http断点续传简单实现（java)

/* G}l9 [lE  
**SiteFileFetch.java (n>Gi;u(R  
*/ 5RWqHPw+  
package NetFox; '-N5F  
import java.io.*; H? z~V-8  
import java.net.*; 2BF455e   
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 *BM#fe  
public class SiteFileFetch extends Thread { L;M@]  
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SiteInfoBean siteInfoBean = null; //文件信息Bean O#[bNLV  
long[] nStartPos; //开始位置 | Z7j s"  
long[] nEndPos; //结束位置 *JFkqbf  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 B-KMlHe  
long nFileLength; //文件长度 n^|xp;] :  
boolean bFirst = true; //是否第一次取文件 JCBX?rM/  
boolean bStop = false; //停止标志 d6[' [
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File tmpFile; //文件下载的临时信息 zvq}7,  
DataOutputStream output; //输出到文件的输出流 OS<GA
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类）
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public SiteFileFetch(SiteInfoBean bean) throws IOException t&w.Wc X)  
{ m(9I+
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siteInfoBean = bean; D{\o*\TN  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); (*6 .-Xn  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 2-
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if(tmpFile.exists ()) zd$?2y8  
{ Hu6Qr  
bFirst = false; .IY@Q  
read_nPos(); ,66(*\xT  
} b|Ge#o  
else C_q2bI  
{ oO3^9?Z  
nStartPos = new long[bean.getNSplitter()]; svxjad@l/  
nEndPos = new long[bean.getNSplitter()]; V*2*5hx  
} {4/*2IRN9h  
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} +p jB/#4  
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public void run() ?
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{ &XI9%h9|  
//获得文件长度 -^`s#0( y^  
//分割文件 _](y<O^9yO  
//实例FileSplitterFetch b5]<!~Fv:`  
//启动FileSplitterFetch线程 T;{}bc&I  
//等待子线程返回 L.-qTh^P  
try{ AsuugcN*  
if(bFirst) $`\qY ^.(  
{ :a2[d1  
nFileLength = getFileSize(); G~u
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if(nFileLength == -1) nr&|  
{ wexX|B^u  
System.err.println("File Length is not known!"); [Rq|;p  
} II _CT=  
else if(nFileLength == -2) XA>uCJf  
{ rB]2qk`/'  
System.err.println("File is not access!"); ~rjK*_3/  
} Yuf+d-%  
else E'mT%@MOM  
{ }Ptv[{q]GE  
for(int i=0;i<nStartPos.length;i++) tzgaHN  
{  %rlqq*  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); SQU@JKi;g  
} ARnq~E@1  
for(int i=0;i<nEndPos.length-1;i++) ^jS1g*nrN  
{ u^^jt(j  
nEndPos = nStartPos[i+1]; `.pd %\  
} nwfu@h0G  
nEndPos[nEndPos.length-1] = nFileLength; 0(u}z  
} d { P$}b  
} {0fQ
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:?z@T[-  
//启动子线程 u-jc8W`Zd  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; B+R|fQ  
for(int i=0;i<nStartPos.length;i++) Z]2z*XD  
{ nB :iG  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Df2$2VU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ^e_uprZWm  
nStartPos,nEndPos,i); QALr   
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @J6r;4|&  
fileSplitterFetch.start(); N|@tP:j  
} @sZ' --Y  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), T:K}mLSg  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); #fx"tx6  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ",
uuh._H}-  
nEndPos = " + nFileLength); IS[q'Cv*  
// fileSplitterFetch[nPos.length-1].start(); "B"ql-K  
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//等待子线程结束 ,SdxIhL  
//int count = 0; 7iv g3*  
//是否结束while循环 "9hD4R  
boolean breakWhile = false; `e7vSp  
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#a|r ^%D  
while(!bStop) o,J8n;"l  
{ V^n=@CZT9C  
write_nPos(); %)dp a  
Utility.sleep(500); x+'Ea.^  
breakWhile = true; kDQE*o  
l$HBYA\Qh  
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for(int i=0;i<nStartPos.length;i++) &ns??:\+T  
{ 9X#]Lg?b  
if(!fileSplitterFetch.bDownOver) [;-;{ *{G  
{ L9,GUtK{  
breakWhile = false; ?/@XJcm+  
break; 7rGp^  
} =\i%,YY  
} #1}%=nAsi  
if(breakWhile) @'hkU$N)  
break; 6Qz=g t%I=  
[?,+DY  
#\xy,C'Y  
//count++; 4v5qK  
//if(count>4) SjA'<ZX>TM  
// siteStop(); QiV
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} +yk0ez  
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System.err.println("文件下载结束！"); ^K~=2^sh  
} B'vIL'  
catch(Exception e){e.printStackTrace ();} <+%y  
} 1`Bhis
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}+u<w{-7/  
,ag* /  
//获得文件长度 R Eo{E  
public long getFileSize() {VM^K1  
{ C\bJ_vl;'  
int nFileLength = -1; mB bGj3u;  
try{ mL;oR4{  
URL url = new URL(siteInfoBean.getSSiteURL()); ,]9p&xu  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4/S3hH  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7g oRj  
u-.nR}DM_  
SD:Bw0gzrI  
int responseCode=httpConnection.getResponseCode(); .K#' Fec  
if(responseCode>=400) 2Mw`  
{ hHOx ]  
processErrorCode(responseCode); *'{9(Oj  
return -2; //-2 represent access is error aqi]5,  
} G-vkkNj%e  
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(Nf!E[}Z  
String sHeader; wYv++< z  
%(\et%[]  
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for(int i=1;;i++) Rp_}_hL0  
{ 0Uk;&a0s  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 8f'r_,"  
//Utility.log(in.readLine()); Z{F^qwne  
sHeader=httpConnection.getHeaderFieldKey(i); CzDg?wb  
if(sHeader!=null) 0NvicZ7VR  
{ Z)u_2e  
if(sHeader.equals("Content-Length")) +&M>J|  
{ x;STt3M~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); !0KNA1w,  
break; =C)2DWJ1  
} e>uq/|.!  
