http断点续传简单实现（java)

/* (:qc[,m  
**SiteFileFetch.java /2zan}  
*/ 70GBf"
 
package NetFox; 'AX5V-t  
import java.io.*; 8 eK8-R$  
import java.net.*; $&&E[JY  
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public class SiteFileFetch extends Thread { e*qGrg(E  
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SiteInfoBean siteInfoBean = null; //文件信息Bean nX 9]dz
 
long[] nStartPos; //开始位置 (5 @H  
long[] nEndPos; //结束位置 ;xe.0j0h  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 BO#tn{(#  
long nFileLength; //文件长度 yw$4Hlj5  
boolean bFirst = true; //是否第一次取文件 n8F~!|lQ0  
boolean bStop = false; //停止标志 k'PvTWR  
File tmpFile; //文件下载的临时信息 4")`}T  
DataOutputStream output; //输出到文件的输出流 2?GMKd)  
}mXYS|{  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） QOo'Iv+EL  
public SiteFileFetch(SiteInfoBean bean) throws IOException *Q^z4UY  
{ ) jH`lY)1  
siteInfoBean = bean; ZaU8eg7  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); k`Ifl)  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); -1Dq_!i  
if(tmpFile.exists ()) pd#Sn+&rf  
{ 6_4B!  
bFirst = false; 7M~sol[*  
read_nPos(); Nwz?*~1  
} \OA{&G.  
else VO8rd>b4  
{ jOVF+9M  
nStartPos = new long[bean.getNSplitter()]; cu($mjC@T  
nEndPos = new long[bean.getNSplitter()]; xsB0LUt  
} vo`&  
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} E{&MmrlL,  
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public void run() /V:9*C  
{ [K.1 X=O}  
//获得文件长度 ?}Zt&(#  
//分割文件 ,JE_aje7  
//实例FileSplitterFetch Q0Ft.b  
//启动FileSplitterFetch线程 X)[tb]U/Wx  
//等待子线程返回 }a||@unr  
try{ -p&u=  
if(bFirst) L)bMO8JH~m  
{ ##=$$1Ki  
nFileLength = getFileSize(); OQ&N]P2p  
if(nFileLength == -1) B6Kl_~gT  
{ 7bzm5w@v  
System.err.println("File Length is not known!"); lb.Q^TghU  
} 6sSwSS
 
else if(nFileLength == -2) <'~m1l#2  
{ [&n[p?  
System.err.println("File is not access!"); dHUbaf:e)T  
} Ctz#9[|  
else m+hI3@j  
{ )Xjn:  
for(int i=0;i<nStartPos.length;i++) n(J>'Z  
{ RyJy%|\-S  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); xKG7d8=  
} );h(D!D,  
for(int i=0;i<nEndPos.length-1;i++) 3

