http断点续传简单实现（java)

/* RDGefxv  
**SiteFileFetch.java g$+ $@~  
*/ j6}/pe*;;T  
package NetFox; O!xul$9  
import java.io.*; N;gI %6  
import java.net.*; ?> )(;Ir9  
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public class SiteFileFetch extends Thread {
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SiteInfoBean siteInfoBean = null; //文件信息Bean Vh=10Et  
long[] nStartPos; //开始位置 cc37(=oKL  
long[] nEndPos; //结束位置 {-a8^IK,  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ;XAj/6pm  
long nFileLength; //文件长度 20h+^R3{Z  
boolean bFirst = true; //是否第一次取文件 II;   
boolean bStop = false; //停止标志 <l>o6K  
File tmpFile; //文件下载的临时信息 ?9W2wqN>o  
DataOutputStream output; //输出到文件的输出流 J7a_a>Y  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） oQ YmywY  
public SiteFileFetch(SiteInfoBean bean) throws IOException `0)'&HbLY  
{ |%\>+/j$  
siteInfoBean = bean; /fh[_!qN  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); '
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); @ (4$<><  
if(tmpFile.exists ()) }*Z *wC  
{ uP
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bFirst = false; 3FetyWl'  
read_nPos(); xWR<>Og.  
} A-S!Z2m\  
else ):<9j"Z;At  
{ 'TwvkU"  
nStartPos = new long[bean.getNSplitter()]; \+,%RN.  
nEndPos = new long[bean.getNSplitter()]; | 6/ # H*  
} }:SWgPfc  
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} h=*eOxR"4^  
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public void run() &-R(u}m-F  
{ mqrV:3}  
//获得文件长度 LeEv']  
//分割文件 ;Gnk8lIsb  
//实例FileSplitterFetch NLnfCY-h  
//启动FileSplitterFetch线程 ^t0Yh%V7  
//等待子线程返回 lE|Hp  
try{ >n(Ga9E  
if(bFirst) xQU$E|I  
{ lD+f{GR  
nFileLength = getFileSize(); ,2>nr goM  
if(nFileLength == -1) Fm-D>PR
 
{ p#A{.6Pa:  
System.err.println("File Length is not known!"); OUM^u*  
} MqKf'6z  
else if(nFileLength == -2) D2N<a=#  
{ N Ftmus  
System.err.println("File is not access!"); T#OrsJdu  
} <4Ev3z*;Z  
else `514HgR  
{ OK8|w]-A  
for(int i=0;i<nStartPos.length;i++) _-6IB>  
{ (Vz\02,K  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Thc"QIk&4  
} !TwH;#U w  
for(int i=0;i<nEndPos.length-1;i++) xQKRUHDc  
{ -mfdngp3  
nEndPos = nStartPos[i+1]; f?Am)  
} -5X*y4#  
nEndPos[nEndPos.length-1] = nFileLength; a]]>(Txc  
} myq:~^L ;  
} _]aA58,j  
AhA4IOG`.  
.).}ffhOL  
//启动子线程
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; N0mP EF2  
for(int i=0;i<nStartPos.length;i++) #0uD&95<  
{ $-*E   
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(),  "o{o9.w  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), yH<a;@C  
nStartPos,nEndPos,i); qvHRP@  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Bj1{=Pvl  
fileSplitterFetch.start(); Or:a\qQ1  
} KB@F^&L {  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), S!oG|%VuB#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); \""sf{S9  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", :i};]pR  
nEndPos = " + nFileLength); 8`]1Nt!*B  
// fileSplitterFetch[nPos.length-1].start(); ~E^lKe  
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y/9aI/O'
  
//等待子线程结束 {3H)c
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//int count = 0; D-KQRe2@  
//是否结束while循环 Et0[HotO  
boolean breakWhile = false; 7SVqfWp  
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while(!bStop) Ex`!C]sQ  
{ ]>_Ie?L)<  
write_nPos(); v<u`wnt  
Utility.sleep(500); |,)=-21&;  
breakWhile = true; 9V/:1I0?&0  
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for(int i=0;i<nStartPos.length;i++) {9_}i#,vR  
{ K
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if(!fileSplitterFetch.bDownOver) 552yzn1  
{ }]BH
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breakWhile = false; +r<d z  
break; I}hY @  
} V;-$k@$b.  
} 9\J6G8b>|I  
if(breakWhile) kKlcK_b;  
break; *= ;M',nx  

