NOT_FOUND);
        }

    }
}

public class APISend {
    public void getPayment(String username) throws IOException, TimeoutException {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        try (Connection con = factory.newConnection();
             Channel channel = con.createChannel()) {
            channel.queueDeclare("getPayment", false, false, false, null);
            channel.basicPublish("", "getPayment", null, username.getBytes(StandardCharsets.UTF_8));
            System.out.println(" [x] SEND GET DATA SALDO '" + username + "'");
        }
    }

}

public void con() {
        this.entityManager = Persistence
                .createEntityManagerFactory("user-unit")
                .createEntityManager();
        naDao = new UserDAO(entityManager);
        try {
            entityManager.getTransaction().begin();
        } catch (IllegalStateException e) {
            entityManager.getTransaction().rollback();
        }
    }

public void com() {
    try {
        entityManager.getTransaction().commit();
        entityManager.close();
    } catch (IllegalStateException e) {
        entityManager.getTransaction().rollback();
    }
}

public void connectRabbitMQ() throws IOException, TimeoutException {
    factory = new ConnectionFactory();
    factory.setHost("localhost");
    connection = factory.newConnection();
}

public void getSaldo() {
        try {
            connectRabbitMQ();
            channel = connection.createChannel();
            channel.queueDeclare("getPayment", false, false, false, null);
            DeliverCallback deliverCallback = (consumerTag, delivery) -> {
                String username = new String(delivery.getBody(), StandardCharsets.UTF_8);
                System.out.println(" [x] Received '" + username + "'");
                con();
                int res = naDao.checkUser(username);
                String payment = "";
                if (res != 0){
                    User nb = new User();
                    nb.setId_user(res);
                    int money = naDao.getPayment(nb);
                    payment = String.valueOf(money);
                } else {
                    payment="0";
                }
                try {
                    send.sendToAPI(payment);
                } catch (Exception e) {
                    System.out.println("ERROR SEND TO API GET PAYMENT: " + e);
                }
                com();
            };
            channel.basicConsume("getPayment", true, deliverCallback, consumerTag -> { });
        } catch (Exception e) {
            System.out.println("ERROR GET PAYMENT = " + e);
        }
    }

public int checkUser(String username) {
        String select = "SELECT id FROM User WHERE username=:username AND loginStatus=:loginStatus";
        Query q = entityManager.createQuery(select);
        q.setParameter("username", username);
        q.setParameter("loginStatus", "true");

        if (q.getResultList().size() != 0) {
            return (int) q.getResultList().get(0);
        } else {
            return q.getResultList().size();
        }
    }

public int getPayment(User nb) {
    String query = "SELECT n.payment FROM User n WHERE n.id=:id";
    Query q = entityManager.createQuery(query);
    q.setParameter("id", nb.getId());
    if (q.getResultList().size()!=0){
        return (int)q.getResultList().get(0);
    } else {
        return q.getResultList().size();
    }
}

public void sendToAPI (String message) throws IOException, TimeoutException {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        try (Connection connection = factory.newConnection();
             Channel channel = connection.createChannel()) {
            channel.queueDeclare("paymentFromDB", false, false, false, null);
            channel.basicPublish("", "paymentFromDB", null, message.getBytes(StandardCharsets.UTF_8));
            System.out.println(" [x] Sent '" + message + "'");
        } catch (Exception e) {
            System.out.println("ERROR SEND TO API" + e);
        }
    }

public class APIReceive {
    protected String message = "";
    private String paymentResponse = "";

    public void setMessage(String message) {
        this.message = message;
    }

    public String getpaymentResponse() {
        return paymentResponse;
    }
    public void setpaymentResponse(String paymentResponse) {
        this.paymentResponse = paymentResponse;
    }
    
        public String getPayment() throws IOException, TimeoutException {
        try {
            ConnectionFactory factory = new ConnectionFactory();
            factory.setHost("localhost");
            Connection connection = factory.newConnection();
            Channel channel = connection.createChannel();

            channel.queueDeclare("paymentFromDB", false, false, false, null);
            System.out.println(" [*] Waiting for messages from database");

