http断点续传简单实现（java)

/* ue$\i=jw  
**SiteFileFetch.java pWB)N7x&  
*/ _'dsEF  
package NetFox; }$;T.[ ~  
import java.io.*; ^;$f-e  
import java.net.*; VzMoWD;  
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public class SiteFileFetch extends Thread { ~^IS{
1  
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SiteInfoBean siteInfoBean = null; //文件信息Bean gNzQ"W=  
long[] nStartPos; //开始位置 6lq7zi}'w  
long[] nEndPos; //结束位置 M>0=A  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 NJ7N*  
long nFileLength; //文件长度 7Z"mVh}  
boolean bFirst = true; //是否第一次取文件 wI}5[m  
boolean bStop = false; //停止标志 ZsUxO%jP  
File tmpFile; //文件下载的临时信息 ~|pVz/s|G  
DataOutputStream output; //输出到文件的输出流 GOa
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） l0u6nGkh  
public SiteFileFetch(SiteInfoBean bean) throws IOException F1)Q#ThF\  
{ ^,b*.6t  
siteInfoBean = bean; l@<^V N@  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); B.K"1o  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); OcMd'fwO  
if(tmpFile.exists ()) Yk:fV&]  
{ )"jG)c^1*  
bFirst = false; 9ToM5oQ  
read_nPos(); 7|T5N[3?l,  
} .?_wcp=  
else |VlAt#E  
{ Rmn|"ZK  
nStartPos = new long[bean.getNSplitter()]; zV4%F"-  
nEndPos = new long[bean.getNSplitter()]; %7O`]ik:  
} {mw,U[C  
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} PFG):i-?  
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public void run() }o=R7n%  
{ X5qU>'?`  
//获得文件长度 EFf<|v  
//分割文件 &EXql']  
//实例FileSplitterFetch \@['V   
//启动FileSplitterFetch线程 "
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//等待子线程返回 p4W->AVv$  
try{ 68Wm=j.m  
if(bFirst) ~{Tus.jk  
{ 2[9hl@=%  
nFileLength = getFileSize(); idPkJf/  
if(nFileLength == -1) zBB4lC{q  
{ y= cBpC  
System.err.println("File Length is not known!"); 05DK-Wh?  
} }N2T/U  
else if(nFileLength == -2) C n\'sb{  
{ -q(,}/Xf  
System.err.println("File is not access!"); A<9ZX=DAjw  
} H=Yl @  
else OjE wJ$$  
{ ;r^8In@6  
for(int i=0;i<nStartPos.length;i++) 3r+v
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{ H]UM2.  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 4zpprh+`K  
} I@+dE V`Lf  
for(int i=0;i<nEndPos.length-1;i++) k-Jj k3  
{ L;fhJ~r  
nEndPos = nStartPos[i+1]; aMZ6C <N  
} DD"]as"#  
nEndPos[nEndPos.length-1] = nFileLength; D gY2:&0  
} 2ztP'  
} G5"UhnOD'  
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//启动子线程 ,U]
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 7AV!v`  
for(int i=0;i<nStartPos.length;i++) 6}n_r}kNR  
{ f/*Xw{s#  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(),  #XQEfa  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ysGK5kFz  
nStartPos,nEndPos,i); 4FGcCE3  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~-A5h(  
fileSplitterFetch.start(); >e=tem~/
 
} ;[ pyKh  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), p8%x@%k  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); xo6-Y=c8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", jGb+bN5U7  
nEndPos = " + nFileLength); _?Rprmjx}  
// fileSplitterFetch[nPos.length-1].start(); Jq<&`6hn  
_j}|R(s*+V  
-PBm@}*  
//等待子线程结束 a7%5Qg9B;  
//int count = 0; \P
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//是否结束while循环 deQ0)A 4g  
boolean breakWhile = false; )
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while(!bStop) 52C>f6w  
{ +Z/*=;  
write_nPos(); P"XF|*^U  
Utility.sleep(500); R',Q)<  
breakWhile = true; )_,*2|b  
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for(int i=0;i<nStartPos.length;i++) pTprU)sa7  
{ Kxn/@@z>u  
if(!fileSplitterFetch.bDownOver) ZMt9'w;  
{ PL@hsZty~c  
breakWhile = false; !)?n n3  
break; K``MS  
} Cf91#%:cN  
} =$X5O&E3'  
if(breakWhile) Oq7M1|{  
break; 58DkVQ6  
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//count++; MT[V1I{LV  
//if(count>4) P6u9Ngay  
// siteStop(); -=H*(M  
} )^qM%k8  
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System.err.println("文件下载结束！"); IlVz 5#R  
} MCZTeYnx  
catch(Exception e){e.printStackTrace ();} E2 Q[  
} 6}6;%{p"Gu  
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//获得文件长度 qjFz}6  
public long getFileSize() N7Kq$G2O  
{ V7U&8UPb  
int nFileLength = -1; >v7fR<(%s  
try{ V7[6jWgH  
URL url = new URL(siteInfoBean.getSSiteURL()); 9utiev~
3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); = NHuj.  
