http断点续传简单实现（java)

/* !e'0jf-
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**SiteFileFetch.java }=hoATs  
*/ ^dnz=FB  
package NetFox; ),]2`w&k  
import java.io.*; r^A#[-VyNP  
import java.net.*; '95E;RV&  
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public class SiteFileFetch extends Thread { N 2"3~  #  
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SiteInfoBean siteInfoBean = null; //文件信息Bean akhL\-d)al  
long[] nStartPos; //开始位置 ,B%fjcn  
long[] nEndPos; //结束位置 E ;!<Z4  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ZjZhz`  
long nFileLength; //文件长度 #t@x6Vt  
boolean bFirst = true; //是否第一次取文件 )J+{oB[>b  
boolean bStop = false; //停止标志 $}nh[@  
File tmpFile; //文件下载的临时信息 S&3X~jD(1  
DataOutputStream output; //输出到文件的输出流 N<06sRg#  
;}WtJ&y=M  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） F@$RV_M  
public SiteFileFetch(SiteInfoBean bean) throws IOException )@,90Vhh  
{ < m enABN4  
siteInfoBean = bean; xIQ/$[&v  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 0TO_1 0D  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); nU&NopD+*G  
if(tmpFile.exists ()) \- =^]]b=  
{ S\9t4Ki_'  
bFirst = false; zr.+'  
read_nPos(); q#99iiG1  
} TF=k(@9J?  
else N^\2 _T  
{ z!s.9  
nStartPos = new long[bean.getNSplitter()]; G#
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nEndPos = new long[bean.getNSplitter()]; d1V^2Hb?  
} E-)VPZ1D  
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} S jVsF1d_  
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public void run() v/R[?H)  
{ Z5G]p4  
//获得文件长度 Ot`LZ"H:  
//分割文件 xF( bS+(o  
//实例FileSplitterFetch \3Dk5cSDk+  
//启动FileSplitterFetch线程 zoZ<)x=;  
//等待子线程返回 C.J`8@a]?  
try{ iq"ob8.  
if(bFirst) rv9B}%e  
{ T'
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nFileLength = getFileSize(); FXP6zHsV  
if(nFileLength == -1) ;V_.[aX  
{ h+,'B&=|_  
System.err.println("File Length is not known!"); 6'xomRpYN  
} 0QMTIAW6h  
else if(nFileLength == -2) /g_9m  
{ I=K!)X$  
System.err.println("File is not access!"); S6v
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} v*E(/}<v  
else D.'h?^kA  
{ qysTjGwa]  
for(int i=0;i<nStartPos.length;i++) w8O" =},  
{ KZ=
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); NS`07#z^  
} !fY7"E{%%  
for(int i=0;i<nEndPos.length-1;i++) YT>KJ  
{ ^Ye\u1n4  
nEndPos = nStartPos[i+1]; #/Ruz'H1>  
} qv[[Q[RK-5  
nEndPos[nEndPos.length-1] = nFileLength; M)&Io6>  
} \(I0wEQo$  
} TZ[Zm  
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//启动子线程 /<);=&[  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; C5xag#Z1  
for(int i=0;i<nStartPos.length;i++) !8sgq{
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{ 
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), u*3NS$vH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), F^QQ0h]2  
nStartPos,nEndPos,i); `vd= ec  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >ys[I0bo  
fileSplitterFetch.start(); 62)d22  
} H~noJIw#
 
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $9 +YNgW>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); *U;'OWE[  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ]hA,LY f  
nEndPos = " + nFileLength); )p<WDiX1!e  
// fileSplitterFetch[nPos.length-1].start(); +
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//等待子线程结束 -(i(02PX
 
