http断点续传简单实现（java)

/* 4Em mh=A  
**SiteFileFetch.java %U&O \GB  
*/ &_^t
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package NetFox; . _5g<aw;  
import java.io.*; HD(4Ms  
import java.net.*; }jQxwi)  
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public class SiteFileFetch extends Thread { XA~Cc<v  
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SiteInfoBean siteInfoBean = null; //文件信息Bean +P?!yH,n  
long[] nStartPos; //开始位置 Awo H d7M  
long[] nEndPos; //结束位置 I
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 tSVN}~1\  
long nFileLength; //文件长度 y\DR,$Py  
boolean bFirst = true; //是否第一次取文件 p`jkyi  
boolean bStop = false; //停止标志 x=g=
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File tmpFile; //文件下载的临时信息 Zl69d4vG  
DataOutputStream output; //输出到文件的输出流 4+ BWHV  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） i`3h\ku  
public SiteFileFetch(SiteInfoBean bean) throws IOException |'$E-[  
{ T r|B:)X  
siteInfoBean = bean; CH!>RRF  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ch|4"&g  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); KIyhvY~  
if(tmpFile.exists ()) N03)G2  
{ 7jss3^.wA  
bFirst = false; dQX<X}  
read_nPos(); ]mDsd*1  
}  -&N^S?  
else V}?*kx~T2C  
{ n}KF)W=  
nStartPos = new long[bean.getNSplitter()]; 8+HXGqcv  
nEndPos = new long[bean.getNSplitter()]; nitKX.t8  
} &J>XKO nl  
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} up(6/-/
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public void run() #%Z 0!  
{ Ll" Kxg  
//获得文件长度 K fM6(f:  
//分割文件 <+7]EwVcn^  
//实例FileSplitterFetch Y^Of  
//启动FileSplitterFetch线程 Pu|PIdu!08  
//等待子线程返回 4b\R@Knu  
try{ .<#oLM^  
if(bFirst) UweXz.x7  
{ ,iUWLcOM  
nFileLength = getFileSize(); |hx"yy'ux  
if(nFileLength == -1) Alo;kt@x  
{
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System.err.println("File Length is not known!"); j ^Tb=  
} mP!=&u fcU  
else if(nFileLength == -2) p(B
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{ !hMD>B2Z  
System.err.println("File is not access!"); }da}vR"iL  
} Th\
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else [h5~1N
 
{ 6_G[&   
for(int i=0;i<nStartPos.length;i++) (]_smsok  
{ *5e"suS2  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); D)O2=aQ;]  
} <\44%M"iC-  
for(int i=0;i<nEndPos.length-1;i++) 'P AIh*qA  
{ [9<c;&$LU  
nEndPos = nStartPos[i+1]; 5`_UIYcI  
} Z=[qaJ{]  
nEndPos[nEndPos.length-1] = nFileLength; Jw+k=>  
} (h8RthQt  
} f9%M:cl  
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//启动子线程 a^#\"c  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; l:@`.'-=  
for(int i=0;i<nStartPos.length;i++) U%:K11Kr  
{ E;o "^[we  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]QJN` ;b0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), YcRo>:I  
nStartPos,nEndPos,i); n<)gS7  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6"o,)e/z  
fileSplitterFetch.start(); F `4a0~?  
} r(ZMZ^  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), p2=+cS"HC  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); j7XUFA  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", kB! iEoIBA  
nEndPos = " + nFileLength); P&snIJ  
// fileSplitterFetch[nPos.length-1].start(); /bSAVSKR  
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//等待子线程结束  Qi;62M  
//int count = 0; j^T i6F>f  
//是否结束while循环 nb30<h  
boolean breakWhile = false; sZDxTP+  
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{<P{
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while(!bStop) b(HbwOt~3  
{
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write_nPos(); Y00hc8<  
Utility.sleep(500); "y7IH GJ\3  
breakWhile = true; 4!U)a  
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for(int i=0;i<nStartPos.length;i++) ?*/1J~<(@  
{ 9F"^MzZ  
if(!fileSplitterFetch.bDownOver) xTGdh  
{ PK&\pkX  
breakWhile = false; 4(D1/8  
break; "*T4%3dA  
} C}=9m A  
} +HSKFp  
if(breakWhile) 
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break; /D>G4PP<  
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//count++; $/FL)m8.3  
//if(count>4) S\S31pYT  
// siteStop(); 6k6}SlN[  
} 0% zy 6{  
9=}&evGm89  
/=@V5)  
System.err.println("文件下载结束！"); |44 E:pA  
} C@P*:L_  
catch(Exception e){e.printStackTrace ();} _@D"XL#L  
} [Te"|K':  
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//获得文件长度 >$:_M*5  
public long getFileSize()  nJ|M  
{ d "%6S*dL  
int nFileLength = -1; ]j+J^g  
try{ F T$x#>  
URL url = new URL(siteInfoBean.getSSiteURL()); 0x2[*pJ|IW  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1EHL8@.M  
httpConnection.setRequestProperty("User-Agent","NetFox"); "KKw\
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int responseCode=httpConnection.getResponseCode(); V'8Rz#Gc5  
if(responseCode>=400) }G ^nK m  
{ *cy!PF&  
processErrorCode(responseCode); 1a tQ9  
return -2; //-2 represent access is error Zq"  
} &Vy.)0  
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String sHeader; Zv5vYe9Ow  
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for(int i=1;;i++) h1+y.4   
{ bWg!/K55  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); R*l3 zn>  
//Utility.log(in.readLine()); 1'!%$D  
sHeader=httpConnection.getHeaderFieldKey(i); sP@7%p>wt  
if(sHeader!=null) (2(y9r*1  
{ #A 7|=E  
if(sHeader.equals("Content-Length")) jL0=a.;  
{ eZ|_wB'r  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); lQqP4-E?  
break; 5I&Dk4v  
} Y(;u)uN_  
} ^ pNA_s!S  
else
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break; j_0xE;g"]  
} yqKSaPRA  
} ziXI$B4-  
catch(IOException e){e.printStackTrace ();} N gagzsJ=  
catch(Exception e){e.printStackTrace ();} [{.9#cQ"  
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Utility.log(nFileLength); Gx;-1  
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return nFileLength; ke19(r Ch  
} v<vaPvW  
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//保存下载信息（文件指针位置） zsr;37  
private void write_nPos() >9,LN;Ic
 
