http断点续传简单实现（java)

/* " twq#Alx  
**SiteFileFetch.java > ?<C+ZHh  
*/ WJF#+)P:Y  
package NetFox; * vW#XDx  
import java.io.*; yp\sJc`  
import java.net.*; Y/Q/4+  
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public class SiteFileFetch extends Thread { HZEDr}RN  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Nlk'  
long[] nStartPos; //开始位置 <
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long[] nEndPos; //结束位置 0MX``/Z72  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 XfYhLE  
long nFileLength; //文件长度 ?JI:>3e  
boolean bFirst = true; //是否第一次取文件 fFNwmH-jv  
boolean bStop = false; //停止标志 TF-k|##G  
File tmpFile; //文件下载的临时信息 ^Uq"hT(41  
DataOutputStream output; //输出到文件的输出流 3PgiV%]  
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1  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 2m0laJ3p9  
public SiteFileFetch(SiteInfoBean bean) throws IOException I'>r  
{ g1B[RSWv  
siteInfoBean = bean; '/v@q]!  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); @WfX{
485  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 5fDnr&DR  
if(tmpFile.exists ()) Jrm 9,7/  
{ X0e#w?  
bFirst = false; kZJ.G  
read_nPos(); )ND%MYJSq  
} g}Esj"7  
else P8=!/L2?  
{ l4smAT  
nStartPos = new long[bean.getNSplitter()]; ExJexjOWI^  
nEndPos = new long[bean.getNSplitter()]; x9s1AzM{  
} YMfjTt@Q  
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} xIb^x=|h  
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public void run() ,sln0  
{ o:8*WCiqrN  
//获得文件长度 ZQ'bB5I  
//分割文件 .uwD;j +#  
//实例FileSplitterFetch !i77v, (#|  
//启动FileSplitterFetch线程 Q{"QpVY8  
//等待子线程返回 sm>5n_Vw  
try{ C=uYX"  
if(bFirst) FEzjP$  
{ I|oS`iLl$  
nFileLength = getFileSize(); w\QMA3  
if(nFileLength == -1) y1@*)| r  
{ oGXndfd"  
System.err.println("File Length is not known!"); oP 4z>  
} M9scZuj  
else if(nFileLength == -2) ERQc1G]3Dd  
{ j!;y!g  
System.err.println("File is not access!"); :^[HDI-[2  
} Kfl#78$d  
else Z<^TO1xs9B  
{ 67{>x[  
for(int i=0;i<nStartPos.length;i++) eg$y,Tx  
{ `7mRUDz  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); k}h\RCy%f  
} k;W`6:Kjp  
for(int i=0;i<nEndPos.length-1;i++)  a }m>  
{ n%Df6zQ<@s  
nEndPos = nStartPos[i+1]; l6O8:XI  
} Vim*4^[#L  
nEndPos[nEndPos.length-1] = nFileLength; @#CZ7~Hn  
} y_e$W3bON,  
} "-HmXw1+t  
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//启动子线程 W$b
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; H$o=kQN  
for(int i=0;i<nStartPos.length;i++) {Z^ G]@  
{ [;n/|/m,  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), r(Vz(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), &3t[p=  
nStartPos,nEndPos,i); 3j2#'Jf|:  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7Fd`MTo  
fileSplitterFetch.start(); p,'Z{7HG  
} r3_O?b  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), yoc;`hO-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Z2cumx(  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", -4IHs=`;I  
nEndPos = " + nFileLength); /suW{8A(E  
// fileSplitterFetch[nPos.length-1].start(); eKw!%97>  
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b)1v:X4Bv=  
//等待子线程结束 F\G-. 1  
//int count = 0; HZDeQx`*s  
//是否结束while循环 +thkx$o  
boolean breakWhile = false; f+K vym.  
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while(!bStop) K
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{ W3.(s~)o  
write_nPos(); `z)q/;}fC  
Utility.sleep(500); ZD(VH6<g%  
breakWhile = true; C ks;f
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for(int i=0;i<nStartPos.length;i++) a6<UMJ  
{ &uMx*TTY  
if(!fileSplitterFetch.bDownOver) d)yu`U  
{ iXsX@ S^F  
breakWhile = false; 6";ew:Ih^  
break; !Yi2g-(  
} ?Xq"Q^o4#e  
} 9>I&Z8J$M  
if(breakWhile) (O@fgBM  
break; uZ/XI {/  
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//count++; ><Awk~KR  
//if(count>4) 3<%ci&B  
// siteStop(); ^_rBEyz@  
} Nm.G,6<J  
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System.err.println("文件下载结束！"); YQ7\99tj  
} P]mJ01@'  
catch(Exception e){e.printStackTrace ();} TEN~3 Ef#  
} }gR!]Cs)^  
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#q mv(VB4  
//获得文件长度 rY,zZR+@  
public long getFileSize() |mp~d<&  
{  Ww&r  
int nFileLength = -1; !+(c/ gwBh  
try{ gx ]5)O  
URL url = new URL(siteInfoBean.getSSiteURL()); y`Nprwb  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2P(6R.8;6  
httpConnection.setRequestProperty("User-Agent","NetFox"); C4H$w:bVk  

