http断点续传简单实现（java)

/* i&Xjbcbp  
**SiteFileFetch.java X3Yi|dyn T  
*/ Q~zs]{\  
package NetFox; ~Hb2-V  
import java.io.*; t*(buAx  
import java.net.*; aM!%EaT  
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public class SiteFileFetch extends Thread { DtglPo_(  
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SiteInfoBean siteInfoBean = null; //文件信息Bean lqZUU92;  
long[] nStartPos; //开始位置 wHE1Jqpo  
long[] nEndPos; //结束位置 TaNcnAY>9  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 +Z1y1%a  
long nFileLength; //文件长度 GFfZ TA  
boolean bFirst = true; //是否第一次取文件 3fd?xhWbN  
boolean bStop = false; //停止标志 7;3;8Q FX  
File tmpFile; //文件下载的临时信息 9six]
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DataOutputStream output; //输出到文件的输出流 J|.n bSE  

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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） F/w*[Xi Sh  
public SiteFileFetch(SiteInfoBean bean) throws IOException v/[*Pze,C  
{ Kw87 0n<  
siteInfoBean = bean; e=sV>z>  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Yc2dq e>  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 0}q
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if(tmpFile.exists ()) Jm[_X  
{ +V9<ug6T  
bFirst = false; PS'SIX  
read_nPos(); -W.bOr  
} Wo+^R%K'4  
else Y^-D'2P]P  
{ )JXy>q#  
nStartPos = new long[bean.getNSplitter()]; YES-,;ZQ'  
nEndPos = new long[bean.getNSplitter()]; h42dk(B  
} 8Bwm+LYr-  
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} 9?zi  
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public void run() sM6o(=>  
{ ,u^%[ejH  
//获得文件长度 @r3,|tkrz  
//分割文件 !eA6Ejf  
//实例FileSplitterFetch
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//启动FileSplitterFetch线程 <m0m8p"G  
//等待子线程返回 $8WeWmY  
try{ a+,zXJQYq  
if(bFirst) :b"&Rc&s.  
{ Hh`HMa'q  
nFileLength = getFileSize(); >TG#  
if(nFileLength == -1) -fT}Nj\  
{ w" ,ab j  
System.err.println("File Length is not known!"); h)h%y)1  
} q$7/X;A  
else if(nFileLength == -2) )(-aw,iK  
{ 1a_
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System.err.println("File is not access!"); S0H|:J  
} \e' oAhM  
else 8/zv3.+[  
{ Uc( z|  
for(int i=0;i<nStartPos.length;i++) sOhKM
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{ r:--DKt  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Q9{f'B  
} .tA=5QY,  
for(int i=0;i<nEndPos.length-1;i++) NKMVp/66D  
{ L!0}&i;u~5  
nEndPos = nStartPos[i+1]; r;@"s g  
} FE3uNfQs|  
nEndPos[nEndPos.length-1] = nFileLength; 2U&+K2  
} x<1t/o  
} #+(@i|!ifo  
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//启动子线程 \:9<d@?  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; VfkQc$/  
for(int i=0;i<nStartPos.length;i++) >/G[Oo  
{ z yrjb8  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), zvR;Tl6]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Yd]  
nStartPos,nEndPos,i); B_S))3   
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~WKWx.ul  
fileSplitterFetch.start(); 1^tM%2rP'  
} 9gac7(2`)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?D['>Rzu  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ZwMd 22  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", : $N43_
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nEndPos = " + nFileLength); mNKcaM?h  
// fileSplitterFetch[nPos.length-1].start(); -FQc_k?VF  
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//等待子线程结束 ~T!D:2G  
//int count = 0; &"d :+!4h  
//是否结束while循环 vDC
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boolean breakWhile = false; JfRqOEP4Y  
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while(!bStop) ]sJjV A  
{ Uj^Y\w-@Z  
write_nPos(); =Y*zF>#lP  
Utility.sleep(500); 5h6-aQU[  
breakWhile = true; T[kS;-x  
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for(int i=0;i<nStartPos.length;i++) g=jB'h?  
