http断点续传简单实现（java)

/* TXjloGv^  
**SiteFileFetch.java PY?8[A+  
*/ C}q>YRubZ  
package NetFox; .jA
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import java.io.*; ld.7`)  
import java.net.*; joqWh!kv7U  
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public class SiteFileFetch extends Thread { []zua14F6  
 A^ViDP  
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SiteInfoBean siteInfoBean = null; //文件信息Bean <?YA,"~  
long[] nStartPos; //开始位置 9t?L\
  
long[] nEndPos; //结束位置 Vo\H<_=
G  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 >)NQH9'1  
long nFileLength; //文件长度 eX"''PA  
boolean bFirst = true; //是否第一次取文件 eJHp6)2  
boolean bStop = false; //停止标志 3+ =I;nj  
File tmpFile; //文件下载的临时信息 mk%b9Ko<F  
DataOutputStream output; //输出到文件的输出流 f8=]oa]  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） S/.^7R7{f  
public SiteFileFetch(SiteInfoBean bean) throws IOException oaK.kOo  
{ JEhm1T  
siteInfoBean = bean; Q8q@Y R#  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Zsj`F9*e  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); e`iEy=W  
if(tmpFile.exists ()) :lgi>^  
{ IxOc':/jY  
bFirst = false; )1lu=gc  
read_nPos(); zC=a3  
} Lu=O+{*8  
else je%ldY]/@  
{ UX2lPgKdLz  
nStartPos = new long[bean.getNSplitter()]; :HRT 
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nEndPos = new long[bean.getNSplitter()]; y(5:}x&E  
} dY!u)M;~~  
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} jAC78n,Fi@  
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public void run() KxIyc7.  
{ Y.sz|u 1  
//获得文件长度 +Rwx%=  
//分割文件 wfR&li{  
//实例FileSplitterFetch [|RjHGf  
//启动FileSplitterFetch线程 )K;]y-Us[  
//等待子线程返回 kccWoU,  
try{ Y/fJQ6DY  
if(bFirst) k_ Y~;P@  
{ Dz;HAyPj  
nFileLength = getFileSize();  \S4SI  
if(nFileLength == -1) bcH_V|5
}  
{ U]R~gy}#  
System.err.println("File Length is not known!"); Zgamd1DJ[l  
} G-u]L7t&1  
else if(nFileLength == -2) QM'X@  
{ 6B" egYv  
System.err.println("File is not access!"); 0 )}$^TV  
} *jITOR!uF`  
else pK}=*y~$  
{ ?mv:neh  
for(int i=0;i<nStartPos.length;i++) o&SSvW  
{ r2\c'9uH  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); -Q"hZ9  
} j}f[W [2  
for(int i=0;i<nEndPos.length-1;i++) "& 25D  
{ 2S~R!   
nEndPos = nStartPos[i+1]; ZVih=Y-w  
} gb" 4B%Hm  
nEndPos[nEndPos.length-1] = nFileLength; DHw<%Z-J  
} W0I4Vvh_"  
} H:QhrL+7_  
V
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$_Nf-:D*  
//启动子线程 w0lT%CPx  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; fCw*$:O  
for(int i=0;i<nStartPos.length;i++) /M=3X||  
{ *[}^[J x  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "rhYCZ B  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), [k<1`z3  
nStartPos,nEndPos,i); {tiKH=&J  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [}z,J"Un  
fileSplitterFetch.start(); f&KdlpxKv  
} ~h$wH{-U#  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Bc5+ss  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); vXE0%QE'Q  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", &,:h)  
nEndPos = " + nFileLength); `A@w7J'  
// fileSplitterFetch[nPos.length-1].start(); w@-M{?R  
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//等待子线程结束 'b&yrBFD  
//int count = 0; zM#sOg  
//是否结束while循环 H t(n%;<  
boolean breakWhile = false; u<xo/=Z  
=r2]uW9  
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while(!bStop) 9+=gke  
{ $IQw=w7p  
write_nPos(); % Zjdl  
Utility.sleep(500); <0P5 o|  
breakWhile = true; 8\.b4FNJ  
}UwO<#  
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for(int i=0;i<nStartPos.length;i++) I\O\,yPhhP  
{ a_~=#]a  
if(!fileSplitterFetch.bDownOver) k[j90C5  
{ zUJZ`seF  
breakWhile = false; <
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break; ;&b.T}Nf06  
} Q\ppfc{,  
} OHv!  
if(breakWhile) <ABX0U[*  
break; Ifc]K?  
saf&dd  
Fh$slow4!  
//count++; yLE7>48  
//if(count>4) M5357Q  
// siteStop(); NPa\Cg[  
} co8"sz0(U  
SRIA*M.B}  
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System.err.println("文件下载结束！"); kYzKU2T\W  
} "Jq8?FoT  
catch(Exception e){e.printStackTrace ();} (V`Md\NL`  
} K<`osdp=&  
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//获得文件长度 DyJ.BQdk)  
public long getFileSize() r0;:t  
{ -a,-J]d0+  
int nFileLength = -1; <EO$]>;0  
try{ u$#Wv2|mk  
URL url = new URL(siteInfoBean.getSSiteURL()); q[q?hQ/b  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); B%CTOi  
httpConnection.setRequestProperty("User-Agent","NetFox"); }je,")
#W  
S-Y=-"  
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int responseCode=httpConnection.getResponseCode(); \wcam`f
  