//int count = 0; `s|]"'rX  
//是否结束while循环 G O{.9_2  
boolean breakWhile = false; )=J5\3O
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while(!bStop) {o0qUX>[  
{ -'`TL$  
write_nPos(); O:'?n8rWL  
Utility.sleep(500); *)<B0SjT  
breakWhile = true; o!OMm!  
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for(int i=0;i<nStartPos.length;i++) *>NX%by)  
{ n(1')?"mA  
if(!fileSplitterFetch.bDownOver) iDoDwq!l_  
{
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breakWhile = false; J@_ctGv  
break; IvHh4DU3Z  
} POAw M  
} JTU#vq:TY  
if(breakWhile) )w h%|  
break; cc}Key@D  
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//count++; {2&m`Dbm  
//if(count>4) &<y2q/U}  
// siteStop(); 1PH:\0}  
} :#5xA?=* S  
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System.err.println("文件下载结束！"); 6at1bQ$  
} rH8@69,B  
catch(Exception e){e.printStackTrace ();} 0'5/K ,  
} kDvc" ,SD#  
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//获得文件长度 \1"'E@+  
public long getFileSize() g.py+ ZFJ  
{ 1Xu?(2;NF  
int nFileLength = -1; Fd]\txOXj  
try{ fq )vK  
URL url = new URL(siteInfoBean.getSSiteURL()); KRAcnY;u  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); k%s_0 @  
httpConnection.setRequestProperty("User-Agent","NetFox"); %`MQmXgM  
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int responseCode=httpConnection.getResponseCode(); Wj|alH9<  
if(responseCode>=400) ncu`vYI.  
{ {8$=[;  
processErrorCode(responseCode); {S/yL[S.  
return -2; //-2 represent access is error "@R>J?Cc+  
} C%d_@*82  
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String sHeader; K 0gI):  
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for(int i=1;;i++) j/=iMq  
{ !+>v[(OzM  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); F+R?a+e  
//Utility.log(in.readLine()); =_$Qtq+h  
sHeader=httpConnection.getHeaderFieldKey(i); j',W 64  
if(sHeader!=null) <,o>Wx*1C  
{ d->|EJP  
if(sHeader.equals("Content-Length")) .2d9?p3Y  
{ X%z }VA  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); V7#v6!7A@  
break; 8
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} R_M?dEtE>  
} 7Q\|=$2  
else >U F  
break; 5T sUQc  
} BA\/
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} COH<Tj  
catch(IOException e){e.printStackTrace ();} " \I4u{zC  
catch(Exception e){e.printStackTrace ();} UOQEk22  
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Utility.log(nFileLength); @`\VBW  
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return nFileLength; 74!oe u.>  
} V_plq6z  
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//保存下载信息（文件指针位置） 8~5cJPi6  
private void write_nPos() C9p"?vX  
{ hiNEJ_f  
try{ f~}H  
output = new DataOutputStream(new FileOutputStream(tmpFile)); gZ5[ C  
output.writeInt(nStartPos.length); aF03a-qw<  
for(int i=0;i<nStartPos.length;i++) 1lv2@QH9  
{ bn |zl!Pq  
// output.writeLong(nPos); apE  
output.writeLong(fileSplitterFetch.nStartPos); 4CGPOc  
output.writeLong(fileSplitterFetch.nEndPos); Z7 E
  
} @?h/B=56  
output.close(); ?%H):r  
} M'_9A  
catch(IOException e){e.printStackTrace ();} l<M'=-Y  
catch(Exception e){e.printStackTrace ();} A*W)bZs.  
} lJ@][;  
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//读取保存的下载信息（文件指针位置） >E*$ E  
private void read_nPos() Ivb4P`{  
{ {rcnM7 S1L  
try{ [s<^&WM/  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); #r3l[bKK  
int nCount = input.readInt(); ! !
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nStartPos = new long[nCount]; :d ~|jS  
nEndPos = new long[nCount]; 6~*9;!th  
for(int i=0;i<nStartPos.length;i++) A&>.74}p  
{ *OQG4aWy  
nStartPos = input.readLong(); s3W@WH^.  
nEndPos = input.readLong(); ([xo9FP;  
} TRsE %  
input.close(); <})'Y~i  
} +iI&c s  
catch(IOException e){e.printStackTrace ();} .L~Nq%g1  
catch(Exception e){e.printStackTrace ();} u[{tb  
} !+:ov'F  
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private void processErrorCode(int nErrorCode) T~b>B`_  
{ t='# |');  
System.err.println("Error Code : " + nErrorCode); 7w3CXY  
} Q:$Zy  
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>CkjUZu]&  
//停止文件下载 `)QCn<  
public void siteStop() Ux+Q  
{ B
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bStop = true; O iFS}p  
for(int i=0;i<nStartPos.length;i++) pJ ?~fp  
fileSplitterFetch.splitterStop(); d[;.r  
}6 K^`!  
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} D\e8,,H  
} mXXt'_"  
//负责部分文件的抓取 #]'r
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**FileSplitterFetch.java /x1MPP>fu
 