httpConnection.setRequestProperty("User-Agent","NetFox"); Jr$,w7tQn@  
}TY}sr  
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int responseCode=httpConnection.getResponseCode(); *1"xvle  
if(responseCode>=400) gHdNqOy c  
{ #?\$*@O  
processErrorCode(responseCode); H
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return -2; //-2 represent access is error `Fnl<C<  
} B>Tfyo  
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String sHeader; @ x_.  
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for(int i=1;;i++) w^OV;gp  
{ 8,B?!%FP  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Fa<>2KkOr  
//Utility.log(in.readLine()); i[_(0P+Da  
sHeader=httpConnection.getHeaderFieldKey(i); Q6blX
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if(sHeader!=null) }<R,)ZV^G  
{ [Jv0^"]  
if(sHeader.equals("Content-Length")) .c__<I<G<  
{ mN^w?R41m  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); URU,&gy=  
break; ,;;7+|`  
} \ #<.&`8B  
} sZe$?k|  
else KaVNRS  
break; s?Lx\?T  
} b-?wJSf|  
} paKur%2u  
catch(IOException e){e.printStackTrace ();} & -r^Q  
catch(Exception e){e.printStackTrace ();} LLyw9y1  
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Utility.log(nFileLength); ~8 >Tb  
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return nFileLength; CD^C}MB  
} WX"iDz.  
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//保存下载信息（文件指针位置） 7Qdf#DG  
private void write_nPos() ,+w9_Gy2H  
{ Z9 z!YaOL  
try{ \c')9g@  
output = new DataOutputStream(new FileOutputStream(tmpFile)); o<h2]TN  
output.writeInt(nStartPos.length); x[?N[>uw  
for(int i=0;i<nStartPos.length;i++) k1lo{jw`  
{ SjosbdD  
// output.writeLong(nPos); (vX) <Z !  
output.writeLong(fileSplitterFetch.nStartPos); ;X_bDiG$  
output.writeLong(fileSplitterFetch.nEndPos); oW}nr<G{
<  
} J`6
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output.close(); o*MiKgQ&  
} .7K)'  
catch(IOException e){e.printStackTrace ();} 5)5$h]Nz>  
catch(Exception e){e.printStackTrace ();} @h&:xA56  
} Ky0}phGRu  
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//读取保存的下载信息（文件指针位置） C/$bgK[ev  
private void read_nPos() "D\>oFu  
{ *S xDwN  
try{ !hs33@*u~  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); $e~MKLd  
int nCount = input.readInt(); ?^whK<"]  
nStartPos = new long[nCount]; ` 0$i^,}  
nEndPos = new long[nCount]; U[0x\~[$K  
for(int i=0;i<nStartPos.length;i++) bO i-QD  
{ {MRXKnm;e  
nStartPos = input.readLong(); gt(^9t;  
nEndPos = input.readLong(); mEm=SpO[$o  
} <ni_7
8  
input.close(); T_)g/,5>  
} 57fl<IM  
catch(IOException e){e.printStackTrace ();} iQJa6QF&:  
catch(Exception e){e.printStackTrace ();} $:?Dyu(Il  
} ZveNe~D7C  
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private void processErrorCode(int nErrorCode) S$O5jX 0  
{ 2tb+3K1  
System.err.println("Error Code : " + nErrorCode); "ejsz&n  
} {Gr"lOi*@  
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//停止文件下载 Z0/$XS9|h;  
public void siteStop() 6b7c9n Z  
{ PNz]L  
bStop = true; s{Og3qUy  
for(int i=0;i<nStartPos.length;i++) y6dQ4Whv&  
fileSplitterFetch.splitterStop(); {Rdh4ZKh  
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} $bDaZGy  
}  Y(  
//负责部分文件的抓取 A<] $[2qPj  
**FileSplitterFetch.java bv;.6C(T<  
*/ sf0\#Q  
package NetFox; hx*4xF  
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import java.io.*; 8(Q|
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import java.net.*; K.=5p/^a
 