if(responseCode>=400) .IBp\7W!?E  
{ 'rp }G&m  
processErrorCode(responseCode); bV+(b9  
return -2; //-2 represent access is error tGvG  
} &Mq~T_S  
@hQlrq5c  
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String sHeader; Z;Ez"t&U  
[qUN4x5b  
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for(int i=1;;i++) a7zcIwk '{  
{ . o7m!  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); fZ04!R  
//Utility.log(in.readLine()); I-y#Ks1p+  
sHeader=httpConnection.getHeaderFieldKey(i); KqBk~-G  
if(sHeader!=null)  McH>"`  
{ 9EDfd NN  
if(sHeader.equals("Content-Length")) 3$.deYa$R  
{ 0R{dNyh{  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); X[ q+619  
break; 3vhnwDcK  
} {"oxJ`z4  
} "Ve.cP,7(  
else eAv4FA4g  
break; wO ?+Nh  
} |(5W86C,ju  
} m8'C_U^89  
catch(IOException e){e.printStackTrace ();} ];'v8
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catch(Exception e){e.printStackTrace ();} \%PaceH  
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Utility.log(nFileLength); S}APQ  
}bY;q-  
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return nFileLength;  N\:. M  
} eP*lI<NQ1  
{ eCC$&"  
FZ!`B]]le,  
//保存下载信息（文件指针位置） ~|<WHHN
(  
private void write_nPos() \
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{ bM8If"  
try{ 7VcmVq}X  
output = new DataOutputStream(new FileOutputStream(tmpFile)); =mA: ctu~v  
output.writeInt(nStartPos.length); }ci#>  
for(int i=0;i<nStartPos.length;i++) 3"o"fl  
{ 'smWLz}  
// output.writeLong(nPos); 8} =JKR^cK  
output.writeLong(fileSplitterFetch.nStartPos); ono4U.C9  
output.writeLong(fileSplitterFetch.nEndPos); PH"n{lW.T  
} 5>BK%`  
output.close(); f$NMM >z  
} =t6z \WB  
catch(IOException e){e.printStackTrace ();} [2"<W!p  
catch(Exception e){e.printStackTrace ();} T]2q?;N  
} tOfg?)h{dc  
]-ZEWt6lsc  
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//读取保存的下载信息（文件指针位置） 7AYd!n&S  
private void read_nPos() $O9^SB  
{ Fx-8M
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try{ !9Aaj<yxm  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); T&Lb<'f  
int nCount = input.readInt(); ^i:`ZfA#
 
nStartPos = new long[nCount]; (aD_zG=k5  
nEndPos = new long[nCount]; !\&;h  
for(int i=0;i<nStartPos.length;i++) z9aY]lHY  
{ TMYd47  
nStartPos = input.readLong(); w@
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nEndPos = input.readLong(); ]\7]%(  
} z5)s/;Sc  
input.close(); .'Y]R3\M+  
} jDQZQ NS  
catch(IOException e){e.printStackTrace ();} ^f# FI&  
catch(Exception e){e.printStackTrace ();} os/vtyP:a  
} ,o)d3g-&g  
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private void processErrorCode(int nErrorCode) 8Y5  
{ v{}#?=I5  
System.err.println("Error Code : " + nErrorCode); 0v9rv.Y"  
} HttiX/2~  
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'` pDngX  
//停止文件下载 <~ Sz04  
public void siteStop() 7)s^8+  
{ *zr(Zv  
bStop = true; r$2P;Cxj  
for(int i=0;i<nStartPos.length;i++) AhZ8 0!  
fileSplitterFetch.splitterStop(); N!g9*Z
 
