使用 CompletableFuture 构建具有多种方法的对象
我正在尝试了解CompletableFuture以及如何利用它来构建一个包含从多个端点获得的信息的对象。我遇到过几个例子，但没有一个是完全适合我的问题的。例如，这个并行运行相同的方法来获取字符串列表，我想在其中并行运行多个方法来构建和返回一个对象。
我为员工创建了一个简单的 DTO：
@Builder
@Data
@AllArgsConstructor
public class EmployeeDTO {
private String name;
private String accountNumber;
private int salary;
}
我创建了一个服务来模拟调用三个独立的 API 来设置 DTO 的值，等待时间相当长：
public class EmployeeService {
public EmployeeDTO setName() {
try {
Thread.sleep(10 * 1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
return EmployeeDTO.builder().name("John Doe").build();
}
public EmployeeDTO setAccountNumber() {
try {
Thread.sleep(10 * 1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
return EmployeeDTO.builder().accountNumber("1235").build();
}
public EmployeeDTO setSalary() {
try {
Thread.sleep(10 * 1000);
} catch (InterruptedException e) {
throw new RuntimeException(e);
}
return EmployeeDTO.builder().salary(100000).build();
}
}
我可以使用supplyAsync所有三种方法然后运行，allOf但它什么也没做：
private void run() {
EmployeeService employeeService = new EmployeeService();
CompletableFuture<EmployeeDTO> employeeCfWithName = CompletableFuture
.supplyAsync(employeeService::setName);
CompletableFuture<EmployeeDTO> employeeCfWithAccountNumber = CompletableFuture
.supplyAsync(employeeService::setAccountNumber);
CompletableFuture<EmployeeDTO> employeeCfWithSalary = CompletableFuture
.supplyAsync(employeeService::setSalary);
CompletableFuture allCompletableFutures = CompletableFuture.allOf(employeeCfWithName, employeeCfWithAccountNumber, employeeCfWithSalary);
}
如何将结果组合成一个 EmployeeDTO？
ibeautiful2回答
-
www说
您必须将三个CompletableFutures 的结果合并为一个EmployeeDTO. 这不是魔术般地完成的allOf。尝试这样的事情（未经测试）：CompletableFuture allCompletableFutures = CompletableFuture.allOf( employeeCfWithName, employeeCfWithAccountNumber, employeeCfWithSalary);// Wait for all three to complete.allCompletableFutures.get();// Now join all three and combine the results.EmployeeDTO finalResult = EmployeeDTO.builder() .name(new employeeCfWithName.join()) .accountNumber(new employeeCfWithAccountNumber.join()) .salary(new employeeCfWithSalary.join()) .build();这看起来有点傻。我们在每种方法中都使用一个构建器，只是为了使用第四个构建器组合它们的结果。 -
茅侃侃
让您的员工服务函数将EmployeeDTO.builder()作为输入，然后在 run() 函数中创建一个构建器，并在所有 supplyAsync 调用中将该构建器传递给服务。还要确保在调用 allOf() 之后调用 build() ，这保证了每个服务调用都完成了它的一部分。也不要内置单独的服务功能 -public class EmployeeService { public EmployeeDTO setName(EmployeeDTO.EmployeeDTOBuilder builder) { try { Thread.sleep(10 * 1000); } catch (InterruptedException e) { e.printStackTrace(); } return builder.name("John Doe"); } public EmployeeDTO setAccountNumber(EmployeeDTO.EmployeeDTOBuilder builder) { try { Thread.sleep(10 * 1000); } catch (InterruptedException e) { e.printStackTrace(); } return builder.accountNumber("1235"); } public EmployeeDTO setSalary(EmployeeDTO.EmployeeDTOBuilder builder) { try { Thread.sleep(10 * 1000); } catch (InterruptedException e) { throw new RuntimeException(e); } return builder.salary(100000); }}private void run() { EmployeeService employeeService = new EmployeeService(); EmployeeDTO.EmployeeDTOBuilder builder = EmployeeDTO.builder(); CompletableFuture<EmployeeDTO> employeeCfWithName = CompletableFuture .supplyAsync(()-> emoplyeeService.setName(builder)); CompletableFuture<EmployeeDTO> employeeCfWithAccountNumber = CompletableFuture .supplyAsync(()-> emoplyeeService.setAccount(builder)); CompletableFuture<EmployeeDTO> employeeCfWithSalary = CompletableFuture .supplyAsync(()-> emoplyeeService.setSalary(builder)); CompletableFuture allCompletableFutures = CompletableFuture.allOf(employeeCfWithName, employeeCfWithAccountNumber, employeeCfWithSalary); builder.build(); }
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相关分类
Java