我试图通过Java SDK运行EMR作业.
但它根本没有发射.
我正在粘贴我正在使用的代码.
我也查看了文档.但它没有多大帮助.
package com.zedo.aws.emr;
import com.amazonaws.auth.AWSCredentials;
import com.amazonaws.auth.BasicAWSCredentials;
import com.amazonaws.services.elasticmapreduce.AmazonElasticMapReduceClient;
import com.amazonaws.services.elasticmapreduce.model.JobFlowInstancesConfig;
import com.amazonaws.services.elasticmapreduce.model.RunJobFlowRequest;
import com.amazonaws.services.elasticmapreduce.model.RunJobFlowResult;
import com.amazonaws.services.elasticmapreduce.model.StepConfig;
import com.amazonaws.services.elasticmapreduce.util.StepFactory;
public class ExampleEMR {
/**
* @param args
*/
public static void main(String[] args) {
AWSCredentials credentials = new BasicAWSCredentials("<my key>", "<my secret key>");
AmazonElasticMapReduceClient emr = new AmazonElasticMapReduceClient(credentials);
StepFactory stepFactory = new StepFactory();
StepConfig enableDebugging = new StepConfig()
.withName("Enable Debugging")
.withActionOnFailure("TERMINATE_JOB_FLOW")
.withHadoopJarStep(stepFactory.newEnableDebuggingStep());
StepConfig installHive = new StepConfig()
.withName("Install Hive")
.withActionOnFailure("TERMINATE_JOB_FLOW")
.withHadoopJarStep(stepFactory.newInstallHiveStep());
StepConfig hiveScript = …有人可以帮我理解Spring Web Flow的优点.我所理解的是
还有其他我没有调整过的吗？
我一直在学习实现微服务,但我无法理解术语"有界上下文"？
我可以理解它是由域驱动设计产生的概念.但我无法理解它的技术实现.
我看了下面的链接:
我有一个Person的对象结构，如下所示，我想根据其名字搜索一个Person。
public Person{
String name;
List<Person> person;
}
我们该如何实现搜索方法？
将存在一个根对象，即Person，它与其他人有链接，依此类推。
人的名字是唯一的。
搜索签名可以是
public Person findPerson(Person root, String name){
}
有人可以为此建议其他解决方案吗？
我有一个解析器类,它解析文档并在Map中返回解析的数据.
这是我的课程的样子.
public interface DocumentParser {
public Map<String, String> parse(Document document);
}
public class ExcelParser implements DocumentParser{
@Override
public Map<String, String> parse(Document document) {
// TODO Auto-generated method stub
return new HashMap<String, String>();
}
}
public interface Document {
public InputStream getInputStream();
}
public class ExcelDocument implements Document{
@Override
public InputStream getInputStream() {
// TODO Auto-generated method stub
return null;
}
}
public interface DocumentValidator {
public void validate(Map<String, String> documentData, Map<String, String> referenceData, List<String> referenceKeyList);
}
public class ExcelValidator …我正在尝试做这样的编译好的事情:
public interface Training {
public void train();
}
public class JavaTraining implements Training{
@Override
public void train() {
// TODO Auto-generated method stub
}
}
import java.util.*;
public class TestClass {
/**
* @param args
*/
public static void main(String[] args) {
List<Training> trainingList = new ArrayList<Training>();
trainingList.add(new JavaTraining());
for(Training trainingItem : trainingList){
trainingItem.train();
}
}
}
这个编译很好并且也可以运行.
但是当我尝试更改下面的main方法时,它会产生编译时错误.
这是为什么？
import java.util.*;
public class TestClass {
/**
* @param args
*/
public static void main(String[] args) {
List<Training> trainingList …我试图创建一个JSON对象,但在JSON对象中获取"类"键.
我正在使用这个库.
以下是我正在使用的代码.
//Class being used for JSON conversion.
package com.test;
public class Sample {
public String name;
public String surname;
public Sample(String name, String surname) {
this.name = name;
this.surname = surname;
}
public String getName() {
return name;
}
public String getSurname() {
return surname;
}
}
public static void main(String[] args){
Sample sample = new Sample("Sam", "Sammy");
System.out.println(new JSONObject(sample));
}
我得到了json:
{"class":"class com.test.Sample","surname":"Sammy","name":"Sam"}