http断点续传简单实现（java)

/* k`\DC\0RG  
**SiteFileFetch.java Z~$&
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*/ atl0#FBd  
package NetFox; &yVii^  
import java.io.*; ;'=!Fv  
import java.net.*; K}
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/\#
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public class SiteFileFetch extends Thread { N;Hf7K  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 0B3*\ H}5  
long[] nStartPos; //开始位置 $9Z8P_^.0(  
long[] nEndPos; //结束位置 We9C9)0  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 mE^6Zu  
long nFileLength; //文件长度
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boolean bFirst = true; //是否第一次取文件 ^f3F~XhY3  
boolean bStop = false; //停止标志 7cvbYP\<lv  
File tmpFile; //文件下载的临时信息 sVh!5fby&  
DataOutputStream output; //输出到文件的输出流 kFuaLEJi  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） o
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public SiteFileFetch(SiteInfoBean bean) throws IOException LX*T<|c`'  
{ `"-)ObO
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siteInfoBean = bean; OmKT}D~ 4  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Q6
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); K 7YpGGd5  
if(tmpFile.exists ()) b?H
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{ Q&n
  
bFirst = false; `' 6]Z*  
read_nPos(); B;7L:  
} 299; N  
else #kma)_X  
{ m"+9[d_u  
nStartPos = new long[bean.getNSplitter()]; O a-ZeCq  
nEndPos = new long[bean.getNSplitter()]; 9"MC<  
}
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} oSy[/Y44a  
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public void run()
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{ xj%
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//获得文件长度 ]u2!)vZh'  
//分割文件 (A(d]l  
//实例FileSplitterFetch G4<'G c  
//启动FileSplitterFetch线程 ;QgJw2G  
//等待子线程返回 ^>k[T.  
try{ wU+ofj; +I  
if(bFirst) !;iySRZr  
{ WW==  
nFileLength = getFileSize(); =xa`)#4(  
if(nFileLength == -1) :X2B+}6_&  
{ c&F"tLl  
System.err.println("File Length is not known!"); >@y5R^B`  
} . 6Bz48*  
else if(nFileLength == -2) S ._9  
{ 7,Z%rqf\)  
System.err.println("File is not access!"); G}f.fRY  
} M;3uG/E\  
else O'$:wc#  
{ J. {[>  
for(int i=0;i<nStartPos.length;i++) pw&l.t6.  
{ xmq~:fcU=  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ^*}L9Ot~  
} ]j_S2lt  
for(int i=0;i<nEndPos.length-1;i++) hc~--[1c:  
{ Hh54&YKZ  
nEndPos = nStartPos[i+1]; 6!b96bV  
} 6,s@>8n  
nEndPos[nEndPos.length-1] = nFileLength; 
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} =%$ _)=}J  
} 52-^HV  
r=qb[4HiV  
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//启动子线程 e&]XiV'  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; "t4~xs`~X  
for(int i=0;i<nStartPos.length;i++) {-<h5_h@  
{ <7)Vj*VxC  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [ &R-YQ@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), #i:p,5~")  
nStartPos,nEndPos,i); d [K56wbpx  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8(uxz84ce  
fileSplitterFetch.start(); PO |p53  
} m}F1sRkdQ  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1z[WJ}$u  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 6RzTSb  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", S/7D}hJ  
nEndPos = " + nFileLength); CBi
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// fileSplitterFetch[nPos.length-1].start(); Ig5J_Z
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//等待子线程结束 \<;/)!Nmw  
//int count = 0; 183'1Z$KA  
//是否结束while循环 p&XbXg-  
boolean breakWhile = false; "FG6R'  
TKj9
s'/  
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while(!bStop) ^R K[-tVV  
{ 3H4p$\;C  
write_nPos(); +J.^JXyp0  
Utility.sleep(500); l2n>Wce9  
breakWhile = true; I>ofSaN  
0]i#1Si~@  
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for(int i=0;i<nStartPos.length;i++) NaAq^F U  
{ |$6GpAq!  
if(!fileSplitterFetch.bDownOver) PT>,:zY  
{ _Se>X=  
breakWhile = false; &/a/V  
break; d{9jd{ _#G  
} 6,cyi|s  
} w3,QT}WvY  
if(breakWhile) S{fNeK  
break; c3K(mM:  
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//count++; 9J l9\y9  
//if(count>4) (8H "'  
// siteStop(); |urohua  
} |@V<}2zCZ  
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System.err.println("文件下载结束！"); sA}=o.\j:  
} MIi:\m5  
catch(Exception e){e.printStackTrace ();} Yckl,g_  
} srg#<oH|{c  
~#(bX]+A  
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//获得文件长度 shP,-Vs#  
public long getFileSize() 5TzMv3;in2  
{ kO/dZ%vj  
int nFileLength = -1; Av+
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try{ 5k<HO_]  
URL url = new URL(siteInfoBean.getSSiteURL()); mxDy!:@=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *3. ]  
httpConnection.setRequestProperty("User-Agent","NetFox"); mlIc`GSI  
=`.9V<  
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int responseCode=httpConnection.getResponseCode(); ihs@ 'jh  
if(responseCode>=400) b:W]L3Z8  
{ C 5)G^  
processErrorCode(responseCode); /UM9g+Bb  
return -2; //-2 represent access is error W}JJaZR*X  
} ]TD]
  
