http断点续传简单实现（java)

/* >[nR$8_J-l  
**SiteFileFetch.java sV0NDM0  
*/ GjN6Af~}  
package NetFox; q<^MC/]  
import java.io.*; 9;
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import java.net.*; g HxR
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public class SiteFileFetch extends Thread { e7-IqQA{3C  
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SiteInfoBean siteInfoBean = null; //文件信息Bean t.
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long[] nStartPos; //开始位置 (F3R!n  
long[] nEndPos; //结束位置 CGb4C(%-7  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 c/j+aj0.v  
long nFileLength; //文件长度 Eg}U.ss^  
boolean bFirst = true; //是否第一次取文件 SjF(;0kC  
boolean bStop = false; //停止标志 1*6xFn  
File tmpFile; //文件下载的临时信息 9&6P,ts%Q  
DataOutputStream output; //输出到文件的输出流 wZJbI[r  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） W|E %  
public SiteFileFetch(SiteInfoBean bean) throws IOException 'mm>
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{ a2]ZYY`R7  
siteInfoBean = bean; %] :ZAmN  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); _7qa~7?f  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); cF EO}  
if(tmpFile.exists ()) YdIZikF#  
{ 19[!9ci  
bFirst = false; MZWv#;.]  
read_nPos(); 8^_e>q*W  
} mH\2XG8nV  
else B~@Gfb>`'  
{ .A_R6~::
 
nStartPos = new long[bean.getNSplitter()]; }L%2K"8?}  
nEndPos = new long[bean.getNSplitter()]; 4b,+;  
} oIj-Y`92!  
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} LCzeE7x  
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public void run() CvEIcm=t  
{ > sQ&5-i  
//获得文件长度 L.JL4;U P  
//分割文件 M)Z!W3  
//实例FileSplitterFetch x;/dSfv_  
//启动FileSplitterFetch线程 >Y+m54EE  
//等待子线程返回 Br{(sL0e  
try{ L8Z@Dk7Y  
if(bFirst) p-w:l*-`  
{ Y" rODk1  
nFileLength = getFileSize(); jT F"  
if(nFileLength == -1) nZ#u#V  
{ tGbx/$Y   
System.err.println("File Length is not known!"); voTP,R[}85  
} [f[Wz{Q#Y  
else if(nFileLength == -2) !"-.D4*r  
{ iTT%_-X-  
System.err.println("File is not access!"); %""h:1/S  
} Gxxz4   
else B(} 'yY@%u  
{ vM$hCV~N  
for(int i=0;i<nStartPos.length;i++) {^:NII]  
{ EQw7(r|v:  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Di}M\!-[  
} F?cwIE\J  
for(int i=0;i<nEndPos.length-1;i++) e{XzUY6  
{ Rh$+9w  
nEndPos = nStartPos[i+1]; y7rT[f/J  
} wf\7sz  
nEndPos[nEndPos.length-1] = nFileLength; p&)d]oV>  
}
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} iC>%P&|-)|  
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//启动子线程 V\]j^$  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; @t*D<B$  
for(int i=0;i<nStartPos.length;i++) ukc 7Z OQ  
{ Tow!5VAM  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~_F;>N~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), T(]*jaB  
nStartPos,nEndPos,i); 0*oavY*  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 02NVdpo[wU  
fileSplitterFetch.start();  ylS
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} guf*>qNr  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )^"V}z t  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); K)+]as  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 2+C:Em0yI  
nEndPos = " + nFileLength); ;4GGXT++L  
// fileSplitterFetch[nPos.length-1].start(); f4F%\ "  
19
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//等待子线程结束 D`'Cnt/  
//int count = 0; qK2jJ3)>  
//是否结束while循环 Hi/[  
boolean breakWhile = false; G]EI!-y  
0S'@(p[A  
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while(!bStop) L$+_  
{ ;O{bF8U  
write_nPos(); ~ISY( &  
Utility.sleep(500); :xbj&
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breakWhile = true; =YfzB!ld  
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for(int i=0;i<nStartPos.length;i++) /0fHkj/J=B  
{ 9vwm RVN  
if(!fileSplitterFetch.bDownOver) [F;\NJp6?^  
{ mE>{K  
breakWhile = false; E`hR(UL ?  
break; e
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} GRV
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} W\5 -Yg(@  
if(breakWhile) t.VVE:A^%  
break; 3;wiwN'  
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//count++; l?V#;  
//if(count>4) A"s?;hv\fS  
// siteStop(); gu~R4@3  
} B.;@i;7L
 
