http断点续传简单实现（java)

/* G
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**SiteFileFetch.java |q$br-0+  
*/ ],%}}UN  
package NetFox; +M9=KVr  
import java.io.*;
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import java.net.*; @:DS/#!  
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public class SiteFileFetch extends Thread { cm]D"GFLY  
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SiteInfoBean siteInfoBean = null; //文件信息Bean k|l"Rh<\~  
long[] nStartPos; //开始位置 [!>2
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long[] nEndPos; //结束位置 5Am*1S^  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Fs:l"5~>1  
long nFileLength; //文件长度 [|~X~AO%  
boolean bFirst = true; //是否第一次取文件 ZMJ\C|S:  
boolean bStop = false; //停止标志 s#sr1[9}G  
File tmpFile; //文件下载的临时信息 <_""4  
DataOutputStream output; //输出到文件的输出流 ^r=#HQGt  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） M38,SH<  
public SiteFileFetch(SiteInfoBean bean) throws IOException %V;k/w~[  
{ 6m21Y8N  
siteInfoBean = bean; Cm}ZeQ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Zl"h-~31  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); >fo &H_a  
if(tmpFile.exists ()) LJZEM;;}  
{ 3 Yl[J;i  
bFirst = false; 'dj}-
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read_nPos(); dQA J`9B  
} 5n.4>yOY  
else W5:S+  
{ pM[UC{  
nStartPos = new long[bean.getNSplitter()]; I?-9%4 8iM  
nEndPos = new long[bean.getNSplitter()]; R|!4Y`  
} (B]Vw+/  
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} 7Yj\*N  
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public void run() \/K>Iv'$  
{ RW>Z~Nj  
//获得文件长度 ; @Gm@d  
//分割文件 X+iA"B  
//实例FileSplitterFetch w/G5I )G  
//启动FileSplitterFetch线程 R52q6y:<x  
//等待子线程返回 )IZ$R*Y{  
try{ Ev0V\tl>0  
if(bFirst) s3kh (N  
{ mq'q@@:c  
nFileLength = getFileSize(); 7SAu">lI
l  
if(nFileLength == -1) m/Yi;>I(  
{ D zDt:.JZ  
System.err.println("File Length is not known!"); m U7Ad"  
} aeUm,'Y$  
else if(nFileLength == -2) ci3{k"  
{ qLYv=h$,  
System.err.println("File is not access!"); t4s}w$4  
} F>*w)6 4~  
else zi*D8!_C  
{ ]]%C\Ryy}  
for(int i=0;i<nStartPos.length;i++) ` S85i*  
{ ?wwY8e?S  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); JI\u -+BE  
} SKRD{MRsux  
for(int i=0;i<nEndPos.length-1;i++) j1d#\  
{ yMz@-B  
nEndPos = nStartPos[i+1]; 2?-}(F;Z  
} hDp'=}85@  
nEndPos[nEndPos.length-1] = nFileLength; a+]=3o  
} yx/:<^"-$  
} `hH1rw@7<  
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//启动子线程 ,9+@
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; _'j>xK  
for(int i=0;i<nStartPos.length;i++) PS=crU@"H  
{ PwDQ<   
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @$(4;ar  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 2EE#60  
nStartPos,nEndPos,i); +U6! bu>C  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); * rs_k/2(  
fileSplitterFetch.start(); q(uu;l[  
} \*_a#4a  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2,_BO6 !d  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); =~HX/]zF  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 6(ja5)sn*  
nEndPos = " + nFileLength); 9Xm"kVqd/  
// fileSplitterFetch[nPos.length-1].start(); {ZfTUt)-P  
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&$+y
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//等待子线程结束 ]q?<fEG2<  
//int count = 0; St(7@)gvY  
//是否结束while循环 LTa9' q0  
boolean breakWhile = false; :W'1Q2  
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while(!bStop) da2BQ;  
{ 2oq>tnYyV[  
write_nPos(); q+m&V#FT%  
Utility.sleep(500); K):)bL(B  
breakWhile = true; )I5f`r=Ry  
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for(int i=0;i<nStartPos.length;i++) Kk/qd)nk  
{ P|64wq{B8  
if(!fileSplitterFetch.bDownOver) ]*v%(IGK  
{ :z^c<KFX  
breakWhile = false; G-;pMFP(?  
