http断点续传简单实现（java)

/* G9Xrwk<g4  
**SiteFileFetch.java p@r~L(>+3  
*/ -fG;`N5U  
package NetFox; +sgishqn9  
import java.io.*; lg1?g)lv  
import java.net.*; F5+f?B~?R?  
n6L}#aZG  
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public class SiteFileFetch extends Thread { G+\2Aj  
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SiteInfoBean siteInfoBean = null; //文件信息Bean h\D y(\  
long[] nStartPos; //开始位置 5OKbW!  
long[] nEndPos; //结束位置 7U?x8%H*  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Nz5gu.a6{L  
long nFileLength; //文件长度 IU Dp5MIuR  
boolean bFirst = true; //是否第一次取文件 g w}t.3}  
boolean bStop = false; //停止标志 +uv]d
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File tmpFile; //文件下载的临时信息 Zf?>:P  
DataOutputStream output; //输出到文件的输出流 u^iK?S#Ci8  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ;znIY&Z  
public SiteFileFetch(SiteInfoBean bean) throws IOException Y}nE/bmx&9  
{ eCk}B$ 2  
siteInfoBean = bean; 'y;[ fwo7  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); iSIj ?.  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); g%RL9-z  
if(tmpFile.exists ()) ";s?#c  
{ <K4'|HU/  
bFirst = false; zy+|)^E  
read_nPos(); nuKjp Ap!  
} Cd6^aFoK!  
else LA"`8  
{ Bv!j.$0d{  
nStartPos = new long[bean.getNSplitter()]; #,!.
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nEndPos = new long[bean.getNSplitter()]; (B,CL222x  
} [",W TZ:  
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} tR0o6s@v/<  
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public void run() `){*JPl  
{ mv<z%y?Oj  
//获得文件长度 2hmV1gj  
//分割文件 x*bM C&Ea  
//实例FileSplitterFetch AP/5,M<  
//启动FileSplitterFetch线程 yy/wSk  
//等待子线程返回 Ngh9+b6[  
try{ Q@/wn  
if(bFirst) Ojie.+'SB  
{ dbE $T  
nFileLength = getFileSize(); K.b-8NIUW  
if(nFileLength == -1) ddlLS  
{ eNN%%Q  
System.err.println("File Length is not known!"); 4wBMBCJ;P  
} )Q6R6xW  
else if(nFileLength == -2) +?nW  
{  ]|~],\  
System.err.println("File is not access!"); VJZ   
} EvQN(
_  
else G~u94rw|:  
{ 4J-)+C/edx  
for(int i=0;i<nStartPos.length;i++) ZqS'xN:k  
{ s{`r$:!  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 2-]gHAw%  
} 8cR4@Hqx  
for(int i=0;i<nEndPos.length-1;i++) 0=L:8&m  
{ l"b78n  
nEndPos = nStartPos[i+1]; Mq6.!j  
} .CrahV1G  
nEndPos[nEndPos.length-1] = nFileLength; }_gCWz-5?  
} a|TP2m  
} hpLo  
3V LwMF?  
:eei<cn2  
//启动子线程 e!G I<  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; i&{8a3B  
for(int i=0;i<nStartPos.length;i++) (Dq3e9fX  
{ j4+hWalm
 
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !=|3^A  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 8$xg\l0?KK  
nStartPos,nEndPos,i); Bb8lklQ  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); p24sWDf  
fileSplitterFetch.start(); b!<?,S  
} ak0KrVF  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,R ]]]7)+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); X:@nROL^7  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", MDl  
nEndPos = " + nFileLength); rkG*0#k  
// fileSplitterFetch[nPos.length-1].start(); yhgHwES"  
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AEOo]b*&d  
//等待子线程结束 Aj SIM.  
