http断点续传简单实现（java)

/* *xXa4HB  
**SiteFileFetch.java O`U&0lKi'  
*/ Oz!#);v  
package NetFox; ,T?8??bZ  
import java.io.*; "40Jxqt  
import java.net.*; .P.TqT@)r  
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public class SiteFileFetch extends Thread { jftoqK- p  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Ath^UKO"  
long[] nStartPos; //开始位置 aPaGnP:^  
long[] nEndPos; //结束位置 4A.ZMH  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 C
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long nFileLength; //文件长度 nJ |O,*`O  
boolean bFirst = true; //是否第一次取文件 T;X8T  
boolean bStop = false; //停止标志 X64OX9:YF  
File tmpFile; //文件下载的临时信息 ]0.? 1se  
DataOutputStream output; //输出到文件的输出流 n!~mdI&  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） JyWBLi;Z  
public SiteFileFetch(SiteInfoBean bean) throws IOException r 11:T3  
{ M@fUZh  
siteInfoBean = bean; Dp!3uR']p  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); '`$a l7D  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); n}PK0  
if(tmpFile.exists ()) {C Qo}@.7  
{ He="S3XON  
bFirst = false; =XsdR?C  
read_nPos(); l j*ELy  
} <n< @ O5  
else a
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{ gsd9QW  
nStartPos = new long[bean.getNSplitter()]; &#aQ mgDF  
nEndPos = new long[bean.getNSplitter()]; >lQ&^9EI%  
} 2 |w;4  
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} 2j8^Z  
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public void run() @gc lks/M  
{ S]iM
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//获得文件长度 Vd^_4uqnV  
//分割文件 5f2ah4 g  
//实例FileSplitterFetch t_5b  
//启动FileSplitterFetch线程 cy8+
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//等待子线程返回 .f 4a+w  
try{ B4 5B`Ay  
if(bFirst) !4d6wp"  
{ J;4x-R$W  
nFileLength = getFileSize(); L+2!Sc,>  
if(nFileLength == -1) pvM;2  
{ :L<$O7  
System.err.println("File Length is not known!"); i|+ EC_^<  
} 8`}(N^=}  
else if(nFileLength == -2) Z\6&5r=  
{ -=,%9r  
System.err.println("File is not access!"); [?$ZB),L8  
} 0 ;kcSz  
else iaBy/!i  
{ 2MwRjh_  
for(int i=0;i<nStartPos.length;i++) c(Zar&z,E  
{ ]bCeJE.+)  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); cn#JO^8  
}
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for(int i=0;i<nEndPos.length-1;i++) xxOo8+kA  
{ `"QUA G  
nEndPos = nStartPos[i+1]; g{wIdV  
} ;V]EF  
nEndPos[nEndPos.length-1] = nFileLength; bUbM}  
} DODo !  
} MVHj?  
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//启动子线程 T677d.zaT  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 4qo4g+  
for(int i=0;i<nStartPos.length;i++) 9'F-D  
{ 6dQa|ACX_  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7qSlqA<Hs  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Dt?O_Bdv[  
nStartPos,nEndPos,i); 2xRb$QF  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); uV.3g 1m  
fileSplitterFetch.start(); ?PORPv#
 
} %:^,7 .H@  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Ai\"w0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 9frP`4<)  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", |VMc,_D  
nEndPos = " + nFileLength);  s
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// fileSplitterFetch[nPos.length-1].start(); Kd^{~Wlz&z  
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//等待子线程结束 9],;i7c  
//int count = 0; 3nv7Uz  
//是否结束while循环 Ry*NRP;  
boolean breakWhile = false; -}|GkTM  
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while(!bStop) W Da;wt  
{ I7b(fc-r  
write_nPos(); ]$(::'pmK  
Utility.sleep(500); ,t5X'sY L  
breakWhile = true;
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for(int i=0;i<nStartPos.length;i++) l!e8=QlJ  
{ l=*^FK]L`  
if(!fileSplitterFetch.bDownOver) {V%ZOdg9  
{ Ib.`2@o&  
breakWhile = false; 0z{S@  
break; +aRjJ/*  
} 8=ubMqr[  
} tVQfR*=  
if(breakWhile) pgz3d{]ua  
break; 1;r^QAK&  
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//count++; adtK$@Yeg  
//if(count>4) B'6^E#9  
// siteStop(); hk4f)z  
} R-]QU`c  
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System.err.println("文件下载结束！"); quk~z};R>\  
} #EtS9D'd+  
catch(Exception e){e.printStackTrace ();} Mp;t?C4  
} m>2b %GTh  
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//获得文件长度 !3Fj`Oh  
public long getFileSize() "{;]T  
{ AWCzu5ve  
int nFileLength = -1; :/ns/~5xa:  
try{ Ne*I$T 5  
URL url = new URL(siteInfoBean.getSSiteURL()); r:K)Q@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); vgOmcf%;  