break; CP={|]>+S  
} -$mzzYH  
} US Q{o  
if(breakWhile) p_mP'
  
break; 8~
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//count++; EW YpYMkm  
//if(count>4) 8# 9.a]AX  
// siteStop(); 3tgct <"  
} o 0fsM;K  
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System.err.println("文件下载结束！"); JZai{0se  
} %40|7O  
catch(Exception e){e.printStackTrace ();} !$&K~>`  
} 8vchLl#  
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=G*
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//获得文件长度 1vQ*Br  
public long getFileSize() O~igwFe  
{ `@eQL[Z9x  
int nFileLength = -1; ?HU(0Vgn'  
try{ rw58bkh6  
URL url = new URL(siteInfoBean.getSSiteURL()); QDLtilf :  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); hXZk$a'  
httpConnection.setRequestProperty("User-Agent","NetFox"); _d,_&
7  
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int responseCode=httpConnection.getResponseCode(); w 8T#~Dc  
if(responseCode>=400) i]YH"t8GY  
{ (AV j_Cw  
processErrorCode(responseCode); Lw2EA 5  
return -2; //-2 represent access is error Y+lZT4w  
} 4fQ<A <2/  
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String sHeader; C+jlIT+  
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for(int i=1;;i++) T[q2quXgk  
{ -PoW56  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); arET2(h  
//Utility.log(in.readLine()); PA&Ev0`+  
sHeader=httpConnection.getHeaderFieldKey(i); RMDzPda.  
if(sHeader!=null) Z`T]jm-3  
{ ^e1@o\]  
if(sHeader.equals("Content-Length")) }k~ih?E^s  
{  l|j  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); +d>?aqI\A  
break; yX0nyhq  
} <
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} X@RS /  
else +0_e a~{  
break; m%]1~b}"  
} i}[cq_wJ  
} Y 3h`uLQ  
catch(IOException e){e.printStackTrace ();} ose(#n40  
catch(Exception e){e.printStackTrace ();} :m]H?vq] \  
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Utility.log(nFileLength); xy))}c%  
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return nFileLength; y)vK=,"  
} EMQGP<[  
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//保存下载信息（文件指针位置） {ppzg
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private void write_nPos() /s*.:cdH  
{ @GUlw[vi  
try{ 'b)qP|  
output = new DataOutputStream(new FileOutputStream(tmpFile)); <yl%q*gls  
output.writeInt(nStartPos.length); Co>e<be%S  
for(int i=0;i<nStartPos.length;i++) 76H>ST@G|  
{ VWq]w5oQO  
// output.writeLong(nPos); s@Dln Du.  
output.writeLong(fileSplitterFetch.nStartPos); plL|Ubn  
output.writeLong(fileSplitterFetch.nEndPos); A:yHClmn  
} J0V`sK  
output.close(); bTU[E  
} e,
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catch(IOException e){e.printStackTrace ();} m8@&-,T   
catch(Exception e){e.printStackTrace ();} n{u\t+f  
} d~1uK-L]*  
Mg#yl\v  
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//读取保存的下载信息（文件指针位置） &rGB58  
private void read_nPos()  ^M{,{bG  
{ WQ{[q" O  
try{ _0(%^5
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ak7kb75o  
int nCount = input.readInt(); D"rbQXR7$  
nStartPos = new long[nCount]; s3HVX'  
nEndPos = new long[nCount]; h%:rJ_#Zl  
for(int i=0;i<nStartPos.length;i++) As<B8e]  
{ W%4=x>J-  
nStartPos = input.readLong(); GlnO8cAB  
nEndPos = input.readLong(); ,Cb3R|L8  
} Nai5!_'  
input.close(); @^A
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} HcgvlFb  
catch(IOException e){e.printStackTrace ();} XEgJ7h_  
catch(Exception e){e.printStackTrace ();} %8,$ILN  
} TG%B:^Yz!  
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private void processErrorCode(int nErrorCode) MF8-q'upyT  
{ b~J)LXj]w  
System.err.println("Error Code : " + nErrorCode); N ~{N Nf Y  
} X*QS/\  
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LWyr  
//停止文件下载 1@DC#2hPr  
public void siteStop() D7;9D*o\  
{ {drc}BL_  
bStop = true; L5-|-PP|;  
for(int i=0;i<nStartPos.length;i++) EU$.{C_O(  
fileSplitterFetch.splitterStop(); TaN{xpo  
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} l4>^79**  
} qI+2,6 sGI  
//负责部分文件的抓取 <h/%jM>9/  
**FileSplitterFetch.java .UG`pRC  
*/ [d:
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package NetFox; >?, Zn  
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FEaT}/h;
 
import java.io.*; ilA45
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import java.net.*; s/E|Z1pg3  
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public class FileSplitterFetch extends Thread { i[o 2(d,  
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String sURL; //File URL x HRSzYn$  
long nStartPos; //File Snippet Start Position gc9R;B1  
long nEndPos; //File Snippet End Position 9a}9cMJ^"  
int nThreadID; //Thread's ID eU[g@Pq:Y  
boolean bDownOver = false; //Downing is over 2cR[~\_9.  
