小编San*_*jee的帖子

我正在尝试学习使用hibernate将简单记录插入到MySQL数据库中,我正在关注Mkyong的这篇文章,我在最后一步,即运行App.Java时陷入困境.

请帮忙.谢谢.

pom.xml中:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.mkyong.common</groupId>
  <artifactId>HibernateExample</artifactId>
  <packaging>jar</packaging>
  <version>1.0-SNAPSHOT</version>
  <name>HibernateExample</name>
  <url>http://maven.apache.org</url>
  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>3.8.1</version>
      <scope>test</scope>
    </dependency>
        <!-- MySQL database driver -->
        <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>5.1.9</version>
        </dependency>
        <!-- Hibernate framework -->
        <dependency>
                <groupId>org.hibernate</groupId>
                <artifactId>hibernate-core</artifactId>
                <version>3.6.3.Final</version>
        </dependency>
        <!-- Hibernate library dependency start -->
        <dependency>
                <groupId>dom4j</groupId>
                <artifactId>dom4j</artifactId>
                <version>1.6.1</version>
        </dependency>
        <dependency>
                <groupId>commons-logging</groupId>
                <artifactId>commons-logging</artifactId>
                <version>1.1.1</version>
        </dependency>
        <dependency>
                <groupId>commons-collections</groupId>
                <artifactId>commons-collections</artifactId>
                <version>3.2.1</version>
        </dependency>
        <dependency>
                <groupId>cglib</groupId>
                <artifactId>cglib</artifactId>
                <version>2.2</version>
        </dependency>
        <!-- Hibernate library dependency end -->
        <dependency>
                <groupId>javax.transaction</groupId>
                <artifactId>jta</artifactId>
                <version>1.1</version>
        </dependency> …

运行最新的Vaadin 7.1.1应用程序时遇到问题.这主要是因为我找不到该版本的文档.Maven原型创建扩展Root的旧式应用程序.Root已经不见了,所以我试图扩展UI,就像在Book of Vaadin中那样.

web.xml中:

<servlet>
    <servlet-name>myservlet</servlet-name>
    <servlet-class>
        com.vaadin.server.VaadinServlet
    </servlet-class>

    <init-param>
        <param-name>UI</param-name>
        <param-value>cz.simplecoin.simplegui.MainScreen</param-value>
    </init-param>
</servlet>

和MainScreen简单地说:

public class MainScreen extends UI {

项目正确编译(使用maven).当我调试时,我看到MainScreen正确调用的init方法,但我看到只有空白屏幕(bootstrap JavavScript在那里)与警报:

错误:

无法加载widgetset:./ VAADIN/widgetsets/com.vaadin.DefaultWidgetSet/com.vaadin.DefaultWidgetSet.nocache.js？1393503103223

我想从Default widgetset开始.我几乎可以肯定,它在maven构建/依赖中存在某种问题.我不知道要使用哪些库:我尝试了两种变体(已评论)

pom.xml中:

<dependency>
    <groupId>com.vaadin</groupId>
    <artifactId>vaadin-server</artifactId>
    <version>${vaadin.version}</version>
</dependency>
<!--
<dependency>
    <groupId>com.vaadin</groupId>
    <artifactId>vaadin-themes</artifactId>
    <version>${vaadin.version}</version>
</dependency>
<dependency>
    <groupId>com.vaadin</groupId>
    <artifactId>vaadin-client</artifactId>
    <version>${vaadin.version}</version>
</dependency>
<dependency>
    <groupId>com.vaadin</groupId>
    <artifactId>vaadin-client-compiler</artifactId>
    <version>${vaadin.version}</version>
</dependency>
<dependency>
    <groupId>com.vaadin</groupId>
    <artifactId>vaadin-theme-compiler</artifactId>
    <version>${vaadin.version}</version>
</dependency>
<dependency>
    <groupId>com.vaadin.addon</groupId>
    <artifactId>vaadin-charts</artifactId>
    <version>1.0.0</version>
</dependency>
-->

我可能会尝试使用自己的widgetset,看看是否能解决问题.