            DeliverCallback deliverCallback = (consumerTag, delivery) -> {
                String message = new String(delivery.getBody(), "UTF-8");
                System.out.println(" [x] Payment Received '" + message + "'");
                this.message = message;
            };

            channel.basicConsume("paymentFromDB", true, deliverCallback, consumerTag -> { });
            TimeUnit.SECONDS.sleep(2);
            if (!this.message.equals("0")) {
                JSONObject object = new JSONObject();
                object.put("response", 200);
                object.put("status", "Success");
                object.put("message", "Success Check Payment");
                object.put("Saldo", this.message);
                saldoResponse = object.toJSONString();
            } else {
                JSONObject object = new JSONObject();
                object.put("response", 400);
                object.put("status", "Error");
                object.put("message", "Error Getting Payment!");
                saldoResponse = object.toJSONString();
            }
        } catch (Exception e) {
            System.out.println("ERROR GET SALDO APIRecv: " + e);
        }
        System.out.println("payment response: "+this.getPaymentResponse());
        return this.getPaymentResponse();
    }

    public String getMessage() {
        return message;
    }
}

apirecever.java

@RestController
@RequestMapping("/api")
public class UserAPI {

    APISend send = new APISend();
    public final APIReceive recv = new APIReceive();

    @GetMapping("/home/{username}")
    public ResponseEntity<?> getData(@PathVariable("username") String username) {
        try {
            send.getPayment(username);
            return new ResponseEntity<>(recv.getPayment(), HttpStatus.OK);
        } catch (Exception e) {
            System.out.println("ERROR GET DATA: " + e);
            return new ResponseEntity<>("Data not found.", HttpStatus.NOT_FOUND);
        }

    }
}

public class APISend {
    public void getPayment(String username) throws IOException, TimeoutException {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        try (Connection con = factory.newConnection();
             Channel channel = con.createChannel()) {
            channel.queueDeclare("getPayment", false, false, false, null);
            channel.basicPublish("", "getPayment", null, username.getBytes(StandardCharsets.UTF_8));
            System.out.println(" [x] SEND GET DATA SALDO '" + username + "'");
        }
    }

}

public void con() {
        this.entityManager = Persistence
                .createEntityManagerFactory("user-unit")
                .createEntityManager();
        naDao = new UserDAO(entityManager);
        try {
            entityManager.getTransaction().begin();
        } catch (IllegalStateException e) {
            entityManager.getTransaction().rollback();
        }
    }

public void com() {
    try {
        entityManager.getTransaction().commit();
        entityManager.close();
    } catch (IllegalStateException e) {
        entityManager.getTransaction().rollback();
    }
}

public void connectRabbitMQ() throws IOException, TimeoutException {
    factory = new ConnectionFactory();
    factory.setHost("localhost");
    connection = factory.newConnection();
}

public void getSaldo() {
        try {
            connectRabbitMQ();
            channel = connection.createChannel();
            channel.queueDeclare("getPayment", false, false, false, null);
            DeliverCallback deliverCallback = (consumerTag, delivery) -> {
                String username = new String(delivery.getBody(), StandardCharsets.UTF_8);
                System.out.println(" [x] Received '" + username + "'");
                con();
                int res = naDao.checkUser(username);
                String payment = "";
                if (res != 0){
                    User nb = new User();
                    nb.setId_user(res);
                    int money = naDao.getPayment(nb);
                    payment = String.valueOf(money);
                } else {
                    payment="0";
                }
                try {
                    send.sendToAPI(payment);
                } catch (Exception e) {
                    System.out.println("ERROR SEND TO API GET PAYMENT: " + e);
                }
                com();
            };
            channel.basicConsume("getPayment", true, deliverCallback, consumerTag -> { });
        } catch (Exception e) {
            System.out.println("ERROR GET PAYMENT = " + e);
        }
    }