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//count++; r0'6\MS13  
//if(count>4) HQ0fY  
// siteStop(); 2Y-NxW^]  
} d) i64"  
}bA@QEJ  
j
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System.err.println("文件下载结束！"); sc)}r_|g  
} GB&^<@  
catch(Exception e){e.printStackTrace ();}
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} yd+.hg&J  
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//获得文件长度
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public long getFileSize() yzH[~O7  
{ D.;iz>_}Y  
int nFileLength = -1; RASPOc/]   
try{ \.l8]LH  
URL url = new URL(siteInfoBean.getSSiteURL()); ?BA~$|lfxu  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @)< 3Z  
httpConnection.setRequestProperty("User-Agent","NetFox"); qW"  
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int responseCode=httpConnection.getResponseCode(); fFiFS\''V  
if(responseCode>=400) ='z4bU  
{ Yb?L:,a(I  
processErrorCode(responseCode); zho$g9*  
return -2; //-2 represent access is error ,)beK*Iw  
} 8?z7!k]  
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String sHeader; gAxf5A_x)  
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for(int i=1;;i++) [,?5}
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{ XtP5IN\S  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); E,wOWs*  
//Utility.log(in.readLine()); ?#]wxH,  
sHeader=httpConnection.getHeaderFieldKey(i); ?VRf5 Cr-  
if(sHeader!=null)
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{ L[rxs[7~  
if(sHeader.equals("Content-Length")) tH^]`6"QUa  
{ i[7<l&K]  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 2M$^|j:[  
break; n=1_-)  
} 8{)j"rghah  
} l1#F1q`^t  
else }T1.~E  
break; FA7q pc  
} ~[
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} 3<A$lG  
catch(IOException e){e.printStackTrace ();} qC4Q+"'  
catch(Exception e){e.printStackTrace ();} `-)Hot)  
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Utility.log(nFileLength); H:5-S  
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return nFileLength; )0UXTyw^  
} ~M Mv+d88  
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//保存下载信息（文件指针位置） LAjreC<W  
private void write_nPos() RIV + _}R  
{ n5s2\(  
try{ 6*r#m%|   
output = new DataOutputStream(new FileOutputStream(tmpFile)); Zog&:]P'F  
output.writeInt(nStartPos.length); fMluVND  
for(int i=0;i<nStartPos.length;i++) `
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{ 3D^!U}E  
// output.writeLong(nPos); mnm7{?#[  
output.writeLong(fileSplitterFetch.nStartPos); IDn$w^"  
output.writeLong(fileSplitterFetch.nEndPos); +JlPQ~5  
} SDHJX8Hq  
output.close(); dW#T1mB  
} 5h7M3s  
catch(IOException e){e.printStackTrace ();} ,We'AR3X  
catch(Exception e){e.printStackTrace ();} -.t/c}a#  
} ]X\p\n'@j  
'MK"*W8QRM  
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//读取保存的下载信息（文件指针位置） sp8P[W1a  
private void read_nPos() eFXQ~~gOj  
{ S!6 ? b5  
try{ 9?38/2kX4  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); :c}"a(|  
int nCount = input.readInt(); u6MHdCJ0y  
nStartPos = new long[nCount]; ]9hXiY  
nEndPos = new long[nCount]; GJj}|+|  
for(int i=0;i<nStartPos.length;i++) k\<8h%
 
{ :/XWk %  
nStartPos = input.readLong(); N;mJHr3[F  
nEndPos = input.readLong(); 5v_vv'~  
} 0i4XS*vPv  
input.close(); o~`KOe  
} yBkcYHT  
catch(IOException e){e.printStackTrace ();} 6R'z3[K9  
catch(Exception e){e.printStackTrace ();} kkU#0p?7  
} kA4bv}  
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private void processErrorCode(int nErrorCode) ./@C  
{ YS0^!7u  
System.err.println("Error Code : " + nErrorCode); U>0~/o  
} Nf!WqD*je  
VxW>XxG0  
8{DW$ZtR  
//停止文件下载 Ge^(Ag}vE  
public void siteStop() %pj T?G7  
{ 8z)J rO}  
bStop = true; K)N'~jCG  
for(int i=0;i<nStartPos.length;i++) 9(pF!}1%\  
fileSplitterFetch.splitterStop(); }P\J?8  
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} Dj9ecV`  
} EV[ BB;eb  
//负责部分文件的抓取 %v)+]D
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**FileSplitterFetch.java {&uN q^Ch  
*/ Vu5Djx'  
package NetFox; F#KUu3;B  
WGA"e  
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import java.io.*; #&,~5  
import java.net.*; [pX cKN  
w:h([q4X  
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public class FileSplitterFetch extends Thread { THy{r_dx  
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String sURL; //File URL Y,M2D  
long nStartPos; //File Snippet Start Position b NR@d'U  
long nEndPos; //File Snippet End Position _jM+;=f
 