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{ ^PTf8o  
nEndPos = nStartPos[i+1]; 3&+dyhL'w  
} Z5>~l  
nEndPos[nEndPos.length-1] = nFileLength; ?b,>+v-w::  
} &2y4k"B&)  
} ::oFL#+  
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//启动子线程 g[O?wH-a  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ;Zd_2CZ  
for(int i=0;i<nStartPos.length;i++) N $) G8  
{ W5 F\e[Ax5  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "Gp[.=.z?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 985F(r  
nStartPos,nEndPos,i); HE,L8S  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); K:a8}w>Up  
fileSplitterFetch.start(); sQa;l]O:NC  
} [34N/;5  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), JcR|{9ghT  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); xmv%O&0^}  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", LpU}.  
nEndPos = " + nFileLength); HU $"o6ap  
// fileSplitterFetch[nPos.length-1].start(); ;o!p9MEpz;  
CJ\a7=*i  
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//等待子线程结束 `F7]M  
//int count = 0; =\oH= f  
//是否结束while循环 }tW-l*\U  
boolean breakWhile = false; %+(AKZu:  
t]LiFpy2IC  
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while(!bStop) R ZY=c  
{  vmqa_gU\  
write_nPos(); il5C9ql$  
Utility.sleep(500); f+^6.%  
breakWhile = true; m1X7zUCy  
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for(int i=0;i<nStartPos.length;i++) x%}D+2ro-t  
{ u#@/^h;  
if(!fileSplitterFetch.bDownOver) W`;;fJe  
{
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breakWhile = false; zeHF-_{  
break; U>E: Ub0r  
} fwFJe(.  
} xol%\$|  
if(breakWhile) 6{y7e L3!  
break; I\.|\^  
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1Z# $X`  
//count++; gJ6`Kl985O  
//if(count>4) LTWkHyx  
// siteStop(); V)^Xz8H_  
} egaX[j r  
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System.err.println("文件下载结束！"); ] 3{t}qY$A  
}
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catch(Exception e){e.printStackTrace ();} ?F"o+]i+^  
} G(&[1V%x  
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//获得文件长度 u
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public long getFileSize() /f3/}x!po  
{ {@InOo!4w]  
int nFileLength = -1; KZ
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try{ ?"x4u#x  
URL url = new URL(siteInfoBean.getSSiteURL()); C}8#yAS9M  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); b(*\4n  
httpConnection.setRequestProperty("User-Agent","NetFox"); E3uu vQ#|  
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2Vx4"fHP#N  
int responseCode=httpConnection.getResponseCode(); y(COB6r  
if(responseCode>=400) Pd91<L  
{ z#tIa  
processErrorCode(responseCode); iq; | i!  
return -2; //-2 represent access is error 75# 8P?i  
} g&$=Y7G  
tIuM9D{P  
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String sHeader; axC|,8~tq  
,;g%/6X  
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for(int i=1;;i++) P(D>4/f3"  
{ rnIjpc F  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); #A/OGi  
//Utility.log(in.readLine()); ")Fd'&58  
sHeader=httpConnection.getHeaderFieldKey(i); ?@b6(f xX  
if(sHeader!=null) h*S"]ye5  
{ -n _Y.~  
if(sHeader.equals("Content-Length")) LDlYLsF9  
{ tu -a`h_NJ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); #1<m\z7l  
break; t+?Bb7p,H  
} P
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} l]]NVBA])  
else fs!dI  
break; \dk1a  
}  FOiwA.:0  
} qOo4T@t3  
catch(IOException e){e.printStackTrace ();} %N8I'*u  
catch(Exception e){e.printStackTrace ();} f8Hq&_Pn  
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Utility.log(nFileLength); 6FB0g8  
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return nFileLength;
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} fbq$:Q44
 
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;(NTzBq!1  
//保存下载信息（文件指针位置） Z0<Vss  
private void write_nPos() ,&o9\|ih7]  
{ k1B ](@xt  
try{ !1$x4 qxS  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 7<j!qWm0  
output.writeInt(nStartPos.length); #HcQ*BiF3  
for(int i=0;i<nStartPos.length;i++) ,P~e)<.  
{ J}V4.R5d  
// output.writeLong(nPos); aq?bI:>8  
output.writeLong(fileSplitterFetch.nStartPos); scV%p&{a  
output.writeLong(fileSplitterFetch.nEndPos); ?@"@9na  
} xQFRM aQE  
output.close(); 5{! fa  
} r^,_m,s'<  
catch(IOException e){e.printStackTrace ();} b<u\THy#  
catch(Exception e){e.printStackTrace ();} eb_.@.a  
} .}dLqw  
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//读取保存的下载信息（文件指针位置） ~^F]t$rz  
private void read_nPos() |O8e;v72g^  
{ 0LQRQuh1  
try{ #}~tTL  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 9wL2NC31Q  
int nCount = input.readInt(); 7ZUN;mr  
nStartPos = new long[nCount]; 0F$|`v"0  
nEndPos = new long[nCount]; nDrRK  
for(int i=0;i<nStartPos.length;i++) RZz?_1'  
{ Il=6t
  
