http断点续传简单实现（java)

/* |gA@WV-%  
**SiteFileFetch.java 3)y1q>CQf  
*/ @"@|O>KJ  
package NetFox; +Yc^w5 !(  
import java.io.*; lN#j%0MaUo  
import java.net.*; 1EXT^2!D  
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public class SiteFileFetch extends Thread { -67Z!N  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ~;3yjO)l?)  
long[] nStartPos; //开始位置 z'U.}27&o  
long[] nEndPos; //结束位置 vN'+5*Cgy6  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 !fzS' pkk.  
long nFileLength; //文件长度 !+%gJiu:  
boolean bFirst = true; //是否第一次取文件 [UA*We 1  
boolean bStop = false; //停止标志 ,*J@ic7"  
File tmpFile; //文件下载的临时信息 s/tLY/U/  
DataOutputStream output; //输出到文件的输出流 XgC^-A w  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 9j:]<?D,A  
public SiteFileFetch(SiteInfoBean bean) throws IOException kk /#&b2  
{ 'F d+1 3  
siteInfoBean = bean; `eMZhYo  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); gz~oQ l)zJ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); WT'-.UX m  
if(tmpFile.exists ()) )Ka-vX)D@  
{ :)~l3:O  
bFirst = false; a+E 8s7C/D  
read_nPos(); DK74s  
} eUcbe33  
else h mRmU{(Y  
{ t`Kpbfk  
nStartPos = new long[bean.getNSplitter()]; LDr?'M!D  
nEndPos = new long[bean.getNSplitter()];

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} '2.ey33V  
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} 2Mt$Dah  
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public void run() x4I!f)8Q
 
{ |dgiW"tUm  
//获得文件长度 F9 r5 Z  
//分割文件 h9QM nH'  
//实例FileSplitterFetch SaXt"Ju,AH  
//启动FileSplitterFetch线程 EHwb?{  
//等待子线程返回 klUV&O+=%  
try{ ^ 8}P_  
if(bFirst) K1 "HJsj  
{ yMNJHiE/  
nFileLength = getFileSize(); TRi'l#m4  
if(nFileLength == -1) ,Vi_~b  
{ 6
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System.err.println("File Length is not known!"); ]`$6=)_X  
} IU8zidn&  
else if(nFileLength == -2) cb^IJA9}  
{ $VmV>NZ  
System.err.println("File is not access!"); e3ZRL91c  
} F_qApyU,7  
else rr tMd  
{ k*C69  
for(int i=0;i<nStartPos.length;i++) /(^-=pAX  
{ 4;6"I2;zfG  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); =3035{
\  
} nX (bVT4i  
for(int i=0;i<nEndPos.length-1;i++) Z
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{ ,7B7X)m{3  
nEndPos = nStartPos[i+1]; P8YnKyI,.  
} LA6XTgcu  
nEndPos[nEndPos.length-1] = nFileLength; g=\(%zfsxr  
} !0l|[c4 e>  
} jA1S|gV  
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//启动子线程 T
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; aH"d
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for(int i=0;i<nStartPos.length;i++) #`_W?-%^  
{ K6->{!8]k  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]V/5<O1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), q]="ek&_  
nStartPos,nEndPos,i); E:9RskI  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &}u_e`A  
fileSplitterFetch.start(); w: BJ4bi=  
} ._0$#J S[  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5S4Nx>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); X?haHM#]  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", /RB%m8@;  
nEndPos = " + nFileLength); %`bs<ZWT  
// fileSplitterFetch[nPos.length-1].start(); DNmC   
%1{S{FB  
q?j7bp]  
//等待子线程结束 e)HFI|>  
//int count = 0; wf  ]Wm  
//是否结束while循环 s>DFAu!  
boolean breakWhile = false; 0")_%  
C/!P&`<6  
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while(!bStop) >7WT4l)7!b  
{ iX?j"=!  
write_nPos(); .Yk}iHcW.  
Utility.sleep(500); 4M"'B A<  
breakWhile = true; Ue9d0#9  
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for(int i=0;i<nStartPos.length;i++) k x:+mF  
{ 8;qOsV)UDT  
if(!fileSplitterFetch.bDownOver) mg*iW55g  
{ NkUY_rKPb  
breakWhile = false; F42^Uoaz  
break; ;R+Gf!1  
} s1OSuSL>  
} ~Xx}:@Ld  
if(breakWhile) S>5w=RK 
 
