http断点续传简单实现（java)

/* ^?]-Q*w3Qs  
**SiteFileFetch.java b IxH0=f  
*/ QiA}0q3]0  
package NetFox; H9'psv  
import java.io.*; c?<)!9:  
import java.net.*; tKyGD|g S  
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public class SiteFileFetch extends Thread { Q%~BD@Io  
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SiteInfoBean siteInfoBean = null; //文件信息Bean / j "}e_Q  
long[] nStartPos; //开始位置 A*:|d~  
long[] nEndPos; //结束位置 feS$)H9-  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 %
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long nFileLength; //文件长度 2Y9u9;ah  
boolean bFirst = true; //是否第一次取文件 tz?3R#rM  
boolean bStop = false; //停止标志 wWx{#!W  
File tmpFile; //文件下载的临时信息 iEI#J!
~  
DataOutputStream output; //输出到文件的输出流 P9:5kiP H  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） >jiez,  
public SiteFileFetch(SiteInfoBean bean) throws IOException sk07|9nU  
{ O..{wdZy  
siteInfoBean = bean; 6d5J*y2
 
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); RX{} UmU<  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); kWa5=BW2f  
if(tmpFile.exists ()) Y|wjt\M  
{ trjpq{,[U  
bFirst = false; e*`ht+  
read_nPos(); GzaGTd.b  
} s5G`?/  
else }^Sk.:;n3  
{ *@^@7`W  
nStartPos = new long[bean.getNSplitter()]; K:XP;#OsP  
nEndPos = new long[bean.getNSplitter()]; E_'H=QN c  
} V=fh;p  
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} Vp1ct06^  
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public void run() %t6-wWM97  
{ >}+R+''nR  
//获得文件长度 :81d~f7  
//分割文件 {A< 961  
//实例FileSplitterFetch ckV\f({  
//启动FileSplitterFetch线程 KkTE -$-  
//等待子线程返回 T(Yp90'6  
try{ w\D !e  
if(bFirst) vw:GNpg'R6  
{ /9gn)q2f(  
nFileLength = getFileSize(); 8PVjNS/  
if(nFileLength == -1) \}4*}Lr  
{ \`z%5/@f;  
System.err.println("File Length is not known!"); 04}8x[t  
} )\D{5j  
else if(nFileLength == -2) f|_\GVW  
{ <@GO]vY  
System.err.println("File is not access!"); 2
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} u23_*W\  
else x'\C'zeF  
{ |.m)UFV  
for(int i=0;i<nStartPos.length;i++) S:i#|T."  
{ V'>Plb.A  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ig YYkt  
} a6;[Z  
for(int i=0;i<nEndPos.length-1;i++) -l_B;Sb:e  
{ i5Sya]FN  
nEndPos = nStartPos[i+1]; : qK-Rku  
} |By[ev"Kh%  
nEndPos[nEndPos.length-1] = nFileLength; %,~\,+NP  
} $mAC8a_Zu  
} 5oCg&aT  
~4=*kJ#7  
~@6l7H6{  
//启动子线程 }[lP^Qs  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; jDQ?b\^  
for(int i=0;i<nStartPos.length;i++) -G/qfd|s/  
{ Fx.Ly]L  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Ye$j43b  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), sCt)Yp+8}B  
nStartPos,nEndPos,i); 9M($_2,44  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); :2M&C+f[  
fileSplitterFetch.start(); 'Nt)7U>oC9  
} VJTO:}Q  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), c'3N;sZ*B  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); `)cH(Rj  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", iSoQ1#MP)2  
nEndPos = " + nFileLength); u_+iH$zA
 
// fileSplitterFetch[nPos.length-1].start(); u;t~ z  
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//等待子线程结束 %1jcY0zEQ  
//int count = 0; pZ\7!rON  
//是否结束while循环 T^`; wD  
boolean breakWhile = false; li\=mH,Wr  
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while(!bStop) -3)jUzD  
{ o<3$|`S&  
write_nPos(); $Z;/Sh  
Utility.sleep(500); pw4^E|X  
breakWhile = true; M
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for(int i=0;i<nStartPos.length;i++) u<cnz%@  
{ ]OdZlZBsJ  
if(!fileSplitterFetch.bDownOver) 4c(Em+4  
{ .?QYqGcG  
breakWhile = false; dTK0lgkUE  
break; $fg@g7_:  
} P[G>uA>Z1  
} #>bj6<  
if(breakWhile)
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break; B1!xr-kC  
*n EkbI/  