{ ,0aRHy_^  
try{ 3 p!t_y|SX  
output = new DataOutputStream(new FileOutputStream(tmpFile)); w3FEX$`_  
output.writeInt(nStartPos.length); D77s3AyHK  
for(int i=0;i<nStartPos.length;i++) "eIE5h  
{ TGZr [  
// output.writeLong(nPos); e3WEsD+  
output.writeLong(fileSplitterFetch.nStartPos); >">grDX  
output.writeLong(fileSplitterFetch.nEndPos); ss4YeZa  
} E&;;2  
output.close(); hu5o{8[  
} ~_|CXPiQ8  
catch(IOException e){e.printStackTrace ();} `k-|G2
 
catch(Exception e){e.printStackTrace ();} a,eEP43dn  
} h|.{dv  
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//读取保存的下载信息（文件指针位置） N
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private void read_nPos() BeFXC5-qat  
{ \t]_UNGyW  
try{ x$) E^|A+  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); +&[X7r<  
int nCount = input.readInt(); Z@i,9 a  
nStartPos = new long[nCount]; = ,c!V  
nEndPos = new long[nCount]; TTJj=KPA  
for(int i=0;i<nStartPos.length;i++) 11B8 LX  
{ I+rLKGZC  
nStartPos = input.readLong(); gp-rTdN  
nEndPos = input.readLong(); s1J(-O  
} |XJ|vQGU  
input.close(); p/gf  
} Hv</Xam  
catch(IOException e){e.printStackTrace ();} il7gk<  
catch(Exception e){e.printStackTrace ();} o`.5NUn  
} vk<4P;
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private void processErrorCode(int nErrorCode) UB]]oC<  
{ pE6r7  
System.err.println("Error Code : " + nErrorCode); -H$C3V3]  
} %JuT'7VB  
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Wb;D9Z  
//停止文件下载 -+WE9  
public void siteStop() 5>>JQ2'W  
{ iZ9ed]mf  
bStop = true; ]~9YRVeC  
for(int i=0;i<nStartPos.length;i++) 0F<$Zbe2B  
fileSplitterFetch.splitterStop(); "]B%V!@  
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}
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} [{6fyd;  
//负责部分文件的抓取 <X ([VZ  
**FileSplitterFetch.java 8b< 'jft  
*/ |)%;B%  
package NetFox; T]2=  
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import java.io.*; O|*-J  
import java.net.*; &e99P{\D  
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public class FileSplitterFetch extends Thread { {=9"WN
 