{ <vd}oiB
@  
if(!fileSplitterFetch.bDownOver) 85BB{T;  
{ }c=YiH,o  
breakWhile = false; ??z&w`Yy,  
break; ]0=THq\H  
} sNZOm$  
} J|CCTXT  
if(breakWhile) 3{M0iNc1  
break; .p%V]Ka  
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//count++; WF-^pfRq~  
//if(count>4) I].ddR
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// siteStop(); 7>f)pfLM  
} &/?OP)N,}  
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System.err.println("文件下载结束！"); r{wf;5d(  
} BC R]K  
catch(Exception e){e.printStackTrace ();} g ,yB^^%  
} GW2v&Ul7(  
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//获得文件长度 Tsocc5gWZ*  
public long getFileSize() Y4N)yMSl"  
{ ekd;sEO  
int nFileLength = -1; #M<u^$Jz  
try{ !}q@O-}j  
URL url = new URL(siteInfoBean.getSSiteURL()); AmK g;9LS  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .}Hs'co  
httpConnection.setRequestProperty("User-Agent","NetFox"); |WSmpuf  
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int responseCode=httpConnection.getResponseCode(); 99~ZZG  
if(responseCode>=400) QB*n [(?  
{ U["IXR#  
processErrorCode(responseCode); j.:f=`xf  
return -2; //-2 represent access is error 64D4*GQ  
} pp()Hu3J  
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String sHeader; JqtOoR  
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for(int i=1;;i++) =Ds&ArG  
{ ~zDFL15w  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); JC9OL.Ob  
//Utility.log(in.readLine()); `[~LMV&2U  
sHeader=httpConnection.getHeaderFieldKey(i); sI@kS^  
if(sHeader!=null) OT#foP  
{ aZ}z/.b]  
if(sHeader.equals("Content-Length")) (, $Lp0mB7  
{ n +dRAIqB  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 5"w%  
break; Tx(=4ALY  
} 7eG@)5Uy  
} ,.V=y%  
else aZCxyoh+  
break; D!D}mPi[  
} 1~[GGl  
} ~e=KBYDBu  
catch(IOException e){e.printStackTrace ();} S9 @*g3  
catch(Exception e){e.printStackTrace ();} 5K00z?kD2V  
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Utility.log(nFileLength); wV'_{/WM  
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return nFileLength; PcvA/W  
} u43-\=1$T  
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//保存下载信息（文件指针位置） A&_v:z4y/  
private void write_nPos() Pcr;+'q  
{ <9`/Y"\p  
try{ RMa#z [{0  
output = new DataOutputStream(new FileOutputStream(tmpFile)); vr$z6m ^  
output.writeInt(nStartPos.length); $'bb)@_  
for(int i=0;i<nStartPos.length;i++) M B,Z4 ^  
{ dfs1BV'  
// output.writeLong(nPos); Dm`gzGl  
output.writeLong(fileSplitterFetch.nStartPos); J=ot&%  
output.writeLong(fileSplitterFetch.nEndPos); fw0Z- 9*  
} _? u} Jy_  
output.close(); N}q*(r!q<  
} =%wBC;  
catch(IOException e){e.printStackTrace ();} cX5tx]  
catch(Exception e){e.printStackTrace ();} E /V`NqC  
} #uuNH(  
7/BA!V(na  
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//读取保存的下载信息（文件指针位置） -3C$br  
private void read_nPos() F-Ywl)  
{ CxVrnb[`q  
try{ q,(hs]\@  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); / !A&z4;D  
int nCount = input.readInt(); ^7C,GaDsn  
nStartPos = new long[nCount]; h3;RVtS  
nEndPos = new long[nCount]; Wl3fR[@3Q  
for(int i=0;i<nStartPos.length;i++) OoR0>!x Z  
{ T4}q%%7l  
nStartPos = input.readLong(); %`:+A?zL  
nEndPos = input.readLong(); KQ.cd]6  
} IFWP&20  
input.close(); ~<[]l~`  
} iPrAB*  
catch(IOException e){e.printStackTrace ();} jce2lXMm  
catch(Exception e){e.printStackTrace ();} n/IDq$/P  
} r-o6I:y  
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private void processErrorCode(int nErrorCode) m`8tHHF  
{ G)\6W#de
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System.err.println("Error Code : " + nErrorCode); KT8]/T`U  
} &qZ:"k  
@fSqGsSk  
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//停止文件下载 )X-TJ+d  
public void siteStop() U KdCG.E9^  
{ jI807g+  
bStop = true; vC5y]1QDd  
for(int i=0;i<nStartPos.length;i++) eh$T 3_#q  
fileSplitterFetch.splitterStop(); q.PXO3T  
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} 1PT0<C-  
} kam\
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//负责部分文件的抓取 !,PoH  