break; *fY*Wy9  
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# 9bw'm  
//count++; "A[.7w  
//if(count>4) {v!w2p@  
// siteStop(); =&g:dX|q8  
} @[D5{v)S  
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System.err.println("文件下载结束！"); ;-i)}<  
} ~I")-2"B  
catch(Exception e){e.printStackTrace ();} h/5V~ :)  
} ZXhNn<  
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<DMm [V{  
//获得文件长度 ]Y,V)41gCE  
public long getFileSize() +v%+E{F$+  
{ `_&vvJPn@!  
int nFileLength = -1; &xr(Kb  
try{ |s#,^SJ0  
URL url = new URL(siteInfoBean.getSSiteURL()); t^bh2$J  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2L<1]:I  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,wr5DQ  
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int responseCode=httpConnection.getResponseCode(); z>W?\[E<2  
if(responseCode>=400) #H
y9;Q  
{ f/ 3'lPK^  
processErrorCode(responseCode); .mnkV -m  
return -2; //-2 represent access is error 2kgSIvk\  
} -4Q\FLC'k  
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String sHeader; :S`12*_g"  
{
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for(int i=1;;i++) >xRUw5jN  
{ "
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); #m{F*(%  
//Utility.log(in.readLine()); U*EBH  
sHeader=httpConnection.getHeaderFieldKey(i); 4tkb7D q  
if(sHeader!=null) akj#.aYk  
{ KsTE)@F:  
if(sHeader.equals("Content-Length")) $LBgBH&z  
{ t%y i3  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); s_Z5M2o  
break; uv$utu>< *  
} %f\j)qw  
} $5#DU__F/  
else OZKZv,  
break; C,O9?t  
} 1Uah IePf  
} 6XAofN/5f  
catch(IOException e){e.printStackTrace ();} !;t6\Z8&  
catch(Exception e){e.printStackTrace ();} B&(/,.  
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Utility.log(nFileLength); >TGc0 z+  
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return nFileLength; 5H
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} 5rtE/{A  
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=OrVaZ0  
//保存下载信息（文件指针位置） DLq'V.M:  
private void write_nPos() .5~3D97X&  
{ Eg4&D4TGp  
try{ Q*f0YjH!  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Rto/-I0l  
output.writeInt(nStartPos.length); xgsEe3|  
for(int i=0;i<nStartPos.length;i++) /+<G@+(  
{ 6 G,cc  
// output.writeLong(nPos); zo ]-,u  
output.writeLong(fileSplitterFetch.nStartPos); V\c`O  
output.writeLong(fileSplitterFetch.nEndPos); IUG}Q7w5  
} X2<fS~m  
output.close(); ;+3@S`2r  
} /*6[Itm_h  
catch(IOException e){e.printStackTrace ();} L8pKVr  
catch(Exception e){e.printStackTrace ();} ihct~y-9W  
} ?5[$d{ Gjl  
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//读取保存的下载信息（文件指针位置） K,bX<~e5  
private void read_nPos() WxJaE;`Ige  
{ L'e|D=y  
try{ Lq#!}QcW=  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,{'ZP_  
int nCount = input.readInt(); ^C2SLLgeJ  
nStartPos = new long[nCount]; QqC-ztz  
nEndPos = new long[nCount]; R2Q1Rk#  
for(int i=0;i<nStartPos.length;i++) =QwT)KRB%  
{ dA#'HMh@  
nStartPos = input.readLong(); Nc^:v/(P  
nEndPos = input.readLong(); }+:X=@Z@  
} Lu71Qdu09  
input.close(); *y~~~ 'J/  
} I!Fd~g9I4  
catch(IOException e){e.printStackTrace ();} ACEVd! q  
catch(Exception e){e.printStackTrace ();} (F*y27_u  
} (s51GRC  
:c:}_t{%  
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private void processErrorCode(int nErrorCode) b-J6{=k^  
{ [t?:CgI)E  
System.err.println("Error Code : " + nErrorCode); Sq`Zu
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} .;dI&0Z  
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)'/xNR  
//停止文件下载 (Kw%fJT  
public void siteStop() {P==6/<2o  
{ 5',
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bStop = true; .
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for(int i=0;i<nStartPos.length;i++) [KEw5-=i@  
fileSplitterFetch.splitterStop(); ;IT'6m`@W  
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} 4=njM`8Y'  
} [mo9?  
//负责部分文件的抓取 #,SP
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**FileSplitterFetch.java Jn\>Sz(96  
*/ N8*QAekN  
package NetFox; m&--$sr  
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import java.io.*; |-]'~@~  
import java.net.*; !3ji]q;uF  
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public class FileSplitterFetch extends Thread { 4@jX{{^6%  
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String sURL; //File URL :TP\pH7E  
long nStartPos; //File Snippet Start Position `cFNO:  
long nEndPos; //File Snippet End Position g9F?j  
int nThreadID; //Thread's ID iG{xDj{CKv  
boolean bDownOver = false; //Downing is over #a 4X*X.8c  
boolean bStop = false; //Stop identical v
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FileAccessI fileAccessI = null; //File Access interface "i\^GK=  
:>3?|Z"Aj  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ?V =#x.9  
{ we33GMxHl`  
this.sURL = sURL; u"U7aYGkY  
this.nStartPos = nStart; cE*d(g  
this.nEndPos = nEnd; 'Z6x\p  
nThreadID = id; gAK"ShOhG=  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ]&"01M~+K  
} fy>~GFk(  
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public void run() j HEt   
{ m :2A[H+  
while(nStartPos < nEndPos && !bStop) q]Af I(  
{ D1wONss  
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try{ acow  
URL url = new URL(sURL); YN7JJJ/~T  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }k@SmO8  
httpConnection.setRequestProperty("User-Agent","NetFox"); Eg_ram`\R  
String sProperty = "bytes="+nStartPos+"-"; iE^=Vf;  
httpConnection.setRequestProperty("RANGE",sProperty); O0sLcuT$  
