用JavaBean实现文件上载(二)上载文件

上载文件 　　众所周知，JavaBean是Java平台的软件组件，下面要实现的上载功能就是用JavaBean实现，所以它可以方便地应用到任何需要文件上载功能的应用之中。 代码清单如下： package com.brainysoftware.web; import javax.servlet.http.HttpServletRequest; import javax.servlet.ServletInputStream; import java.util.Dictionary; import java.util.Hashtable; import java.io.PrintWriter; import java.io.BufferedWriter; import java.io.FileWriter; import java.io.IOException; public class FileUploadBean { private String savePath, filepath, filename, contentType; private Dictionary fields; public String getFilename() { return filename; } public String getFilepath() { return filepath; } public void setSavePath(String savePath) { this.savePath = savePath; } public String getContentType() { return contentType; } public String getFieldValue(String fieldName) { if (fields == null || fieldName == null) return null; return (String) fields.get(fieldName); } private void setFilename(String s) { if (s==null) return; int pos = s.indexOf("filename=\""); if (pos != -1) { filepath = s.substring(pos+10, s.length()-1); // Windows浏览器发送完整的文件路径和名字 // 但Linux/Unix和Mac浏览器只发送文件名字 pos = filepath.lastIndexOf("\\"); if (pos != -1) filename = filepath.substring(pos + 1); else filename = filepath; } } private void setContentType(String s) { if (s==null) return; int pos = s.indexOf(": "); if (pos != -1) contentType = s.substring(pos+2, s.length()); } public void doUpload(HttpServletRequest request) throws IOException { ServletInputStream in = request.getInputStream(); byte[] line = new byte[128]; int i = in.readLine(line, 0, 128); if (i < 3) return; int boundaryLength = i - 2; String boundary = new String(line, 0, boundaryLength); //-2丢弃换行字符 fields = new Hashtable(); while (i != -1) { String newLine = new String(line, 0, i); if (newLine.startsWith("Content-Disposition: form-data; name=\"")) { if (newLine.indexOf("filename=\"") != -1) { setFilename(new String(line, 0, i-2)); if (filename==null) return; //文件内容 i = in.readLine(line, 0, 128); setContentType(new String(line, 0, i-2)); i = in.readLine(line, 0, 128); //空行 i = in.readLine(line, 0, 128); newLine = new String(line, 0, i); PrintWriter pw = new PrintWriter(new BufferedWriter(new FileWriter((savePath==null? "" : savePath) + filename))); while (i != -1 && !newLine.startsWith(boundary)) { // 文件内容的后一行包含换行字符 // 因此我们必须检查当前行是否是 // 后一行 i = in.readLine(line, 0, 128); if ((i==boundaryLength+2 || i==boundaryLength+4) && (new String(line, 0, i).startsWith(boundary))) pw.print(newLine.substring(0, newLine.length()-2)); else pw.print(newLine); newLine = new String(line, 0, i); } pw.close(); } else { // 普通表单输入元素 // 获取输入元素名字 int pos = newLine.indexOf("name=\""); String fieldName = newLine.substring(pos+6, newLine.length()-3); i = in.readLine(line, 0, 128); i = in.readLine(line, 0, 128); newLine = new String(line, 0, i); StringBuffer fieldValue = new StringBuffer(128); while (i != -1 && !newLine.startsWith(boundary)) { // 后一行包含换行字符 // 因此我们必须检查当前行是否是后一行 i = in.readLine(line, 0, 128); if ((i==boundaryLength+2 || i==boundaryLength+4) && (new String(line, 0, i).startsWith(boundary))) fieldValue.append(newLine.substring(0, newLine.length()-2)); else fieldValue.append(newLine); newLine = new String(line, 0, i); } fields.put(fieldName, fieldValue.toString()); } } i = in.readLine(line, 0, 128); } } } 　　代码的行是包声明，如果你不想让该类从属于任何包，可以删除这行代码。接下来的几行代码声明了该JavaBean所要引用的各个类和接口。 　　FileUploadBean类有5个私有的属性（域），6个公用的方法，2个私有的方法。