http断点续传简单实现（java)

/* KNR7Igw?}  
**SiteFileFetch.java ppGWh  
*/ N%%trlDXD  
package NetFox; Lcf?VV}  
import java.io.*; U2CC#,b!(  
import java.net.*; 8fktk?|  
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public class SiteFileFetch extends Thread { ~y"OyOi&  

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SiteInfoBean siteInfoBean = null; //文件信息Bean *X^C+F  
long[] nStartPos; //开始位置 A5Q4wy`  
long[] nEndPos; //结束位置 x,|fb
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 trB-(B%5  
long nFileLength; //文件长度 VF g(:  
boolean bFirst = true; //是否第一次取文件 .[Qi4jm>`  
boolean bStop = false; //停止标志 \fp'=&tp~a  
File tmpFile; //文件下载的临时信息
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DataOutputStream output; //输出到文件的输出流 "=LeHY=9  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） HZ1nuA  
public SiteFileFetch(SiteInfoBean bean) throws IOException MhJA8|B6|  
{ q
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siteInfoBean = bean; .`(YCn?\  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); .1z=VLKF'  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); .zTkOkL  
if(tmpFile.exists ()) Fk9]u^j  
{ f4&;l|R0a  
bFirst = false; yYSoJqj Q  
read_nPos(); DQ9aq.;  
} ?cn`N|   
else o-JB,^TE  
{ h B_p  
nStartPos = new long[bean.getNSplitter()]; _>;{+XRX[  
nEndPos = new long[bean.getNSplitter()]; XVb9)a  
} L-9;"]d~|  
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} I!SIy&=W  
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public void run() Mpco8b-b  
{ G~ LQM  
//获得文件长度 @"wX#ot  
//分割文件 /a)^)  
//实例FileSplitterFetch LROrhO  
//启动FileSplitterFetch线程 P1Eg%Y6  
//等待子线程返回 Q)lD2  
try{ _dW#[TCF  
if(bFirst) #{
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{ Ro4!y:2|  
nFileLength = getFileSize(); e/#6qCE  
if(nFileLength == -1) 1$`|$V1  
{ 'St?nW3  
System.err.println("File Length is not known!"); /Ak\Q5O'3  
} <0? r# }  
else if(nFileLength == -2) rY8(`a  
{ S9ic4rcd  
System.err.println("File is not access!"); rBi6AM/  
} K\zb+  
else }E[v
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{  dvz6  
for(int i=0;i<nStartPos.length;i++) 3\{\ al   
{ Zg0nsNA   
nStartPos = (long)(i*(nFileLength/nStartPos.length)); $!TMS&Wk  
} -]{ _^
 
for(int i=0;i<nEndPos.length-1;i++) \(;u
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{ D,|TQQ  
nEndPos = nStartPos[i+1]; uH,/S4?X  
} 
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nEndPos[nEndPos.length-1] = nFileLength; 4'`H H  
} (`4&Y-  
} W~a
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WFhppi   
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//启动子线程 qnnRS  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 94|ZY}8|f  
for(int i=0;i<nStartPos.length;i++) W]_a_5  
{ HKJ^6|'  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), l*huKSX}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), eVB43]g  
nStartPos,nEndPos,i); }2:q#}"  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); dLeos9M:  
fileSplitterFetch.start(); XKDX*x G  
} [2>zaag  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9I$}=&"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); :eT\XtxM~{  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ",
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nEndPos = " + nFileLength); EyA(W;r.  
// fileSplitterFetch[nPos.length-1].start(); qR_Np5nHF  
}Kp$/CYd  
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//等待子线程结束 Iza;~8dH5  
//int count = 0; SGba6b31  
//是否结束while循环 {P\Ob0)q  
boolean breakWhile = false; {K}Dpy  
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a=x&sz\x  
while(!bStop) F
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{ "%S-(ue:  
write_nPos(); VUP. \Vry  
Utility.sleep(500); VS_\bIC  
breakWhile = true; q?)5yukeF  
TU6YS<  
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for(int i=0;i<nStartPos.length;i++) "gzn%k[D9m  
{ vu}U2 0@  
if(!fileSplitterFetch.bDownOver) q8.Z7ux  
{ 49O_A[(d  
breakWhile = false; =<)/lz] H  
break; (l9jczi  
} >Q^ mR  
} <P&X0S`O  
if(breakWhile) [eBt Dc*w  
break; Evqy e;  
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^,?>6O  
//count++; ?iEn~9WCS  
//if(count>4) rj
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// siteStop(); g\?07@Zd|  
} gB+CM? LKq  
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,
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System.err.println("文件下载结束！"); ;-l^X%r  
} Ux{QYjFE  
catch(Exception e){e.printStackTrace ();} 5dG+>7Iy}  
} 5|t-CY{?b  
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//获得文件长度 &B=z*m  
public long getFileSize() 'J!Gip ,  
{ yB=R7E7  
int nFileLength = -1; 2n2,MB  
try{ w40*vBz  
URL url = new URL(siteInfoBean.getSSiteURL()); B|+%ExT7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;~WoJlEK3  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7}~nQl2  
.x/H2r'
1  
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int responseCode=httpConnection.getResponseCode(); ~k?
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if(responseCode>=400) ;05lwP*r]  
{ gbh/`  
processErrorCode(responseCode); N1'Yo:_A  
return -2; //-2 represent access is error xB?!nd  
} @{Fa=".Ch  
+W8#]u|  
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String sHeader; [nX{sM%  
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for(int i=1;;i++) d{(Rs.GuP  
{ ;- Vs|X  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); hp}rCy|01  
//Utility.log(in.readLine()); {!{T,_ J  
sHeader=httpConnection.getHeaderFieldKey(i); /X#OX8gb]  
if(sHeader!=null) I\rjw$V#  
{ N"Y%*BkH  
if(sHeader.equals("Content-Length")) 6& hiW]Adm  
{ 7Wiwnv_"  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); O8rd*+  
break; |Xd&aQ  
} sk0/3X*Q%  
} vp d!|/  
else gu'+kw  
break; ~)X;z"y%b  
} |8x_Av0  
} i12G\Ye  
catch(IOException e){e.printStackTrace ();} j.+,c#hFo
 