boolean bStop = false; //Stop identical -U d^\Yy  
FileAccessI fileAccessI = null; //File Access interface Fx9-A8oIR  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException YuXJT*  
{ "mlQ z4D)5  
this.sURL = sURL; v pI9TG  
this.nStartPos = nStart; oBzl=N3<  
this.nEndPos = nEnd; 2jsbg{QS#_  
nThreadID = id; +P/kfY"  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 fz&B$1;8  
} 34@[ZKJ5  
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public void run() wQ}r/2n|^  
{ y.rN(  
while(nStartPos < nEndPos && !bStop) nbi7rcT  
{ /:{%X(8  
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try{ Ve,g9I  
URL url = new URL(sURL); !`DRJ)h  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _plK(g-1J%  
httpConnection.setRequestProperty("User-Agent","NetFox"); !X>u.}?g  
String sProperty = "bytes="+nStartPos+"-"; ~+q1g[6  
httpConnection.setRequestProperty("RANGE",sProperty); !jCgTo y  
Utility.log(sProperty); "M I';6  
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InputStream input = httpConnection.getInputStream(); &#r+a'  
//logResponseHead(httpConnection); 7Cgi&  
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byte[] b = new byte[1024]; n3^(y"q  
int nRead; Zt=|q
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ua\t5M5  
{ 0[;2dc  
nStartPos += fileAccessI.write(b,0,nRead); @^{Hq6_`  
//if(nThreadID == 1) FG?
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7[m?\/K~  
} QY\k3hiqn  
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Utility.log("Thread " + nThreadID + " is over!"); tvkdNMyX%9  
bDownOver = true; 6j#JhcS+  
//nPos = fileAccessI.write (b,0,nRead); <p@Cx
 
} B#sCB&(  
catch(Exception e){e.printStackTrace ();} wxN)dB  
} m[DQ;`Y  
} !avol/*  
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//打印回应的头信息 R@e'=z[%1  
public void logResponseHead(HttpURLConnection con) 6].[z+  
{ BK$y>= `  
for(int i=1;;i++) b@CB +8$  
{ `L1,JE` q  
String header=con.getHeaderFieldKey(i); (?FH`<  
if(header!=null) ]5%0EE64  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); rd <m:r  
Utility.log(header+" : "+con.getHeaderField(header)); QcegT/vO  
else ts]e M1;  
break; }=R]<`Sj.j  
} J^!;$Hkd  
} ?K1B^M=8  
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public void splitterStop() ChBf:`e  
{ >XN[KPTa  
bStop = true; H MOIUd  
} A(Ct^/x-  
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} Ple.fKu  
# :+Nr  
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/* 8$FH;=  
**FileAccess.java s 6Wp"V(  
*//文件访问(定位，写) Bk8}K=%w  
package NetFox; vu0Ql1  
import java.io.*; ,0'GHQWz$  
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public class FileAccessI implements Serializable{ D?Oe";"/  
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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 2- iY:r  
RandomAccessFile oSavedFile; %0\@\fC41  
long nPos; iSfRJ:_&6  
e=]SIR()`  
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public FileAccessI() throws IOException ~DH9iB  
{ +%5L2/n7  
this("",0); "&L8d(ZuA  
} y_PA9#v7  
\p^V~fy7rU  
fECV\Z  
public FileAccessI(String sName,long nPos) throws IOException QO@86{u#Y  
{ 74^v('-2  
oSavedFile = new RandomAccessFile(sName,"rw"); @ZEBtM%.O  
this.nPos = nPos; #p+iwW-  
oSavedFile.seek(nPos); L: $ `8  
} wd:Yy  
*QK) 1Y1W  
2EgvS!"  
public synchronized int write(byte[] b,int nStart,int nLen) V
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{ lpT&v;$`  
int n = -1; @$slGY  
try{ 5OM#_.p  
oSavedFile.write(b,nStart,nLen); fW= N  
n = nLen; }6Pbjm*  
} 4!sK>l!  
catch(IOException e) F .S^KK  
{ CU=sQfE  
e.printStackTrace (); !7t&d  
} |s3;`Nxu7  
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f@}>:x  
return n; Wvl~|Sx]  
} c5p,~z_Dtu  
y;o - @]  
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} ByqVNz0L  
#WjQ'c:  
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/* 6B]=\H  
**SiteInfoBean.java k
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*/ }NDl~5  
package NetFox; !-MY<'  
s.4+5
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public class SiteInfoBean { 4eWv).  