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String sHeader; s)_sLt8?  
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for(int i=1;;i++) Etn]e;z4  
{ MhJq~G p  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 1xcx2L+R  
//Utility.log(in.readLine()); /5zzzaj{  
sHeader=httpConnection.getHeaderFieldKey(i); kw?RUt0-V  
if(sHeader!=null) X~n Kuo  
{ [ub,&j^  
if(sHeader.equals("Content-Length")) YwHnDV
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{ .B>|>W O  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); vmW4a3  
break; tAYu|\]  
} fZXd<Fg+  
} [=..#y!U  
else BKVvu}V(o  
break; 9u"im+=:  
} @Q TG
  
} Z`< +8e  
catch(IOException e){e.printStackTrace ();} _mFb+8C  
catch(Exception e){e.printStackTrace ();} F~<$E*&h@  
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Utility.log(nFileLength); cUS2*7h  
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return nFileLength; @(Q4  
} &X +@,!  
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//保存下载信息（文件指针位置） (Z6[a{}1i  
private void write_nPos() PP$Ig2Q  
{ 1AA(qE  
try{ Yo(8mtYU  
output = new DataOutputStream(new FileOutputStream(tmpFile)); CbK7="48  
output.writeInt(nStartPos.length); qdUlT*fw  
for(int i=0;i<nStartPos.length;i++) F'|,(P  
{ ^3AJYu  
// output.writeLong(nPos); -/7[_,  
output.writeLong(fileSplitterFetch.nStartPos); Tcr&{S&o  
output.writeLong(fileSplitterFetch.nEndPos); 0D0#*J  
} <6-(a;T!7  
output.close(); ,cgC_%  
} [yjC@docH  
catch(IOException e){e.printStackTrace ();} iY.~N#Q  
catch(Exception e){e.printStackTrace ();} `M"b L|[R  
} T73saeN  
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/rJvw  
//读取保存的下载信息（文件指针位置） 9.PY49|  
private void read_nPos() AB+Zc ]  
{ $3"0w   
try{  Zp]Bs  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); dv@6wp:  
int nCount = input.readInt(); 3/]J i^+  
nStartPos = new long[nCount]; 7|65;jm+  
nEndPos = new long[nCount]; lm-ubzJN  
for(int i=0;i<nStartPos.length;i++) v mw7H  
{ r|0C G^:C  
nStartPos = input.readLong(); Re,0RM
\  
nEndPos = input.readLong(); WDgp(Av!  
} nE::9Yh8z  
input.close();  '6 w|z^  
} QR79^A@5  
catch(IOException e){e.printStackTrace ();} &tp5y}=n  
catch(Exception e){e.printStackTrace ();} $
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} zz02F+H$Y  
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|%6B#uy  
private void processErrorCode(int nErrorCode) yf_<o  
{ '_(oa<g  
System.err.println("Error Code : " + nErrorCode); QZQ@C#PR;  
} g/VC$I!'  
BAqu@F\):  
'!IX;OSjH  
//停止文件下载 Fd|:7NRA<  
public void siteStop() <*4=sX@  
{ FKL}6W:  
bStop = true; "D@
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for(int i=0;i<nStartPos.length;i++) <2|x]b8  
fileSplitterFetch.splitterStop(); 5Ko
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} '[Nu;(>a  
} Uf_w o  
//负责部分文件的抓取 V@cRJ3ZF  
**FileSplitterFetch.java mb\vHu*53  
*/ @/|sOF;8W  
package NetFox; Z(U&0GH`  
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import java.io.*; 7 yF#G9,  
import java.net.*; Z<ke!H  
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public class FileSplitterFetch extends Thread { [iL2c=_  
?9=yo5M}  
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String sURL; //File URL oqE h_[.  
long nStartPos; //File Snippet Start Position 2LD4f[a;  
long nEndPos; //File Snippet End Position ) e;F@o3  
int nThreadID; //Thread's ID j-yD;N  
boolean bDownOver = false; //Downing is over /D)@y548~~  
boolean bStop = false; //Stop identical /<|J\G21  