catch(Exception e){e.printStackTrace ();} IBNb!mPu%  
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Utility.log(nFileLength); {4p7r7n'  
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return nFileLength; YYkgm:[  
} ,.gJ8p(0x  
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//保存下载信息（文件指针位置）  60f%J1u  
private void write_nPos() A,= R`m  
{ BP4vOZ0$  
try{ ?o/p}6  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ilQ\
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output.writeInt(nStartPos.length); a"1LF`  
for(int i=0;i<nStartPos.length;i++) miCY?=N`  
{ 7Bf4ojKt  
// output.writeLong(nPos); o(t`XE['<  
output.writeLong(fileSplitterFetch.nStartPos); &qa16
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output.writeLong(fileSplitterFetch.nEndPos); ZC^?ng  
} *S4&V<W>  
output.close(); 6+PP(>em  
} dPgA~~  
catch(IOException e){e.printStackTrace ();} y6s/S.  
catch(Exception e){e.printStackTrace ();} SxC(:k2b;  
} MzlE  
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//读取保存的下载信息（文件指针位置） [!ZYtp?Hf  
private void read_nPos() *t={9h  
{ X&K,,C  
try{ :b#5cMUe  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ~n/:a  
int nCount = input.readInt(); K:pG<oV|}  
nStartPos = new long[nCount]; 1'B=JyR~K  
nEndPos = new long[nCount]; :n x;~f  
for(int i=0;i<nStartPos.length;i++) SBw'z(U  
{ _,-\;  
nStartPos = input.readLong(); )S_%Ip  
nEndPos = input.readLong(); )MX%DQw  
} %U1HvmyK  
input.close(); Ja@?.gW  
} C|QJQ@bj0  
catch(IOException e){e.printStackTrace ();} `X`|]mWj  
catch(Exception e){e.printStackTrace ();}
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} rj5)b:c}  
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private void processErrorCode(int nErrorCode) FOcDBCrOe  
{ ab6D&  
System.err.println("Error Code : " + nErrorCode); >v%UV:7ap  
} ];0:aSi#  
)IE)a[wo  
*I9G"R8  
//停止文件下载 kaC
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public void siteStop() b1ZHfe:  
{ qEjsAL  
bStop = true; 7G_lGV_  
for(int i=0;i<nStartPos.length;i++) `R$bx 64  
fileSplitterFetch.splitterStop(); {Z[kvXf"mZ  
):Ekf2  
s: MJ{r(s  
} TR{dNO!q  
} ayA_[{j%X  
//负责部分文件的抓取 [@s5v  
**FileSplitterFetch.java bW'Y8ok[v  
*/ 6M8(KN^  
package NetFox; 'FN3r  
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import java.io.*; H329P*P  
import java.net.*; q?&JS  
[3W+h1  
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public class FileSplitterFetch extends Thread { j7HOh
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"QY~V{u5  
Q $>SYvW  
String sURL; //File URL ,
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long nStartPos; //File Snippet Start Position K%vGfQ8Er-  
long nEndPos; //File Snippet End Position wtGb3D"am  
int nThreadID; //Thread's ID lHPhZ(Z  
boolean bDownOver = false; //Downing is over *P[N.5{  
boolean bStop = false; //Stop identical i"hn%u$V  
FileAccessI fileAccessI = null; //File Access interface P`M1sON~  
/p@0Q[E  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException #kQLHi3##  
{ c-
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this.sURL = sURL; %M05& <  
this.nStartPos = nStart; {|@N~c+  
this.nEndPos = nEnd; >[g'i+{  
nThreadID = id; 7jF2m'(  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 2?owXcbx  
} &44?k:  
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public void run() \Ng[lN  
{ PFeK;`[  
while(nStartPos < nEndPos && !bStop) *(<3 oIRS  
{ dtq]_HvTJ  
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~