*/ w;l<[q?_  
package NetFox; +CI1V>6^  
rm} R>4  
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import java.io.*; }cN@[3v  
import java.net.*; )$,"u4  
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public class FileSplitterFetch extends Thread { %sRUh0AL  
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String sURL; //File URL ,()0'h}n  
long nStartPos; //File Snippet Start Position B7"PIkk;  
long nEndPos; //File Snippet End Position 7h)iu9j  
int nThreadID; //Thread's ID  ;vb8G$  
boolean bDownOver = false; //Downing is over sUYxT>R  
boolean bStop = false; //Stop identical x\Y $+A,P  
FileAccessI fileAccessI = null; //File Access interface TFcT3]R[rL  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException D?Ux[Ozb  
{ XQ*eP?OS{  
this.sURL = sURL; &
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this.nStartPos = nStart; O=9-Qv|  
this.nEndPos = nEnd; TW^/sx  
nThreadID = id; sp*Vqd  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 [ib P%xb  
} LF0sH)e]  
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public void run() 95<EN(oUD  
{ *]i!fzI']  
while(nStartPos < nEndPos && !bStop) \qUKP"dr  
{ 0dh=fcb  
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try{ &[hLzlrg  
URL url = new URL(sURL); iH.$f /)N  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); wR{'y)$  
httpConnection.setRequestProperty("User-Agent","NetFox"); FaBqj1O1  
String sProperty = "bytes="+nStartPos+"-"; A 8 vbQ  
httpConnection.setRequestProperty("RANGE",sProperty); >s`J5I!  
Utility.log(sProperty); &x >B  
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InputStream input = httpConnection.getInputStream(); q{ /3V  
//logResponseHead(httpConnection); C4}*)a  
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byte[] b = new byte[1024]; FEo269Ur  
int nRead; vF?5].T  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >><.3  
{ 7r{83_B  
nStartPos += fileAccessI.write(b,0,nRead); a {ab*tM  
//if(nThreadID == 1) fo4.JyBk  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); X";@T.ZGut  
}
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Utility.log("Thread " + nThreadID + " is over!"); ~y$!48o  
bDownOver = true; r",]Voibd  
//nPos = fileAccessI.write (b,0,nRead); $3,ryXp7  
} F} d  
catch(Exception e){e.printStackTrace ();} .Gcy>Av  
} 7#<c>~   
} vzn{h)D  
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//打印回应的头信息 YJ:3!B>Zo  
public void logResponseHead(HttpURLConnection con) 5 |/9}^T  
{ }KD;
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for(int i=1;;i++) S60IPya  
{ 8J)xzp`*)  
String header=con.getHeaderFieldKey(i); m4:^}O-#  
if(header!=null) GTv#nnC  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); {iG@U=>  
Utility.log(header+" : "+con.getHeaderField(header)); OMk5{-8B  
else VzJ5.mRQ  
break; Il`tNr  
} }qjCTEs}  
} !Oi~:Pp  
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public void splitterStop() _7
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{ ^h&I H|  
bStop = true; aiCn"j  
} pb0E@C/R  
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} A$.fv5${  
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/* S-+M;@'Rl  
**FileAccess.java [_xyl e  
*//文件访问(定位，写) IaFr&  
package NetFox; 0J~Qq]g  
import java.io.*; I?Q+9Rmm`J  
j8 C8X$  
0|D&"/.R#!  
public class FileAccessI implements Serializable{  BGzI  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 nW?R"@Zm  
RandomAccessFile oSavedFile; _{~]/k  
long nPos; >5T_g2pkv  
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public FileAccessI() throws IOException f=J<*h  
{ x?D/.vrOY  
this("",0); [&Hkn5yq  
} N]5m(@h  
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public FileAccessI(String sName,long nPos) throws IOException -Cid3~mX3  
{ ix Z)tNz  
oSavedFile = new RandomAccessFile(sName,"rw"); o/^;@5\  
this.nPos = nPos; +pqM ^3t|y  
oSavedFile.seek(nPos); cjUL
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} `#IcxweA  
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public synchronized int write(byte[] b,int nStart,int nLen) N<z`yV  
{ !F!3Q4  
int n = -1; K'6[J"dB  
try{ 6ew "fCrH!  
oSavedFile.write(b,nStart,nLen); k5+]SG`]]  
n = nLen; TA}UY7v  
} n<V1|X  
catch(IOException e) )"O{D`uX  
{ G@d`F  
e.printStackTrace (); G5]1s  
} & 7QH^  
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return n; |;;!8VO3J  
} M:ai<TZ]  
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} DpL8'Dib  
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/* "2HY5AE  
**SiteInfoBean.java 7S2C/f  
*/ wFlV=!>,  
package NetFox; >mIg@knE  
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public class SiteInfoBean { Go+[uY^  
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private String sSiteURL; //Site's URL m7 XjP2  
private String sFilePath; //Saved File's Path /! ^P)yU,  
private String sFileName; //Saved File's Name QdDtvJLf  
private int nSplitter; //Count of Splited Downloading File
q=Xg*PM,  
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public SiteInfoBean() g_D-(J`IK,  
{//nSplitter的缺省值为5 \K`jCsT  
//default value of nSplitter is 5 P79R~m`  
this("","","",5); %RFYm  
} mCb 9*|  