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String sURL; //File URL QFIYnxY9  
long nStartPos; //File Snippet Start Position @j=rSS  
long nEndPos; //File Snippet End Position , nW)A/?}  
int nThreadID; //Thread's ID $tDM U3,W  
boolean bDownOver = false; //Downing is over C;']FmK]  
boolean bStop = false; //Stop identical URj2 evYW  
FileAccessI fileAccessI = null; //File Access interface ,&s%^I+CC  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException f'OcW*t  
{ a'?V:3 ]  
this.sURL = sURL; v>sjS3  
this.nStartPos = nStart; fiW2m=h_  
this.nEndPos = nEnd; ~$m:j];  
nThreadID = id; 5QZ}KNJ|t~  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 C%AN4Mo  
} f s2}a  
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public void run() rtz ]PH  
{ t]8nRZ1  
while(nStartPos < nEndPos && !bStop) CB`GiH/j  
{ $.3J1DU  
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try{ smHQ'4x9  
URL url = new URL(sURL); `+@r0:G&v  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [midNC+,  
httpConnection.setRequestProperty("User-Agent","NetFox"); TbgIr  
String sProperty = "bytes="+nStartPos+"-"; na_Wp^;  
httpConnection.setRequestProperty("RANGE",sProperty); ^tI4FQ>Y  
Utility.log(sProperty); x$.0:jP/s  
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InputStream input = httpConnection.getInputStream(); o&Y R\BI/  
//logResponseHead(httpConnection); ,D\}DJ`)C  
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>?r8D48`  
byte[] b = new byte[1024]; SD]rYIu+  
int nRead; Us4#O&  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) #BhcW"@  
{ ;oVFcZSA  
nStartPos += fileAccessI.write(b,0,nRead); SAokW,  
//if(nThreadID == 1) sdXZsQw  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); P5o

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} d5qGTT ~a  
 t`'5|  
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Utility.log("Thread " + nThreadID + " is over!"); y1kI^B  
bDownOver = true; j&Y{ CFuZ  
//nPos = fileAccessI.write (b,0,nRead); @hOT< Uo  
} %KW NY(m  
catch(Exception e){e.printStackTrace ();} NJPp6RZ%  
} bs?&;R.5  
}
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//打印回应的头信息 jDCf]NvOPM  
public void logResponseHead(HttpURLConnection con) "~6IjW*/  
{ ,*g.?q@W2  
for(int i=1;;i++) }W5
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{ SfUbjs@a  
String header=con.getHeaderFieldKey(i); =iE)vY,?"}  
if(header!=null) +=#@1k~  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); cD]#
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Utility.log(header+" : "+con.getHeaderField(header)); VMJK9|JC[  
else 0"DS>:Ntk  
break; 5IFc"  
} M`Q
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} Zxn>
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public void splitterStop() XrN]}S$N  
{ V5S6?V\  
bStop = true; vze|*dKS  
} z i3gE$7  
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} ?<D1]Xv  
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/* _QiGrC  
**FileAccess.java BaOPtBYA:  
*//文件访问(定位，写) h#]LXs  
package NetFox; -59;Zn/  
import java.io.*; >3)AO04
=;  
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public class FileAccessI implements Serializable{ 9~yp=JOV@  
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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 r9$7P?zm  
RandomAccessFile oSavedFile; s]i<D9h  
long nPos; JbW!V
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public FileAccessI() throws IOException Wj\< )cH]  
{ e7JZk6GP#9  
this("",0); bb"x^DtT  
} meR5E?Fm  
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public FileAccessI(String sName,long nPos) throws IOException 3k5F$wf  
{ ZIvP?:=!  
oSavedFile = new RandomAccessFile(sName,"rw"); G,A;`:/  
this.nPos = nPos; i-31Cxb  
oSavedFile.seek(nPos); Z*lZl8(`  
} =.f<"P51k  
h!~u^Z.7<  
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public synchronized int write(byte[] b,int nStart,int nLen) vm`\0VGSW  
{ eHHqm^1z  
int n = -1; t7b\#o  
try{ +B-;.]L T  
oSavedFile.write(b,nStart,nLen); R9O[`~BA2  
n = nLen; ulxy 4] h  
} =1h> N/VJ  
catch(IOException e) _chX {_Hu-  
{ b5d;_-~d  
e.printStackTrace (); ]>k>Z#8E*  
} YlEV@  
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return n; .T }q"  
} ICB'?yZ,  
:} 9Lb)Yp  
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} Wf!<Qot|R#  
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/* sH{4.tw  
**SiteInfoBean.java Jb"0P`senY  
*/ aO>Nev  
package NetFox; =}Xw}X+[WY  
#ysSfM6  
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public class SiteInfoBean {
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/6a617?9J  
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private String sSiteURL; //Site's URL nPo YjQi  
private String sFilePath; //Saved File's Path W! q-WU  
private String sFileName; //Saved File's Name 1!`B8y)  
private int nSplitter; //Count of Splited Downloading File sFWH*kdP?  
+p#Q|o'  
}iCcXZ&5^  
public SiteInfoBean() \"W_\&X  
{//nSplitter的缺省值为5 [_SV$Jz  
//default value of nSplitter is 5 FfR%@ V'  
this("","","",5); <>|/U`  
} _ZU.;0  
a}#Jcy!e  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ]iL>Zxex  
{ ?g\SF}2  
sSiteURL= sURL; SF2<  
sFilePath = sPath; Ko|p&-Z;  
sFileName = sName; BPkqC>w  
this.nSplitter = nSpiltter; 7y2-8eL  
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} mrvPzoF,]  
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public String getSSiteURL() ubvXpK:.  
{ f-b#F2I  
return sSiteURL; 5? rR'0  
} ij/5m-{6)  
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public void setSSiteURL(String value) ka$oUB)iQ  
{ 7,![oY[  
sSiteURL = value; 37M?m$BL  
} iig ({b  
,\cO>y@  
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public String getSFilePath() C@8WY  
{ JIobs*e0m  
return sFilePath; P)$q  
} Hlg Q0qb  
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public void setSFilePath(String value) ?{Gf'Y}y&  
{ KASw3!.W  
sFilePath = value; 9 yE   
} Gap\~Z@L  
T)QT_ST.9  
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public String getSFileName() Xw2t
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{ DY~zi  
return sFileName; 1*>lYd8_  
} MSMgaw?  
lN-[2vT<  
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public void setSFileName(String value) mCY+V~^~kz  
{ =H\ig%%E@  
sFileName = value; < x==T4n/  
} X!w&ib-  
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HP /@ _qk  
public int getNSplitter() qL03iV#h*V  
{ 50S >`qi2x  
return nSplitter; BP7&wd  
} 6,*o;<k[  
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MJ
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public void setNSplitter(int nCount) q-;z!iq|!  
{ V+M=@Pvp9  
nSplitter = nCount; (Es0n$Xb  
} ^j1WF[GiSO  
} *k]izWsV*  
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/* Xyrf$R'  
**Utility.java Zu$30&U  
*/ >c~Fgs  
package NetFox; (RL5L=,u  
~S],)E1w  
3r)<:4a u&  
public class Utility { "t{|e6   
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public Utility() 3+%c*}KC~  
{ V ?10O  
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} "uz}`G~O
 