nStartPos = input.readLong(); 2"6L\8hd2  
nEndPos = input.readLong(); oiyvKMHz7  
} QytO0K5  
input.close(); neEqw+#Z  
} ( fFrX_K]  
catch(IOException e){e.printStackTrace ();} HYl+xH'.j  
catch(Exception e){e.printStackTrace ();} %pZT3dcK  
} Q 8]X  
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private void processErrorCode(int nErrorCode) r9f- C  
{ \9+,ynJH8z  
System.err.println("Error Code : " + nErrorCode); I"]E}nd)  
} e{8C0=  
/M5.Z~|/  
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//停止文件下载 W8<QgpV*  
public void siteStop() I]ej ]46K  
{ i3 js'?7E  
bStop = true; xbiprhdv  
for(int i=0;i<nStartPos.length;i++) ~criZI/  
fileSplitterFetch.splitterStop(); l&H-<Z.8m  
{A}T^q!m]  
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} uz8eS'8  
} P0UR{tK  
//负责部分文件的抓取 caEIE0H~  
**FileSplitterFetch.java n^'d8Y(  
*/ aMqt2{f+  
package NetFox; i7H([b<_m  
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import java.io.*; (0`rfYv5.R  
import java.net.*; puOMtCI  
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public class FileSplitterFetch extends Thread { I85wP}c(  
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String sURL; //File URL ;)rhx`"n  
long nStartPos; //File Snippet Start Position z{R Mb  
long nEndPos; //File Snippet End Position &Zz&VwWR  
int nThreadID; //Thread's ID 8h ol4'B  
boolean bDownOver = false; //Downing is over 0,0WdJAe  
boolean bStop = false; //Stop identical y1`%3\  
FileAccessI fileAccessI = null; //File Access interface T3b0"o27  
}5EH67  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException [
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{ wgSFL6Ei  
this.sURL = sURL; `@Z$+  
this.nStartPos = nStart; }r04*P(  
this.nEndPos = nEnd; R1*&rjB  
nThreadID = id; 5!Er;e  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 # l1*#Z  
} ",YNphjAn  
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public void run() T c-fO /0  
{ kU:Q&[/jzH  
while(nStartPos < nEndPos && !bStop) @>`N%wH'  
{  ^Oj^7.T+  
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try{ &*Z)[Bl  
URL url = new URL(sURL);  uvDOTRf  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *o=Z~U9z  
httpConnection.setRequestProperty("User-Agent","NetFox"); x>i =  
String sProperty = "bytes="+nStartPos+"-"; 8U#14U5rS  
httpConnection.setRequestProperty("RANGE",sProperty); ddYb=L+_b  
Utility.log(sProperty); B <Jxj  
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InputStream input = httpConnection.getInputStream(); Y}vV.q  
//logResponseHead(httpConnection); `34+~;;Jh  
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byte[] b = new byte[1024]; >U:-U"rA?  
int nRead; ;{m;CKHI  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) sVO|Ghy65  
{ +MS*YpPW  
nStartPos += fileAccessI.write(b,0,nRead); fN`Prs A  
//if(nThreadID == 1) -6q7ze{@  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (>Sy,  
} 1\jj3Y'i'  
I/h(*~/  
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Utility.log("Thread " + nThreadID + " is over!"); #,jm3Mqj  
bDownOver = true; 3&X5*-U  
//nPos = fileAccessI.write (b,0,nRead); 'fb&3  
} <Rt0 V%}-  
catch(Exception e){e.printStackTrace ();} ziAn9/sT  
} P@etT8|V  
} V2Z
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//打印回应的头信息 X?8bb! g%Q  
public void logResponseHead(HttpURLConnection con) ylmVmHmc  
{ * se),CP!s  
for(int i=1;;i++) ~@^pX*%i  
{ OoOwEV2p_  
String header=con.getHeaderFieldKey(i); <SRSJJR|(  
if(header!=null) Ze`ms96j{  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); pfk)_;>,  
Utility.log(header+" : "+con.getHeaderField(header)); kDKfJp&a  
else ]{-ib:f
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break; J<L"D/  
} uN&49o  
} `yXHb  
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public void splitterStop() r^d:Po  
{ X)Rh&ui  
bStop = true; YZ0Q?7l7  
} e<{Ani0  
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} yV@~B;eW0  
xqVIw!J?/}  
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/* -A8CW9|mk  
**FileAccess.java ~:A=o?V2  
*//文件访问(定位，写) ~
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package NetFox; xqKj&RuLu  
import java.io.*; [
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public class FileAccessI implements Serializable{ O~bzTn
 
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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 ~ Q;qRx  
RandomAccessFile oSavedFile; l;JB;0<s"  
long nPos; "CQ:<$|$  
3}?]G8iL?L  
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public FileAccessI() throws IOException 5 .bU2C  
{ r/ LgmVRn  
this("",0); tw]Q5:6  
} ^X?3e1om  
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public FileAccessI(String sName,long nPos) throws IOException
i\P)P!  
{ rcMSso2  
oSavedFile = new RandomAccessFile(sName,"rw"); f,Dj@?3+  
this.nPos = nPos; z!\)sL/"  
oSavedFile.seek(nPos); &q[`lIV,L  
} )mXu{uowr  
2G`tS=Un  
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public synchronized int write(byte[] b,int nStart,int nLen) X[iQ%Y$/n  
{ .{#J2}+[_}  
int n = -1; 20RISj  
try{ RC]-9gd3Q  
oSavedFile.write(b,nStart,nLen);  Hn,;G`{  
n = nLen; ^&8xfI
6?  
} |rk4,
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catch(IOException e) -6>T0-  
{ 7%^/Jm  
e.printStackTrace (); ^5*9BwH`  
} q vGkTE  
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return n; S_56!  
} _0e;&2')  
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} m&8'O\$  
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niJtgK:H^  
/* OAZ5I)D>  
**SiteInfoBean.java *5|q_K Pt  
*/ <%]i7&8|  
package NetFox; jAb R[QR1%  
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q'[q]  
public class SiteInfoBean { vTU*6
)  
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private String sSiteURL; //Site's URL dBMr%6tz  
private String sFilePath; //Saved File's Path r5g:#m
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private String sFileName; //Saved File's Name #Rcb iV*M  
private int nSplitter; //Count of Splited Downloading File Ves x$!F#  
jpek=4E
 
