使用策略文件读取服务器端文件

WeatherApplet.policy
grant
{ permission java.net.SocketPermission
"iwin.nws.noaa.gov:80", "connect";
};



WeatherApplet.java
import java.net.*;
import java.io.*;
import java.util.*;
import java.awt.*;
import java.awt.event.*;
import java.applet.*;
import javax.swing.*;

public class WeatherApplet extends JApplet
implements ActionListener
{ public void init()
{ Container contentPane = getContentPane();
contentPane.setLayout(new BorderLayout());

JPanel listPanel = new JPanel();
state = makeList(states, 6, listPanel);
report = makeList(reports, 6, listPanel);
contentPane.add(listPanel, "North");


weather = new JTextArea(20, 80);
weather.setFont(new Font("Courier", Font.PLAIN, 12));


contentPane.add(new JScrollPane(weather), "Center");
JPanel buttonPanel = new JPanel();
JButton reportButton = new JButton("Get report");
reportButton.addActionListener(this);
buttonPanel.add(reportButton);
contentPane.add(buttonPanel, "South");
}

public JList makeList(final String[][] items, int visibleRows,
Container parent)
{ JList list = new JList(new AbstractListModel()
{ public Object getElementAt(int i)
{ return items[i][0];
}

public int getSize()
{ return items.length;
}
});
list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
list.setVisibleRowCount(visibleRows);
parent.add(new JScrollPane(list));
return list;
}


public String getItem(JList list, String[][] items)
{ return items[list.getSelectedIndex()][1];
}

public void actionPerformed(ActionEvent evt)
{ weather.setText("");
getWeather(getItem(state, states), getItem(report, reports));
}

public void getWeather(String state, String report)
{ String r = new String();
try
{ String queryBase = getParameter("queryBase");
String query
= queryBase + state + "/" + report + ".html";

URL url = new URL(query);
BufferedReader in = new BufferedReader(new
InputStreamReader(url.openStream()));

String line;
while ((line = in.readLine()) != null)
weather.append(removeTags(line) + " ");
}
catch(IOException e)
{ showStatus("Error " + e);
}
}

public static String removeTags(String s)
{ while (true)
{ int lb = s.indexOf("<");
if (lb < 0) return s;
int rb = s.indexOf(">", lb);
if (rb < 0) return s;
s = s.substring(0, lb) + " " + s.substring(rb + 1);
}
}

private JTextArea weather;
private JList state;
private JList report;

private String[][] states =
{ { "Alabama", "al" },
{ "Alaska", "ak" },
{ "Arizona", "az" },
{ "Arkansas", "ar" },
{ "California", "ca" },
{ "Colorado", "co" },
{ "Connecticut", "ct" },
{ "Delaware", "de" },
{ "Florida", "fl" },
{ "Georgia", "ga" },
{ "Hawaii", "hi" },
{ "Idaho", "id" },
{ "Illinois", "il" },
{ "Indiana", "in" },
{ "Iowa", "ia" },
{ "Kansas", "ks" },
{ "Kentucky", "ky" },
{ "Lousisiana", "la" },
{ "Maine", "me" },
{ "Maryland", "md" },
{ "Massachusetts", "ma" },
{ "Michigan", "mi" },
{ "Minnesota", "mn" },
{ "Mississippi", "ms" },
{ "Missouri", "mo" },
{ "Montana", "mt" },
{ "Nebraska", "ne" },
{ "Nevada", "nv" },
{ "New Hampshire", "nh" },
{ "New Jersey", "nj" },
{ "New Mexico", "nm" },
{ "New York", "ny" },
{ "North Carolina", "nc" },
{ "North Dakota", "nd" },
{ "Ohio", "oh" },
{ "Oklahoma", "ok" },
{ "Oregon", "or" },
{ "Pennsylvania", "pa" },
{ "Rhode Island", "ri" },
{ "South Carolina", "sc" },
{ "South Dakota", "sd" },
{ "Tennessee", "tn" },
{ "Texas", "tx" },
{ "Utah", "ut" },
{ "Vermont", "vt" },
{ "Virginia", "va" },
{ "Washington", "wa" },
{ "West Virginia", "wv" },
{ "Wisconsin", "wi" },
{ "Wyoming", "wy" }
};

private String[][] reports =
{ { "Hourly (State Weather Roundup)", "hourly" },
{ "State Forecast", "state" },
{ "Zone Forecast", "zone" },
{ "Short Term (NOWCASTS)", "shortterm" },
{ "Forecast Discussion", "discussion" },
{ "Weather Summary", "summary" },
{ "Public Information", "public" },
{ "Climate Data", "climate" },
{ "Hydrological Data", "hydro" },
{ "Watches", "watches" },
{ "Special Weather Statements", "special" },
{ "Warnings and Advisories", "allwarnings" }
};
}



WeatherApplet.html









CODE="WeatherApplet.class" WIDTH="600" HEIGHT="400">

---

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