小编the*_*ava的帖子

public class Contact implements Serializable {
    private String name;
    private String email;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }
}

1. 我Serializable什么时候应该实现界面？
2. 我们为什么这样做？
3. 它是否具有任何优势或安全性？

UTF-8和UTF-16之间的区别？我们为什么需要这些？

MessageDigest md = MessageDigest.getInstance("SHA-256");
String text = "This is some text";

md.update(text.getBytes("UTF-8")); // Change this to "UTF-16" if needed
byte[] digest = md.digest();

当我试图改变我的桌子时,我收到了这个错误.

Error Code: 1833. Cannot change column 'person_id': used in a foreign key constraint 'fk_fav_food_person_id' of table 'table.favorite_food'

这是我成功运行的CREATE TABLE STATEMENT.

CREATE TABLE favorite_food(
    person_id SMALLINT UNSIGNED,
    food VARCHAR(20),
    CONSTRAINT pk_favorite_food PRIMARY KEY(person_id,food),
    CONSTRAINT fk_fav_food_person_id FOREIGN KEY (person_id)
    REFERENCES person (person_id)
);

然后我试图执行此语句,我得到了上述错误.

ALTER TABLE person MODIFY person_id SMALLINT UNSIGNED AUTO_INCREMENT;

全局命名空间会被污染是什么意思？

我真的不明白受污染的全局命名空间意味着什么.

我偶然发现了这篇文章:JavaScript的Revealing Module Pattern.我想在我的项目中使用它.

让我们想象一下我有一个函数abc,我在我的主JavaScript文件中调用该函数.

这种模式会使事情变得不同吗？谁能告诉我这种模式的基本例子？

web.xml有什么用？我们为什么要使用？

<filter>
        <filter-name>wicket.mysticpaste</filter-name>
        <filter-class>org.apache.wicket.protocol.http.WicketFilter</filter-class>
        <init-param>
            <param-name>applicationClassName</param-name>
            <param-value>com.mysticcoders.WicketApplication</param-value>
        </init-param>
    </filter>

 <filter-mapping>
  <filter-name>wicket.mysticpaste</filter-name>
    <url-pattern>/*</url-pattern>
 </filter-mapping>

这个文件管理器和文件管理器有什么作用？

Issue:直接使用SimpleDateFormat而不使用显式语言环境 Id:SimpleDateFormat

SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

为什么" 要获取本地格式使用getDateInstance(),getDateTimeInstance()或getTimeInstance(),或使用新的SimpleDateFormat(字符串模板,区域设置区域设置),例如Locale.US用于ASCII日期 "此错误来自此行.

http://developer.android.com/reference/java/text/SimpleDateFormat.html

http://www.vaannila.com/spring/spring-hibernate-integration-1.html

阅读本教程后,他们没有提到在DB中创建表的任何内容.一旦我指定它们,Hibernate是否通过创建表和字段来自动处理它.

这是我的bean配置.

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:p="http://www.springframework.org/schema/p"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver" p:prefix="/WEB-INF/jsp/" p:suffix=".jsp" />

    <bean id="myDataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
        <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
        <property name="url" value="jdbc:mysql://127.0.0.1:3306/spring"/>
        <property name="username" value="monwwty"/>
        <property name="password" value="www"/>
    </bean>

    <bean id="mySessionFactory" class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
        <property name="dataSource" ref="myDataSource" />
        <property name="annotatedClasses">
            <list>
                <value>uk.co.vinoth.spring.domain.User</value>
            </list>
        </property>
        <property name="hibernateProperties">
            <props>
                <prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
                <prop key="hibernate.show_sql">true</prop>
                <prop key="hibernate.hbm2ddl.auto">create</prop>
            </props>
        </property>
    </bean>

    <bean id="myUserDAO" class="uk.co.vinoth.spring.dao.UserDAOImpl">
        <property name="sessionFactory" ref="mySessionFactory"/>
    </bean>

    <bean name="/user/*.htm" class="uk.co.vinoth.spring.web.UserController" >
        <property name="userDAO" ref="myUserDAO" />
    </bean>

</beans>

可能重复:
Android如何在其他类中运行OnUiThread？

我的Asyn类是一个单独的类文件.

public class AdamTask extends AsyncTask<String, Void, String>{
         public void showToast(final String toast)
        {
            runOnUiThread(new Runnable() {
                public void run()
                {
                    Toast.makeText(context, toast, Toast.LENGTH_SHORT).show();
                }
            });
        }
}

我如何在AsyncTask类中执行此方法？我收到一个错误的方法runOnUiThread(new Runnable(){}) is undefined for the type AdamTask

新的AdamTask(Eve.this,How to pass the eve activity here).execute();

当我尝试提交我的注册表单时,我收到以下错误.param丢失或值为空:user

def user_params
   params.require(:user).permit(:name, :email, :password, :password_confirmation)
end

以下是要求:

{"utf8"=>"?",
 "authenticity_token"=>"YX0+4AeWlGWJiQZgbhV9cxi6TUCoibZfwh95BrK9iCQ=",
 "name"=>"asasa",
 "email"=>"asasas@asas.com",
 "password"=>"[FILTERED]",
 "confirm_password"=>"[FILTERED]",
 "commit"=>"Register"}

以下是我的观点

<%= form_tag users_path, class: "form-horizontal", id: "signupform" do %>

<%= end %>