int nThreadID; //Thread's ID /RemLJP F  
boolean bDownOver = false; //Downing is over ^KUM4. 6  
boolean bStop = false; //Stop identical &Pe[kCO]  
FileAccessI fileAccessI = null; //File Access interface R/P9=yvg0  
auHP^O>4L  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException *0/%R{+S  
{ YJB/*SV^  
this.sURL = sURL; /[+qw%>  
this.nStartPos = nStart; =|V[^#V  
this.nEndPos = nEnd; vRMGNz_P7[  
nThreadID = id; 4vyJ<b  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 )^7- qy  
} _#y=T20'3  
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public void run() qk=OodEMK  
{ ;nw}x4Y[  
while(nStartPos < nEndPos && !bStop) H,Yrk(O-  
{ WQBpU?O  
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try{ $g '4'  
URL url = new URL(sURL); [/Xc},HbMe  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ZN}U^9m=  
httpConnection.setRequestProperty("User-Agent","NetFox"); bo[[
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String sProperty = "bytes="+nStartPos+"-"; qdxDR 2]U  
httpConnection.setRequestProperty("RANGE",sProperty); L8?;A9pc()  
Utility.log(sProperty); plgiQr #  
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InputStream input = httpConnection.getInputStream(); C j:  
//logResponseHead(httpConnection); 'tY y_  
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byte[] b = new byte[1024]; N4w&g-  
int nRead; Dpkc9~z  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) g-<[* nF  
{ 5@EX,$h  
nStartPos += fileAccessI.write(b,0,nRead); wpa^]l  
//if(nThreadID == 1) VWW(=j  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); u"-."_  
} ,B$e'KQ  
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Utility.log("Thread " + nThreadID + " is over!"); nmoC(| r  
bDownOver = true; t'*2)U  
//nPos = fileAccessI.write (b,0,nRead); /_i]bM7W  
} $!K,5^+  
catch(Exception e){e.printStackTrace ();} k(dNHT  
} $j&2bO5M  
} Oee>d
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@!::_E+F]  
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//打印回应的头信息 Nrzg>WQa  
public void logResponseHead(HttpURLConnection con) e!P]$em|1E  
{ \4n9m  
for(int i=1;;i++) lFD/hz7lc  
{ [cT7Iqip  
String header=con.getHeaderFieldKey(i); LEA^o"NW.  
if(header!=null) Y*YV/E.  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Z[9f8/6<b  
Utility.log(header+" : "+con.getHeaderField(header)); seA=7c5E  
else /OeOL3Y  
break; tx]!|x" F  
} M[6WcH0/T  
} ]?V2L`/  
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public void splitterStop() =z9FjK  
{ 1G 63eH)!  
bStop = true; %$=}ePD  
} m-'+)lB  
02q*z>:^  
3`{[T17  
} cLm{gd4 W  
0b+End#mp  

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/* e@L?jBj8m  
**FileAccess.java %J:2y  
*//文件访问(定位，写) 4H hQzVM{  
package NetFox; I=|}%WO#  
import java.io.*; H#B9
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public class FileAccessI implements Serializable{ 6Lz:J:Q)  
3/*<i  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 &I?d(Z=:\  
RandomAccessFile oSavedFile; kRB2J3Nt.  
long nPos; %-3wR@  
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public FileAccessI() throws IOException }bYk#6KX  
{ 5Cl;h^R|m  
this("",0); c'Zs2s7$  
} wsAijHjJI!  
9P#<T7
  
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public FileAccessI(String sName,long nPos) throws IOException B2)SNhF2Y  
{ ?#VkzT  
oSavedFile = new RandomAccessFile(sName,"rw"); tkf^sGgNO  
this.nPos = nPos; *Zz hN]1  
oSavedFile.seek(nPos); LAv!s/O$=  
} Awlw6?   
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public synchronized int write(byte[] b,int nStart,int nLen) Tw!_=zy(Gw  
{ *!L it:H  
int n = -1; Schvwlm~i  
try{ 7=pJ)4;ZA  
oSavedFile.write(b,nStart,nLen); kT4Oal+4  
n = nLen; a'YK1QX  
} |v= */
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catch(IOException e) YE1X*'4  
{
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e.printStackTrace (); <jtu/U]78|  
} I2*\J)|f  
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return n; .{66q#.  
} H]&^>Pvh  
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} ZqJyuTPv  
h
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/* "oo j;  
**SiteInfoBean.java 5)<}a&;{  
*/ {%XDr,myd  
package NetFox; j$}W%ibj
 
