檔案操作是網站編程的重要內容之一，asp關於檔案操作討論的已經很多了，讓我們來看看jsp中是如何?的。
這裡用到了兩個檔案，一個jsp檔案一個javabean檔案，通過jsp中調用javabean可以輕鬆寫文字檔，注意請建立一個test目錄到web根目錄下，程式將會建立一個afile.txt檔案，javabean檔案編譯後將class檔案放到對應的class目錄下(tomcat環境)。
有了在jsp下讀取和寫入檔案的方法，要做出一個簡單的計數器來相信不是一件困難的事情了，大家可以嘗試一下:)
WriteOver.Jsp
<html>
<head>
<title>寫一個檔案</title>
</head>
<body bgcolor="#000000">
<%--建立javabean並設定屬性 --%>
<jsp:useBean id="writer" class="WriteOver" scope="request">
<jsp:setProperty name="writer" property="path" value="/test/afile.txt" />
<jsp:setProperty name="writer" property="something" value="初始化somthing屬性" />
</jsp:useBean>
<h3>寫一個檔案</h3>
<p>
<%--設定要寫入的字串 --%>
<% writer.setSomething("寫點東西到檔案"); %>
<%--讀取上面設定的字串 --%>
<% out.print(writer.getSomething()); %>
<%--調用writer的writeSomething方法寫入檔案並返回成功或者出錯資訊 --%>
<% out.print(writer.writeSomething()); %>
</p>
</body>
</html>
//WriteOver.java javabean檔案
import java.io.*;
public class WriteOver {
private String path; //檔案路徑
private String something;//寫入的字串
//初始化
public WriteOver() {
path = null;
something = "預設文字";
}
//設定檔案路徑
public void setPath(String apath) {
path = apath;
}
//得到檔案路徑
public String getPath() {
return path;
}
//得到字串
public void setSomething(String asomething) {
something = asomething;
}
//設定字串
public String getSomething() {
return something;
}
//寫入字串到檔案中，成功則返回success字串
public String writeSomething() {
try {
File f = new File(path);
PrintWriter out = new PrintWriter(new FileWriter(f));
out.print(this.getSomething() + "
");
out.close();
return "Success.";
} catch (IOException e) {
return e.toString();
}
}
}
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