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} qh`t-  
} qi_Jywd:w  
//负责部分文件的抓取 D9z|VIw8  
**FileSplitterFetch.java r#XT3qp$d  
*/ O BN2 ) j  
package NetFox; {)-aSyw
e  
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import java.io.*; )E~79!  
import java.net.*; eut-U/3:#  
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public class FileSplitterFetch extends Thread { 8QM
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String sURL; //File URL ^k]XEW{PG  
long nStartPos; //File Snippet Start Position *hw\35%P`?  
long nEndPos; //File Snippet End Position 2$Tj84'X  
int nThreadID; //Thread's ID #5f-`~^C{  
boolean bDownOver = false; //Downing is over M@5?ZZ4L  
boolean bStop = false; //Stop identical -{ H0g]  
FileAccessI fileAccessI = null; //File Access interface ;UxP Kpl  
ONe# rKJ_  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException
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{ 0(S"{Ov
 
this.sURL = sURL; y~FV2$  
this.nStartPos = nStart; &}A[x1x06)  
this.nEndPos = nEnd; gSh+}r<7  
nThreadID = id; w
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 ~J P=T  
} 1R,:  
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public void run() zzyHoZJP  
{ RO.k]x6  
while(nStartPos < nEndPos && !bStop) o#skR4lwe  
{ Rb.SY{}C  
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>k'c'7/  
try{ jrS[f  
URL url = new URL(sURL); l g-X:Z.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {DR`;ea])1  
httpConnection.setRequestProperty("User-Agent","NetFox"); ndkti5L,   
String sProperty = "bytes="+nStartPos+"-"; ( vca&wI!  
httpConnection.setRequestProperty("RANGE",sProperty); 9T1Z
L5  
Utility.log(sProperty); Nd;Ku6  
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ia MUsa{  
InputStream input = httpConnection.getInputStream(); <"_d]?,  
//logResponseHead(httpConnection); /K(o]J0F  
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+ ~>Aj  
byte[] b = new byte[1024]; *FMMjz  
int nRead; |6$p;Aar  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) MgY0q?.S=  
{ `5C,N!d8X  
nStartPos += fileAccessI.write(b,0,nRead); og kD^   
//if(nThreadID == 1) Wr( y)D<y}  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =17t- [  
} #Jw1IcuH
 
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Utility.log("Thread " + nThreadID + " is over!"); %oO4|JkJX  
bDownOver = true; 2n
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//nPos = fileAccessI.write (b,0,nRead); !Ze5)g%H  
} 4 XAQVq5  
catch(Exception e){e.printStackTrace ();} sashzVwJ-=  
} D8xmE2%  
} 1A\OC  
<?@NRFTe  
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//打印回应的头信息 ~FN9 [aJF+  
public void logResponseHead(HttpURLConnection con)
zaK#Z?V}  
{ {$wjO7Glp  
for(int i=1;;i++) D`$hPYK|_  
{ c|#8T*`C  
String header=con.getHeaderFieldKey(i); eY|  
if(header!=null) z[3L2U~6  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); +w+}b^4  
Utility.log(header+" : "+con.getHeaderField(header)); fIsp;ca[k  
else =,UWX3`f  
break; Y$?9Zkp>  
} tQBRA/  
} , T8>}U(  
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public void splitterStop() 6,0_)O}\b  
{ 5Er2}KZJv,  
bStop = true; L{8xlx`  
} E6pMT^{K  
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} ::
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/* [m|YWT=  
**FileAccess.java ~4 `5tb  
*//文件访问(定位，写) Np"exFqN k  
package NetFox; j
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import java.io.*; 70eb]\%  
Z\k&gio5C^  
z}MP)|aH:  
public class FileAccessI implements Serializable{ {o.FlX  
U 15H2-`  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 <|SRe6m  
RandomAccessFile oSavedFile; b)e *$)  
long nPos; [O?z@)dx  
a_'2V;  
//s:5S<Z  
public FileAccessI() throws IOException
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{ ''0fF_P  
this("",0); W7 #9jo  
} w tiny,6  
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public FileAccessI(String sName,long nPos) throws IOException n%k!vJ)]  
{ O=
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oSavedFile = new RandomAccessFile(sName,"rw"); *+\SyO  
this.nPos = nPos; "=+7-`  
oSavedFile.seek(nPos); mdq;R*`  
} ;Ww7"-=sw  
(d<4"!  
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public synchronized int write(byte[] b,int nStart,int nLen) UQ+?\wi*  
{ >j'ZPwj^  
int n = -1; :k3Nt5t!  
try{ .9"Y_/0   
oSavedFile.write(b,nStart,nLen); ]]&M@FM2z  
n = nLen; ,daKC  
} @E-\ J7 yh  
catch(IOException e) _x?
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{ `8I&7c  
e.printStackTrace (); GD:4"$)[o  
} X*,%&6O*  
FP>)&3>_  
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return n; 3Te^  
} vk?sk
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} LK;k'IJ  
n':!,a[  
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/* ~{D[ >j][  
**SiteInfoBean.java Ga^Zb^y  
*/ 7As|Ns`  
package NetFox; ! /NG.Wf  
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public class SiteInfoBean { Hw|AA?,0-  
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:gB[O>'<m  
private String sSiteURL; //Site's URL H{AMZyV0/d  
private String sFilePath; //Saved File's Path zOSs[[  
private String sFileName; //Saved File's Name TeWMp6u,r  
private int nSplitter; //Count of Splited Downloading File +E;2d-x*p  
NFr:y<0>z  
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public SiteInfoBean() 8UMFq  
{//nSplitter的缺省值为5 =fYL}m5E  
//default value of nSplitter is 5 PT^c^{V  
this("","","",5); AxZD-|.  
} <n:}kQTT  
Zo}y(N1K}  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) xy<`#  
{ )'
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sSiteURL= sURL; dDD<E?TjD  
sFilePath = sPath; yR~R:  
sFileName = sName; LT~YFS  
this.nSplitter = nSpiltter; LFZiPu  
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} YqV8D&I  
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public String getSSiteURL() %"X-&1vV  
{ %+F"QI1~0  
return sSiteURL; ~fa(=.h  
} N6T{  
M^7MU}5w  
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public void setSSiteURL(String value) `$YP<CJeq  
{ ?+t1M
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sSiteURL = value; k78Vh$AA6%  
} {Rear2  
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oR~e#<$;  
public String getSFilePath() 97,rE$bC  
{ 20TCG0%x  
return sFilePath; bpkwn<7
-  
} lg}HGG  
7JDN{!jT  
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public void setSFilePath(String value) ;oNhEB:F  
{ gUR]{dq^'  
sFilePath = value; LrCk*@  
} QI!F6pGF  
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public String getSFileName() $2MAZGJV
 
