http断点续传简单实现（java)

/* RFC;1+Jn  
**SiteFileFetch.java kUt9'|9!  
*/ LJy'wl  
package NetFox; f3>/6C  
import java.io.*; $ZU(bEUOG  
import java.net.*;
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public class SiteFileFetch extends Thread { >DRs(~|V#  
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 M9K).P=  
SiteInfoBean siteInfoBean = null; //文件信息Bean ;]Aa  
long[] nStartPos; //开始位置 oc(bcU  
long[] nEndPos; //结束位置 [f0HUbPX  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 @nP}q!y  
long nFileLength; //文件长度 mSfhl(<L  
boolean bFirst = true; //是否第一次取文件 ^H4iHjg  
boolean bStop = false; //停止标志 c)8wO=!  
File tmpFile; //文件下载的临时信息 DBUwf1=qj  
DataOutputStream output; //输出到文件的输出流 :RsPGj6  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） lF(!(>YZ  
public SiteFileFetch(SiteInfoBean bean) throws IOException L{f>;[FR  
{ #P#R~b]  
siteInfoBean = bean; #!jRY!2Vt  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); <o+ 7
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); p2vBj.*J  
if(tmpFile.exists ()) :dN35Y]a  
{ \bic.0-  
bFirst = false; nZCpT |M5  
read_nPos(); EcoUpiL%2  
} Jche79B  
else S=,1} XZ  
{ rR@n> Xx  
nStartPos = new long[bean.getNSplitter()]; "t:.mA<v  
nEndPos = new long[bean.getNSplitter()]; <IyL
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} }c4E 2c  
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} -ouJf}#R  
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public void run() u45h{i-e  
{ h:jI  
//获得文件长度 SKSAriS~  
//分割文件 m0\"C-Bk  
//实例FileSplitterFetch "1!.^<V*  
//启动FileSplitterFetch线程 :+ 9Ft>  
//等待子线程返回 7lDaok  
try{ <]Pix)  
if(bFirst) )/WA)fWkT  
{ y>7VxX0xi  
nFileLength = getFileSize(); fteyG$-s  
if(nFileLength == -1) S?nNZW\6[  
{ /[|}rqX(  
System.err.println("File Length is not known!"); 0(9I\j5`TT  
} 2>MP:yY;K  
else if(nFileLength == -2) oj^5G ]_<  
{ K*Nb_|~  
System.err.println("File is not access!");
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} 1RI#kti-"  
else k\Z;Cmh>  
{ &Qtp"#{  
for(int i=0;i<nStartPos.length;i++) 1(:b{Bl  
{ Q_dXRBv=n  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); )-Mn"1ia  
} vbWJhjK0h  
for(int i=0;i<nEndPos.length-1;i++) kKxL04  
{ []=FZ`4  
nEndPos = nStartPos[i+1]; [L*[j.r7[  
} <nOuyGIZ  
nEndPos[nEndPos.length-1] = nFileLength; AF*ni~  
} m0BG9~p|  
} [NCXn>Z  
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//启动子线程 f gK2.;>  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; _o
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for(int i=0;i<nStartPos.length;i++) F;d%@E_Bc  
{ VGTeuu5i  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), r{R[[]p  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Eo7 _v  
nStartPos,nEndPos,i); rnMG0  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =A0"0D{\  
fileSplitterFetch.start(); +?"HTDBE||  
} E,*JPK-A x  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), dt-Qu},8-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); A=v lC?&Z  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", AQnJxIL:  
nEndPos = " + nFileLength); Pg*?[^*  
// fileSplitterFetch[nPos.length-1].start(); "%.|n|  
Njy9JX  
w2uRN?   
//等待子线程结束 xVsa,EX b  
//int count = 0; #[k~RYS3  
//是否结束while循环 aWHd}%  
boolean breakWhile = false; 8Z9MD<RLw  

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while(!bStop) aJK-O"0/  
{ b[J-ja.   
write_nPos(); }"%!(rx  
Utility.sleep(500); 7.7Cluh5,  
breakWhile = true; l]a^"4L4`o  
5}-)vsa`  
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for(int i=0;i<nStartPos.length;i++) 4 o3)*  
{ 8_^'(]  
if(!fileSplitterFetch.bDownOver) t/v@vJ`vSH  
{ pX>ua5Z  
breakWhile = false; $\0cJCQ3  
break; bjM-Hd/K  
} v?Z'[l  
} R7E]*:0}  
if(breakWhile) *fxep08B  
break; Ux_EpC   
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//count++; Ep^B
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//if(count>4) lSZ"y Q+  
// siteStop(); (/T+Wpy?  
} v t^r1j  
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System.err.println("文件下载结束！"); [WcS[](ob  
} ggrI>vaw  
catch(Exception e){e.printStackTrace ();} C$KaT3I  
} ::p-9F  
%3]3r*e&5  