httpConnection.setRequestProperty("User-Agent","NetFox"); B5Rmz&  
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int responseCode=httpConnection.getResponseCode(); U,)Ngnd  
if(responseCode>=400) _v4
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{ k\_>/)g  
processErrorCode(responseCode); W]5kM~Q@  
return -2; //-2 represent access is error 5)V]qV$   
} XG<J'3  
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String sHeader; D h]+HF  
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for(int i=1;;i++) M]!\X6<_  
{ w<j6ln+nM  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); eJ)Bs20Q  
//Utility.log(in.readLine()); g.f!Uc{  
sHeader=httpConnection.getHeaderFieldKey(i); V S2p"0$3D  
if(sHeader!=null) ,HS\(Z  
{ TveCy&  
if(sHeader.equals("Content-Length")) H? N!F7s  
{ "-XL Y_  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 0*VRFd4  
break; C.@R#a'  
} KL*ZPKG  
} N^q*lV#kob  
else +xRja(d6  
break; 3O%[k<S\VO  
} i:OD)l  
} G,>tC`!  
catch(IOException e){e.printStackTrace ();} tr7FV1p  
catch(Exception e){e.printStackTrace ();} z_!P0`  
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Utility.log(nFileLength); N-jFA8n  
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return nFileLength; JI )
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} \l_RyMi  
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] =b?^'  
//保存下载信息（文件指针位置） :Y
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private void write_nPos() al=Dy60|z  
{ R|{AIa{}  
try{ kxoJL6IC  
output = new DataOutputStream(new FileOutputStream(tmpFile)); O(,Ezyx  
output.writeInt(nStartPos.length); 9?gLi!rd  
for(int i=0;i<nStartPos.length;i++) m\U@L+L  
{ /MsXw/],  
// output.writeLong(nPos); ~^" cNv  
output.writeLong(fileSplitterFetch.nStartPos); ;E:ra_l  
output.writeLong(fileSplitterFetch.nEndPos); 2|tZ xlt-  
} n?&G>`u*  
output.close(); Rg<y8~|'}  
} A)040n  
catch(IOException e){e.printStackTrace ();}
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catch(Exception e){e.printStackTrace ();} dTyTj|"x{  
} (rt DT  
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//读取保存的下载信息（文件指针位置） W5$jIQ}Bw  
private void read_nPos() Z4}Yw{=f  
{ Y[$[0  
try{ FOB9CsMe  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); p}uL%:Vr  
int nCount = input.readInt(); ]N-K`c]  
nStartPos = new long[nCount]; //Ioh (N  
nEndPos = new long[nCount]; ho#]?Z#  
for(int i=0;i<nStartPos.length;i++) B^U5=L[:p  
{ )<DL'  
nStartPos = input.readLong(); J[L$8y:  
nEndPos = input.readLong(); Y1{6lhxgE  
} "My \&0-  
input.close(); #p*{p)]HiA  
} vhTte |(  
catch(IOException e){e.printStackTrace ();} ocAoqjlT[  
catch(Exception e){e.printStackTrace ();} d '4c?vC  
} a[xEN7L~4D  
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private void processErrorCode(int nErrorCode) PS`v3|d}}}  
{ %1@+pf/  
System.err.println("Error Code : " + nErrorCode); GasIOPzK  
} d;:+Xd`  
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//停止文件下载 )+N%!(ki  
public void siteStop() ^&h|HO-5  
{ a)Qx43mOS  
bStop = true; I Vq9z  
for(int i=0;i<nStartPos.length;i++) _yJd@  
fileSplitterFetch.splitterStop(); }7X85@jC  
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} 7od!:<v/  
} {#zJx(2yG  
//负责部分文件的抓取 <{3VK  
**FileSplitterFetch.java :I+%v  
*/ lk%rE  
package NetFox; 3vHEPm]  
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import java.io.*; `+\+  
import java.net.*; 9$)TAI&P  
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public class FileSplitterFetch extends Thread { CcLP/  
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String sURL; //File URL P
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long nStartPos; //File Snippet Start Position ;5q=/  
long nEndPos; //File Snippet End Position 6S2D\Bt,_  
int nThreadID; //Thread's ID * "~^k^_b}  
boolean bDownOver = false; //Downing is over 31 QT  
boolean bStop = false; //Stop identical `Q,moz  
FileAccessI fileAccessI = null; //File Access interface Qi w "
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Zc{
at}{  
{ O6YYOmt3  
this.sURL = sURL; BQ)zm  
this.nStartPos = nStart; L@ql)Lc);  
this.nEndPos = nEnd; {&4+W=0 n  
nThreadID = id; ZxwI< T:&  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 }Rt?p8p  
} =sG C  
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public void run() 'eLO#1Ipf  
{ U9SByqa1  
while(nStartPos < nEndPos && !bStop) b_|`jHes  
{ >(|T]u](q  
}