{ '>k{tPi.  
return sFileName; Dw2Q 'E  
} \@~UDP]7  
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public void setSFileName(String value) QJW`}`R
 
{ M|[ZpM+  
sFileName = value;
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} G2#d$  
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public int getNSplitter() >qo~d?+  
{ RkuuogZ  
return nSplitter; 9]>iSG^H  
} D\~e&0*  
#g5^SR|qE  
o\
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public void setNSplitter(int nCount) GOSI3RRn  
{ _0pO8o-x  
nSplitter = nCount; q+a.G2S  
} {C
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} FZH\Q~IUV  
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/* *fO{ a  
**Utility.java t=R6mjb  
*/ 6S.~s6o,  
package NetFox; [WB{T3j  
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public class Utility { 6<5Jq\-h  
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public Utility() 3,);0@I  
{ 7W9~1 .SC  
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} m=b~i^@  
gor<g))\  
//线程睡眠 WA)Ij(M8 p  
public static void sleep(int nSecond) !]S=z^"<  
{ -qebQv  
try{ fj4^VXD  
Thread.sleep(nSecond); cX At:m  
} b>~RSO*  
catch(Exception e) Y'Z+, CNf  
{ mEQ!-p  
e.printStackTrace (); m
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} t]^_l$  
} >Jm"2U}lZW  
hN(L@0)  
//日志 T+RZ  
public static void log(String sMsg) g-yi xU  
{ O
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System.err.println(sMsg); r(}nhUQ%E  
} m1.B\~S3  
aQcN&UA@  
5#_tE<uM  
public static void log(int sMsg) &.*uc|{  
{ cD{8|B*  
System.err.println(sMsg); XKq@]=\F  
} V2yveNz\7  
} \]Z&P,}w  
z};ZxN  
{TL +7kiX/  
/* 'Kis hXOn]  
**TestMethod.java 
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*/ *\LyNL(  
package NetFox; h39e)%x1  
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public class TestMethod { (G8  
Ko}2%4on  
V:\]cGA{  
public TestMethod() <lOaor c  
{ ///xx/weblogic60b2_win.exe +8UdvMN  
try{ <*YO~S(R  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); b|ZLX:  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Lp~^*j(  
SiteFileFetch fileFetch = new SiteFileFetch(bean); [A_r1g&_  
fileFetch.start(); ogeRYq,g  
} |mj# 0  
catch(Exception e){e.printStackTrace ();} lcig7%  
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} 99KVtgPm  
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public static void main(String[] args) 6_U|(f  
{ n{=7 yK  
new TestMethod(); >tEK+Y|N}  
} G{A)H_o*  
} gUGOHd(A  
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