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//获得文件长度 CMC?R,d  
public long getFileSize() GYFgEg}  
{ X }m7@r@  
int nFileLength = -1; $@_
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try{ LTg?5GwD\j  
URL url = new URL(siteInfoBean.getSSiteURL()); V8-4>H}Cb/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); o:Ln._bj  
httpConnection.setRequestProperty("User-Agent","NetFox"); aF D="Zh  
,)Yao;Cvd  
; qO@A1Hq  
int responseCode=httpConnection.getResponseCode(); #uQrJh1o8  
if(responseCode>=400) ,yTN$K%M  
{ ].LJt['%8  
processErrorCode(responseCode); Xfj)gPt}  
return -2; //-2 represent access is error cL6 6gOEL  
} jeY4yM  
cB{%u '  
4+)Zk$E  
String sHeader; H!p!sn  
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!&Z*yH  
for(int i=1;;i++) QxKAXq@)i  
{ {PL,VY)Z  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Lt>?y&CcQ  
//Utility.log(in.readLine()); yU> T8oFh  
sHeader=httpConnection.getHeaderFieldKey(i); cvxIp#FbW  
if(sHeader!=null) STv(kQs  
{ 6KVV z/  
if(sHeader.equals("Content-Length")) n:F@gZd`  
{ 2%bhW,?I  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); RTA%hCr!  
break; fQxSMPWB  
} &.hoCPo$  
} =+`D  
else o.v2z~V  
break; r|M'TA~:  
} JW-|<CJ  
} "=FIFf  
catch(IOException e){e.printStackTrace ();} se!g4XEWD  
catch(Exception e){e.printStackTrace ();} FZeP<Ban  
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Utility.log(nFileLength); @?m+Z"o|z  
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return nFileLength; O!/ekU|,r  
} %,XI]+d  
tO7I&LNE  
$%B5$+  
//保存下载信息（文件指针位置） j+nv=p  
private void write_nPos() xwi!:PAf,o  
{ $<:'!#%  
try{ R#D#{cC(  
output = new DataOutputStream(new FileOutputStream(tmpFile)); YKNb59k  
output.writeInt(nStartPos.length); QOd!]*W`?m  
for(int i=0;i<nStartPos.length;i++) f P+QxOz  
{ Y^yG/F  
// output.writeLong(nPos); f*v1J<1#  
output.writeLong(fileSplitterFetch.nStartPos); v
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output.writeLong(fileSplitterFetch.nEndPos); ?H<~ac2e  
} <;aJ#qT  
output.close(); wz h.$?~  
} Q4=|@|U0  
catch(IOException e){e.printStackTrace ();} C>NQ-w^  
catch(Exception e){e.printStackTrace ();} dt<~sOT3s  
} Rh[Ibm56  
sSz%V[XWL  
w1cw1xX*  
//读取保存的下载信息（文件指针位置） >2u y  
private void read_nPos() -IbbPuRq  
{ i0iez9B  
try{ @"w2R$o  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); QE3ryD  
int nCount = input.readInt(); ?3Pazc]+|  
nStartPos = new long[nCount]; IKo;9|2U  
nEndPos = new long[nCount]; p0Z:Wkz]  
for(int i=0;i<nStartPos.length;i++) r,Ds[s)B  
{ \
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nStartPos = input.readLong(); W-ez[raY  
nEndPos = input.readLong(); h07eEg  
} Ww=O=c5uOu  
input.close(); qfa}3k8et  
} =&N$
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catch(IOException e){e.printStackTrace ();} ~GA8_B  
catch(Exception e){e.printStackTrace ();} 8<{;=m8cQ  
} e62y  
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private void processErrorCode(int nErrorCode) >J@egIKzP  
{ L_k9g12  
System.err.println("Error Code : " + nErrorCode); W_%W%i|  
} M!#AfIyB  
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,z[(k"  
//停止文件下载 ewym1}o  
public void siteStop() ||XIWKF<n2  
{  $WR?  
bStop = true; K#wK1
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for(int i=0;i<nStartPos.length;i++) L1{T ?aII  
fileSplitterFetch.splitterStop(); @/ k x er  
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<6R"h-u"  
} m:3J!1  
} RG&6FRoq  
//负责部分文件的抓取 AEqq1A
 