//int count = 0; ~*THL0]~  
//是否结束while循环 G5bi,^G7  
boolean breakWhile = false; qmtVk  
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while(!bStop) YeYFPi#  
{ 8O("o7~"  
write_nPos(); 9V[|_  
Utility.sleep(500); +cQ4u4  
breakWhile = true; u5$\E]+_  
q8P| ]  
u23^* -  
for(int i=0;i<nStartPos.length;i++) 6>SP5|GG  
{ =TwV_Dro~  
if(!fileSplitterFetch.bDownOver) M2%<4(UwI  
{ ]^/:Xsk$  
breakWhile = false; KX[_eOL  
break; >bEH&7+@_'  
} -O^b  
} ZTMzL%i  
if(breakWhile) T_y 'cvh  
break; 6=MejT  
dB^J}_wp  
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//count++; 2AzF@Pi^z  
//if(count>4) O&E1(M|*>  
// siteStop(); FFK79e/5  
} o5i?|HJ  
r-H~MisL  
vA;ml$  
System.err.println("文件下载结束！"); ZRsDn  
} $9M>B<]  
catch(Exception e){e.printStackTrace ();} 8/ZJkI  
} LN" bGe  
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//获得文件长度 aq0J }4U  
public long getFileSize() CZxQz  
{ no)Sp
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int nFileLength = -1; }\OLBg/  
try{ +mMn1&  
URL url = new URL(siteInfoBean.getSSiteURL()); ( y'i{:B  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4YXtl+G  
httpConnection.setRequestProperty("User-Agent","NetFox"); _ZC4O&fL  
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int responseCode=httpConnection.getResponseCode(); m:/nw,  
if(responseCode>=400) rV[#4,}PF  
{ :-Ho5DHg  
processErrorCode(responseCode); q'hMf?_  
return -2; //-2 represent access is error *8kg6v%  
} hy3[MOD$G  
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[/6$P[  
String sHeader; eP(%+[g  
lVARe3#  
9kH~+  
for(int i=1;;i++) C>:F4"0  
{ S%kE<M?  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); rs=wEMq/  
//Utility.log(in.readLine()); 3!Rb{  
sHeader=httpConnection.getHeaderFieldKey(i); Xi4!7IOmo  
if(sHeader!=null) f?2Y np=@  
{ s~IOc%3  
if(sHeader.equals("Content-Length")) OzX\s=  
{ `P)1RTVx  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); j<R,}nmD3\  
break; va95/(  
} x,5$VLs\+  
} b+[9)B)a?  
else &&M-5XD  
break; >O9j},X  
} jf$6{zO6j  
} X>wB=z5PXK  
catch(IOException e){e.printStackTrace ();} zi:GvTG  
catch(Exception e){e.printStackTrace ();} \G#Qe*"'K  
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Utility.log(nFileLength); bqsb (C  
^ Gq2"rDM  
*P61q\2Z  
return nFileLength; yodJGGAzk  
} 4+$<G/K  
~Rs|W;  
9hmCvQgtf  
//保存下载信息（文件指针位置） \-#~)LB]M  
private void write_nPos() xX{uDMYa;  
{ L<1"u.3Z`}  
try{ mE}``  
output = new DataOutputStream(new FileOutputStream(tmpFile)); {YcVeCq+N  
output.writeInt(nStartPos.length); x98LOO  
for(int i=0;i<nStartPos.length;i++) OcQ_PE5\  
{ w>IkC+.?  
// output.writeLong(nPos); Q2Yv8q_}Uq  
output.writeLong(fileSplitterFetch.nStartPos); o%Vf#W  
output.writeLong(fileSplitterFetch.nEndPos); -=Q_E^'  
} y$r9Y!?s  
output.close(); U^+9l?ol  
} l#\z3"b  
catch(IOException e){e.printStackTrace ();} !6@xX08z  
catch(Exception e){e.printStackTrace ();} {l0;G)-  
} rPaD#GA[7  
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+&4PGv53J  
//读取保存的下载信息（文件指针位置） E,c~.jYc  
private void read_nPos() h:z;b;  
{ -E2[PW4$  
try{ k{s#wJA  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Av.(i2  
int nCount = input.readInt(); ngsa
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nStartPos = new long[nCount]; it&c ,+8  
nEndPos = new long[nCount]; ^W_}Gd<-#Y  
for(int i=0;i<nStartPos.length;i++) o*qEAy?  
{ FT[oM<M\Xd  
nStartPos = input.readLong(); Zv7@  
nEndPos = input.readLong(); 0k:&7(j  
} @E,{p"{  
input.close(); q-o=lU"  
} #_2V@F+,  
catch(IOException e){e.printStackTrace ();} [9BlP  
catch(Exception e){e.printStackTrace ();} "2HRuqf  
}
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private void processErrorCode(int nErrorCode) ?OZbns
~  
{ S4qh8c  
System.err.println("Error Code : " + nErrorCode);
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} wju~5  
r?{Vqephz  
Gxi;h=J2)>  
//停止文件下载 JEdtj1v{O  
public void siteStop() ii2oWU  
{ \CUxGyu  
bStop = true; g"(N_sv?  
for(int i=0;i<nStartPos.length;i++) pcur6:8W!  