.[Z<r>  
//线程睡眠 p.gaw16}>  
public static void sleep(int nSecond) n 2k&yL+a  
{ kO]],Vy`  
try{ BJM_kKH  
Thread.sleep(nSecond); {~"&$DY2  
} gCMwmanX  
catch(Exception e) M-Az2x;6  
{ Zz
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e.printStackTrace (); 6QCU:2IiL  
} LM*#DLadk  
} ;t.LLd  
p~T)Af<(  
//日志 X676*;:!.  
public static void log(String sMsg) ^cE|o&Rm;  
{ kp~@Ub @O3  
System.err.println(sMsg); (W<n<sl:-  
} z;dD }Fo  
"Q:m0P xb  
F8\nAX  
public static void log(int sMsg)  xZ*.@Pkr  
{ :EISms  
System.err.println(sMsg); edt(Zzk@3-  
} 'V reO52  
} V@0Z\&  
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3Z*'  
/* N798("  
**TestMethod.java $
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*/ kKV`9&d
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package NetFox; OPp>z0p%6X  
\($EYhx  
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public class TestMethod { "#
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9/rX%  
a'f0Wv0%"  
public TestMethod() 2;@#i*\Y  
{ ///xx/weblogic60b2_win.exe #`tn:cP  
try{ {wWh;  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); `!?SA<a:  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 6e1/h@p\7  
SiteFileFetch fileFetch = new SiteFileFetch(bean); D2$"!7O1H  
fileFetch.start(); 3YyB0BMW  
} CwKo'PAJ  
catch(Exception e){e.printStackTrace ();} M<t>jM@'A#  
-G<$wh9~3  
;~Eb Q  
} Jsee8^_~  
&8R%W"<K  
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public static void main(String[] args) =W1`FbR  
{ M6E.!Cs  
new TestMethod(); Hcw@24ic  
} k^3|A3A  
} @\ip?=  
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