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int responseCode=httpConnection.getResponseCode(); \Aq$h:<  
if(responseCode>=400) Zb4+zps^-  
{ m<liPl uv  
processErrorCode(responseCode); L4t(Y7  
return -2; //-2 represent access is error ?;xL]~Q~1  
} epm ~
 
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String sHeader; JUpb*B_z  
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for(int i=1;;i++) ~LF1$Cai  
{ rf=oH }  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); N eC]MW  
//Utility.log(in.readLine()); 9@^N* E+  
sHeader=httpConnection.getHeaderFieldKey(i); ;BmPP
,  
if(sHeader!=null) \`oP\|Z  
{ s/\<;g:u^  
if(sHeader.equals("Content-Length")) me+u"G9I;  
{ 8mM`v  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); &WJ;s*  
break; "~:P-]`G  
} uGU-MC*  
} >v'@p  
else j^)=<+Q;=  
break; *bl|[(pP  
} 6c[Slq!KA  
} ZU68\cL  
catch(IOException e){e.printStackTrace ();} 8O| w(z  
catch(Exception e){e.printStackTrace ();} =v(&qh9Q2  
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Utility.log(nFileLength); OD6dMql  
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return nFileLength; ufB9\yl{~  
} Egi(z9|Pp  
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)u=46EU_  
//保存下载信息（文件指针位置） 4Dw| I${O  
private void write_nPos() t;b1<TLn0  
{ _+ERX[i  
try{ x }.&?m  
output = new DataOutputStream(new FileOutputStream(tmpFile)); jP31K{G?  
output.writeInt(nStartPos.length); MZ%S3'  
for(int i=0;i<nStartPos.length;i++) V(=3K
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{ *(o^w'5  
// output.writeLong(nPos); p>1Klh:8.'  
output.writeLong(fileSplitterFetch.nStartPos); c?}{>ig/)  
output.writeLong(fileSplitterFetch.nEndPos); ekCt1^5Y  
} "Z#MR`;&29  
output.close(); #&Fd16ov  
} {4B7a6
 