fileSplitterFetch.splitterStop(); w?jmi~6  
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} u\t[rC=yd  
} l]sO[`X  
//负责部分文件的抓取 v0"|J3  
**FileSplitterFetch.java I;P?P5H  
*/ X-:Ni_O\ty  
package NetFox; F#X\}MvEU  
.Z%7+[  
px//q4U  
import java.io.*; n 8AND0a1C  
import java.net.*; h,FP,w;G  
+}mj6I  
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public class FileSplitterFetch extends Thread {

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String sURL; //File URL g+ 2SB5 2D  
long nStartPos; //File Snippet Start Position RVI],O  
long nEndPos; //File Snippet End Position Vq9hAD|k  
int nThreadID; //Thread's ID %(6f  
boolean bDownOver = false; //Downing is over ?z:xQ*#X  
boolean bStop = false; //Stop identical 82O`<Ci  
FileAccessI fileAccessI = null; //File Access interface ~gI%   
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a Q`a>&R0  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException mNb+V/*x3  
{ ;Ic3th%u  
this.sURL = sURL; }s}9@kl;&  
this.nStartPos = nStart; &CUkR
6  
this.nEndPos = nEnd; MYN1zYT6j  
nThreadID = id; `(Q58wR}  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 hZ2PP ^  
} 2i,Jnv=sR  
=_^g]?5i  
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public void run() et9c<'  
{ f\r$T Nd6  
while(nStartPos < nEndPos && !bStop) nJ*NI)  
{ /jj!DO#  
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try{ \
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URL url = new URL(sURL); p-*BB_J"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); uUc[s"\  
httpConnection.setRequestProperty("User-Agent","NetFox"); XJ?@l3D:  
String sProperty = "bytes="+nStartPos+"-"; Bj@&c>  
httpConnection.setRequestProperty("RANGE",sProperty); 
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Utility.log(sProperty); l\$C)q6O  
Y Nq<%i!>  
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InputStream input = httpConnection.getInputStream(); ^
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//logResponseHead(httpConnection); 5.GBd_;  
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byte[] b = new byte[1024]; e}K
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int nRead; P]6pPS  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) gvcT_'  
{ nF=Ig-NX^  
nStartPos += fileAccessI.write(b,0,nRead); 4a!L/m*  
//if(nThreadID == 1) 3J(STIxg  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kY_UY~E  
} OVj,qL)  
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Utility.log("Thread " + nThreadID + " is over!"); F&cA!~  
bDownOver = true; ?nt6vqaV  
//nPos = fileAccessI.write (b,0,nRead); /OxF5bN2  
} ^eZqsd8a  
catch(Exception e){e.printStackTrace ();} brTB /(E  
} 7XR[`Tn9<  
} "UAW  
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Z>M*!mQi  
//打印回应的头信息 q5HHMHB  
public void logResponseHead(HttpURLConnection con) OmoY] 8N}  
{ Mm/GIa  
for(int i=1;;i++) O$&p<~  
{ n"dT^ g  
String header=con.getHeaderFieldKey(i); ,9A[o`b  
if(header!=null) PMrvUM62  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Nm;ka&'  
Utility.log(header+" : "+con.getHeaderField(header)); Q2fa]*Z
5  
else MaM
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break; 5@v!wms  
} <?Lj!JGX  
} ~z< ? Wh  
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public void splitterStop() 7 'f>  
{ D2?7=5DgS  
bStop = true; g8qN+Gg  
} l7x%G@1#~W  
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} 0&mz'xra  
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5|>jz `  
/* G7),!Qol  
**FileAccess.java 5k\61(*s  
*//文件访问(定位，写) kwyvd`J8  
package NetFox; ^T<<F}@q  
import java.io.*; #K4wO!
d  
6'Lij&,f?{  
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public class FileAccessI implements Serializable{ |5FyfDaFBX  
|H |ewVUY  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 sXfx[)T<  
RandomAccessFile oSavedFile; k*n5+[U^tP  
long nPos;
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=nY*,Xu<  
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public FileAccessI() throws IOException `GSfA0?  
{ \y0abxIHS  
this("",0); U,+=>ns>  
} CF$^w
e  
>yL8C:J9  
cy}2~w&s4  
public FileAccessI(String sName,long nPos) throws IOException N:d" {k  
{ Q}m)Q('Rk  
oSavedFile = new RandomAccessFile(sName,"rw"); 4~Z\tP|Q.  
this.nPos = nPos; qvab>U`  
oSavedFile.seek(nPos); \ (X~Z  
} Tlf G"HzZ%  
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N}^\$
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public synchronized int write(byte[] b,int nStart,int nLen) C"YM"9JSJ  
{ M/#<=XhA  
int n = -1; EmH2 Dbw  
try{ yCmiW %L4  
oSavedFile.write(b,nStart,nLen); X#pE!mT  
n = nLen; p'_*>%4~  
} tt`b+NOH>  
catch(IOException e) m"xw5aa>  
{ u/``*=Y@  
e.printStackTrace (); hB|LW^@v  
} 5$jKw\FF=  
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^TDHPBlG  
return n; cl{;%4$9  
} }b~ZpUL!  