} Wh%@  
else ojIGfQV  
break; "%rU1/@#  
} J~ z00p`E  
} 69odE+-X.  
catch(IOException e){e.printStackTrace ();} V4,\vgGu  
catch(Exception e){e.printStackTrace ();} 3 }#rg  
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Utility.log(nFileLength); /|v b)J  
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return nFileLength; eh
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} b0N7[M1Xl  
h?->A#  
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//保存下载信息（文件指针位置） 2jP(D%n  
private void write_nPos() IG:CWPU  
{ qUQP.4Z95  
try{ '|&?$g(\h  
output = new DataOutputStream(new FileOutputStream(tmpFile)); r|953e  
output.writeInt(nStartPos.length);  SmAF+d
 
for(int i=0;i<nStartPos.length;i++) _2}/rwVg  
{ _znn`_N:v  
// output.writeLong(nPos); i$!K{H1{9  
output.writeLong(fileSplitterFetch.nStartPos); U[ogtfv`
m  
output.writeLong(fileSplitterFetch.nEndPos); qvJQbo[.9P  
} Y)AHM0;g  
output.close(); >IZ$ .-  
} `n`HwDo;i  
catch(IOException e){e.printStackTrace ();} ,!^;<UR:  
catch(Exception e){e.printStackTrace ();} -e+im(2D=  
} {]7lh#M  
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{^R"V ,)  
//读取保存的下载信息（文件指针位置） Gs*X> D  
private void read_nPos() Z/e[$xT <  
{ `TDS4Y  
try{ _G^4KwYp  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); -x>2Wb~%  
int nCount = input.readInt(); lt0byn$vz  
nStartPos = new long[nCount]; LdX'V]ITh  
nEndPos = new long[nCount]; d}^hZ8k|  
for(int i=0;i<nStartPos.length;i++) nc#} \  
{ M&
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nStartPos = input.readLong(); lBG"COu  
nEndPos = input.readLong(); CG
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} @@6c{r^P  
input.close(); |q\Rvt$d  
} yV)9KGV+:  
catch(IOException e){e.printStackTrace ();} z) "(&__  
catch(Exception e){e.printStackTrace ();} [XNDYaF8
 
} #b;TjnC5{$  
9_%??@^>  
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private void processErrorCode(int nErrorCode) (+bt{Ma  
{ hx}X=7w  
System.err.println("Error Code : " + nErrorCode); ,#(k|Zztc  
} Tnnj8I1v  
Y0o{@)Y:  
eqU y>  
//停止文件下载 7<93n`byM  
public void siteStop() o-<.8Z}>at  
{ :CXm@yF~4=  
bStop = true; f(c#1AJE53  
for(int i=0;i<nStartPos.length;i++) mqQC`Aqx:  
fileSplitterFetch.splitterStop(); @dhnpR:L  
6J3<k(#:  
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} 8+&Da  
} D[K!xq  
//负责部分文件的抓取 edfb7prfTl  
**FileSplitterFetch.java mfgUf  
*/ lnrs4s Km  
package NetFox; =n_>7@9l  
&^F'ME  
-EWC3,3  
import java.io.*; 4FJA+  
import java.net.*; )H*BTfmt  
G;^,T/q47  
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public class FileSplitterFetch extends Thread { ]l=iKl  
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String sURL; //File URL g_(O7  
long nStartPos; //File Snippet Start Position
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long nEndPos; //File Snippet End Position C ?aa)H  
int nThreadID; //Thread's ID #>">fs]  
boolean bDownOver = false; //Downing is over N/8B@}@n  
boolean bStop = false; //Stop identical Oa'T$'  
FileAccessI fileAccessI = null; //File Access interface f2i9UZ$=e!  