FileAccessI fileAccessI = null; //File Access interface mc9$"  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException j|+B|  
{ r("7 X2f  
this.sURL = sURL; aY3kww`  
this.nStartPos = nStart; 9f BD.9A  
this.nEndPos = nEnd; {L<t6A  
nThreadID = id; #1m!,tC  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ?]5wX2G^|J  
} :4)mv4Q  
Z/Mp=273  
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public void run()
:Z1_;`>CT  
{ QKHmOVh]  
while(nStartPos < nEndPos && !bStop) rZ
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{ XUMCz7&j  
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try{ 5{cA
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URL url = new URL(sURL); qZ8lU   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); X Phw0aV  
httpConnection.setRequestProperty("User-Agent","NetFox"); _$Z46wHmB  
String sProperty = "bytes="+nStartPos+"-"; Do2y7,jv  
httpConnection.setRequestProperty("RANGE",sProperty); <_42h|-  
Utility.log(sProperty); Q^0K8>G^  
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InputStream input = httpConnection.getInputStream(); -AcQ_dS  
//logResponseHead(httpConnection); C"0gAN  
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byte[] b = new byte[1024]; /B}]{bcp$  
int nRead; Fb-NG.Z#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) *sL'6"#Cre  
{ +.>O%pNj  
nStartPos += fileAccessI.write(b,0,nRead); H<1C5-  
//if(nThreadID == 1) :()4eK/\  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); wBeOMA  
} uOougSBV,  
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1X#`NUJ?2  
Utility.log("Thread " + nThreadID + " is over!");
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bDownOver = true; xES+m/?KlZ  
//nPos = fileAccessI.write (b,0,nRead); 6EPC$*Xp!  
} drb_GT  
catch(Exception e){e.printStackTrace ();} u6B (f;  
} Zc%S`zK`7  
} urtcSq&H'  
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//打印回应的头信息
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public void logResponseHead(HttpURLConnection con) ^z)lEO  
{ li;P,kg$  
for(int i=1;;i++) )Hev-C"  
{ 5i1
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String header=con.getHeaderFieldKey(i); n,V`Y'v)  
if(header!=null) $F/&/Aa  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); QP\vN|r  
Utility.log(header+" : "+con.getHeaderField(header)); 4&`66\p;  
else I~q}M!v~  
break; %t<Y6*g  
} <v5toyA  
} EH,uX{`e  
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(& ~`!]  
public void splitterStop() <GoE2a4Va  
{ n.7 $*9)#  
bStop = true; QjQJ "  
} {]Lc]4J  
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} 4J I;NN  
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/* ?Bh}  
**FileAccess.java ~t#'X8.)  
*//文件访问(定位，写) [r]USCq  
package NetFox; 9Ft)VX  
import java.io.*; 59EAqz[:  
,t)mCgbcO  
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public class FileAccessI implements Serializable{ v`v+M4upC  
?]P&3UU>0z  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 {/ty{  
RandomAccessFile oSavedFile; 71)HxC[6vA  
long nPos; 2;kab^iv'  
,,{Uz)>'W6  
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public FileAccessI() throws IOException N%Lh_2EzqV  
{ F htf4  
this("",0); Sfvi|kZX  
} O#k?c }  
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public FileAccessI(String sName,long nPos) throws IOException ;dB=/U>3U  
{ xJO[pT v  
oSavedFile = new RandomAccessFile(sName,"rw"); Kvk;D ]$  
this.nPos = nPos; s';jk(i3
 
