http断点续传简单实现（java)

/* o!=lBfI  
**SiteFileFetch.java xjK_zO*dLq  
*/ fZ6 fV=HEF  
package NetFox; .mT#%ex  
import java.io.*; txml*/zL  
import java.net.*; x>^3]m  
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public class SiteFileFetch extends Thread { j FPU zB"  
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SiteInfoBean siteInfoBean = null; //文件信息Bean *TM;trfz  
long[] nStartPos; //开始位置 ksu}+i,a  
long[] nEndPos; //结束位置 '6o`^u>  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 hEv=T'*,K)  
long nFileLength; //文件长度 CP]S-o}yd  
boolean bFirst = true; //是否第一次取文件 k'@7ZH  
boolean bStop = false; //停止标志 z;y^t4 ^9  
File tmpFile; //文件下载的临时信息 YXX36  
DataOutputStream output; //输出到文件的输出流 J+71FP`ZH  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） .|-l+  
public SiteFileFetch(SiteInfoBean bean) throws IOException hg?j)jl|  
{ XVrm3aj(m  
siteInfoBean = bean; so!w!O@@  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 1tc]rC4h  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); :
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if(tmpFile.exists ()) b46[fa  
{ M[YTk=IM#  
bFirst = false; g5tjj.  
read_nPos(); 80?6I%UB<  
} .~.``a  
else m"gni #  
{ t['k%c  
nStartPos = new long[bean.getNSplitter()]; Pt6hGSo.  
nEndPos = new long[bean.getNSplitter()]; Ml8 YyF/~  
} Uvjdx(fY[a  
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} E0"10Qbi  
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public void run() Q_&}^  
{ hrs#ZZ:E  
//获得文件长度 q&X
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//分割文件 M.ZEqV+
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//实例FileSplitterFetch jWH{;V&ZV  
//启动FileSplitterFetch线程 f^W[;w  
//等待子线程返回 E?30J3S  
try{ m:)Z6  
if(bFirst) lx\qp`w  
{ 0U8
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nFileLength = getFileSize(); cGgM8  
if(nFileLength == -1) }>MP{67Dm  
{ )uQ-YC('0  
System.err.println("File Length is not known!"); (^sh  
} L`9TB"0R+  
else if(nFileLength == -2) UL86-R!  
{ 4. 1rJa  
System.err.println("File is not access!"); -DTB6}kw  
} v5(q)h  
else 9[cp7
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{ @S
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for(int i=0;i<nStartPos.length;i++) +>JdYV<?0  
{ C=fsJ=a5;  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); tIq>Oojdx  
} 5]
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for(int i=0;i<nEndPos.length-1;i++) 8YNu<   
{ yGU .AM  
nEndPos = nStartPos[i+1]; S8 :"<B)  
} 7OB%A&  
nEndPos[nEndPos.length-1] = nFileLength; gks ==|s.  
}
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} z0#-)AeS  
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//启动子线程 x&'o
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; M'kVL0p?vN  
for(int i=0;i<nStartPos.length;i++) rkkU"l$v  
{ led))qd@V-  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), z"tjDP  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), j5PL
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nStartPos,nEndPos,i); >D 97c|?c  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); z9[[C^C  
fileSplitterFetch.start(); YRPm^kW  
} 7 _`L$<-n  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), J , V  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); pgT9hle/  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", [`d$X^<y;  
nEndPos = " + nFileLength); p8Iw!HE  
// fileSplitterFetch[nPos.length-1].start(); 7_-w_"X  
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q#MM
  
//等待子线程结束 !lAD q|$  
//int count = 0; _2b
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//是否结束while循环 zbN
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boolean breakWhile = false; dm6~  
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while(!bStop) g?B3!,!9  
{ MU'@2c  
write_nPos(); zF8'i=b&  
Utility.sleep(500); PocYFhWQ`  
breakWhile = true; qD#VbvRc9+  
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for(int i=0;i<nStartPos.length;i++) 9M_(He -  
{ Z`Pd2VRp  
if(!fileSplitterFetch.bDownOver) 6SVqRD<`  
{ b.s9p7:J  
breakWhile = false; '0:i<`qv#g  
break; 2jl)mL  
} D==Mb~  
} .x!T+`l>8I  
if(breakWhile) i(*I@ku  
break; *5e+@rD`  
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//count++; ZQ3_y $  
//if(count>4) %r;w;`/hA  
// siteStop(); {^5?)/<  
} NBjeHtT  
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System.err.println("文件下载结束！"); YD\]{,F|  
} pQMtj0(y  
catch(Exception e){e.printStackTrace ();} HG%Z"d  
} Tv5g`/e=Ej  
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; dd Q/  
//获得文件长度 S_v(S^x6  
public long getFileSize() M"{uX
  