e
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException X[1w(dU[  
{ ##yH*{/&  
this.sURL = sURL; zQsW*)L  
this.nStartPos = nStart; RnUud\T/  
this.nEndPos = nEnd; hJ*#t<.<P;  
nThreadID = id; :eR\0cn  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 eY'RDQa  
} 'F^"+Xi  
#UqE%g`J  

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public void run() &MJ`rj[%  
{ 1,pPLc(  
while(nStartPos < nEndPos && !bStop) VJ-To}  
{ cwI3ANV  
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:}ZY*ind  
try{ ~Z$Ro/;l  
URL url = new URL(sURL); _16r8r$V  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *XluVochrb  
httpConnection.setRequestProperty("User-Agent","NetFox"); NV;T*I8O  
String sProperty = "bytes="+nStartPos+"-"; L=kETJ:g  
httpConnection.setRequestProperty("RANGE",sProperty); Q6%Pp_$k  
Utility.log(sProperty); W,[iRmxn  
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InputStream input = httpConnection.getInputStream(); !+3nlG4cw  
//logResponseHead(httpConnection); *30T$_PiX|  
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7y=1\K
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byte[] b = new byte[1024]; CjmF2[|  
int nRead; :2AlvjvjZ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Qsr+f~"W  
{ (bGk=q=M  
nStartPos += fileAccessI.write(b,0,nRead); #c`/ f6z  
//if(nThreadID == 1) L?b;TjLe  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); x{,W<oXg  
} Ft
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-}"nb-RR\  
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Utility.log("Thread " + nThreadID + " is over!"); ffem7eQ  
bDownOver = true; [g$
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//nPos = fileAccessI.write (b,0,nRead); *4[P$k$7  
} V_jGL<X|  
catch(Exception e){e.printStackTrace ();} SnGXEQ  
} 6MelN^\[7  
} T&]IPOH9  
E&> 2=$~  
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//打印回应的头信息 FdS'0#$  
public void logResponseHead(HttpURLConnection con) jluv}*If  
{ O2oF\E_6  
for(int i=1;;i++) Twpk@2=l  
{ '$q3Ze  
String header=con.getHeaderFieldKey(i); q 7hoI]  
if(header!=null) uUh6/=y  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); K,@} 'N  
Utility.log(header+" : "+con.getHeaderField(header)); C@@PLsMg  
else D1Q]Z63,  
break; ]|B_3*A  
} p}|<EL}Z9  
} 9oj0X>| 1  
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public void splitterStop() GCp90  
{ d"}lh:L9  
bStop = true; gyOAvx  
} <P-AlHYV-  
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} mN'
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/* mJME1#j$/|  
**FileAccess.java 7}vx]p2  
*//文件访问(定位，写) =T#?:J#a  
package NetFox; \1#~]1~ s  
import java.io.*; FES0lw{G#  
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"QM2YJ55m`  
public class FileAccessI implements Serializable{ lk4$c1ao2@  
14p{V}f3  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Mqm9i  
RandomAccessFile oSavedFile; Y$
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long nPos; L^L.;1  
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public FileAccessI() throws IOException E=qfI>2U&  
{ /X?%K't2r  
this("",0); ^*WO*f>y  
} 5[H1nC @C  
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public FileAccessI(String sName,long nPos) throws IOException K(_8oB784  
{ k(_^Lq f-  
oSavedFile = new RandomAccessFile(sName,"rw"); }XRRM:B|)(  
this.nPos = nPos; &}FWpo!  
oSavedFile.seek(nPos); 0
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} CZ,2Rq  
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public synchronized int write(byte[] b,int nStart,int nLen) 6tup^Rlo;$  
{ #x(3>}  
int n = -1; ]9hhAT44  
try{ /rv=mlpRL  
oSavedFile.write(b,nStart,nLen); 6#kK  
n = nLen; K]ds2Kp&  
} Sh7
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catch(IOException e) T,v5cc:nO  
{ G[Jz(/yNH  
e.printStackTrace (); TGI`}#  
} j15t8du&O  
36
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:  
return n; !FeNx*31i  
} q=+wQ[a<  
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} 8lF:70wia  
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/* (+
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**SiteInfoBean.java EP8R[Q0_"  
*/ >!#or- C  
package NetFox; Ej'N!d.  