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public class FileSplitterFetch extends Thread { i)]f0F  
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String sURL; //File URL aX~Jk >a0  
long nStartPos; //File Snippet Start Position Lu~E5 ,  
long nEndPos; //File Snippet End Position lUaJC'~p  
int nThreadID; //Thread's ID gAh#H ?MM  
boolean bDownOver = false; //Downing is over ^D
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boolean bStop = false; //Stop identical Uqz.Q\A  
FileAccessI fileAccessI = null; //File Access interface @tJ4^<`P{  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException blWtC/!Aq;  
{ ,N_/J4Us  
this.sURL = sURL; ?S'aA
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this.nStartPos = nStart; Vo6+|ztk|  
this.nEndPos = nEnd; *T#^|<.XG  
nThreadID = id; ?K;l 5$?%  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 F\hVunPVx  
} pH2/."zE<  
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public void run() -$kIVh  
{ pGfGGY>i%  
while(nStartPos < nEndPos && !bStop) gTgoS:M"_O  
{ i6A9|G$H
 
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try{ $Mj\ 3  
URL url = new URL(sURL); V%)Tu{L  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *7-rm  
httpConnection.setRequestProperty("User-Agent","NetFox"); ).IyjHY  
String sProperty = "bytes="+nStartPos+"-"; }JWkV1  
httpConnection.setRequestProperty("RANGE",sProperty); *`|xa@1v`  
Utility.log(sProperty); ;c)( 'k<  
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InputStream input = httpConnection.getInputStream(); +Z2XP76(4A  
//logResponseHead(httpConnection); Qclq^|O0  
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byte[] b = new byte[1024]; w~'}uh  
int nRead; f1v4h[)-
  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) |IV7g*J89  
{ W8$0y2  
nStartPos += fileAccessI.write(b,0,nRead); t$~'$kM)<  
//if(nThreadID == 1) oPF]]Imu  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); GB^`A  
} `'^o45  
"&/2@

 
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Utility.log("Thread " + nThreadID + " is over!"); i9De+3VqKK  
bDownOver = true; JB].ht  
//nPos = fileAccessI.write (b,0,nRead); [FrLxU  
} *!JB^5(H  
catch(Exception e){e.printStackTrace ();} uDXV@;6<  
} QRK\74'uY  
} enZZ+|h  
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//打印回应的头信息 <qpzs@  
public void logResponseHead(HttpURLConnection con) O
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{ 1%*\*z  
for(int i=1;;i++) PZJ9f8V  
{ __Ksn^I  
String header=con.getHeaderFieldKey(i);
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if(header!=null) (AtyM?*  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); mB"I(>q*M  
Utility.log(header+" : "+con.getHeaderField(header)); 7L6L{~8 W  
else Fz,jnV9=j  
break; Y1I)w^}:  
} _fu <`|kc  
} #"rK1Z  
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public void splitterStop() (g/A uL  
{ isd-b]@:Lc  
bStop = true; [%^sl>,7  
} 1S!}su,uH  
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} ?YS>_MN  
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/* -ycYQ~
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**FileAccess.java o}114X4q;  
*//文件访问(定位，写) QJ4$) Fr(  
package NetFox; "QNQ00[T`>  
import java.io.*; Vez8~r3  
 jK]1X8  
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public class FileAccessI implements Serializable{ =dDPQZEin  
4k@n5JNa  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 aMhVO(+FW  
RandomAccessFile oSavedFile; wCNn/%C  
long nPos; %eg+.  