{ 3xNMPm  
int nFileLength = -1; 8!mc@$Z  
try{ I;7nb4]AmF  
URL url = new URL(siteInfoBean.getSSiteURL()); 1tB[_$s  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); BByCMY  
httpConnection.setRequestProperty("User-Agent","NetFox"); .R5y:O  
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int responseCode=httpConnection.getResponseCode();
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if(responseCode>=400) -h#mn2U~3r  
{ N j4IQ<OV  
processErrorCode(responseCode); ,Q/Ac{C  
return -2; //-2 represent access is error W2Luz;(U  
} :B|Dr v  
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String sHeader; 9b;A1gu  
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for(int i=1;;i++) FJNF%a)x2I  
{ ?":'O#E  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); >u0w.3r#  
//Utility.log(in.readLine()); j>Ag\@2ME  
sHeader=httpConnection.getHeaderFieldKey(i); la <npX  
if(sHeader!=null) ceT&Y{T  
{ d2S~)/@S  
if(sHeader.equals("Content-Length")) VR5fqf|*  
{ (*\jbK
 
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); i)ASsYG!  
break; k+^'?D--'P  
} GiFXX  
} Q;u SWt<{  
else U__(; /1;  
break; ZJ,cQ+fn  
} Thr*^0$C  
} {g6Qv-  
catch(IOException e){e.printStackTrace ();} Bi3+)k>u7  
catch(Exception e){e.printStackTrace ();} q<#>HjC  
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Utility.log(nFileLength); C'A]i5  
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return nFileLength; o*g|m.SjL  
} ,TJD$^  
U
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//保存下载信息（文件指针位置） AJ^#eY5  
private void write_nPos() j2l55@  
{ clw%B  
try{ ;Xvp6.:  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Gfp1mev  
output.writeInt(nStartPos.length); -62'}%?A<C  
for(int i=0;i<nStartPos.length;i++) ;a{:%t  
{ W5L iXM  
// output.writeLong(nPos);
;6ecrQMw&  
output.writeLong(fileSplitterFetch.nStartPos); gb=/#G0R  
output.writeLong(fileSplitterFetch.nEndPos); y! .J  
} aVL=K  
output.close(); =qy=-j]  
} NcPgq?3p  
catch(IOException e){e.printStackTrace ();} P +"Y  
catch(Exception e){e.printStackTrace ();} :u8
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} 5}$b0<em~  
)Or.;  
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//读取保存的下载信息（文件指针位置） cRd0S*QN2  
private void read_nPos() vDl- "!G1  
{ !o=U19)  
try{ `Q3s4VEC  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ]ul$*  
int nCount = input.readInt(); [.hyZ}B  
nStartPos = new long[nCount]; !zj0/QG\  
nEndPos = new long[nCount]; 0;4t&v7  
for(int i=0;i<nStartPos.length;i++) ;,i]w"*  
{ N>(g?A; Z+  
nStartPos = input.readLong(); 8t@p@Td|  
nEndPos = input.readLong(); "s!7dKXI"  
} Ev7J+TmXM  
input.close(); -V,v9h^  
} Yt|6 X:l  
catch(IOException e){e.printStackTrace ();} uZfnzd)c  
catch(Exception e){e.printStackTrace ();} OO?]qZa1  
} F:y[@Yn  
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private void processErrorCode(int nErrorCode) ~4P%%b0,o  
{ Mu'8;9_6  
System.err.println("Error Code : " + nErrorCode); (b'B%rFO  
}
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//停止文件下载 xss`Y,5?  
public void siteStop() z
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{ 8 k3S  
bStop = true; =K{\p`?  
for(int i=0;i<nStartPos.length;i++) +)2s-A f-  
fileSplitterFetch.splitterStop(); N3u((
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} .U T@p  
} yHxosxd<*  
//负责部分文件的抓取 ~z"=G5|  
**FileSplitterFetch.java NPFpq,P>  
*/ ooUk O  
package NetFox; QWMdn  
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import java.io.*; hWH:wB  
import java.net.*; uYE`"/h,1e  
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public class FileSplitterFetch extends Thread { sZW^!
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String sURL; //File URL dnj}AVfQx  
long nStartPos; //File Snippet Start Position hs}8xl  
long nEndPos; //File Snippet End Position `'V4PUe  
int nThreadID; //Thread's ID fu90]upz~  
boolean bDownOver = false; //Downing is over ^h{)Gf,+\  
boolean bStop = false; //Stop identical ~ o1x;Y6  
FileAccessI fileAccessI = null; //File Access interface sg+uBCGB  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException <!pY$  
{ !qX_I db\  
this.sURL = sURL; B/` !K  
this.nStartPos = nStart; i86>]  
this.nEndPos = nEnd; E*jP87g  
nThreadID = id; d>{nQF;c  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 <vXGi  
} Y5F]:gs@  
( H6c{'&  
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public void run() `X3^fg  
{ I_A@BnM{I  
while(nStartPos < nEndPos && !bStop) .l@xsJn  
{ _Gu- uuy  
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try{ 1
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URL url = new URL(sURL); =C~/7N,lW]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); b!)<-|IK  
httpConnection.setRequestProperty("User-Agent","NetFox"); TC<@e<-%Sq  
String sProperty = "bytes="+nStartPos+"-"; C:H
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httpConnection.setRequestProperty("RANGE",sProperty); A]XZnQ  
Utility.log(sProperty); W^G>cC8.L  
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InputStream input = httpConnection.getInputStream();
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//logResponseHead(httpConnection);
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byte[] b = new byte[1024]; U*3uq7  
int nRead; 5< ja3  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) zL\OB?)5J  
{ *6} N =Z  
nStartPos += fileAccessI.write(b,0,nRead); hcyM6:}  
//if(nThreadID == 1) /c,(8{(O  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); lg(bDKm  
} *k19LI.5  
hXA6D)
  