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try{ k+cHx799  
URL url = new URL(sURL); cGjkx3l*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); eD 7Rv<  
httpConnection.setRequestProperty("User-Agent","NetFox"); W-ECmw(
 
String sProperty = "bytes="+nStartPos+"-"; rYr.mX  
httpConnection.setRequestProperty("RANGE",sProperty); cNqw(\rr  
Utility.log(sProperty); {eo?vA8SE  
/?QBMI  
p&;,$KDA  
InputStream input = httpConnection.getInputStream(); :~9F/Jx  
//logResponseHead(httpConnection); w9a6F  
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byte[] b = new byte[1024]; <3Hu(Jx<O  
int nRead; iD9hqiX&  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) MMUw+jM4  
{ #Y<b'7yJ  
nStartPos += fileAccessI.write(b,0,nRead); BLhuYuON  
//if(nThreadID == 1) Cqk6Igw  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); LIHf]+  
} o>Z+=&BZ@a  
-n'%MT=Cd  
P(Hh%
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Utility.log("Thread " + nThreadID + " is over!"); ZCVN+::Y  
bDownOver = true; :YZMRJL
 
//nPos = fileAccessI.write (b,0,nRead); l,3[hx  
} 5bKn6O)K  
catch(Exception e){e.printStackTrace ();} Ss7XjWP.}  
} *,DBRJ_*7  
} !b+Kasss9  
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//打印回应的头信息 3bPvL/\Lb  
public void logResponseHead(HttpURLConnection con) 'H,l\i@"  
{ I*K~GXWs#  
for(int i=1;;i++) yS-owtVCGF  
{ `_v|O{DC{  
String header=con.getHeaderFieldKey(i); ^UK6q2[  
if(header!=null) x_5H_! \#  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); sxLq'3(  
Utility.log(header+" : "+con.getHeaderField(header)); !P0
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q  
else +P<LoI  
break; +<H)DPG<  
} -.E<~(fad  
} P1ab2D  
Wz7jB6AWA  
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public void splitterStop() z7J2O  
{ oFV>b  
bStop = true; vH#^|u  
} Ofg-gCF8  
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} fm\IQqIK%  
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jM90 gPX>,  
/* y(8AxsROp  
**FileAccess.java f+huhJS5e  
*//文件访问(定位，写) gI^*O@Q4{b  
package NetFox; # -
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import java.io.*; UpS`KgF"v  
.r?-O{2t  
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public class FileAccessI implements Serializable{ 7m=tu?@  
puz~Rfn#*  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 PQ|kE`
'  
RandomAccessFile oSavedFile; }ya9 +?I  
long nPos; pRj1b^F5y  
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public FileAccessI() throws IOException *eytr#0B-  
{ iVt6rX  
this("",0); x,z+l-y  
} ?8n`4yO0  
n
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DEL#MD!  
public FileAccessI(String sName,long nPos) throws IOException n-{G19?  
{ p/xxoU  
oSavedFile = new RandomAccessFile(sName,"rw"); snV,rZ  
this.nPos = nPos; s7<x~v+^  
oSavedFile.seek(nPos); FHI`/  
} AjK'P<:/  
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public synchronized int write(byte[] b,int nStart,int nLen) _*+ 7*vAL  
{ PK5xnT:  
int n = -1; w7]@QTC  
try{ BXVmt!S5F  
oSavedFile.write(b,nStart,nLen); D`LcL|nmH  
n = nLen; ,.uPlnB_  
} 4*_9Gl
 
catch(IOException e) M yr [  
{ =LS?:Mhm  
e.printStackTrace (); jyf[O -  
} -Vk+zEht  
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return n; 2*5Z| 3aX  
} v*1UNXU\  
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} Be+vC=\K  
d:6?miMH]t  
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/* <IGQBu#ZH  
**SiteInfoBean.java {SW}S_  
*/ Ym5q#f)|  
package NetFox; { D1.
  