public int checkUser(String username) {
        String select = "SELECT id FROM User WHERE username=:username AND loginStatus=:loginStatus";
        Query q = entityManager.createQuery(select);
        q.setParameter("username", username);
        q.setParameter("loginStatus", "true");

        if (q.getResultList().size() != 0) {
            return (int) q.getResultList().get(0);
        } else {
            return q.getResultList().size();
        }
    }

public int getPayment(User nb) {
    String query = "SELECT n.payment FROM User n WHERE n.id=:id";
    Query q = entityManager.createQuery(query);
    q.setParameter("id", nb.getId());
    if (q.getResultList().size()!=0){
        return (int)q.getResultList().get(0);
    } else {
        return q.getResultList().size();
    }
}

public void sendToAPI (String message) throws IOException, TimeoutException {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        try (Connection connection = factory.newConnection();
             Channel channel = connection.createChannel()) {
            channel.queueDeclare("paymentFromDB", false, false, false, null);
            channel.basicPublish("", "paymentFromDB", null, message.getBytes(StandardCharsets.UTF_8));
            System.out.println(" [x] Sent '" + message + "'");
        } catch (Exception e) {
            System.out.println("ERROR SEND TO API" + e);
        }
    }

public class APIReceive {
    protected String message = "";
    private String paymentResponse = "";

    public void setMessage(String message) {
        this.message = message;
    }

    public String getpaymentResponse() {
        return paymentResponse;
    }
    public void setpaymentResponse(String paymentResponse) {
        this.paymentResponse = paymentResponse;
    }
    
        public String getPayment() throws IOException, TimeoutException {
        try {
            ConnectionFactory factory = new ConnectionFactory();
            factory.setHost("localhost");
            Connection connection = factory.newConnection();
            Channel channel = connection.createChannel();

            channel.queueDeclare("paymentFromDB", false, false, false, null);
            System.out.println(" [*] Waiting for messages from database");

            DeliverCallback deliverCallback = (consumerTag, delivery) -> {
                String message = new String(delivery.getBody(), "UTF-8");
                System.out.println(" [x] Payment Received '" + message + "'");
                this.message = message;
            };

            channel.basicConsume("paymentFromDB", true, deliverCallback, consumerTag -> { });
            TimeUnit.SECONDS.sleep(2);
            if (!this.message.equals("0")) {
                JSONObject object = new JSONObject();
                object.put("response", 200);
                object.put("status", "Success");
                object.put("message", "Success Check Payment");
                object.put("Saldo", this.message);
                saldoResponse = object.toJSONString();
            } else {
                JSONObject object = new JSONObject();
                object.put("response", 400);
                object.put("status", "Error");
                object.put("message", "Error Getting Payment!");
                saldoResponse = object.toJSONString();
            }
        } catch (Exception e) {
            System.out.println("ERROR GET SALDO APIRecv: " + e);
        }
        System.out.println("payment response: "+this.getPaymentResponse());
        return this.getPaymentResponse();
    }

    public String getMessage() {
        return message;
    }
}

我得到的答复是：程序首次运行

[x] Waiting for messages from database
Payment response: {"response":200,"Payment":"","message":"Success Check Payment","status":"Success"}

第一个请求：

[x] SEND GET DATA Payment 'user1'
[x] Waiting for messages from database
[x] Payment Received '5000000'
Payment response: {"response":200,"Payment":"","message":"Success Check Payment","status":"Success"}

第二项请求：

[x] SEND GET DATA Payment 'user1'
[x] Waiting for messages from database
[x] Payment Received '5000000'
Payment response: {"response":200,"Payment":"5000000","message":"Success Check Payment","status":"Success"}

当我将

protected String message=”“

设置为

protected String message

时，我将得到错误

java.lang.NullPointerException:无法调用“String.equals（Object）”，因为“this.message”为null

有人能帮帮我吗？

请提供一个最简单的代码示例来说明您的问题。没有人会去挖掘你发布的大量代码。请提供一个最小的代码示例来说明你的问题。没有人会去挖掘你发布的大量代码。