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System.err.println("文件下载结束！"); >H5t,FfQL  
} %6Vb1?x  
catch(Exception e){e.printStackTrace ();} kzNRRs\e  
} KK4e'[Wf  
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7 b(  
//获得文件长度 YjJ^SU`*  
public long getFileSize() ?9!9lSH6%  
{ H+]h+K9\7  
int nFileLength = -1; 1LhZmv  
try{ p5w9X+G%  
URL url = new URL(siteInfoBean.getSSiteURL()); gyV`]uqG  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7N@[Rtv  
httpConnection.setRequestProperty("User-Agent","NetFox"); NXDkGO/*  
>&R@L KP  
UL#:!J/34  
int responseCode=httpConnection.getResponseCode(); 2Oyw#1tdn  
if(responseCode>=400) ["Tro;K#  
{ #CAZ}];Qx  
processErrorCode(responseCode); m']$)Iqw  
return -2; //-2 represent access is error }u$c*}  
} dTu*%S1Z  
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String sHeader; Nh/i'q/  
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for(int i=1;;i++) /FpPf[  
{ O@W/s!&lFa  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ZWzr8oY)  
//Utility.log(in.readLine()); yV(9@lj3;  
sHeader=httpConnection.getHeaderFieldKey(i); j8bA"r1  
if(sHeader!=null) S~ S>62  
{  "^BA5  
if(sHeader.equals("Content-Length")) ggkz fg&  
{ u^c/1
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); XeY[;}9  
break; 9HiyN>(  
} ;lrO?sm
 
} CR2.kuM0~  
else G %\/[ B  
break; H\E%.QIx  
} ?"<m{,yQI  
} *zDDi(@vtK  
catch(IOException e){e.printStackTrace ();} M5dEZ  
catch(Exception e){e.printStackTrace ();} -MsL>F.
]  
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Utility.log(nFileLength); qwnVtD  
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return nFileLength; |8[!`T*s  
} BhbfPQ  
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//保存下载信息（文件指针位置） aaN
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private void write_nPos() .3n\~Sn  
{ ydY 7 :D  
try{ $UK m[:7  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ?$tD  
output.writeInt(nStartPos.length); +/kOUz/]  
for(int i=0;i<nStartPos.length;i++) B B'qbX3xK  
{ _h,_HW)G  
// output.writeLong(nPos); 3fXrwmBT8  
output.writeLong(fileSplitterFetch.nStartPos); c+T`X?.j  
output.writeLong(fileSplitterFetch.nEndPos); YRf$?xa  
} +oO7UWs>6  
output.close(); i^Jw`eAmT  
} F^%\AA]8  
catch(IOException e){e.printStackTrace ();} Fv$w:r]q6  
catch(Exception e){e.printStackTrace ();} 
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} Mw-L?j0o[k  
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//读取保存的下载信息（文件指针位置） DTo"{!  
private void read_nPos() wL>*WLfR  
{ +%KkzdS'  
try{ #Z `Tk)u/  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 5WxN
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int nCount = input.readInt(); iyr8*L\  
nStartPos = new long[nCount]; 99By.+~pX  
nEndPos = new long[nCount]; O0`ofFN  
for(int i=0;i<nStartPos.length;i++) AFvv+ ss  
{ 77aUuP7Iw  
nStartPos = input.readLong(); n_LK8
 