**FileSplitterFetch.java 4'm q_o#4W  
*/ {_(+>v"eJ  
package NetFox; nj  
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&[~[~m|  
import java.io.*; 2( _=SfQ  
import java.net.*; 0bSz4<}  
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public class FileSplitterFetch extends Thread { 'hF@><sqk  
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:<%vE!$  
String sURL; //File URL n_9x"m$  
long nStartPos; //File Snippet Start Position s!de2z  
long nEndPos; //File Snippet End Position V7@ {D  
int nThreadID; //Thread's ID L/fRF"V  
boolean bDownOver = false; //Downing is over dhtb?n{  
boolean bStop = false; //Stop identical 8(Fu  
FileAccessI fileAccessI = null; //File Access interface \igaQ\~  
+ Kk@Q  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 7kd
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{ `)tA YH  
this.sURL = sURL; /< QSe  
this.nStartPos = nStart; l[*sHi  
this.nEndPos = nEnd; LwQH6 !;[  
nThreadID = id; CjKRP;5  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 m8AAp1=  
} .CS v|:'1  
m[rL\](-  
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public void run() p:tN642  
{ tT-=hDw  
while(nStartPos < nEndPos && !bStop) $eX*  
{ L$hc,  
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;($1Z7j+  
try{ wv^b_DR  
URL url = new URL(sURL); *8UYSA~v  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); f[}|rf  
httpConnection.setRequestProperty("User-Agent","NetFox"); t:T?7-XIE  
String sProperty = "bytes="+nStartPos+"-"; oyW00]ka  
httpConnection.setRequestProperty("RANGE",sProperty); h.^o)T  
Utility.log(sProperty); xYwkFB$$*  
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+?V0:Kz]  
InputStream input = httpConnection.getInputStream(); !tBeuemN%  
//logResponseHead(httpConnection); MS{{R+&  
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byte[] b = new byte[1024]; Mz\yP
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int nRead; ]>vf9]  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) f?0D%pxc}&  
{ y;:]F|%<  
nStartPos += fileAccessI.write(b,0,nRead); bP03G=`6w  
//if(nThreadID == 1) y1u9B;Fd  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Yw[{beo  
} 5H*>  
xKb"p4k9d  
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Utility.log("Thread " + nThreadID + " is over!"); `oVB!eapl  
bDownOver = true; gDv$DB8-  
//nPos = fileAccessI.write (b,0,nRead); \n;g2/VjO  
} _4!{IdR  
catch(Exception e){e.printStackTrace ();} Wxs>osq  
} ArL-rJ{}  
} 9t}J|09i  
#]X2^ND47  
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//打印回应的头信息 =%L@WVbM  
public void logResponseHead(HttpURLConnection con) n.I2$._(b  
{ 9M]^l,
 
for(int i=1;;i++) P{Lg{I_w.B  
{ u>m'FECXj  
String header=con.getHeaderFieldKey(i); >fg4x+0%  
if(header!=null) gg(k7e
 
//responseHeaders.put(header,httpConnection.getHeaderField(header)); h(|;\~  
Utility.log(header+" : "+con.getHeaderField(header)); =+4 _j  
else @ge LW!  
break; .8x@IWJD
 