oSavedFile.seek(nPos); g[eI-J+F
 
} XPY66VC&_  
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public synchronized int write(byte[] b,int nStart,int nLen) wS:323 !l$  
{ <'gCIIa2  
int n = -1; sL!6-[N  
try{ rc;| ,\  
oSavedFile.write(b,nStart,nLen); _$, .NK,6  
n = nLen; G=b`w;oL:  
} AE<AEq  
catch(IOException e) hl# 9a?  
{ nbOMtK  
e.printStackTrace (); &Nec(q<  
} QDgOprha  
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3Um\?fj>}(  
return n; o>W}1_  
} ?j $z[_K  
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} #s]]\  
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b%v1]a[  
/* Q2Q`g`*O:  
**SiteInfoBean.java XKR?vr7A2  
*/ ;APg!5X  
package NetFox; \l]jX: 9(  
2 3>lE}^G  
Z4t9q`}h  
public class SiteInfoBean { @B1rtw6  
5))?,YkrrI  
|5Z@7  
private String sSiteURL; //Site's URL ff{ESFtD  
private String sFilePath; //Saved File's Path `T~M:\^D  
private String sFileName; //Saved File's Name 6}<PBl%qe  
private int nSplitter; //Count of Splited Downloading File ['sIR+c%'O  
t(ZiQ<A  
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public SiteInfoBean() y`\/eX  
{//nSplitter的缺省值为5 .oSKSld  
//default value of nSplitter is 5 @NV$!FB<  
this("","","",5); S'?XI@t[  
} Z0-W%W  
|1t30_ /gS  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) WM>9sJf  
{ d;'@4NX5+  
sSiteURL= sURL; w0 "h,{  
sFilePath = sPath; m&; t;&#  
sFileName = sName; >~ne(n4qy  
this.nSplitter = nSpiltter; j)J4[j  
"e(OO/EZS  
ss-Be  
} Q
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public String getSSiteURL() <'s1+^LC  
{ q4U?}=PD  
return sSiteURL; fT 8"1f|w  
} w0Us8JNGz  
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public void setSSiteURL(String value) C\}m_`MR  
{ X1A;MA@0Ro  
sSiteURL = value; 4;j#7  
} yqB{QFXO  
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public String getSFilePath() YDDwvk H  
{ ;rk}\M$+  
return sFilePath; /'ybl^Km  
} bC)<AG@Z\  
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public void setSFilePath(String value) jMd's|#OP  
{ v&uIxFCR  
sFilePath = value; JRl8S   
} a
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v[HxO?x^  
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public String getSFileName() *rW]HNz  
{ ko  ~iDT  
return sFileName; )Hw;{5p@  
} [q_Yf!(m-  
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public void setSFileName(String value) uwf3  
{ lOZ.{0{f,  
sFileName = value; ~;U!?  
} &_!BMzp4  
>~XX'}  
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public int getNSplitter() yqCy`TK8  
{ #7'ww*+  
return nSplitter; W+1V&a}E  
} S0"OU0`N  
$\0j:<o  
(4b&}46  
public void setNSplitter(int nCount) vA+RZ  
{ 4W^0K|fq  
nSplitter = nCount; "7gS*v,r  
} ;'cv?3Y  
} Lu-owP7nB  
@NX^__sa  
#JTi]U6`  
/*
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**Utility.java 6G1Z"9<2*  
*/ @dcW0WQ\  
package NetFox; qf7.Sh  
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V ;>{-p  
public class Utility { LscAsq<H<  
f'r/Q2{n  
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public Utility() Wx:_F;  
{ Gb~q:&IUr  
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} }eB\k,7L  
gR1X@j$_  
//线程睡眠 +n)(\k{
 
public static void sleep(int nSecond) AV%Q5Mi}  
{ !nykq}kPN\  
try{ Gt- -7S  
Thread.sleep(nSecond); 9:@
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} |5g*pXu{  
catch(Exception e) 0&EX-DbV  
{ n>iPAD  
e.printStackTrace (); {4:En;  
} #=
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} A7: oq7b  
*~fN^{B'!  
//日志 z<@$$Z=0UF  
public static void log(String sMsg) i*2z7MY  
{ f+/^1~^  
System.err.println(sMsg); 6bqJM#y@  
} 21cIWvy  
2|Tt3/Rn  
,PIdPaV--  
public static void log(int sMsg) R]ppA=1*_l  
{ _NZ) n)  
System.err.println(sMsg); 0BE%~W  
} 2%WZ-l!i  
} s?_b[B d  
6`+DBr  
-=g`7^qa>  
/* HWe.|fH:  
**TestMethod.java 3V,X=  
*/ yy#Xs:/  
package NetFox; c#G(7.0MU  
%\-+SeC  

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public class TestMethod { !!` zz  
O<%U*:B  
0<>iMrD  
public TestMethod() gXf_~zxS  
{ ///xx/weblogic60b2_win.exe gR?3)m  
try{ JWxPH5L  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 8YYY *>  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); KY_qK)H  
SiteFileFetch fileFetch = new SiteFileFetch(bean); .h*
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fileFetch.start(); ` D4J9;|;]  
} Y
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catch(Exception e){e.printStackTrace ();} g%\e80~1(  
8
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} )6AOP-M.9  
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public static void main(String[] args) auGt>,Zj\Q  
{ {= z%('^  
new TestMethod(); ,e>ugI_;*  
} `|PxEif+J  
} zu;Yw=cM)  
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