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try{ ,~hvF
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URL url = new URL(sURL); &+xNR2";  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); p4fU/  
httpConnection.setRequestProperty("User-Agent","NetFox"); K!).QB'  
String sProperty = "bytes="+nStartPos+"-"; H .JA)*b-  
httpConnection.setRequestProperty("RANGE",sProperty); {3i.U028]  
Utility.log(sProperty); 0AZ Vc  
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InputStream input = httpConnection.getInputStream(); ~Ub'5
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//logResponseHead(httpConnection); ~N;kF.q&>&  
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byte[] b = new byte[1024]; 'Wn'BRXq3  
int nRead; \@N8[  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Y#=0C*FS  
{ \uc]+nV!o  
nStartPos += fileAccessI.write(b,0,nRead); Ev,>_1#Xm  
//if(nThreadID == 1) ^r?ZrbS
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }Cvf[
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} 7ykpDl^@  
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Utility.log("Thread " + nThreadID + " is over!"); Ovq-rI{  
bDownOver = true; 5hr$tkkL  
//nPos = fileAccessI.write (b,0,nRead); MXh0a@*]  
} ||;V5iR
:  
catch(Exception e){e.printStackTrace ();} 0>6J-   
} F *=>=  
} 7.,C'^ci  
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//打印回应的头信息 -lQ8 &eB  
public void logResponseHead(HttpURLConnection con) t3}>5cAxy  
{ ",k"c}3G  
for(int i=1;;i++) yTm/P!1S  
{ 2`9e20  
String header=con.getHeaderFieldKey(i); 5V':3o;D__  
if(header!=null) 6U Q~Fv`]  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); M2W4 RovfR  
Utility.log(header+" : "+con.getHeaderField(header)); z\]]d?d?;  
else 7y5`YJ}!  
break; G|H+ ,B  
} Cvry
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} UMILAoR  
bBk_2lg=4)  
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public void splitterStop() pZ,=iqr  
{ uZL,+Ce|  
bStop = true;
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} {0RwjPYp  
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} <j,ZAA&5%Y  
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/* HL]8E}e\"  
**FileAccess.java t6DgWKT6  
*//文件访问(定位，写) j#G4A%_  
package NetFox; hfE5[  
import java.io.*; RL4J{4
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public class FileAccessI implements Serializable{ .)59*'0  
,P ~jO  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 'i+j;.  
RandomAccessFile oSavedFile; \NU^Jc_k7  
long nPos; :%7y6V
*  
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public FileAccessI() throws IOException UR?biq  
{ x7J8z\b"O  
this("",0); l7 Pn5c  
} 2T 3tKX  
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public FileAccessI(String sName,long nPos) throws IOException xl2;DFiYt  
{ %])U(  
oSavedFile = new RandomAccessFile(sName,"rw"); 'tvX.aX2  
this.nPos = nPos; Jx@_OE_vp  
oSavedFile.seek(nPos); ~/^q>z!\4  
} [wOz<<  
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public synchronized int write(byte[] b,int nStart,int nLen) m&vuBb3  
{ '^B[Krs'Z`  
int n = -1; Cq8.^=}_  
try{ 8! eYax   
oSavedFile.write(b,nStart,nLen); [GQn1ZLc  
n = nLen; FxU a5n  
} USd7gOq(  
catch(IOException e) +a3H1 tt~  
{ jKr\mb  
e.printStackTrace (); rf?%- X(V  
} T,@s.v  
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+2xgMN6B@  
return n; g$f+X~Q  
} R*0]*\C z  
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} Ui?iMtDr  
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/* Jlp nR#@  
**SiteInfoBean.java Sf*1Z~P|  
*/ %\"<lyD
 
package NetFox; UahsX  
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public class SiteInfoBean { BSH2Kq  
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private String sSiteURL; //Site's URL r)S:-wP  
private String sFilePath; //Saved File's Path 0:I[;Qt  
private String sFileName; //Saved File's Name sGFvSW  
private int nSplitter; //Count of Splited Downloading File %>'Zy6C<j  
_=Z?5{7S>  
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public SiteInfoBean() S5o,\wT  
{//nSplitter的缺省值为5 eWWqK9B.-  
//default value of nSplitter is 5 ] M`%@ps  
this("","","",5); qP{F
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} 7+9o<j@@o  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) r[g  
{ xO[V>Ud  
sSiteURL= sURL; T<oDLJA\  
sFilePath = sPath; S-'R84M,F  
sFileName = sName; mF:Pplf<  
this.nSplitter = nSpiltter; +Jm~Um!  