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Utility.log("Thread " + nThreadID + " is over!"); sVl-N&/  
bDownOver = true; VZ\B<i  
//nPos = fileAccessI.write (b,0,nRead); A,`8#-AX  
} lEV]4 t_H  
catch(Exception e){e.printStackTrace ();} 9-rNw?7  
} $#]]K  
} L:z?Zt)|  
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+=:#wzK@  
//打印回应的头信息 Z.M,NR  
public void logResponseHead(HttpURLConnection con) EI^06q4x  
{ ~{Mn{  
for(int i=1;;i++) n(el]_d  
{ -Y='_4s  
String header=con.getHeaderFieldKey(i); `(3/$%  
if(header!=null) `P9XqWr  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); K3=3~uY  
Utility.log(header+" : "+con.getHeaderField(header)); 6qp%$>$Vt;  
else 7P9=)$(EH  
break; 1Uqu>'  
} ,dx3zBI  
} PK"c4>q  
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public void splitterStop() V<j.xd7  
{ ,13Lq-  
bStop = true; ;f"0~D2  
} Yboiwy,n  
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} 3}/&w\$  
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*Q,0W:~-  
/* 4vwTs*eB`  
**FileAccess.java Rb{U+/gq  
*//文件访问(定位，写) X#e1KZ  
package NetFox; }5(Ho$S(  
import java.io.*; QPfc(Z  
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public class FileAccessI implements Serializable{ |P%DkM*X  
D&/L:   
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 z5r$M  
RandomAccessFile oSavedFile; L*~J%7  
long nPos; ^/U|2'$'>E  
8f3vjK'  
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public FileAccessI() throws IOException 4Z/Q=Mq2  
{ G^`1]?  
this("",0); -
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} ]~E0gsq  
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public FileAccessI(String sName,long nPos) throws IOException aG92ay  
{ n2fbp\I  
oSavedFile = new RandomAccessFile(sName,"rw"); <Ce2r"U1e  
this.nPos = nPos; $]A/ o(  
oSavedFile.seek(nPos); mD/MJt5  
} 7Ddaf>  
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public synchronized int write(byte[] b,int nStart,int nLen) 'FS?a  
{ :M6+p'`j  
int n = -1; uIDuGrt  
try{ Xt
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oSavedFile.write(b,nStart,nLen); ~R@Nd~L  
n = nLen; )}_a 0bt  
} XQ~Ke-QW)  
catch(IOException e) H[='~%
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{ I;1lX L  
e.printStackTrace (); ?A )hN8  
} &[;HYgp  
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return n; #2EI\E&$  
} _z1(y}u}  
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} Rh>}rGvCUN  
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/* ?2g`8[">  
**SiteInfoBean.java Qx'`PNU9\  
*/ QQV~?iW{~  
package NetFox; izx#
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public class SiteInfoBean { vVgg0Y2  
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private String sSiteURL; //Site's URL ZPD[5)~  
private String sFilePath; //Saved File's Path Qr$;AZ G  
private String sFileName; //Saved File's Name _Y[jyD1>  
private int nSplitter; //Count of Splited Downloading File KR%{a(V;7  
'_$uW&{NI  
h)Ff2tX  
public SiteInfoBean() !0dNQ[$82  
{//nSplitter的缺省值为5 A+UU~?3y  
//default value of nSplitter is 5 Q(\4]i< S  
this("","","",5); IEcf  
} edK|NOOZ
 