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//count++; E}S%yD[  
//if(count>4) 51y"#\7  
// siteStop(); 8a
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} h ':ZF  
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System.err.println("文件下载结束！"); 7CuZ7!>$  
} }kr?+)wB  
catch(Exception e){e.printStackTrace ();} ;XawEG7" U  
} T#3@r0M  
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1
s  
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//获得文件长度 "EMW'>&m  
public long getFileSize() T{3nIF   
{ 7>j~;p{  
int nFileLength = -1; 5a_8`csu  
try{ PgK7CG7G  
URL url = new URL(siteInfoBean.getSSiteURL()); ]r|oNGD)G  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :[
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httpConnection.setRequestProperty("User-Agent","NetFox"); $+7uB-KsU  
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int responseCode=httpConnection.getResponseCode(); Qw'905;(  
if(responseCode>=400) nDC0^&  
{ BXYH&2]Q  
processErrorCode(responseCode); Wj(#!\ 7F  
return -2; //-2 represent access is error 9|}Pf_5]%[  
} thJ~* 0^  
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String sHeader; m]AT-]*f  
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for(int i=1;;i++) esnq/  
{ 6ABK)m-y  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); [#q>Aq$11  
//Utility.log(in.readLine()); W~ET/h  
sHeader=httpConnection.getHeaderFieldKey(i); (n*:LS=0  
if(sHeader!=null) LQ# E+id&  
{ C{zp8 A(Dh  
if(sHeader.equals("Content-Length")) I8 :e`L  
{ s4"OsgP+  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); -<6?ISF2  
break; rYr*D[m]  
} |M?vFF]TN  
} kUgfFa#_  
else V3t#kv  
break; R);Hd1G  
} ~bhS$*t64  
} rtj`FH??11  
catch(IOException e){e.printStackTrace ();} \]u;NbC]  
catch(Exception e){e.printStackTrace ();} _
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Utility.log(nFileLength); t+8e?="  
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return nFileLength; $mn0I69  
} D=#RQ-  
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"{  
//保存下载信息（文件指针位置） BHUI1y5t  
private void write_nPos() :dSda,!z  
{ ! ;t\lgMl  
try{ fgdR:@]-  
output = new DataOutputStream(new FileOutputStream(tmpFile)); wu)+n\mt'  
output.writeInt(nStartPos.length); EsMX#1>/m  
for(int i=0;i<nStartPos.length;i++) lhGJ/By- -  
{ v4n< G-  
// output.writeLong(nPos); Vb(b3  
output.writeLong(fileSplitterFetch.nStartPos); kUf i  
output.writeLong(fileSplitterFetch.nEndPos); (aa2uctTn  
} 3T2]V?   
output.close(); @b,Az{EH  
} gA!@oiq@  
catch(IOException e){e.printStackTrace ();} Wb-C0^dTn  
catch(Exception e){e.printStackTrace ();} pd|KIs%jl  
} y QW7ng7D0  
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//读取保存的下载信息（文件指针位置） 7 $e6H|j@  
private void read_nPos() CF '&Yo  
{ >qmCjY1  
try{ Qn!mS[l  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); +i&<`ov  
int nCount = input.readInt(); Q
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nStartPos = new long[nCount]; 3f[Yk#"  
nEndPos = new long[nCount]; .S/5kLul  
for(int i=0;i<nStartPos.length;i++) o.{W_k/n  
{ D:1@1Jr  
nStartPos = input.readLong(); e73=*~kfR  
nEndPos = input.readLong(); ^m|@pp  
} l-+=Yk!X  
input.close(); zt(lV  
} 6:ettdj  
catch(IOException e){e.printStackTrace ();} mM,HMrgLqK  
catch(Exception e){e.printStackTrace ();} q>$MqKWM  
} 51jgx,-|$  
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private void processErrorCode(int nErrorCode) ZZY#.  
{ K~TwyB-h  
System.err.println("Error Code : " + nErrorCode); (~GQncqa  
} C^J<qq&  
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//停止文件下载  w4U,7%V  
public void siteStop() y{%0[x*N<m  
{ s#9q3JV0  
bStop = true; wFJf"@/vJ  
for(int i=0;i<nStartPos.length;i++) 7~Y\qJ4b  
fileSplitterFetch.splitterStop(); >h\y1IrAaG  
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} _K^Q]V[nZ  
} qoO`)<  
//负责部分文件的抓取 4&
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**FileSplitterFetch.java ytZo
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*/ kxMvOB$  
package NetFox; $w0TEO!  
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import java.io.*; U#jz5<r  
import java.net.*; @/z\p7e  
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public class FileSplitterFetch extends Thread { H;/do-W[  
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String sURL; //File URL *~vB6V|1  
long nStartPos; //File Snippet Start Position Er;/zxg9p  
long nEndPos; //File Snippet End Position %{u@{uG0'3  
int nThreadID; //Thread's ID nip6|dN  
boolean bDownOver = false; //Downing is over )1s
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boolean bStop = false; //Stop identical )?F&`+  
FileAccessI fileAccessI = null; //File Access interface DrJ?bG;[  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException  %?ElC  
{ \|HEe{nA  
this.sURL = sURL; $n\Pw  
this.nStartPos = nStart; ]auvtm-[  
this.nEndPos = nEnd; 'nCVjO7o  
nThreadID = id; AV5={KK  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 [wGj?M}  
} %K6veB{M  
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}`uyOgGg*  
public void run() 6"&cQ>$xh  
{ d?zSwLsl  
while(nStartPos < nEndPos && !bStop) 1}(22Q;  
{ BEDkyz;:  
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try{ ;wn9 21r  
URL url = new URL(sURL); y )QLR<wf  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `YNzcn0x  
httpConnection.setRequestProperty("User-Agent","NetFox"); Sdu\4;(  
String sProperty = "bytes="+nStartPos+"-"; {wqT$( (<  
httpConnection.setRequestProperty("RANGE",sProperty); bb6x} jR  
Utility.log(sProperty); (GJtTp~2C4  
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InputStream input = httpConnection.getInputStream(); eZ'8JU]  
//logResponseHead(httpConnection); IW~R{ ]6  
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byte[] b = new byte[1024]; PLCm\Oh$l  
int nRead; Na0^csPm  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) +kL7"  
{ r w?wi}}gn  
nStartPos += fileAccessI.write(b,0,nRead); 6jq*lnA%  
//if(nThreadID == 1) q0.!T0i  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);
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} (i~UH04r>s  
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Utility.log("Thread " + nThreadID + " is over!"); B2;P%B  
bDownOver = true; `16'qc  
//nPos = fileAccessI.write (b,0,nRead); 1j?P$%p  
} Y~"tL(WfJl  
catch(Exception e){e.printStackTrace ();} _*mn4n=  
} P5Xp #pa  
} $qNF /rF  
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%2QGbnt_*  
//打印回应的头信息 p{Lrv%-j  
public void logResponseHead(HttpURLConnection con) )z[C=  
{ ,^/Wv!uPE  
for(int i=1;;i++) ]Lv