Utility.log(sProperty); vSwRj<|CF  
(~?p`g+I.P  
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InputStream input = httpConnection.getInputStream(); OgCz[QXr_  
//logResponseHead(httpConnection); (J.k\d   
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byte[] b = new byte[1024]; 5wC,:c[H7  
int nRead; }`+9ie7]/  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Cq}E5M  
{ 2CV?cm  
nStartPos += fileAccessI.write(b,0,nRead); yg82a7D  
//if(nThreadID == 1) 4i+H(d n  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); jaQH1^~l/-  
} 1;~|[C  
9D7i>e%,;-  
!9_'_8  
Utility.log("Thread " + nThreadID + " is over!"); ,k}(]{ -  
bDownOver = true; R#W=*cN  
//nPos = fileAccessI.write (b,0,nRead); G|z%T`!U1;  
} cT nC  
catch(Exception e){e.printStackTrace ();} V}Ce3wgvA  
} FQ u c}A  
} I MG^L  
=OFx4#6a  
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//打印回应的头信息 0CK3jdZ+X  
public void logResponseHead(HttpURLConnection con) k\-h-0[|  
{ Hm
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for(int i=1;;i++) $#E!/vVwD7  
{ N{uVh;_  
String header=con.getHeaderFieldKey(i); plM:7#eA  
if(header!=null) ,OFNV|S$  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 0xfF  
Utility.log(header+" : "+con.getHeaderField(header)); 7\yh<?`V8  
else k +Cwnp  
break; &"^U=f@v  
} dd*p_4;  
} $4BvDZDk`B  
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public void splitterStop() WJN
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{ #Sg"/Cc  
bStop = true; Yh;A)Np  
} R1(3c*0f  
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} Pk;YM}  
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`i<Z< <c>  
/* ?@;#|^k9  
**FileAccess.java PJ^qE|X  
*//文件访问(定位，写) -B?cF9  
package NetFox; aP#/%  
import java.io.*; Q"H/RMo-  
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public class FileAccessI implements Serializable{ B:Hr{%O  
t(jE9t|2e6  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 lSc=c-iOv  
RandomAccessFile oSavedFile; gFsqCx<q  
long nPos; Z58{YCY  
_<=h#lH  
 K
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public FileAccessI() throws IOException h}kJ,n  
{ F<XOt3VY.  
this("",0); Q!_d6-*u  
} %r8;i  
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public FileAccessI(String sName,long nPos) throws IOException 'gHg&E9E&  
{ Kxg@(Q  
oSavedFile = new RandomAccessFile(sName,"rw"); AQmHa2P  
this.nPos = nPos; 5{
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oSavedFile.seek(nPos); XK})?LTD  
} vrcIwCa  
SMzq,?-`  
W/AF  
public synchronized int write(byte[] b,int nStart,int nLen) 6q6xqr:W  
{ `.J17mQe"  
int n = -1; h9/fD5  
try{ LD1&8kJ*l  
oSavedFile.write(b,nStart,nLen); 8g Z)c\  
n = nLen; t"Ah]sD  
} c+ e~BN  
catch(IOException e) j[.nk  
{ 0^sY>N"  
e.printStackTrace (); {M5t)-  
} Q$v00z]f*  
b $JS|  
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return n; CH&{x7$he  
} lo(
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}
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/* U||GeEd  
**SiteInfoBean.java `$S&:Q,  
*/ w"wW0uE^  
package NetFox; %1.F;-GdsW  
Q
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public class SiteInfoBean { owQ,op#  
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private String sSiteURL; //Site's URL %l
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private String sFilePath; //Saved File's Path 849,1n^  
private String sFileName; //Saved File's Name 6Eu(C]nC(  
private int nSplitter; //Count of Splited Downloading File 3ie k>'T  
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public SiteInfoBean() _X~O6e-!  
{//nSplitter的缺省值为5 X<$Tn60,  
//default value of nSplitter is 5 {0Y6jk>I  
this("","","",5); o+'|j#P  
} VMRfDaO9  
} &B6  
hdHz", )  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) j2<+[h-  
{ ld@+p  
sSiteURL= sURL; 94BH{9b5  
sFilePath = sPath; i7XY3yhC  
sFileName = sName; hm! J@  
this.nSplitter = nSpiltter; ?$ e]K/
*  
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:5,~CtF5 `  
} 6dR+qJa6i  
W~;Jsd=f  
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public String getSSiteURL() V;xPZ2C;  
{ aC\f;&P>  
return sSiteURL; e^>>"tr  
} =wdh#{  
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public void setSSiteURL(String value) BX0lk  
{ $qQYxx@  
sSiteURL = value; ;rT'~?q  
} ,r
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.
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GHcx@||C?  
public String getSFilePath() ZyUcL_  
{ ='o3<}  
return sFilePath; <J&S[`U!  
} sX%n`L  
ju{Y6XJ)  
[! $NTt_  
public void setSFilePath(String value) CvY+b^;  
{ o{sv<$  
sFilePath = value; ca_mift  
} ^el+ej/=  
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public String getSFileName() }8ubGMr,Y  
{ 2e1KF=N+  
return sFileName; e Wux  
} RhE~-b[X  
{=ox1+d  
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public void setSFileName(String value) {-\U)&6#v  
{ ^z{szy?Fg  
sFileName = value; -eG~  
} Food<(!.>  
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*U[y
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.  
public int getNSplitter() 9=>f
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{ |"gL{De  
return nSplitter; 4nsJZo#S/  
} e2O6q05 ?Q  
$d?W1D<A  
R/hIXO  
public void setNSplitter(int nCount) +X=*>^G(-  
{ R*[sO*h\k  
nSplitter = nCount; &?@C^0&QV  
} p~$c
wbQ!  
} DzAZv/h76  
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/* 4VJUu`[  
**Utility.java R=z])  
*/ yix[zfQt0  
package NetFox; [;u#79aE
 