=m1B1St2  
>-]Y%O;}  
} 9?]4s-~  
n32BHOVE  
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/* 'GNT'y_  
**SiteInfoBean.java 2AU_<Hr6  
*/ nC2A&n&>  
package NetFox; :}j{NM#  
IF@)L>-%  
Rb\\6BU0  
public class SiteInfoBean { U*,5t81  
$%sOL( r  
6R#f 8  
private String sSiteURL; //Site's URL -x7b6o>$  
private String sFilePath; //Saved File's Path !R4`ihi1  
private String sFileName; //Saved File's Name &{"aD&  
private int nSplitter; //Count of Splited Downloading File hPH=.rX  
UX(#C,qgG  

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public SiteInfoBean() mO]>(^c  
{//nSplitter的缺省值为5 h*&-[nSo  
//default value of nSplitter is 5 p"Fj6T2  
this("","","",5); rr2|xL?+u  
} wD"Y
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) >H?8?a D  
{ rsA K0R+  
sSiteURL= sURL; i!jxjP  
sFilePath = sPath; |WlWZ8]  
sFileName = sName; ^qYJx  
this.nSplitter = nSpiltter; `0Qzu\gRb  
k6.}.  
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} gHA"O@HgDI  
>STWt>s  
@)|62Dv /  
public String getSSiteURL() E_7N^htv  
{ PJS\> N&u  
return sSiteURL; X>=`{JS1  
} _KC()OIeC  
\h?C G_|]  
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public void setSSiteURL(String value) /J8y[aa  
{ (wnkdI{  
sSiteURL = value; ErHbc2  
} U c$RYPq  
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public String getSFilePath() HTvA]-AuM  
{ LZ}C{M{=5A  
return sFilePath; 6Jrh'6o@  
} V-Oy<  
Z$~Wr3/  
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public void setSFilePath(String value) Ztr,v$  
{ AWc7TW  
sFilePath = value; YrL:!\p.  
} @|idlIey  
"i(k8+iK  
ab: yH ')  
public String getSFileName() 2D>WIOX  
{ j0~]o})@i  
return sFileName; O4S~JE3o  
} g%Sl+gWdJ  
y08.R. l  
>PGW>W$  
public void setSFileName(String value) db'Jl^  
{ M6[&od  
sFileName = value; OV_Y`u7YR  
} nK)U.SZ  
"FwbhD0Gb  
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public int getNSplitter() 7H %>\^A^  
{ # 4L[8(+V  
return nSplitter; q okgu$2  
} py6|uGN  
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public void setNSplitter(int nCount)
4siNY4i"  
{ gu7mGHn-  
nSplitter = nCount; ba^B$$?Bo  
} yIC8Rl  
} @7e h/|Y,  
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s{4|eYR  
/* # y%Q{  
**Utility.java %O#)=M~  
*/ R'`q0MoN1  
package NetFox; UR>zL3  
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J=JYf_=4bc  
public class Utility { 6sJN@dFA  
: 9wW*Ix  
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public Utility() 33z)F  
{ ^1sX22k  
lTBPq?4{  
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} PGF=q|j9K  
*7u~`  
//线程睡眠 c=p`5sN)  
public static void sleep(int nSecond) a;WRTV  
{ $1y8gm  
try{ B
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Thread.sleep(nSecond); SSEK9UX  
} <csz4tL}P  
catch(Exception e) BU(:6  
{ xb1
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e.printStackTrace (); >~8;H x].d  
} O$%M.C'  
} $O9Nprf  
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//日志 YBqu7
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public static void log(String sMsg) bi;?)7p&ZY  
{ T[]2]K[&B  
System.err.println(sMsg); e33j&:O  
} 9JYrP6I!_  
[@fw9@_'  
,:Qy%k}f  
public static void log(int sMsg) Fa:fBs{  
{ h U\)CM  
System.err.println(sMsg); {>PN}fk2QP  
} EhL 8rR  
} KJ M:-z@  
ufyqfID  
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/* q1}HsTnBH  
**TestMethod.java /T1zz2l~  
*/ yV[9 (  
package NetFox; "Ah (EZAR  
l$N b1&  
#-*7<wN   
public class TestMethod { sLrSi  
Z M_ 6A1  
*5?a%p  
public TestMethod() RZ 4xR  
{ ///xx/weblogic60b2_win.exe G|MjKe4}  
try{ &~gqEl6RF  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ^L#\z7  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); k`FCyO  
SiteFileFetch fileFetch = new SiteFileFetch(bean); feU]a5%XZ  
fileFetch.start(); 5mxHOtvtWM  
} /J!C2  
catch(Exception e){e.printStackTrace ();} z(V?pHv+  
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} aV"K%#N  
E]$YM5  
Jf6uE?.  
public static void main(String[] args) Elthxj  
{ 9 f$S4O5  
new TestMethod(); 8fA9yQ8  
} l}odW  
} ;sJUTp5\h  
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