小编nik*_*hil的帖子

问题陈述是创建命名路由.它应该生成一个类似'/ zombies /:name'的路径,其中:name是一个参数,并指向ZombiesController中的索引操作.将路线命名为"墓地"

资源是资源

zombies
id  name    graveyard
1   Ash     Glen Haven Memorial Cemetary
2   Bob     Chapel Hill Cemetary
3   Jim     My Fathers Basement

我的解决方案是

TwitterForZombies::Application.routes.draw do
  match ':name' => 'Zombies#index', :as => 'graveyard'
end

我也试过了

TwitterForZombies::Application.routes.draw do
      match ':name' => 'Zombie#index', :as => 'graveyard'
    end

我在两种情况下得到的错误是

Sorry, Try Again
Did not route to ZombiesController index action with :name parameter

我究竟做错了什么？？

这是我一直在研究的Rational类:

rational.h

#include<iostream>

using namespace std;

#ifndef RATIONAL_H
#define RATIONAL_H

class Rational
{
  int numerator,denominator;
  public:
  // the various constructors
  Rational();
  Rational(int);
  Rational(int,int);

  //member functions
  int get_numerator()const{return numerator;}
  int get_denominator()const{return denominator;}

  // overloaded operators
  // relational operators
  bool operator==(const Rational&)const;
  bool operator<(const Rational&)const;
  bool operator<=(const Rational&)const;
  bool operator>(const Rational&)const;
  bool operator>=(const Rational&)const;

  //arithmetic operators
  Rational operator+(const Rational&);
  Rational operator-(const Rational&);
  Rational operator*(const Rational&);
  Rational operator/(const Rational&);

  //output operator
  friend ostream& operator<<(ostream&, const Rational&);
};
#endif //RATIONAL_H

rational.cpp

#include "rational.h"

// …

#include<iostream>

using namespace std;

class abc
{
    int a;
};
class xyz : public virtual abc
{
    int b;
};

int main()
{
    abc obj;
    xyz obj1;
    cout<<endl<<sizeof(obj);
    cout<<endl<<sizeof(obj1);
    return 0;
}

答案将取决于编译器,但当我看到这个结果时,我感到很惊讶

~/Documents/workspace/tmp ‹.rvm-›  $ ./class_sizes   

4
16

如果我删除虚拟关键字,那么分配的大小分别为4和8,这正是我的预期.

为什么额外的空间被准确占用？我怀疑它是针对vptr表或其他类似但不确定的.

我有一个Map<Range<Double>, String>检查特定Double值(分数)映射到String(级别)的位置.最终用户希望能够动态地更改此映射,从长远来看,我们希望有一个基于Web的GUI控制权,但从短期来看,他们很高兴有一个文件进入S3和编辑每当需要改变时.我不想S3为每个请求点击并希望缓存它,因为它不会太频繁地更改(每周一次左右).我不想让代码更改并退回我的服务.

这是我想出的 -

public class Mapper() {
    private LoadingCache<Score, String> scoreToLevelCache;

public Mapper() {
    scoreToLevelCache = CacheBuilder.newBuilder()
            .expireAfterWrite(10, TimeUnit.MINUTES)
            .build(new CacheLoader<Score, String>() {
                public String load(Score score) {
                    Map<Range<Double>, String> scoreToLevelMap = readMappingFromS3(); //readMappingFromS3 omitted for brevity
                    for(Range<Double> key : scoreToLevelMap.keySet()) {
                        if(key.contains(score.getCount())) { return scoreToLevelMap.get(key); }
                    }
                    throw new IllegalArgumentException("The score couldn't be mapped to a level. Either the score passed in was incorrect or the …

我想基于索引删除向量的元素,比如所有偶数索引元素.我已经阅读了关于擦除删除习惯用法,但看不到如何应用它.这是我试过的:

    vector<int> line;
    line.reserve(10);
    for(int i=0;i<10;++i)
    {
      line.push_back(i+1);
    }
    for(unsigned int i=0;i<line.size();++i)
    {
      //remove the even indexed elements
      if(i%2 == 0)
      {
        remove(line.begin(),line.end(),line[i]);
      }
    }
line.erase( line.begin(),line.end() );

这会擦除整个矢量.我希望只删除已删除算法标记的元素.