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public class Utility { IO\4dU)  
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public Utility() Y sM*d  
{ }Pcm'o_wT  
#a
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} M-o'`e'  
F$7!j$ Z  
//线程睡眠 n>Ff tVZNJ  
public static void sleep(int nSecond) k#].nQG  
{ _ \D%  
try{ /I%z7f91O  
Thread.sleep(nSecond); @5>#<LV=E#  
} nKx)R^]k  
catch(Exception e) (>al-vZ6A  
{ 8dczC  
e.printStackTrace (); <tr]bCu}  
} X6HaC+P  
} 8u[_t.y4m  
7L!JP:v  
//日志 @>2pY_  
public static void log(String sMsg) b($hp%+yJ  
{ SVCh!/qe\  
System.err.println(sMsg); xRh 22z  
} V1aP_G
-:  
)^j_O^T5  
:{7+[LcH7  
public static void log(int sMsg)  W2vL<  
{ P?0X az  
System.err.println(sMsg); /v{+V/'+  
} /fI}QY1  
} .~]|gg~  
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UC!mp?   
/* $RD~,<oEm  
**TestMethod.java [|(|"dh@^H  
*/ ~ ld.I4  
package NetFox; yJA~
4  
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public class TestMethod { z0 "DbZ;d  
5zl+M`  

#AD_EN9  
public TestMethod() QS#@xhH  
{ ///xx/weblogic60b2_win.exe ?@64gdlwq  
try{ oRV}Nz7hr  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ^m\o(R  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 1/DtF  
SiteFileFetch fileFetch = new SiteFileFetch(bean); .;? Bni  
fileFetch.start(); ^FVdA1~/  
} SuE~Wb5&  
catch(Exception e){e.printStackTrace ();} "hIYf7r##  
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} cO?*(e1m=  
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ptCF))Zm'  
public static void main(String[] args) LlTD =tJ0  
{ Y{Z&W9U  
new TestMethod(); oF%m
  
} 
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} At7!Pas#@g  
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