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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) >C2HC6O3  
{ )W9_qmYd"  
sSiteURL= sURL; FP;":iRL  
sFilePath = sPath; Hhf72IX  
sFileName = sName; @P70W<<  
this.nSplitter = nSpiltter; T]2U fi.  
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} +L6" vkz  
91;HiILgT  
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public String getSSiteURL() 6:RMU  
{ U(3(ZqP  
return sSiteURL; /oDpgOn  
} i_YW;x  
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 [`bZ5*&  
public void setSSiteURL(String value) o_:Qk;t  
{ l4`^!  
sSiteURL = value; <[8@5?&&  
} _sm;HH7'*  
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public String getSFilePath() AgI>
 
{ x)\V lR  
return sFilePath; afy
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} a8NVLD>7}  
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public void setSFilePath(String value) Okoo(dfM
 
{ W2n*bNI  
sFilePath = value; 4zX=3iBt  
} \A
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public String getSFileName() () <`t}FQ  
{ \L %q[  
return sFileName; R%W@~o\p]  
} ,M{Q}:$+4  
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public void setSFileName(String value) ;fkSrdj  
{ 86#-q7aX  
sFileName = value; O*ImLR)i+s  
} y-<$bA[K~  
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public int getNSplitter() 5<^'Cy
 
{ Vl4Z_viNH  
return nSplitter; a0{[P$$  
} hXPocP  
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public void setNSplitter(int nCount) 2aFT<T0  
{ \w3%[+c  
nSplitter = nCount; 2Gm-\o&Td"  
} P6:;Y5e0  
} CJm.K  
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CJv>/#$/F  
/* v7L"`  
**Utility.java /%5_~Jkr,  
*/ 5cgo)/3M@}  
package NetFox; A3z/Bz4]:#  
M5F(<,n;  
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public class Utility { -}E)M}W  
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public Utility() >dyhox2*"  
{ TNJ<!6  
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} Y~:
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//线程睡眠 5dqQws-,?1  
public static void sleep(int nSecond) Q,D0kS P  
{ ]7v81G5E  
try{ r|*:9|y{"/  
Thread.sleep(nSecond); O+p]3u  
} 3R'.}^RN  
catch(Exception e) Ir!2^:]!  
{ 0{-`Th+h  
e.printStackTrace (); {d^Q7A:`  
} K2*1T+?X  
} r@olC7&  
+mivqR~{{  
//日志 kNRyOUy  
public static void log(String sMsg) nrF%wH/5  
{ "|F.'qZrm  
System.err.println(sMsg); 2dXU0095  
} %I_&Ehu  
w
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public static void log(int sMsg) sk~za  
{ = vY]G5y  
System.err.println(sMsg);   YfTd  
} 4Y`! bT`  
} /z/hUa  
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/* V/`#B$6  
**TestMethod.java axWM|Bw<+  
*/ #:]vUQ  
package NetFox; issT{&T  
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public class TestMethod { 8o!  
qRgK_/[]  
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public TestMethod() h |s*i  
{ ///xx/weblogic60b2_win.exe "CIpo/ebL  
try{ oN.Mra]D  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); h{Oz*Bq  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); yfPCGCOW?  
SiteFileFetch fileFetch = new SiteFileFetch(bean); {[l'S  
fileFetch.start(); j'G"ZPw1  
} 29R_n)ne  
catch(Exception e){e.printStackTrace ();} {KW&wsI  
M
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} RH<@c^ S  
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o@qN#Mg?>}  
public static void main(String[] args) 3c1o,2  
{ #gxRTx  
new TestMethod(); F7k4C2r  
} &>d:ewM\  
} ,m #@%fa  
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