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{ S\GWMB!oF  
String header=con.getHeaderFieldKey(i); Nq8ON!<<  
if(header!=null) (TZK~+]@sb  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); "qmSwdM  
Utility.log(header+" : "+con.getHeaderField(header)); *C_A(n5"V  
else q/s-".%P  
break; K=gg<E<  
} #C
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} f_~T  
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public void splitterStop() &g:(I  
{ kWr1>})'  
bStop = true; U0&myj 8L  
} _Ewh:IM-  
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} "laf:Ty1  
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/* yYz{*hq  
**FileAccess.java u?,>yf.;s  
*//文件访问(定位，写) 6z\!lOVjb  
package NetFox; a 0SZw  
import java.io.*; v5[gFY(?  
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public class FileAccessI implements Serializable{ &y? |$p\;/  
|8` }8vo)  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ex>7f%\  
RandomAccessFile oSavedFile; 9\8ektq}Z  
long nPos; V(ELrjB0  

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public FileAccessI() throws IOException L^qCE-[  
{ w%L4O;E]*{  
this("",0); fI1CT)0<e  
} A7L;ims7  
[4"(\r\f  
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public FileAccessI(String sName,long nPos) throws IOException f ,e]jw@  
{ vHi%UaD-y  
oSavedFile = new RandomAccessFile(sName,"rw"); ] (e ,J  
this.nPos = nPos; vu( 5s  
oSavedFile.seek(nPos); A@?0(  
} @b(@`yz.a  
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public synchronized int write(byte[] b,int nStart,int nLen) F_079~bJ  
{ =z. hJu  
int n = -1; ,!Wo6{'  
try{ 8g-u  
oSavedFile.write(b,nStart,nLen); %n$f#Ml_r  
n = nLen; [{Wo:c9Qq1  
} 6FDj:~  
catch(IOException e) "](Q2  
{ wR_mJMk_  
e.printStackTrace (); 3EYEd39E  
} z</C)ObL  
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return n;  ?s,oH  
} !Q\*a-C  
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} @lB{!j&q  
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/* _|e&zr  
**SiteInfoBean.java +.Vh<:?
 