&~2m@X(o  
WIU]>_$.  
private String sSiteURL; //Site's URL J4+WF#xI2  
private String sFilePath; //Saved File's Path Y. J!]|  
private String sFileName; //Saved File's Name Bq$IBAot  
private int nSplitter; //Count of Splited Downloading File rp\`uj*D  
0n:cmML)D  
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public SiteInfoBean() I^EZ
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{//nSplitter的缺省值为5 'goKYl#1Q  
//default value of nSplitter is 5 )l9KDObis  
this("","","",5); {m!5IR  
} r10VFaly  
gcnX^[`S  
2|x !~e.  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) =?$~=1SL+  
{ X<5fn+{]S:  
sSiteURL= sURL; tN<X3$aN  
sFilePath = sPath; M(L6PyEa!Y  
sFileName = sName; t Cb34Wpf  
this.nSplitter = nSpiltter; WOZuFS13  
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} f I=G>[  
qkKl;Z?Y:  
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public String getSSiteURL() |!] "y<  
{ 7;|"1H:cmw  
return sSiteURL; S3/%;=|  
} E"9(CjbQ[  
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public void setSSiteURL(String value) Ho&:Zs  
{ 6!>p<p"Ns  
sSiteURL = value; 2*Qi4%s#  
} y5F+~z}{  
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public String getSFilePath() Mv%Qze,\V^  
{ oc)`hg2=  
return sFilePath; lIS`_H}  
} (1|wM+)"  
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public void setSFilePath(String value) .KKecdd?=  
{ Uk]jy>7;!  
sFilePath = value; Awa| (]  
} )Mdddz4  
\{`^Q+<  
}| MX=:@*  
public String getSFileName() !O%!A<3  
{ d7](fw@c  
return sFileName; joskKik^  
} n[0u&m8  
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-9FGFBm4]  
public void setSFileName(String value) (9RfsV4^  
{ i<F7/p "
-  
sFileName = value; LUD.  
} z |llf7:  
ss%,  
}
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public int getNSplitter() @U8u6JNK'  
{ 4*qBu}(  
return nSplitter; 0Qa0  
} uCr& `  
`sqr>QD  
"6\5eFN;  
public void setNSplitter(int nCount) WF`%7A39Af  
{ g8uqW1E^  
nSplitter = nCount; pZ'q_Oux  
} " Bx@(  
} cZ_)'0  
vQLYWRXiA  
^'E^*R  
/* fYjmG[4  
**Utility.java y/\b0&  
*/ I9zs  
package NetFox; '(@q"`n  
l SdA7  
nC p/.]Y*  
public class Utility { w{aGH/LN  
*@''OyL  
[T_[QU:A  
public Utility() }{N#JTmjB#  
{ ,;}
   
!6=s{V&r1  
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} 5%\K  
:ir#7/  
//线程睡眠 gGvL6Fu  
public static void sleep(int nSecond) VYb,Hmm>kC  
{ m+'1c}n^7  
try{ 4j3_OUwWZx  
Thread.sleep(nSecond); ;>Z+b#C[  
} )8oyo~4?  
catch(Exception e) >97YK =  
{ \@Cz 32wg  
e.printStackTrace (); |.Vgk8oTl  
} D Z*c.|W  
} ppIXS(  
.)tQ&2  
//日志  P s>Y]  
public static void log(String sMsg) 3\Xk)a_  
{ R-zS7Jyox  
System.err.println(sMsg); `/T.u&QF  
} |Jx:#OM  
)8^E{w^D}  
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public static void log(int sMsg) }R+#>P  
{ AAfU]4
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System.err.println(sMsg); ?wkT=mv  
} D,..gsg  
} #Db^*  
r(wf>w3  
ep
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/* ,1 H|{<  
**TestMethod.java tOVTHx3E]  
*/ v @M6D}  
package NetFox; c86?-u')  
-,*m\Fe}  
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public class TestMethod { 56YqY
u.  
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public TestMethod() c[,Rhf  
{ ///xx/weblogic60b2_win.exe 7p'pz8n`X  
try{ %Qj$@.*:  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); v" #8^q  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); !ckluj  
SiteFileFetch fileFetch = new SiteFileFetch(bean);  IN6L2/Q  
fileFetch.start(); HrLws95'  
} H;a) `R3  
catch(Exception e){e.printStackTrace ();} EpACd8Fb  
@ukL!AV?Y  
J s33S)  
} )RFY2}  
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public static void main(String[] args) (oCpQDab@  
{ qldm"Ul  
new TestMethod(); Z8h;3Ek  
} j?t
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} 6C"${}SF`  
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