catch(IOException e){e.printStackTrace ();} V>"NVRY  
catch(Exception e){e.printStackTrace ();} `^: v+!  
} GXwQ )P5]  
:MILOwF  
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//读取保存的下载信息（文件指针位置） &`}ACTY'P  
private void read_nPos() <ahcE1h  
{ ?MD\\gN  
try{ 4`p[t;q  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); )AXa.y  
int nCount = input.readInt(); i|N(=Z=  
nStartPos = new long[nCount]; )%bY2 pk  
nEndPos = new long[nCount]; 6Z!OD(/e  
for(int i=0;i<nStartPos.length;i++) 7,ffY/  
{  V/t-  
nStartPos = input.readLong(); ,a\pdEPj  
nEndPos = input.readLong(); 24I~{Qy  
} V&>mD"~MP  
input.close(); , R $ZZ4  
} 7Yly^  
catch(IOException e){e.printStackTrace ();} /S`d?AV  
catch(Exception e){e.printStackTrace ();} e[%g'}D:-  
} Ew2ksZ>B]&  
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private void processErrorCode(int nErrorCode) ^w~Utx4  
{ PHqIfH[  
System.err.println("Error Code : " + nErrorCode); j6&7tK,  
} cp5  
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gg QI  
//停止文件下载 htHnQ4Q  
public void siteStop() ZJ}|t  
{ "uD^1'IW2  
bStop = true; Zl7m:b2M  
for(int i=0;i<nStartPos.length;i++) _.BX#BIF  
fileSplitterFetch.splitterStop(); uDG#L6  
 `AxhA.&V  
:\,3=suWq  
} X-J<gI(Y  
} Ng1uJa[k!d  
//负责部分文件的抓取 XkuZ2(  
**FileSplitterFetch.java yWZ%|K~$  
*/ qb$f,E[  
package NetFox; j~`rc2n%  
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import java.io.*; I~NQt^sg  
import java.net.*; 3&7$N#v  
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public class FileSplitterFetch extends Thread { Oz7
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String sURL; //File URL L }&$5KiwV  
long nStartPos; //File Snippet Start Position ^n8r mh_%  
long nEndPos; //File Snippet End Position I:,D:00+  
int nThreadID; //Thread's ID Wo~#R   
boolean bDownOver = false; //Downing is over y1+~IjY  
boolean bStop = false; //Stop identical ee{8C~  
FileAccessI fileAccessI = null; //File Access interface O;~dao  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException -<.b3Mh  
{ mqb6MnK -  
this.sURL = sURL; e$y VV#  
this.nStartPos = nStart; ~$Pz`amT|  
this.nEndPos = nEnd; FT.;}!"l  
nThreadID = id; Oj^qh+r  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 )]3(ue  
} y}!}*Qj+/  
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public void run() Z4@GcdZ  
{ *WpDavovyB  
while(nStartPos < nEndPos && !bStop) i& ybvTl  
{ (lR9x6yf  
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h?ZxS  
try{ x"Q
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URL url = new URL(sURL); FZ^j|2.L*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); V+2C!)f(  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9`p|>d!.  
String sProperty = "bytes="+nStartPos+"-"; dSm; e_s  
httpConnection.setRequestProperty("RANGE",sProperty); U
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Utility.log(sProperty); ESt@%7.F  
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InputStream input = httpConnection.getInputStream(); =g+Rk+jn  
//logResponseHead(httpConnection); "iY=1F"\R  
.#ASo!O5q  
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byte[] b = new byte[1024]; I,d5Y3mC  
int nRead; FOx&'dH%@  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) O$,MdhyXC  
{ >|@i8?|E  
nStartPos += fileAccessI.write(b,0,nRead); ~i y]X:U  
//if(nThreadID == 1) ?#0|A?U  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0O:')R&  
} D<d4"*qo  
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Utility.log("Thread " + nThreadID + " is over!"); :7-2^7z)  
bDownOver = true; :AM5EO  
//nPos = fileAccessI.write (b,0,nRead); &?xZHr`  
} -*T<^G;rK  
catch(Exception e){e.printStackTrace ();} ij<6gv~ n"  
} c;dMXv   
} e=m=IVY#W  
1$#{om9  
fyE#8h_>4  
//打印回应的头信息 s35`{PR  
public void logResponseHead(HttpURLConnection con) aX$Q}mgb  
{ 3EN(Pz L  
for(int i=1;;i++) _`(WX;sK  
{ ;9rS[$^$O  
String header=con.getHeaderFieldKey(i); "bC1dl<  
if(header!=null) t5Oeb<REz  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); O.% $oV  
Utility.log(header+" : "+con.getHeaderField(header)); :]hNw1e  
else #7}1W[y9}l  
break; y:R!E *.L'  
} 86AZ)UP2D  
} 7}2Aq  
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public void splitterStop() ,s9gGCA  
{ A3|hFk  
bStop = true; :ENdF `nC  
} KtO|14R:  
4
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} e>] gCa  
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ot  
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/* aVvma=  
**FileAccess.java x,% %^(  
*//文件访问(定位，写) a7@':Rb n  
package NetFox; ("r\3Mvs  
import java.io.*; .V   
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J_S8=`f%  
public class FileAccessI implements Serializable{ $&~moAl  
2t,N9@u=UN  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 J{!U;r!6  
RandomAccessFile oSavedFile; |Fi{]9(G2  
long nPos; 6|G&d>G$_  
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public FileAccessI() throws IOException |8q:sr_  
{ j"F?^0aR,Q  
this("",0); L}a-c(G+8  
} 1p5n}|  
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public FileAccessI(String sName,long nPos) throws IOException .mbqsb]&Y  
{ @u @~gEt  
oSavedFile = new RandomAccessFile(sName,"rw"); qipV'T,S  
this.nPos = nPos; 2rV]n  
oSavedFile.seek(nPos); OAauD$Hh  
} \
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SNJSRqWL/  
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public synchronized int write(byte[] b,int nStart,int nLen) tiGBjTPt  
{ jP{&U&!i  
int n = -1; yiw4<]{IX  
try{ `+m:@0&L  
oSavedFile.write(b,nStart,nLen); y '[VZ$^i  
n = nLen; Gl"|t't(  
} N<PDQ  
catch(IOException e) 0MI4"<  
{ .0Kc|b=w  
e.printStackTrace (); Uc;~q-??#  
} 0,/I2!dF?  
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return n; hp1+9vEN  
} -|GKtZ]}  
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} (Z0_e&=*  
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7-  
/* ~].?8C.>*  
**SiteInfoBean.java CkV5PU  
*/ Qhq' %LR  
package NetFox; 3_ly"\I\  
v YJ9G"E  
;_=N YG.  
public class SiteInfoBean { PU,%Y_xR  
UCt}\IJ  
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private String sSiteURL; //Site's URL )qRH?Hsb7  
private String sFilePath; //Saved File's Path Vel}lQD  
private String sFileName; //Saved File's Name %s! |,Cu  
private int nSplitter; //Count of Splited Downloading File H76iBJ66  
s IFE:/1,  
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public SiteInfoBean() ^)(-7H  
{//nSplitter的缺省值为5 xg}Q~,:  
//default value of nSplitter is 5 bksv2@ar  
this("","","",5); ?I[*{}@n"  
} : eCeJ~&E  
3vs{*T"  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) N=PSr4  
{ EE^x34&=  
sSiteURL= sURL; kuI~lBWI  
sFilePath = sPath; `a%MD>R_Lg  
sFileName = sName; g#MLA5%=u  
this.nSplitter = nSpiltter; Gp{,v  
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q;}iW:r&Q  
} j4<K0-?  
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public String getSSiteURL() P(3k1SM  
{ Sx[ eX,q  
return sSiteURL; P6&%`$  
} egvb#:zW?  
R RE8|%p;B  
m"T}em#  
public void setSSiteURL(String value) !E_Zh*lgm  
{ u0GHcpOm  
sSiteURL = value; `BQv;NtP  
} Z\$M)