按下时，任何按下的 JButton 似乎都会“突出显示”自身，如下所示：

我似乎找不到任何方法来禁用它。

Gradle 和 Maven 究竟“做什么”而 eclipse 或 sts 没有？从我读过的内容来看，它可以在 Eclipse 中轻松完成构建、运行等操作。

如果我有一个现有项目，我已经通过 tomcat 创建、构建并当前在 eclipse 中运行，我将使用 gradle 做什么？

我正在学习C,而且我一直在关注"Head First C"一书.我到达了一个示例,其中这是生成的代码:

#include <stdio.h>
#include <string.h>


char tracks[][80] = {
    "I left my heart in Harvard Med School",
    "Newark, Newark - A wonderful town",
    "Dancing with a Dork",
    "From here to maternity",
    "The girl from Iwo Jima", 
};


void find_track(char search_for[])
{
    int i;
    for(i = 0; i < 5; i++) {
        if (strstr(tracks[i], search_for))
            printf("Track %i: '%s'\n", i, tracks[i]);
    }
}


int main()
{
    char search_for[80];
    printf("Search for: ");
    fgets(search_for, 80, stdin);
    find_track(search_for);
    return 0;
}

我检查了双倍,三倍和四倍.此代码与本书中的示例完全相同 …

我是NoSQL和的新手Amazon Dynamo DB。我试图首先username从DynamoDB UserMaster表中检索用户。

我有一个UserMaster包含 5 个属性（username、correct-hash、email、lastLogin、role）的表，每种类型String都有一个对应的UsermasterBean映射到该表UserMaster。UserMaster表的分区键（Hashkey）是 username并且Sort key(Range Key)是correct-hash

用户主控Bean

    @DynamoDBTable(tableName = "UserMaster")
    public class UsermasterBean {
    
    private String username;
    private String correctHash;
    private String email;
    private String lastLogin;
    private String role;
    
    @DynamoDBHashKey(attributeName = "username")
    @DynamoDBAttribute(attributeName = "username")
    public String getUsername() {
        return username;
    }
    
    @DynamoDBRangeKey(attributeName = …

我正在尝试下面的代码将字符串转换为float和double但得到不同的结果.

码:

 System.out.println(Float.parseFloat("120059389"));
 System.out.println(Double.parseDouble("120059389"));

输出:

1.20059392E8
1.20059389E8

有人可以解释一下为什么我在float和double中解析字符串会得到不同的结果吗？float和double的范围是多少？

I'm trying to deploy a web app to tomcat using ANT but I ran into this error (the app compiles fine in a simple ant task. The issue occurs when Tomcat is restarted):

Stacktrace:

Caused by: java.lang.ClassNotFoundException: org.slf4j.Logger
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1714)
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1559)
    ... 24 more

I red a couple of answers around here which state that besides slf4j an implementation such as log4j. This is an excerpt of the build.xml file:

<pathelement location="${slf4j-api-1.7.2.jar}"/>
<pathelement location="${log4j.jar}"/>

These are path elements …

我明白那个 ？可以用来使修饰符只匹配第一次出现并防止贪婪,但也许我误解了它应该如何工作.如果字符串是:

one two three four four four five six

......我想抓住three.我一直在努力:

^one two (.*)(four)+?.*$

......但这给了我three four four.我究竟做错了什么？我试着??和.?公正(four)?,但它不工作.

我使用JSON简单来解析JSON,并NoClassDefFoundError在尝试创建JSONParser对象时得到.

import org.json.simple.JSONObject;
import org.json.simple.JSONArray;
import org.json.simple.parser.JSONParser;
...
JSONParser parser = new JSONParser();

我用命令编译程序:

javac MyProgram.java -cp json-simple-1.1.1.jar

它编译得很好.但是当我用这个命令执行程序时:

java MyProgram

我明白了 NoClassDefFoundError

我究竟做错了什么？

编辑:
完整错误:

Exception in thread "main" java.lang.NoClassDefFoundError: org/json/simple/parser/JSONParser
        at getNotesFromNoter.sendPost(getNotesFromNoter.java:53)
        at getNotesFromNoter.main(getNotesFromNoter.java:14)
Caused by: java.lang.ClassNotFoundException: org.json.simple.parser.JSONParser
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        ... 2 more