nEndPos = input.readLong(); TvT>UBqj=  
} 3B,dL|q(@J  
input.close(); ~]?EV?T  
} ,3MHZPJ?k]  
catch(IOException e){e.printStackTrace ();} 6@FhDj2X  
catch(Exception e){e.printStackTrace ();} On!+7is'  
} Cc`-34/%  
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private void processErrorCode(int nErrorCode) *&_cp]3-WF  
{ 5=p<"*zJ  
System.err.println("Error Code : " + nErrorCode); *3@8,~_t
p  
} ;!t?*  
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*14:^neoI  
//停止文件下载 -O=xgvh"  
public void siteStop() T<Qa`|5>  
{ v''J@F7  
bStop = true; {YrA[9  
for(int i=0;i<nStartPos.length;i++) c'Ibgfx%
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fileSplitterFetch.splitterStop(); oAB:H\  
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} ?Ov~\[) F  
} AS~!YR  
//负责部分文件的抓取 %{:pBt:Z  
**FileSplitterFetch.java h<$%y(lP  
*/ &sBD0R(a  
package NetFox; opN4@a7l  
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import java.io.*; LN<rBF[_:f  
import java.net.*; @W$ha y  
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public class FileSplitterFetch extends Thread { Q!=`|X|:  
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String sURL; //File URL y x#ub-A8  
long nStartPos; //File Snippet Start Position
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long nEndPos; //File Snippet End Position h?B1Emlq  
int nThreadID; //Thread's ID !?+0O]`}  
boolean bDownOver = false; //Downing is over Xc" %-  
boolean bStop = false; //Stop identical =OPX9oG  
FileAccessI fileAccessI = null; //File Access interface `Eu,SvkFw  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException %0}}Qt  
{ 2DJg__("  
this.sURL = sURL; L;{{P7  
this.nStartPos = nStart; cVO-iPK  
this.nEndPos = nEnd; [cznhIvyO  
nThreadID = id; K
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 @o'L!5Y  
} 83'+q((<  
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public void run() g`
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{ c9CFGo?)N  
while(nStartPos < nEndPos && !bStop) .;ofRx<  
{ jJt4{c  
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try{ |/%5~=%7  
URL url = new URL(sURL); d&Nji%Ej  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); i^A=nsD`  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9b,0_IMHH  
String sProperty = "bytes="+nStartPos+"-"; J:ka@2>|  
httpConnection.setRequestProperty("RANGE",sProperty); |r)QkxdU,  
Utility.log(sProperty); 41+WIa L  
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InputStream input = httpConnection.getInputStream(); T:2f*!r  
//logResponseHead(httpConnection); @)[8m8paV  
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byte[] b = new byte[1024]; _JTK$\  
int nRead; (aSuxl.Dq  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) zF{~Md1  
{ K`<HZK  
nStartPos += fileAccessI.write(b,0,nRead); WwtVuc|  
//if(nThreadID == 1) wpi$-i`  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); P6ktA-Hv>  
} LayK&RwL  
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Utility.log("Thread " + nThreadID + " is over!"); :&:P4Y1 E  
bDownOver = true; -%%Xx5D  
//nPos = fileAccessI.write (b,0,nRead); _~C1M&b(X3  
} *!*%~h8V  
catch(Exception e){e.printStackTrace ();} XE2rx2k  
} G{>PYLxOb  
} e"bzZ!c&~V  
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) )FLM^dj  
//打印回应的头信息 |s(Ih_Zn  
public void logResponseHead(HttpURLConnection con) l`A&LQ[  
{ 4E2/?3D  
for(int i=1;;i++) |mbD q\U  
{ nHq4f&(H  
String header=con.getHeaderFieldKey(i); <%m1+%mA.  
if(header!=null) -KfK~P3PF  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); /QVwZrch  
Utility.log(header+" : "+con.getHeaderField(header)); j&Xx{ 4v  
else h*!oHS~/l  
break; mD&I6F[s  
} %eIaH!x:  
} wF%RM$  
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public void splitterStop() ']I!1>v$[  
{ o~\.jQQxa  
bStop = true; P6La)U`VA  
} Tbv w?3  
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} AJ
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/* Ml{ ]{n  
**FileAccess.java ?nbu`K6T  
*//文件访问(定位，写) EQd<!)HZ  
package NetFox; 1ywdcg  
import java.io.*; 19y,O0# _  
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@n.n[zb\|  
public class FileAccessI implements Serializable{ Aaq%'07ihW  
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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 i '*!c  
RandomAccessFile oSavedFile; n^hkH1vY  
long nPos; >1Hv c7DP  
8zlvzp  
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public FileAccessI() throws IOException iDl#foXa`  
{ Yk?q\1  
this("",0); B&B:P  
} DQP!e6Of  
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srAWet  
public FileAccessI(String sName,long nPos) throws IOException ~TS!5Wiv  
{ 8]b;l; W5  
oSavedFile = new RandomAccessFile(sName,"rw"); \9` ~9#P  
this.nPos = nPos; ?a% F3B  
oSavedFile.seek(nPos); cHT\sJo`l  
} y {Bajil  
 +PADy8  
%Y=r5'6l  
public synchronized int write(byte[] b,int nStart,int nLen) \~+b&  
{ 8OV=;aM?{  
int n = -1; G6W|l2P!  
try{ PLz+%L;{  
oSavedFile.write(b,nStart,nLen); K\fD';  
n = nLen; Y%0rji  
} ")vtS}Ekt  
catch(IOException e) /!?Tv8TPp  
{ ;|?_C8  
e.printStackTrace (); @{_X@Wv4iV  
} 4;AQ12<[1  
O< /b]<[
 
