Debug:
java.io.FileNotFoundException: E:\temp (拒绝访问。)
at java.io.FileOutputStream.open(Native Method)
at java.io.FileOutputStream.<init>(FileOutputStream.java:179)
at java.io.FileOutputStream.<init>(FileOutputStream.java:131)
at java.io.FileWriter.<init>(FileWriter.java:73)
at TextFTPFileTran.downLoadText(TextFTPFileTran.java:140)
at TextFTPFileTran.actionPerformed(TextFTPFileTran.java:72)
解决办法：
desFile = desFile + "\\" + souFile;//即在目标文件夹下要有完整的名称，包括存储路径和文件名