} KD=bkZ&  
} N;g$)zCV1  
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public void splitterStop() 'mUI-1GkT  
{ 1xIFvXru  
bStop = true; s{B_N/^  
} &\c5!xQ9*  
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@'Q%Jc(  
} (s;zRb!4L  
,$ mLL  
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/* ,bJx| K  
**FileAccess.java n)yqb  
*//文件访问(定位，写) $8)/4P?OL  
package NetFox; = j -  
import java.io.*; =*pu+o,?  
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public class FileAccessI implements Serializable{ %{Gqhb=u\  
\KTX{qI"f  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 FN G]  
RandomAccessFile oSavedFile; QqRL>.)W  
long nPos; .}^m8
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/:B!hvpw  
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public FileAccessI() throws IOException d}Q;CF3m:  
{ At"@`1n_u'  
this("",0); 7%C6gU!r  
} BeBa4s  
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Lb(=:Z!{  
public FileAccessI(String sName,long nPos) throws IOException Fvg>>HVu  
{ WxFVbtw  
oSavedFile = new RandomAccessFile(sName,"rw"); \:y oS>G  
this.nPos = nPos; Opavno%&  
oSavedFile.seek(nPos); TsVU
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} ?*LVn~y  
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public synchronized int write(byte[] b,int nStart,int nLen) i/|}#yw8A  
{ HQ:Y:  
int n = -1; f*o+g:]3  
try{ )5Wt(p:T6_  
oSavedFile.write(b,nStart,nLen); qf T71o(  
n = nLen; *(E]]8o  
} L%;fYi;n  
catch(IOException e) <c3Te$.  
{ %\^VxM  
e.printStackTrace (); #?"^:,Y  
} rHiBW!  
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return n; RBHU5]5  
} zDBm^ s  
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} ,&g-DCag  
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/* qoZe<jW (  
**SiteInfoBean.java @vL0gzE?nB  
*/ !^EA}N.u  
package NetFox; a5(9~.9  
>}/T&S  
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public class SiteInfoBean { L3\(<[  
J\N&u#  
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private String sSiteURL; //Site's URL >QPCYo<E  
private String sFilePath; //Saved File's Path {].]`#4Jx  
private String sFileName; //Saved File's Name E&Zt<pRf;2  
private int nSplitter; //Count of Splited Downloading File %L$?Mey  
(,|eE)+  
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public SiteInfoBean() \=$G94%  
{//nSplitter的缺省值为5 Js.G hTs  
//default value of nSplitter is 5 ^5)=)xVF  
this("","","",5); R-2Abyts2  
} BDX>J3h  
b
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) vtzbF1?O  
{ LRdV_O1e6M  
sSiteURL= sURL; }!WuJz"  
sFilePath = sPath; Zlv`yC*r  
sFileName = sName; !F2JT@6  
this.nSplitter = nSpiltter; BtQqUk#L2  
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} J$(79gH{  
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public String getSSiteURL() +1eb@bX  
{ }dEf |6_  
return sSiteURL; #BIY[{!  
} I=k`VId:  
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J& D0,cuk  
public void setSSiteURL(String value) bGik~  
{ K48QkZ_gY  
sSiteURL = value; h|EHK!<"8  
} x`K"1E{2  
nd h\+7  
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public String getSFilePath() p0pA|  
{ v5L#H=P  
return sFilePath; KPa@~rU  
} - ysd`&  
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public void setSFilePath(String value) `yM9XjEl>  
{ TEbE-h0)]  
sFilePath = value; hNF,sA  
} _!
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public String getSFileName() |YrvY1d!  
{ wR9gx-bE 4  
return sFileName; _9z+xl  
} Fz]!2rt  
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public void setSFileName(String value) '~pZj"uy  
{ NOtwgZ-  
sFileName = value; Y_nl
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} -M-y*P
)  
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public int getNSplitter() q94*2@KV  
{ Kxsj_^&|i  
return nSplitter; J 77*Ue^  
} Bh6lK}9
  
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public void setNSplitter(int nCount) lp5b&I_  
{ ,fyqa  
nSplitter = nCount; t=dZM}wj_\  
} $#
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} ,.,Y{CP  
V V Aw y6  
9<*<-x{A17  
/* >V@,K z1  
**Utility.java w%kaM=  
*/ %&
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package NetFox; NqN9  
*G,r:Bnb  
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public class Utility { [Ny'vAHOj  
$)7Af6xD  
Oz.Zxw  
public Utility() &0J/V>k  
{ #M8>
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13I~   
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} *9}~?#b  
i-&"1D[&  
//线程睡眠 <u"#Jw/VP  
public static void sleep(int nSecond) pDlh^?cux  
{ %;PPu$8K9  
try{ xTM&SVNbL_  
Thread.sleep(nSecond); 3Pp*ID  
} <..%@]+  
catch(Exception e) /BVNJNhz  
{ 0r=Lilu{q  
e.printStackTrace (); nZN]Q9  
} k 9Kv  
} bah5 f  
eeb8v:4  
//日志 vVLR9"rHM  
public static void log(String sMsg) 4aB`wA^x  
{ ld[]f*RuW  
System.err.println(sMsg); e= "/oo  
} Qq]UEI `Go  
4[.- a&!}  
n*iaNaU"'  
public static void log(int sMsg) =OO_TPEZ  
{ ?-\KVha  
System.err.println(sMsg); qm]ljut  
} 8gBqur{  
} T:.J9  
hY'"^?OP  
a/^YgrC\T  
/* .#WF'  
**TestMethod.java 2 >xV&  
*/ NnHM$hEI"U  
package NetFox; <)n
  
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_[  
public class TestMethod { `(B1 "qRi  
Z/x<U.B  

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public TestMethod() {/0,lic  
{ ///xx/weblogic60b2_win.exe @1Zf&'/6  
try{ 1NOz $fW  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ha8do^x  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ={L:q8v)  
SiteFileFetch fileFetch = new SiteFileFetch(bean); c@nl;u)n  
fileFetch.start(); $V~%$  
} =C3l:pGMB;  
catch(Exception e){e.printStackTrace ();} z
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} Ha+FH8rZ  
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public static void main(String[] args) BxZop.zwE(  
{ q75F^AvH  
new TestMethod(); <&L;9fr  
} J0=`n(48B  
} x(=kh%\;  
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