**FileSplitterFetch.java a5%IjgQ&z  
*/ sTO9>~sj  
package NetFox; (1Ii86EP  
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import java.io.*; WhR'MkfL  
import java.net.*; I`EgR?5 `  
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public class FileSplitterFetch extends Thread { Q GDfX_  
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String sURL; //File URL >zB0+l  
long nStartPos; //File Snippet Start Position I?i,21:5  
long nEndPos; //File Snippet End Position CT#N9  
int nThreadID; //Thread's ID ~UV$(5&-  
boolean bDownOver = false; //Downing is over ,Mw;kevw  
boolean bStop = false; //Stop identical yS(tF`H[  
FileAccessI fileAccessI = null; //File Access interface 00@y,V_]  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException &(HIBF'O  
{ q3R?8Mb  
this.sURL = sURL; kc70HrG  
this.nStartPos = nStart; 4f> s2I&pQ  
this.nEndPos = nEnd; %q 7gl;'  
nThreadID = id; n+uDg  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 h^"OC$  
} ?BnjtefIe  
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public void run() G=%SMl>[  
{ mmrz:_  
while(nStartPos < nEndPos && !bStop) >vY5%%}  
{ .m\'|%  
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try{ au 5qbP  
URL url = new URL(sURL); ;p'Ej'E  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %{M&"Mv  
httpConnection.setRequestProperty("User-Agent","NetFox"); :0RfA%  
String sProperty = "bytes="+nStartPos+"-"; G[5z3  
httpConnection.setRequestProperty("RANGE",sProperty); F%>`?NG+c  
Utility.log(sProperty); 4I^8f||b_  
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InputStream input = httpConnection.getInputStream(); 'w5g s
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//logResponseHead(httpConnection); }H<87zH  
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byte[] b = new byte[1024]; rb@{ir  
int nRead; #q%V|Ajq  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ",qJG]_ <  
{ OAXF=V F#  
nStartPos += fileAccessI.write(b,0,nRead); vtVc^j4  
//if(nThreadID == 1) b^]@8I[M  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /DBldL7
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} \zPcnDB  
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Utility.log("Thread " + nThreadID + " is over!"); 1#<KZN =$  
bDownOver = true; )mw&e}jRV  
//nPos = fileAccessI.write (b,0,nRead); N/&t)7  
} 41V}6+$g  
catch(Exception e){e.printStackTrace ();} }hv" ku6!  
} '+c
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} B#U:6Ty  
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//打印回应的头信息 NYcF]K}[  
public void logResponseHead(HttpURLConnection con)  9>k-";  
{ |}>;wZ[7  
for(int i=1;;i++) +Tw]u`  
{ J< U,~ra\  
String header=con.getHeaderFieldKey(i);
!3'&_vmG$  
if(header!=null) @(mXiK  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); `<:D.9vO "  
Utility.log(header+" : "+con.getHeaderField(header)); 1v^eXvY  
else #U j~F  
break; Iq[Z5k(K  
} 1]<wZV}.  
}
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public void splitterStop()  1ZF>e`t8  
{ %IbG@}54  
bStop = true; p/k6}Wl  
} rpu{YC1C%  
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} 3'zm)SXJ  
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/* +/E yX=  
**FileAccess.java F};G&  
*//文件访问(定位，写) =,-&h V  
package NetFox; ]wQ#8}zO  
import java.io.*;
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public class FileAccessI implements Serializable{ \Y{^Q7!>:8  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 eQRY xx{  
RandomAccessFile oSavedFile; vF,iHzv  
long nPos; jo_wBJKE  
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public FileAccessI() throws IOException hi30|^l-  
{ =#"ZO  
this("",0);
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} #&cNR_"w  
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public FileAccessI(String sName,long nPos) throws IOException R}-<ZJe  
{ +W6QtB6  
oSavedFile = new RandomAccessFile(sName,"rw");  H?(I-vO  
this.nPos = nPos; VkNg Vjg  
oSavedFile.seek(nPos); W_E0+  
} {|kEGq~aE  
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6?3f+=e"~!  