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public FileAccessI() throws IOException }rfikm  
{ w=WF$)ZU  
this("",0); |*NZ^6`@  
} Lo!hyQ)  
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public FileAccessI(String sName,long nPos) throws IOException EwN{|34C  
{ 8(\}\4
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oSavedFile = new RandomAccessFile(sName,"rw"); Mt-r`W3 q  
this.nPos = nPos; MmjZq  
oSavedFile.seek(nPos); WSH[*jMA  
} vnvpb! @Q  
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public synchronized int write(byte[] b,int nStart,int nLen) _Pqq*  
{ ]A=\P,D  
int n = -1; r9_ ON|  
try{ <N=k&\  
oSavedFile.write(b,nStart,nLen); )dhR&@r*w  
n = nLen; H u;"TG  
} 5U475&  
catch(IOException e) )DXt_leLg  
{ S"h;u=5it  
e.printStackTrace (); xyGwYv>*KO  
} AuXUD9-  
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return n; uxU-N  
} }Kgi!$<aQx  
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} bu _ @>`S  
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/* .pUB.l$)  
**SiteInfoBean.java h(/? 81:  
*/ AfTm#-R  
package NetFox; M?h{'$T  
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public class SiteInfoBean { |:R\j0t  
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private String sSiteURL; //Site's URL L[2qCxB'^  
private String sFilePath; //Saved File's Path I_ZJnu<  
private String sFileName; //Saved File's Name &}p\&4  
private int nSplitter; //Count of Splited Downloading File {S=<(A@  
vMp=\U-~^  
,H7_eVLWR  
public SiteInfoBean() "mJo<i}  
{//nSplitter的缺省值为5 0vqH-)}  
//default value of nSplitter is 5 ElW\;C:K*  
this("","","",5); < c^'$  
} FFw(`[A_  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) zq</(5H  
{ \XB,)XDB  
sSiteURL= sURL; R@3HlGuRKw  
sFilePath = sPath; v"1&xe^4  
sFileName = sName; XE2Un1i}j1  
this.nSplitter = nSpiltter; eV?%3h.   
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} QIkF
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vb~%u;zrC@  
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public String getSSiteURL() }SSg>.48w  
{ Wm
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return sSiteURL; rB+ (  
} En&7e  
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public void setSSiteURL(String value) hFA |(l6  
{ D/=05E%[81  
sSiteURL = value; oqwW  
} ti+e U$  
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public String getSFilePath() -4QZ/*  
{ X{#^O/  
return sFilePath; ODu/B'*  
} PNAvT$0LaZ  
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public void setSFilePath(String value) 3|$?T|#B  
{ v>K|hH  
sFilePath = value; ? /!Fv/  
} zk$h71<{.  
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public String getSFileName() i-0 :Fs  
{ 2f:hz  
return sFileName; ]Qe~|9I  
} Z%o.kd"  
> U3>I^Y  
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public void setSFileName(String value) 3SWDPy  
{ MkVv5C  
sFileName = value; Q']'
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} rIPg,4y*S!  
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N
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public int getNSplitter() 0 F8xS8vK+  
{ !(bYh`Uy  
return nSplitter; n\Is}Czl  
} u^C\aujg  
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Usht\<{  
public void setNSplitter(int nCount) :D}?H@(69  
{ P `<TO   
nSplitter = nCount; ST#)Fl  
} b^[>\s'  
}
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/* uR")@Tc  
**Utility.java dh}"uM}a  
*/ jY9tq[~/  
package NetFox; ,f>^q"  
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public class Utility { ,EH-Sf2Cb  
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public Utility() ~&0lWa  
{ +7"UF) ~k  
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} Rp zuSh  
fm%4ab30T  
//线程睡眠 T?n[1%K  
public static void sleep(int nSecond) ?fU{?nI}>p  
{ 4`CO>Q  
try{ UWCm:eRQ  
Thread.sleep(nSecond); I`{=[.c  
} fb8xs<  
catch(Exception e) >hnhV6ss  
{ @ bvWqMa  
e.printStackTrace (); m&*0<N  
} }/xdHt  
} ^SUo-N''  
&@&^k$du8q  
//日志 0,LUi*10  
public static void log(String sMsg) IxlPpS9Wx  
{ F0'o!A#|(  
System.err.println(sMsg); sYTToanA$?  
} /{ 8.Jcx$  
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public static void log(int sMsg)
n 8|  
{ (yeN> x}_  
System.err.println(sMsg); +zFEx%3^  
} B8-Y)u1G  
} \ ]h$8JwV  
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/* zy9W{{:P(1  
**TestMethod.java 0?g&<q  
*/ 1UH_"Q03  
package NetFox; tUFXx\p  
f2$<4Hhmm  
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public class TestMethod { ;xE1#ZT  
}Tk*?tYt  
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public TestMethod() 0
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{ ///xx/weblogic60b2_win.exe 8g 2'[ci$q  
try{ w>#.id[k  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Mw$.B#  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 'P >h2^z  
SiteFileFetch fileFetch = new SiteFileFetch(bean); \o!B:Vb<
  
fileFetch.start(); r%oXO]X  
} cNuBWLG  
catch(Exception e){e.printStackTrace ();} C'0=eel[  
oth=#hfU^  
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} jowR!rqf  
/\uW[
mt  
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public static void main(String[] args) WG*S:_?  
{ fxX4 !r  
new TestMethod();
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} t.m C q4{  
} RjQdlr6*  
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