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-V4%f{9T3  
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public String getSFilePath() y^"@$   
{ ~nTj't2R  
return sFilePath; kU+|QBA@  
} L R\LC6kM  
drMMf[  
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public void setSFilePath(String value) lxm/*^  
{ M.K^W`  
sFilePath = value; XC5/$3'M&  
} AN:yL a!  
J\Hv
42  
*i}X(sfe  
public String getSFileName() qiB~  
{ o K>(yC[  
return sFileName; S3:
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} lH;V9D^  
A#6zINK#B  
LQHL4jRXU  
public void setSFileName(String value) {O9(<g  
{ 8Z0x*Ssk  
sFileName = value; Z2gWa~dBC  
} {nbT$3=Zt  
<)p.GAZ  
Lo~;pvv  
public int getNSplitter() 1_<x%>zG  
{ 59O-"Sc[  
return nSplitter; o//h|fU@  
} %uN<^
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]q.%_  
O5:bdt.  
public void setNSplitter(int nCount) Z(7kwhP[`  
{ g_1#if&  
nSplitter = nCount; fO$){(]^  
} dYwk
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} v,S5C
  
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/* QYMfxpiC  
**Utility.java yo=L1;H  
*/ Bz<hP*.O  
package NetFox; ZRG Cy5Rk  
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public class Utility { F?|Efpzow?  
*m}8L%<
HT  
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public Utility() =w!ik9  
{ ~x
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} RkE)2q[5  
*3H=t$1G}  
//线程睡眠 _Xt/U>N  
public static void sleep(int nSecond) 16zReI(  
{ V9
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try{ 8i154#l+\  
Thread.sleep(nSecond); dMH_:jb  
} G
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catch(Exception e) r*+~(
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{ .`}TND~  
e.printStackTrace (); @"@|O>KJ  
} q1T)H2S  
} ->rqr#  
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//日志 F(yR\)!C  
public static void log(String sMsg) SO=gG 2E  
{  xgcxA:  
System.err.println(sMsg); Cgx:6TRS  
} k1<^Ept  
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8f9wUPr  
public static void log(int sMsg) ZC N}iQu4  
{ [(heE  
System.err.println(sMsg); %d
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} TP rq:"K  
} NX&dJ 6a  
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?>}p'{I  
/* Nv
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**TestMethod.java i%-yR DIX  
*/ Q>,&@  
package NetFox; z2i
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(oGYnN,2  
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public class TestMethod { Byc;r-Q5V  
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m$p}cok#+S  
public TestMethod() rLsY_7!  
{ ///xx/weblogic60b2_win.exe 5vyg-'  
try{ A|\A|8=b  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,`}yJ*7  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); R iLl\S#  
SiteFileFetch fileFetch = new SiteFileFetch(bean); "E\vdhk  
fileFetch.start(); ,~Mf2Y#m0p  
} ^%$IdDx  
catch(Exception e){e.printStackTrace ();} 9;+&}:IVS  
h$&Tg_/'#D  

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} O>' }q/  
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public static void main(String[] args) x4I!f)8Q
 
{ :}e<
  
new TestMethod(); 8\rca:cF   
} #yoc
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}
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