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public class SiteInfoBean { ]%3o"|  
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private String sSiteURL; //Site's URL 2;NIUMAMM  
private String sFilePath; //Saved File's Path v"Fa_+TVx  
private String sFileName; //Saved File's Name GmB7@-[QA%  
private int nSplitter; //Count of Splited Downloading File b,8W |  
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public SiteInfoBean() {mMrD 5  
{//nSplitter的缺省值为5 T&I*8 R~  
//default value of nSplitter is 5 s2Ivd*=mT  
this("","","",5); veg\A+:'  
} !q! =VC  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) T%Vii*?M  
{ #vYdP#nWb  
sSiteURL= sURL; [J0L7p*6  
sFilePath = sPath; Y!v `0z  
sFileName = sName; G:$wdT(u  
this.nSplitter = nSpiltter; w%)=`'s_  
6|t4\'  
BDyOX6  
} E% Ce/n  
hVI $r  
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public String getSSiteURL() 2:Q9gru  
{ f7}/ {}g  
return sSiteURL; /NaIMo5  
} c$Js<[1  
SY_T\ }  
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public void setSSiteURL(String value) gd-4hR  
{ /Ws@YP  
sSiteURL = value;  a= ;7  
} &96I4su  
#Na3eHT  
d>eVR  
public String getSFilePath() CeoK@y=o  
{ f*7/O |Gp  
return sFilePath; F_U3+J>  
} IY?[0S  
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public void setSFilePath(String value) a;D{P`%n  
{ Zh]d&Xeq  
sFilePath = value; Glcl7f"<^  
} `h/j3fmX?  
[S9T@Q  
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public String getSFileName() {BKu'A  
{ f@T/^|`mh  
return sFileName; ZFNM>C^  
} deHhl(U;  
DTk)Y-eQ  
*<#jr  
public void setSFileName(String value) 4:=']C  
{ Tk9u+;=6$  
sFileName = value; >nkd U  
} MQY^#N  
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UP}Ys*  
public int getNSplitter() <Vm+Lt9  
{ 2?58=i%b  
return nSplitter; r.0IC*Y  
} Q\ TawRK8  
}BS.OK?  
%*lOzC  
public void setNSplitter(int nCount) t&^9o$  
{ ]tL9y<  
nSplitter = nCount; X"YH49?  
} R:P'QM   
} *x2+sgSf_0  
|Xk'd@<  
ifl`QZp_  
/* t6BggO"_u  
**Utility.java lcHwKd  
*/ rlmzbIuI9  
package NetFox; R<@s]xX_  
M5s>;q)  
j|TcmZGO  
public class Utility { XYhN;U}Z  
l7]:b8  
"<H.F87Z)  
public Utility()
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{ S:4'k^E  
a,tzt ]>  
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} MWl?pG!Y  
[X]yj  
//线程睡眠 kg?[  
public static void sleep(int nSecond) R7}=k)U?d@  
{ R)MWO5  
try{ %^f!= *  
Thread.sleep(nSecond); xDv$z.=Y  
} i"Hec9Ri  
catch(Exception e) [74HUw>  
{ c""*Ng*T  
e.printStackTrace (); N7:=%Fy(  
} t+7h(?8L  
} v=e`e68U~  
`&2~\o/  
//日志 bD*V$w*P  
public static void log(String sMsg) {I0b%>r=  
{ +?Vj}p;  
System.err.println(sMsg); q&OF?z7H  
} u+%Ca,6  
EITA[Ba B`  
L)W1bW}  
public static void log(int sMsg) /|V!2dQs"  
{ (|+Sbq(o  
System.err.println(sMsg); ZDuP|" ^  
} (T:OZmEO.  
} jA_wOR7$  
!D6  

/RU'~(  
/* @zo}#.g  
**TestMethod.java w
ZB:7E%  
*/ 2(M^8Bl  
package NetFox; S`g:zb_  
d5h]yIz^  
3<.]+ukm  
public class TestMethod { (?R;u>  
6/_] |4t  
Syv[[Ek  
public TestMethod() ^f*}]`S  
{ ///xx/weblogic60b2_win.exe 1{D_30sG.  
try{ eD5:0;X2  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,p2BB"^_i  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); #yz
5CWu  
SiteFileFetch fileFetch = new SiteFileFetch(bean); W <.h@Rz+  
fileFetch.start(); bW03m_<M<1  
} ,{DZvif   
catch(Exception e){e.printStackTrace ();} ms9zp?M  
!_EL{/ko  
W,<L/ZKJ  
} 4Ufx,]  
?4>uGaU\  
|m{Q_zAB  
public static void main(String[] args) rHe*/nN%*  
{ [MLJs-*   
new TestMethod(); >d#oJ?goX  
} YDh6XD<Z  
} }xhat,9  
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