然后我尝试了这个

for(unsigned int i=0;i<line.size();++i)
    {
      //remove the even indexed elements
      if(i%2 == 0)
      {
        line.erase( remove(line.begin(),line.end(),line[i]),line.end() );
      }
    }

由于在移除时存在问题,这再次不起作用,索引似乎在迭代矢量时移位.应该采取什么样的正确方法来实现这一目标.

我正在为interviewstreet.com挑战编写一些代码我的代码给出了NumberFormatException

import java.io.*;

public class BlindPassenger
{
  public static void main(String [] args) throws IOException
  {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    String line = br.readLine();
    int t,n;
    //System.out.println(line);
    t = Integer.parseInt(line);
    for(int i=0;i<t;++i)
    {
      line = br.readLine();
      n = Integer.parseInt(line); --n;
      if(n == 0)
      {
        System.out.println("poor conductor");
      }
      else
      {
        char direction='l',seat_posn='l';
        int row_no = 0, relative_seat_no = 0;
        row_no = (int) Math.ceil(n/5.0);
        relative_seat_no = n % 5;
        if(row_no % 2 == 0)
        {
          //even row, need to reverse …

我正在使用git-bash在Windows 8 Release Preview上使用gcc-4.7.1.

$ g++ -v
Using built-in specs.
COLLECT_GCC=c:\Users\nikhil bhardwaj\mingw64\bin\g++.exe
COLLECT_LTO_WRAPPER=c:/users/nikhil bhardwaj/mingw64/bin/../libexec/gcc/x86_64-w
64-mingw32/4.7.1/lto-wrapper.exe
Target: x86_64-w64-mingw32
Configured with: /home/drangon/work/mingw-w64-dgn/source/gcc/configure --host=x8
6_64-w64-mingw32 --target=x86_64-w64-mingw32 --disable-nls --enable-languages=c,
c++,objc,obj-c++ --with-gmp=/home/drangon/work/mingw-w64-dgn/build/for_target --
enable-twoprocess --disable-libstdcxx-pch --disable-win32-registry --prefix=/hom
e/drangon/work/mingw-w64-dgn/target --with-sysroot=/home/drangon/work/mingw-w64-
dgn/target
Thread model: win32
gcc version 4.7.1 20120524 (prerelease) (GCC)

当我尝试编译一个小代码片段时,

using namespace std;
struct node
{
    int data;
    node *left, *right;
};
node *newNode(int data)
{
    node *node = new (struct node);
    node->data = data;
    node->left = nullptr;
    node->right = NULL;
    return node;
}

我收到这个错误, …

我正在尝试用Spring 3,JPA 2和Hibernate 3创建一个应用程序.当y持久化实体时我遇到了问题:没有任何反应!数据未插入数据库中,也不执行查询.但是,当我使用query.getResultList()之类的请求时,select正常工作.

所以我认为我的问题只出现在持续/更新和事务管理器上,但我对spring并不是很好.你能帮我吗 ？

这是我的配置文件:

我的applicationContext.xml

    <jee:jndi-lookup id="soireeentreamis_DS" jndi-name="jdbc/soireeentreamis" />

    <bean id="persistenceUnitManager"
        class="org.springframework.orm.jpa.persistenceunit.DefaultPersistenceUnitManager">
        <property name="persistenceXmlLocations">
            <list>
                <value>classpath*:META-INF/persistence.xml</value>
            </list>
        </property>
        <property name="defaultDataSource" ref="soireeentreamis_DS" />
        <property name="dataSources">
            <map>
                <entry key="soireeentreamisDS" value-ref="soireeentreamis_DS" />
            </map>
        </property>
    </bean>

    <bean id="entityManagerFactory"
        class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="persistenceUnitManager" ref="persistenceUnitManager" />
        <property name="persistenceUnitName" value="soireeentreamisPU" />
        <property name="jpaDialect">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaDialect" />
        </property>
        <property name="jpaVendorAdapter">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
                <property name="showSql" value="false" />
            </bean>
        </property>
    </bean>