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public SiteInfoBean() [oh0 )wzB  
{//nSplitter的缺省值为5 E
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//default value of nSplitter is 5 RW04>oxVn  
this("","","",5); wm/=]*jpK  
} h"DxgG  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) z8\z`#g!  
{ '&hk?  
sSiteURL= sURL; 3=~0m  
sFilePath = sPath; 8%D 2G i  
sFileName = sName; {:0TiOP5x  
this.nSplitter = nSpiltter; &`IC3O5  
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} Ryrvu1 k  
Zf~Z&"C)  
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public String getSSiteURL() #?EmC]N7  
{ 48Z0aA~+  
return sSiteURL; CDU$Gi  
} %qqX-SF0C  
.~t.B!rVSB  
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public void setSSiteURL(String value) Xe7/  
{ YA[\|I33  
sSiteURL = value; H!yqIh  
} /f0*NNSat-  
HXp$\%A)  
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public String getSFilePath() xaG( 3  
{ \T]'d@Wyd  
return sFilePath; *kE<7  
} --chU5  
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public void setSFilePath(String value) Tz?0E"yx  
{ 70BLd(?  
sFilePath = value; 7uW=fkxT  
} +<1MY'>y  
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public String getSFileName() 6z keWR  
{ |`,AAa  
return sFileName; -.=:@H}r  
} U8
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>  
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public void setSFileName(String value) kt;uB X3  
{ }a?(}{z-  
sFileName = value; X&14;lu%p  
} y}bliN7;1e  
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public int getNSplitter() y1c2(K>tu  
{ +l)[A{  
return nSplitter; -b`O"Ck*  
} d,d ohi  
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O=E?m=FR"  
public void setNSplitter(int nCount) ,z0~VS:g8  
{ 'YTSakNJ}  
nSplitter = nCount; 1@W*fVn  
} &=S<StH  
} si=m5$V  
z<u*I@;  
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/* Ew
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**Utility.java bDADFitSo  
*/ u]uZc~T  
package NetFox; 0 F-db  
&6q67  
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public class Utility { gHmy?+)  
(29BS(|!  
6[~_;0  
public Utility() fIwG9cR  
{ *mtS\J  
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} RHv|ijYy  
DT#F?@LG(  
//线程睡眠 m:x<maP#E  
public static void sleep(int nSecond) mP[ZlS~"  
{ /JbO$A  
try{ q)rxv7Iu\  
Thread.sleep(nSecond); :F`-<x/  
} c>.=;'2  
catch(Exception e) `m+o^!SGe  
{ P?/Mrz   
e.printStackTrace (); TKs l.|  
} bJ5 VlK67R  
} GX0S9s  
K$kI%eGZA  
//日志 :xy4JRcF  
public static void log(String sMsg) i!u:]14>  
{ =GJ)4
os  
System.err.println(sMsg); ~b;u1;ne  
} .h r$<]  
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public static void log(int sMsg) Bm4fdf#A]  
{  SodYb  
System.err.println(sMsg);  ow2tfylV  
} ;%B:1Z  
} y)uxj-G  
hA:RVeS{  
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/* .{,fb  
**TestMethod.java n}L Jt  
*/ kxWcWl8  
package NetFox; i)=dp!Bx^  
%2,'x  
NnTAKd
8  
public class TestMethod { 88g|(k/  
0f9*=c  
Cc&SHG*R  
public TestMethod() Gc*p%2c  
{ ///xx/weblogic60b2_win.exe |{V@t1`  
try{ 7&w$@zs87  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %Fp1c K  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ,.]1N:   
SiteFileFetch fileFetch = new SiteFileFetch(bean); J7FzOwd1h  
fileFetch.start(); #M@Ki1  
} |*v w(  
catch(Exception e){e.printStackTrace ();} @ebSM#F?  
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} e]zd6{g[m  
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public static void main(String[] args) Aq;WQyZ2  
{ gn)>(MG  
new TestMethod(); aW*8t'm;m'  
} {n 4W3  
} ^E]y >Y  
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