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} zfrNM9C  
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public String getSSiteURL() : &bJMzB  
{ qCkC2Fy(  
return sSiteURL; v]Fw~Y7l!  
} "%}24t%  
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public void setSSiteURL(String value)  8 XQo  
{ N TcojA{V$  
sSiteURL = value; \5|MW)x  
} 5Q;Q  
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/ 3eGt7x#  
public String getSFilePath() GQ(*k)'a  
{ \sz*M B  
return sFilePath; C
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} O^J=19Ri  
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public void setSFilePath(String value) Q.?(h! )9  
{ 4VF4
8  
sFilePath = value; J}NMF#w/;  
} cJerYRjsL  
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public String getSFileName() }.a{;{y  
{ yh2)Pc[  
return sFileName; zLgc j(;  
}  5@DC
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+e^CL#Gs  
E{0e5.{  
public void setSFileName(String value) in K]+H]{  
{ + -uQ] ^n  
sFileName = value; DIABR%0  
} &gJ1*"$9  
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public int getNSplitter() LC4VlfU  
{ r?itd)WC<X  
return nSplitter; =+
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} mPU}]1*p  
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public void setNSplitter(int nCount) hraR:l D  
{ v%$l(  
nSplitter = nCount; OK)>QGl  
} wz1nV}  
} &
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/* \=D+7'3  
**Utility.java 0cSm^a  
*/ vh.-9eD  
package NetFox; Zb=;\l*&  
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public class Utility { cRH(@b Xr  
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public Utility() ZJF"Yo  
{ o{>4PZ}=g  
X1d{7H8A2  
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} w[F})u]E  
(a0(ZOKH  
//线程睡眠 Mk~U/oq  
public static void sleep(int nSecond) e]nP
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{ T ay226  
try{ Auc&dpW  
Thread.sleep(nSecond); 'Kk/ J+6U  
} >;XtJJS  
catch(Exception e) r!1f>F*dt  
{ "f8,9@  
e.printStackTrace (); hP8w3gl
_  
} ^,YTQ.O  
} >-\^)z  
sBYDo{01  
//日志 ZBR^$?nj  
public static void log(String sMsg)
^\g.iuE  
{ yH=<KYk  
System.err.println(sMsg); 6/#+#T  
} '%4fQ%ID}  
*=O]^|]2  
9+MW13?  
public static void log(int sMsg) =dH=3iCG  
{ KB
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System.err.println(sMsg); V,=5}qozQ  
} XlD=<$Nk7  
} !yT=*Cj4  
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/* q6N{N
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**TestMethod.java akk*f+TD`  
*/ FAL#p$y}  
package NetFox; 2*^=)5Gj-h  
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public class TestMethod { ~"0{<mMcX  
.?rs5[th*  
oQrfrA&=M  
public TestMethod() ]]_5_)"4  
{ ///xx/weblogic60b2_win.exe ZnJJ-zP  
try{ 1) K<x  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,"5HJA4  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); T[^&ZS]s  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 4CchE15  
fileFetch.start(); \pkK >R  
} cuH5f}oc  
catch(Exception e){e.printStackTrace ();} EZ{{p+e^  
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9od c :  
} tK[o"?2y  
/k?l%AH  
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public static void main(String[] args) BJ]L@L%  
{ q+4dHS)x  
new TestMethod(); s0]ZE\`H>  
} AA)pV-  
} "9dZ z/{  
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