6KKQ)DNu_  
]?~[!&h  
public class SiteInfoBean { "qw.{{:tf  
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private String sSiteURL; //Site's URL u7bji>j  
private String sFilePath; //Saved File's Path QE`u~  
private String sFileName; //Saved File's Name 3 /LW6W|  
private int nSplitter; //Count of Splited Downloading File 6?= ^8  
tflUy\H>  
4_o+gG%HaM  
public SiteInfoBean() sKDL=c;?j  
{//nSplitter的缺省值为5 JO\KTWtjO  
//default value of nSplitter is 5 @;>Xy!G  
this("","","",5); gdG#;T'  
} 2yA+zJ 46B  
8<Ex`  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) t&rr;W]  
{ i&JI"Dd7  
sSiteURL= sURL; z=DK(b;$z  
sFilePath = sPath; / 2h
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sFileName = sName; L$=a,$  
this.nSplitter = nSpiltter; bdvVPjGc&  
OCI{)r<O2m  
0Y/k/)Ul]  
} ou[Wz{  
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public String getSSiteURL() x!A5j $k0  
{ ;`FR1KIg  
return sSiteURL; n$3w=9EX*  
} 8PvO_Gz5  
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public void setSSiteURL(String value) 4 zipgw  
{ n2&M?MGX  
sSiteURL = value;  A}n7A   
} ?f=7F %  
"IJcKoB  
?)FY7[x.  
public String getSFilePath() LH>h]OTQF  
{ !24g_R[3"  
return sFilePath; 
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} A]m_&A#  
M[KYt"v  
[I%'\CI;  
public void setSFilePath(String value) HG[gJ7  
{ $kn"S>jV  
sFilePath = value; l6HT}x7OiH  
} b
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~)]n67Or~  
H]>7IhJ  
public String getSFileName() e[t1V/ah  
{ P!~B07y  
return sFileName; jQ5FvuNOy  
} #5_pE1  
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+(vL~  
public void setSFileName(String value) KPI[{T\`ZM  
{ >2;
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sFileName = value; G>W:3y  
} `-<m#HF:)d  
Bt"*a=t;  
]`eJSk.  
public int getNSplitter() N"/be  
{ =N{-lyr)  
return nSplitter; "gq_^&  
} L&qY709  
T2i\S9X  
[`=:uUf3  
public void setNSplitter(int nCount) $q$\  
{ }3y Q*<  
nSplitter = nCount; Ui;PmwQc&  
} ,\E5et4  
} ,4kipJ!,yK  
v{TISgZ  
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/* dF0:'y  
**Utility.java Kw,l
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*/ }#9 |au`  
package NetFox; 3Tr}t.mt  
? p^':@=  
Y# ?M%I%j  
public class Utility { v*EErQML8b  
_@ @"'  
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public Utility() ,ikn%l#cm  
{
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`jH0FJQ  
} ({p@Ay  
DwH=ln=  
//线程睡眠 g;<_GL  
public static void sleep(int nSecond) J|[`8 *8  
{ Ov8{ny  
try{ px.]m-  
Thread.sleep(nSecond); aFwfF^\(|,  
} fO$~jxR.  
catch(Exception e) KiG/
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{ [[d@P%X&  
e.printStackTrace (); qVmG"et'J  
} iC\t@BVS  
} 2[$` ]{U  
<t4l5nr#  
//日志 Wy,Tf*[  
public static void log(String sMsg) <=7^D  
{ O8S"B6?$~'  
System.err.println(sMsg); j8#B  
} >l|dLyiae  
YfOO]{x,X  
O{`r.H1',  
public static void log(int sMsg) CF+:9PG  
{ .=-K7.X.)  
System.err.println(sMsg); |&a[@(N:zf  
} ^)|1T#Tz  
} "M5&&\uT  
Og3bV_,"  
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/*  <IL$8a  
**TestMethod.java 
)9JuQ_R  
*/ @ 6{U*vs  
package NetFox; 80qe5WC.2u  
kVb8$Sp  
4>xv7  
public class TestMethod { nH]F$'rtA  
)x*pkE**c  
UHW;e}O5  
public TestMethod() eA(c{  
{ ///xx/weblogic60b2_win.exe 9oA
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try{ XDi[Iyj  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Oy/+uw^  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); HQl_/:Wx  
SiteFileFetch fileFetch = new SiteFileFetch(bean); u6(>?r-  
fileFetch.start(); 7lz"^  
} jNA^ (|:  
catch(Exception e){e.printStackTrace ();} xlWT
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U i ~*]  
x9!vtrM\Zr  
} |J#mgA}(  
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(l3P<[[?  
public static void main(String[] args) sS|N.2*  
{ ,:QDl  
new TestMethod(); BnL
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} lj!f\C}d  
} H|iY<7@  
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