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 3yNU$.g  
{ -Fn}4M  
sSiteURL= sURL; dzkw$m^@^  
sFilePath = sPath; 0]jA<vLR  
sFileName = sName; t2r?N}"P  
this.nSplitter = nSpiltter; PClMQL#  
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} 5A4&+rdU  
0p@k({]<  
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public String getSSiteURL() ?PyG/W  
{ eBJUv]o %  
return sSiteURL; A.5i"Ci[ie  
} /AQMFx4-5  
]7Z{ 8)T  
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public void setSSiteURL(String value) B)QHM+[=F  
{ %.z,+Zz?  
sSiteURL = value; A?@@*$&  
} WsDM{1c  
j6g[N4xr  
A mwa)  
public String getSFilePath() {H{X[p8  
{ #-GJ&m8  
return sFilePath; o^V(U~m]  
} LB.co4  
"hQ_sgz[Z  
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public void setSFilePath(String value) yA3wtm/?  
{ 8Y#\xzod
 
sFilePath = value; DU=dLE6-P;  
} Tc+gdo>G  
2"-S<zM  
~%2pp~1K  
public String getSFileName() sIv)'  
{ ]K*8O<  
return sFileName; sQ8s7l0D  
} 7K{Nb  
G5FaYL.7  
ZKdeB3D  
public void setSFileName(String value) gp-T"l  
{ nIvJrAm4k  
sFileName = value; Z'k|u4ZC  
} -!8(bjlJ&  
_A~4NW{U7  
:(_+7N[KA  
public int getNSplitter() X@|&c]]  
{ g%k`  
return nSplitter; P(a.iu5  
} w\19[U
3  
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U-^[lWn[@4  
public void setNSplitter(int nCount) tM#lFmdd\P  
{ @;?T~^nGj  
nSplitter = nCount; o5n^!gi4  
} v-! u\  
} c c  
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l)-Mq@V  
/* @K:N,@yq  
**Utility.java 1>Q'R  
*/ <vUVP\u~$  
package NetFox; 99EXo+g  
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=@)d5^<5F  
public class Utility { wIf {6z{  
5ZY)nelc  
-<#!DjV6(  
public Utility() hwqbi "o  
{ =KT7nl  
-ti{6:H8  
'>(.%@  
} &Z^l=YH,  
,Os? f:Y6  
//线程睡眠 7zTqNnPnf  
public static void sleep(int nSecond) p*l$Wj  
{ F6hmku>\1  
try{ A!63p$VT;  
Thread.sleep(nSecond); s9oO%e<  
} LG]3hz9^9  
catch(Exception e) &5t :H 8b  
{ -xD*tf*  
e.printStackTrace (); aV1lJ;0  
} Hk
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} ~3RC>8*Qw  
]Zf6Yw.Y  
//日志 mNYl@+:psj  
public static void log(String sMsg) 0L^u2HZYL  
{ M=]5WZO~A  
System.err.println(sMsg); X_$a,"'~)  
} jw ,izxia  
S.|FL%;  
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public static void log(int sMsg)  d^|0R  
{ yGpz,X4x  
System.err.println(sMsg); gf)t)-E  
} \.gEh1HW  
} 3I 0eW%,  
4@;-%H&7  
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/* =iHiPvP0  
**TestMethod.java Fd\e*ww'  
*/ A4mSJ6K]  
package NetFox; gX5&d\y  
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public class TestMethod { Qju`e Eo  
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public TestMethod() uENdI2EY8y  
{ ///xx/weblogic60b2_win.exe M*pRv  
try{ =22ALlxk  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); o5aLUWi-  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); [t0rfl{.  
SiteFileFetch fileFetch = new SiteFileFetch(bean); /b,TpuM^  
fileFetch.start(); TQ9D68 ,  
} eXl=i-'  
catch(Exception e){e.printStackTrace ();} B ?%L  
cyd~2\Kv~  
!~-6wN"k  
} +7}iu/B!9  
h?,\(KjP#  
'b"TH^\  
public static void main(String[] args) #Tp]^ n  
{ Cpx+qQt0  
new TestMethod(); m|svQ-/j  
} R,@g7p  
} y:}sD_m0W  
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