*/ <y7{bk~i  
package NetFox; db
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public class SiteInfoBean { 3$"V,_TBZ  
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private String sSiteURL; //Site's URL {XU!p: x  
private String sFilePath; //Saved File's Path l2;$qNAo  
private String sFileName; //Saved File's Name k (AE%eA  
private int nSplitter; //Count of Splited Downloading File N[eLQe]q  
k -G9'c~  
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public SiteInfoBean() *Xnf}Ozx  
{//nSplitter的缺省值为5 ?=l
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//default value of nSplitter is 5 U-DQ?OtmC@  
this("","","",5); +E. D:  
} =cRm
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) }"+"nf5h  
{ h GA2.{  
sSiteURL= sURL; G^{~'TZv%  
sFilePath = sPath; "d<ucj  
sFileName = sName; (A=PDjP!  
this.nSplitter = nSpiltter; EY]H*WJJ  
*  1}dk`-  
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} YC;@^  
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public String getSSiteURL() _wXT9`|3  
{ ,q%X`F rc  
return sSiteURL; 0WzoI2Q  
} 8b0j rt  
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public void setSSiteURL(String value)  IZrcn  
{ Ch{6=k bK  
sSiteURL = value; Lu^uY7 ?}  
} 0`zdj  
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public String getSFilePath() )xf(4  
{ 2MB>NM<xO  
return sFilePath; ajkV"~w',|  
} Q"s6HZ"YI  
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public void setSFilePath(String value) ^/Hf$tYI!`  
{ a;dWM(;Kw  
sFilePath = value; Yt*NIwWr  
} .@x.   
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public String getSFileName() BHp>(7,  
{ ] K&ca  
return sFileName; 6Z1O:Bou  
} `yq) y>_  
pS-o*!\C.  
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public void setSFileName(String value) n<|8Onw  
{ gna!Q  
sFileName = value; q=e;P;u  
} =P,mix|  
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public int getNSplitter() ]u<U[l-w  
{ D(Z#um8n  
return nSplitter; y}FG5'5$13  
} xN$V(ZX4  
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public void setNSplitter(int nCount) {{gd}g  
{ k6DJ(.n'%a  
nSplitter = nCount; IM6
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} +z9BWo!{I  
} 1c/<2xO~  
}JOz,SQHP  
>=rniHs=?7  
/* iuqJPW^}  
**Utility.java >r)UDa+  
*/ _s-X5xU  
package NetFox; Y,mo}X<>  
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public class Utility { U(+QrC:  
ph)=:*A6&  
?mV2|;  
public Utility() OWfB8*4@  
{ Te!eM{_$T  
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} f dJg7r*  
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//线程睡眠 zZ9Ei-Q  
public static void sleep(int nSecond) Yrf?|,  
{ 4]zn,g?&  
try{ 902A,*qq  
Thread.sleep(nSecond); Eh
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} cMtUb  
catch(Exception e) QH
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{ _eQ-'")  
e.printStackTrace (); b* n#XTV  
} N1E9w:T`  
} X`Lv}6}xT  
L#D)[v"  
//日志 =.J>'9Q  
public static void log(String sMsg) -q)|I|y*7  
{ U3aM^
 
System.err.println(sMsg); \p\p~FVS  
} 1h162  
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public static void log(int sMsg) +yr~UP_ }  
{ D}{]5R  
System.err.println(sMsg); bA6^RIf?  
} x`p908S^  
} -NzOX"V]3  
!}`[s2ji  
V LeYO5'L  
/* }!*|VdL0  
**TestMethod.java nRHlHu  
*/ )g&nI<Mh  
package NetFox; u,@ac[!vP  
va(6?"9  
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public class TestMethod { p&xj7qwp@F  
"FE%k>aV@v  
f/kYm\Zc  
public TestMethod() #~rQ\A!4  
{ ///xx/weblogic60b2_win.exe 7k#>$sY+  
try{ ;$*tn"- ?~  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); KB\ri&bF  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); _=[pW2p  
SiteFileFetch fileFetch = new SiteFileFetch(bean); E^w0X,0XlE  
fileFetch.start(); 0ikA@SAq  
} =L"I[  
catch(Exception e){e.printStackTrace ();} e=tM=i"  
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} H11@ DQ6  
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public static void main(String[] args) PJKxh%J  
{ {poTA+i  
new TestMethod(); m,4'@jg0  
} uW(Ngcpr  
} L]X Lv9J0  
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