小编max*_*mus的帖子

我正在尝试谷歌地图api for android,但eclipse不会导入com.google.android.maps.*文件.

资源:

MyMapActivity:

package org.madmax.map;

import android.app.Activity;
import android.os.Bundle;
import com.google.android.maps.*;

public class MyMapActivity extends MapActivity {
    private MapView map;
    private MapController controller;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
    }
}

在我已经声明的清单文件中:

 <uses-library android:name="com.google.android.maps" />

如何导入com.google.android.maps.*文件？

我正在尝试使用xpath.

这是我用于实验的xml:

<moves>
    <roll player="1">6</roll>
    <piece nr="1" player="1" field="1"/>
    <roll player="2">4</roll>
    <roll player="2">6</roll>
    <piece nr="5" player="2" field="11"/>
    <roll player="1">4</roll>
    <piece nr="1" player="1" field="5"/>
    <roll player="2">6</roll>
    <piece nr="5" player="2" field="17"/>
    <roll player="1">6</roll>
    <piece nr="2" player="1" field="1"/>
    <roll player="2">6</roll>
    <piece nr="6" player="2" field="11"/>
</moves>

那么如何在xpath中实现if else呢？

就像第二个动作来自玩家一,然后做f.ex:给它回来......

更新1:

好的,这就是我的意思:

boolean(/game/moves/roll[2]/@player=1

如果第二个元素是玩家1,那么这会让我回来,所以现在我想添加一个其他路径,如果它会是？那么如何添加呢？

我想将MD5哈希变成一个字符串:

public String MD5ToString(String plain) {
    try {
        MessageDigest md = MessageDigest.getInstance("MD5");
        md.reset();
        md.update(plain.getBytes());
        byte[] digest = md.digest();
        BigInteger bigInt = new BigInteger(1,digest);
        String hashtext = bigInt.toString(16);
        // Now we need to zero pad it if you actually want the full 32 chars.
        while(hashtext.length() < 32 ){
            hashtext = "0"+hashtext;
        }
        return plain;
    } catch (Exception e) {
        System.out.println("Cannot encrypt String to Hash");
        e.printStackTrace();
    }
    return null;
}

但是我刚刚拿回Md5？什么是ms错误？

更新:

我将返回类型更改为hashtext,但是当我想将哈希转换为字符串时我只是得到另一个返回:

String: test
Hash: 098f6bcd4621d373cade4e832627b4f6
String: fb469d7ef430b0baf0cab6c436e70375

我通过delete sql语句获得了Integrity约束违规.发生这种情况是因为表的id在另一个表中用作主键.但是我想通过使用CASCADE删除它们.

但是什么是hsqldb的正确语法？

我有503数据点,我想削减最后250来获得253.

我试过了cut,但这些功能只能让我回来......

我怎么能在R？

我有一个名为Produkt的表,在这个表中有几个名为test的产品.

当我想做那个代码时:

public Produkt findByName(String name) throws SQLException{
    log.error("Enter findByName with parameters: " + name);
    PreparedStatement ps;
    ResultSet rs = null;
    String query = "SELECT * FROM Produkt WHERE name=" + name;
    ps=hsqlmanager.getConnection().prepareStatement(query);
    rs = ps.executeQuery();
    ps.close();
    if(rs.next()) return(new Produkt(rs));
    else return(null);
}

它总是给我一个SQL错误:

Exception in thread "main" java.sql.SQLSyntaxErrorException: user
lacks privilege or object not found: TEST   at
org.hsqldb.jdbc.Util.sqlException(Unknown Source)   at
org.hsqldb.jdbc.Util.sqlException(Unknown Source)   at
org.hsqldb.jdbc.JDBCPreparedStatement.<init>(Unknown Source)    at
org.hsqldb.jdbc.JDBCConnection.prepareStatement(Unknown Source)     at
dao.DAOProdukt.findByName(DAOProdukt.java:157)  at
dao.test_produkt_dao.main(test_produkt_dao.java:23)

为什么？我谴责你的答案!

更新:

为什么PS使用不当？请告诉我,以便我可以从中学到什么？

我正在编写一个java套接字,其中服务器运行,客户端连接到服务器,服务器可以从客户端命令行读取.

首先,我想连接到服务器,这里是代码:

public class Server{
    public static void main(String[] args) throws IOException {

        ServerSocket serverSocket = null;

        try {
            serverSocket = new ServerSocket(10000);
        } catch (IOException e) {
            System.err.println("Could not listen on port: 4444.");
            e.printStackTrace();
            System.exit(1);
        }

        Socket clientSocket = null;
        try {
            clientSocket = serverSocket.accept();
        } catch (IOException e) {
            System.err.println("Accept failed.");
            System.exit(1);
        }

        PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true);
        BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
        String inputLine, outputLine;

        out.close();
        in.close();
        clientSocket.close();
        serverSocket.close();
    }

}

这是我的客户:

public class Client …

我很难将*.xls文件读入R:

我做了以下事情:

我将我的工作目录设置为*.xls文件,然后:

> library(gdata)                   # load the gdata package 
> mydata = read.xls("comprice.xls", sheet=1, verbose=FALSE) 
Mistake in findPerl(verbose = verbose) :  perl executable not found. Use perl= argument to specify the correct path. mistake in file.exists(tfn) : unknown 'file' argument

但是,我的路径是正确的,有文件!怎么了？

UPDATE

我已经安装了它,但是现在我得到了:异常:找不到函数"read.xls"...

我正在尝试实现jsf + primefaces + twitter bootstrap:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
    xmlns:h="http://java.sun.com/jsf/html"
    xmlns:f="http://java.sun.com/jsf/core"
    xmlns:ui="http://java.sun.com/jsf/facelets"
    xmlns:p="http://primefaces.prime.com.tr/ui"
>
<h:head>
    <title>IMPORT JSF SET ATTRIBUTES</title>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta name="description" content="" />
    <meta name="author" content="" />

    <!-- Le styles -->
    <h:outputStylesheet name="css/bootstrap.css" />
    <h:outputStylesheet name="css/bootstrap.min.css" />
    <h:outputStylesheet name="css/override.css" />

    <!-- Le HTML5 shim, for IE6-8 support of HTML5 elements -->
    <!--[if lt IE 9]>
<script src="http://html5shim.googlecode.com/svn/trunk/html5.js"></script>
<![endif]-->

    <!-- Le fav and touch …

我为我的CRUD程序编写了一个gui,当我想运行它时,我得到:

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at gui.guimain$1.run(guimain.java:477)
    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:597)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)

这是NPE来自的代码:

public static void main(String[] args){
    javax.swing.SwingUtilities.invokeLater(new Runnable() {
        public void run(){
                maingui.showStart();// thats the line with the Exception
        }
    });
}

那就是方法showStart():

public void showStart(){
    mainFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    mainFrame.getContentPane().removeAll();
    tabstructure.removeAll();
    Produkt filter=new Produkt();

    JPanel P=new JPanel();
    P=Produktgui(0, filter);
    JPanel R=new JPanel();
    R=Billgui(0);
    JPanel nR=new JPanel();
    nR=Billgui(0);

    tabstructure.addTab("e", P);
    tabstructure.addTab("Bills", R);
    tabstructure.addTab("Pay bill", nR);
    mainFrame.getContentPane().add(tabstructure);
    mainFrame.validate();
    mainFrame.repaint();
    mainFrame.pack(); …