    <bean id="soireeentreamisTransactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
        <property name="entityManagerFactory" ref="entityManagerFactory" />
        <property name="jpaDialect">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaDialect" />
        </property>
    </bean>

    <tx:annotation-driven transaction-manager="soireeentreamisTransactionManager" /> …

当我尝试执行我的 aws lambda function

1) Error injecting constructor, java.lang.NullPointerException
at in.nikhilbhardwaj.path.route.resources.ServicesResource.<init>(ServicesResource.java:66)
at in.nikhilbhardwaj.path.route.resources.ServicesResource.class(ServicesResource.java:56)
while locating in.nikhilbhardwaj.path.route.resources.ServicesResource
for parameter 0 at in.nikhilbhardwaj.path.alexa.intent.HelloWorldIntentAction.<init>(HelloWorldIntentAction.java:44)
while locating in.nikhilbhardwaj.path.alexa.intent.HelloWorldIntentAction
while locating in.nikhilbhardwaj.path.alexa.intent.IntentAction annotated with @com.google.inject.multibindings.Element(setName=,uniqueId=10, type=MAPBINDER, keyType=java.lang.String)
at in.nikhilbhardwaj.path.alexa.intent.IntentModule.configure(IntentModule.java:17) (via modules: in.nikhilbhardwaj.path.alexa.AlexaStarterApplicationModule -> in.nikhilbhardwaj.path.alexa.intent.IntentModule -> com.google.inject.multibindings.MapBinder$RealMapBinder)
while locating java.util.Map<java.lang.String, in.nikhilbhardwaj.path.alexa.intent.IntentAction>
for parameter 0 at in.nikhilbhardwaj.path.alexa.intent.IntentHandlerServiceImpl.<init>(IntentHandlerServiceImpl.java:16)
while locating in.nikhilbhardwaj.path.alexa.intent.IntentHandlerServiceImpl
while locating in.nikhilbhardwaj.path.alexa.intent.IntentHandlerService
for parameter 0 at in.nikhilbhardwaj.path.alexa.AlexaStarterSpeechlet.<init>(AlexaStarterSpeechlet.java:26)
while locating in.nikhilbhardwaj.path.alexa.AlexaStarterSpeechlet
Caused by: java.lang.NullPointerException
at java.io.Reader.<init>(Reader.java:78)
at java.io.InputStreamReader.<init>(InputStreamReader.java:113)
at in.nikhilbhardwaj.path.route.resources.ServicesResource.initializeServiceIds(ServicesResource.java:88)
at in.nikhilbhardwaj.path.route.resources.ServicesResource.<init>(ServicesResource.java:68)
at in.nikhilbhardwaj.path.route.resources.ServicesResource$$FastClassByGuice$$3d6e91ec.newInstance(<generated>)

我已经classpath按照 …

我们ApplicationConfig像这样定义了一些bean-

@Bean
S3Repository s3Repository() {
    AmazonS3 s3 = new AmazonS3Client(s3AdminReadWriteCreds());
    return new S3Repository(s3);
}

@Bean
S3Repository s3PrivateContentRepository() {
    AmazonS3 s3 = new AmazonS3Client(readOnlyS3Creds());
    return new S3Repository(s3);
}

@Bean
S3Repository s3SyncFilesContentRepository() {
    AmazonS3 s3 = new AmazonS3Client(readOnlySpecificBucketCreds());
    return new S3Repository(s3);
}

这就是它们在代码中的用法-

public class AssetReader {
@Autowired
private S3Repository s3PrivateContentRepository;
.... used inside the class ....
}

同样，其他bean的名称与预期产生它们的方法相同。

该应用程序运行良好，但是对此我感到有些惊讶，我不确定是否带有Admin凭据的bean是否会偶然地自动连接到任何地方，或者由于Spring的一些实现细节而是否连接了正确的bean？

我认为，如果自动装配可能产生歧义，则必须指定一个限定符。假设这能按预期进行，那么我们是否有任何理由使这些bean合格？