public synchronized int write(byte[] b,int nStart,int nLen) =V@5W[bV  
{ ~j`;$o  
int n = -1; A#y,B  
try{ ;L gxL Qy;  
oSavedFile.write(b,nStart,nLen); sr&hQ  
n = nLen; f;nO$h[Qb  
} DhAQ|SdCf  
catch(IOException e) K; +w'/{  
{ 6jKZ.S+s)  
e.printStackTrace (); GuV.7&!x  
} ,y+}0q-Ou  

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return n; !4(X9}a  
} U;7Cmti"  
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} 5)rMoYn25  
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/* v^=Po6S[{+  
**SiteInfoBean.java )\bA'LuFy  
*/ 9"=1 O  
package NetFox; a&Stdh  
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public class SiteInfoBean { P@m_tA%  
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private String sSiteURL; //Site's URL 3Vu_-.ID  
private String sFilePath; //Saved File's Path $fhb-c3
 
private String sFileName; //Saved File's Name r{V=)h  
private int nSplitter; //Count of Splited Downloading File %V+hm5Q  
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b=5"*=T{+  
public SiteInfoBean() |
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{//nSplitter的缺省值为5 Lad8C  
//default value of nSplitter is 5 vbo:,]T<A  
this("","","",5); 9\_^"5l  
} ne=?'e4  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) w&vZ$n-|  
{ yl>V'  
sSiteURL= sURL; %[<@$qP  
sFilePath = sPath; tJ{3Z}K  
sFileName = sName; ']N1OVw^vf  
this.nSplitter = nSpiltter; -A?6)ggf.  
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} :6 , `M,  
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public String getSSiteURL() 8QYP\7}o  
{
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return sSiteURL; )(?,1>k`Z  
} j
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public void setSSiteURL(String value) CNo'qlvF5N  
{ qT<OiIMj^  
sSiteURL = value; B<99-7x3  
} kq{PM-]l  
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public String getSFilePath() A5UZUU^  
{ \gBsAZE  
return sFilePath; @O!BQ^'hk#  
} !O`a
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public void setSFilePath(String value) pk%%}tP<  
{ [t
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sFilePath = value; q X"Pg  
} qhdY<[6
 
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public String getSFileName() /IO<TF(X  
{ \]j{  
return sFileName; nY>UYSv  
}  {"RUiL^  
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}f l4^F  
public void setSFileName(String value) =t/"&[r  
{ rZij[6]Y^  
sFileName = value; %`4\ 8H`  
} ;?{N=x8  
*%3%Zj,{  
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public int getNSplitter() #j+0jFu  
{ qZV.~F+  
return nSplitter; 0^0Q0A  
} b1*5#2rs.  
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public void setNSplitter(int nCount) K P1;u#v  
{ ?tA<:.<vtY  
nSplitter = nCount; ;R_H8vp  
} U_&v|2o#3  
} !`A]
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/* \y
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**Utility.java ;kX:k~,]}>  
*/ %KkMWl&:  
package NetFox; LX!MDZz  
F['<;}  
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public class Utility { `y^tCJ2u*  
.|VWYN  
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public Utility() u ? }T)B  
{ hhM?I$t:  
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} |z+K]R8_  
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//线程睡眠 38gHM9T xh  
public static void sleep(int nSecond) ru#CywK{{;  
{ 7 {n>0@_  
try{ @V7HxW7RX  
Thread.sleep(nSecond); q-3e^-S*  
} 
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catch(Exception e) .H33C@  
{ z'!sc"]W6  
e.printStackTrace (); )LdS1%  
} o6v'`p'  
} #cAX9LV  
evLZ<|  
//日志 0dKv%X#\  
public static void log(String sMsg) 7`G FtX}  
{ 4g
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System.err.println(sMsg); zz7#gU  
} ssx#\  
}#Q?\  
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public static void log(int sMsg) 8rNRQOXOa  
{ j,J/iJs  
System.err.println(sMsg); {SOy-  
}
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} %n!7'XF'[  
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/* K]Rb~+a<  
**TestMethod.java /hC'-6:]^  
*/ 7_^JgA|Kk7  
package NetFox; dBG5IOD  
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public class TestMethod { =9;2(<A  
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public TestMethod() B']}n`
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{ ///xx/weblogic60b2_win.exe |{j\7G*5  
try{ DZ*m"Bi  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); d,:3;:CR  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); U'Mxf'q  
SiteFileFetch fileFetch = new SiteFileFetch(bean); nu<kx  
fileFetch.start(); O~bJ<O=?  
} 6$ \69   
catch(Exception e){e.printStackTrace ();} "P9SW?',  
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} !=B=1th4  
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public static void main(String[] args) ~1g)4g~  
{ -NL=^O$G  
new TestMethod(); y/\0qQ/  
} P6~&,a  
} 5W4Tp% Lda  
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