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return n; h^Yh~84T  
} se2Y:v  
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} "T^%HPif  
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,VEE<*'X  
/* ZX`x9/0&  
**SiteInfoBean.java .xmB8 R  
*/ N'&>bO?@`  
package NetFox; ^9LoxU-  
oA~0"}eS  
AA=rjB9  
public class SiteInfoBean { 4[]*=  
glU9A39qx?  
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private String sSiteURL; //Site's URL '/ Hoq  
private String sFilePath; //Saved File's Path <a -a~  
private String sFileName; //Saved File's Name (GL'm[V  
private int nSplitter; //Count of Splited Downloading File SG\ /m'F  
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public SiteInfoBean() !^98o:"x  
{//nSplitter的缺省值为5 ;}U]^LT=  
//default value of nSplitter is 5 8J$1N*J|  
this("","","",5); :{Z%dD  
} h?OSmzRLd  
- ry  
4~$U#$u_  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ~J+ qIZge  
{ e],(d7Jo  
sSiteURL= sURL; RfD#/G3|  
sFilePath = sPath; t g-(e=S4P  
sFileName = sName; DBcR1c&<H  
this.nSplitter = nSpiltter;
+4T.3Njjn  
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Vn{;8hZ:a  
} ^OIo  
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public String getSSiteURL() ^
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{ +MaEet
 
return sSiteURL; GeB&S!F  
}  ?f'`b<o  
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public void setSSiteURL(String value) z2,NWmP|w  
{ $yj*
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sSiteURL = value; 2 V\hG?<  
} >!" Sr3,L  
1pDU}rPJ.  
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public String getSFilePath() tK{#kApHGG  
{ <zvtQ^{]  
return sFilePath; _4S
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} hslT49m>  
lV4TFt,  
7SYe:^Dx  
public void setSFilePath(String value) d#bg(y\G|  
{ %P<fz1  
sFilePath = value; h,BPf5\S  
} $t"QLsk0  
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*& );-r`.  
public String getSFileName() Sw-2vnSdM  
{ Z>Rshtg  
return sFileName; <6+B;brh  
} *
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r^rk@W;[  
public void setSFileName(String value) 5? Y(FhnIC  
{ /@&o%I3h  
sFileName = value; :]Om4Q\-#  
} =B;qy7?  
P~:^bU^F7  
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public int getNSplitter() 7^! zT  
{ Xg_l4!T_l  
return nSplitter; iY2q^z/S
 
} q^wSM  
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public void setNSplitter(int nCount) 4Jc~I  
{ Bt$,=k  
nSplitter = nCount; +/mCYI  
} f!5w+6(  
} BU>R<A5h  
4o@:+T:1  
P()W\+",n  
/* I D-I<Ev  
**Utility.java hDUU_.q)D  
*/ Y|hd!C-x
  
package NetFox; ks%;_~b  
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public class Utility { 5{1=BZftZ  
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public Utility() ]q
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{ .Sa=VC?EZ  
0Db=/sJ>  
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} zYdieE\-  
&%/T4$'+Y+  
//线程睡眠 Q\xDAOEL  
public static void sleep(int nSecond) G OG[^T  
{ 3bo [34  
try{ eUR+j?5I  
Thread.sleep(nSecond); N;!!*
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} 8$iHd  
catch(Exception e) |{ZdAr.;  
{ x*TJYST  
e.printStackTrace (); k_?OEkgUh  
} j!k$SDA-  
} /6y{?0S  
-Ks)1w>l
 
//日志 3N2d@R  
public static void log(String sMsg) 5t_Dt<lIz  
{ 6iEg]FI  
System.err.println(sMsg); @/$i -?E  
} !>Q\Y`a,*  
^vxNS[C`;  
? }`mQ<~  
public static void log(int sMsg) ==%5Ci7qMy  
{
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System.err.println(sMsg);
.Xe_Gp"x  
} u%"5<ll  
} ;Kg7}4`I  
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/* uocFOlU0n  
**TestMethod.java )g3c-W=  
*/ fN<Y3^i"  
package NetFox; N0\<B-8+,>  
seP h%Sa_  
1Id"|/b%$  
public class TestMethod { @"^7ASd%  
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public TestMethod() wHx_lsY;  
{ ///xx/weblogic60b2_win.exe 8.IenU9  
try{ ty%,T.@e  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 10m|?  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 2
1+[9  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Q~' \oWz  
fileFetch.start(); {/aHZ<I&^h  
} Vr%ef:uVV  
catch(Exception e){e.printStackTrace ();} 1B~Z1w  
cb{"1z  
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} 2<w vO 9  
,\RR@~u'  
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public static void main(String[] args) 8=0I4\  
{ ;$4&Qp:#  
new TestMethod(); itc\wn  
} &Ll&A@yU  
} `YMd0*  
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