HbQ+:B]  
#~:@H&f790  
public class SiteInfoBean { o :_'R5  
`Y.Q{5Y  
~"i4"Op&  
private String sSiteURL; //Site's URL cA2
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private String sFilePath; //Saved File's Path LV$`bZ  
private String sFileName; //Saved File's Name !&@
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private int nSplitter; //Count of Splited Downloading File 4%,E;fB?=  
~+bSD<!b  
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public SiteInfoBean() nZ~J&QK-  
{//nSplitter的缺省值为5 >e9xM Gv  
//default value of nSplitter is 5 gukKa  
this("","","",5); 4: S-  
} 3NxwQ,~  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 88M$mjx  
{ Yb Dz{m  
sSiteURL= sURL; Zh3hCxXa  
sFilePath = sPath; }pL#C  
sFileName = sName; a^.5cJ$]  
this.nSplitter = nSpiltter; ad'C&^o5  
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} 7&{[Y^R]"  
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public String getSSiteURL() &/tGT3)  
{ E>3(ff&  
return sSiteURL; } 2P,Z6L  
} 2]/[  
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public void setSSiteURL(String value) <t)D`n
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{ Fun+L@:;  
sSiteURL = value; kSH|+K\M4  
} !(-S?*64l  
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public String getSFilePath() j SXVLyz  
{ y%=t((.Z  
return sFilePath; Cz]NSG5  
} WwYy[3U  
9#ZR0t.cY  
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public void setSFilePath(String value) P*zOt]T  
{ X!ad~bt  
sFilePath = value; 92)e/t iP  
} kqyPb$Wy  
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public String getSFileName() (_$'e%G0  
{ E4dN,^_ F!  
return sFileName; '+*{u]\  
} FCMV1,  
+4*jO5EZ  
:{ Q[kYj  
public void setSFileName(String value) ";$rcg"%X  
{ qZ|>{^a*  
sFileName = value; MW$ X4<*KD  
} (zL(  
}[m,HA<j  
tNbZ{=I>  
public int getNSplitter() v6q oH)n  
{ 'k?*?XxG  
return nSplitter; o9#8q_D9  
} u AmDXqJ3  
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public void setNSplitter(int nCount) Y6r<+#V  
{ x=~$ik++  
nSplitter = nCount; X23#y7:  
} -VVJf5/  
} CBvvvgIo  
N% W298  
Uc<j{U ,  
/* XAF*jevr  
**Utility.java qH1&tW$  
*/ 0.}WZAYy~  
package NetFox; ygn]f*;?kw  
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public class Utility { Nn]|#lLP  
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9C2DW,?  
public Utility() k-N` h  
{ `;vJ\$-<  
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} 1so9w89  
;+-Dg3  
//线程睡眠 sF+Bu'9
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public static void sleep(int nSecond) 5h6c W  
{ y-i6StJ  
try{ eW>Y*l%B  
Thread.sleep(nSecond);  a8wQ,  
} m^M sp:T,  
catch(Exception e) OX!<{9o  
{ vv% o+r-t  
e.printStackTrace (); c^ifHCt|  
} 9yt)9f  
} RC>79e/u<  
G&2`c\u{  
//日志 ;H;c Sn5uL  
public static void log(String sMsg) RAps`)OR?  
{ 0l&#%wmJ,  
System.err.println(sMsg); h~R= ?%H[  
} a(BEm_l3  
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public static void log(int sMsg) Q"+)xj  
{ [x\?._>  
System.err.println(sMsg); ,KyG^;Riy  
} :G\X  
} K.T.?ug;:  
?\7$63gBH  
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/* #Z)8
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**TestMethod.java lk?@ =U~  
*/ 7)U08"  
package NetFox; (o5^
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/ 80Q  
public class TestMethod { 2Sg^SZFH+o  
,/uVq
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public TestMethod() v3q.,I_  
{ ///xx/weblogic60b2_win.exe nS5g!GYY,k  
try{ xh)
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); -m"9v%>
Y  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); S_ELV#X  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Y_SB3 $])  
fileFetch.start(); }Jr!aM'  
} v:7_ZD6kR  
catch(Exception e){e.printStackTrace ();} 4[o/p8*/  
cU  
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} J+o6*t2|  
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public static void main(String[] args) &u}]3E'-k  
{ :*6#(MX  
new TestMethod(); ,u&K(Z%  
} |Y")$pjz  
} W8>
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