http断点续传简单实现（java)

/* )(G<(eiD  
**SiteFileFetch.java S} UYkns*  
*/ H7+z"^s*  
package NetFox; "~ID.G|<  
import java.io.*; SOR\oZ7  
import java.net.*; nqH[ y0  
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public class SiteFileFetch extends Thread { }SWfP5D@  
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SiteInfoBean siteInfoBean = null; //文件信息Bean %EU_OS(u.{  
long[] nStartPos; //开始位置 F8?,}5j  
long[] nEndPos; //结束位置 f0g/`j@Up  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 n@+?tYk*e  
long nFileLength; //文件长度 .eIs$  
boolean bFirst = true; //是否第一次取文件 g5|&6+t.  
boolean bStop = false; //停止标志 HVA:|Z19  
File tmpFile; //文件下载的临时信息 7=N%$]DKZ  
DataOutputStream output; //输出到文件的输出流 4C?{p%3c  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） l\ dPfJ  
public SiteFileFetch(SiteInfoBean bean) throws IOException }K'A/]'  
{ SlB`ktcfI  
siteInfoBean = bean; 5b rM..  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); H'3 pHb  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Vw w 211  
if(tmpFile.exists ()) Kq")|9=d  
{ sP^:*B0  
bFirst = false; Jy:*GW6  
read_nPos(); %6(\Ki6I  
} =k<b* 8  
else O;4S<N  
{ R^`}DlHX  
nStartPos = new long[bean.getNSplitter()]; #"6l+}  
nEndPos = new long[bean.getNSplitter()]; :i>LESJq  
} #tZ!D^GQHq  
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} BywEoS  
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public void run() $DH/  
{ sRT5i9TQ  
//获得文件长度 WY|~E
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//分割文件 CX/[L)|Ru  
//实例FileSplitterFetch b(N+_= n  
//启动FileSplitterFetch线程 ;sA 5&a>!  
//等待子线程返回 4'D^>z!c  
try{ c),UO^EqV  
if(bFirst) pRjEuOc  
{ ;s,1/ kA  
nFileLength = getFileSize(); HAE$Np|>a  
if(nFileLength == -1) 0(c,J$I]Z!  
{ &kdW(;`  
System.err.println("File Length is not known!"); S".|j$  
} <P1nfH  
else if(nFileLength == -2) R5b,/>^'A  
{ MMjewG
xe  
System.err.println("File is not access!"); ):G+*3yb  
} /|U;_F Pmc  
else +xIVlH9`Q  
{ 2Ax(q&`9  
for(int i=0;i<nStartPos.length;i++) dKPXs-5  
{ "8a V~]~Dj  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); R{brf6,  
} ]z7pa^  
for(int i=0;i<nEndPos.length-1;i++) 0o7o;eN  
{ -U>)B  
nEndPos = nStartPos[i+1]; ,hNs{-*  
} RoHX0   
nEndPos[nEndPos.length-1] = nFileLength; qK;J:GT>  
} GKg #nXS  
} $Rze[3  
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//启动子线程 SKf;Fe  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ^K`PYai  
for(int i=0;i<nStartPos.length;i++) L7 FFa:#  
{ I@N/Y{y#  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), w@P86'< v  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 71(ppsHk  
nStartPos,nEndPos,i); uUaDesz~=  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ax _v+v %  
fileSplitterFetch.start(); dn~k_J=p  
} W"/,<xHuh  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #lFsgb  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);  1^hG}#6_  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", s;<]gaonB_  
nEndPos = " + nFileLength); Q%'4jn?H  
// fileSplitterFetch[nPos.length-1].start(); ;YokPiBy  
:[?7,/w  
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//等待子线程结束 /FTP8XHwL)  
//int count = 0; (Ms #)E  
//是否结束while循环 ?aaYka]  
boolean breakWhile = false; ]S(nA!]  
MYJDfI  
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while(!bStop) \o,et9zDJ3  
{ R90chl  
write_nPos();  CU\r I  
Utility.sleep(500); !x-9A  
breakWhile = true; @(/$;I,  
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for(int i=0;i<nStartPos.length;i++) Xhyc2DKa_  
{ 6a]Qg99\  
if(!fileSplitterFetch.bDownOver) FzsW^u+  
{ h/aG."U  
breakWhile = false; G^P9_Sw]d3  
break; :gkn`z  
} o 8^!wGY  
} F9_X^#%L  
if(breakWhile) z5^Se!`5  
break; a#Z#-y!  
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//count++; l Hu8ADva  
//if(count>4) +^,&z}( Ak  
// siteStop(); }i;!p Ue$  
} i[vN3`*B  
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System.err.println("文件下载结束！"); ^7kYG7/  
} -k,}LJj
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catch(Exception e){e.printStackTrace ();} D#ED?Lqf  
} PVq y\i  
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//获得文件长度 W}^>lM\8  
public long getFileSize() on\ahk, y]  
{ jA3Ir;a  
int nFileLength = -1; L@ N\8mf  
try{ Qmv8T ^+  
URL url = new URL(siteInfoBean.getSSiteURL()); :$^sI"hO  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >va9*pdJ  
httpConnection.setRequestProperty("User-Agent","NetFox"); OYfP!,+bn  
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int responseCode=httpConnection.getResponseCode(); #=fd8}9  
if(responseCode>=400) 7&dPrnQX=  
{ "aGpC{  
processErrorCode(responseCode); h
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return -2; //-2 represent access is error o[G,~f\-  
} P

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String sHeader; 40LAG  
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for(int i=1;;i++) O;;vz+ j  
{ ^@q$c  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); V/DdV}n!  
//Utility.log(in.readLine()); `ucr;P  
sHeader=httpConnection.getHeaderFieldKey(i); `{@?O%UB  
if(sHeader!=null) TSd;L u%hr  
{ pc_$,RkN  
if(sHeader.equals("Content-Length")) s9YP =)I  
{ !8%{(;(  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); IPh_QE2g  
break; (XA]k%45  
} h,Tsb:Q"M  
} 1QDAfRx  
else wW;!L=j  
break; )Chx,pcx<  
} /a
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} TCO^9RP<  
catch(IOException e){e.printStackTrace ();} "IsDL^)A9  
catch(Exception e){e.printStackTrace ();} NB/ wJ3 F  
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Utility.log(nFileLength);  ^pZ\:  
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return nFileLength; 0 Pa\:^/6  
} RiAY>:  
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//保存下载信息（文件指针位置） n&uD=-  
private void write_nPos() #%tN2cFDN  
{
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try{ "^@0zy@x  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 4#@zn 2l  
output.writeInt(nStartPos.length); s@bo df&  
for(int i=0;i<nStartPos.length;i++) X5D}<J2"  
{ H`ZUI8-  
// output.writeLong(nPos); fN
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output.writeLong(fileSplitterFetch.nStartPos); ,a,coeL  
output.writeLong(fileSplitterFetch.nEndPos); fqU*y 6]  
} i(XqoR-x  
output.close(); \XlT  
} }Pe0zx.Ge  
catch(IOException e){e.printStackTrace ();} {oN7I'>  
catch(Exception e){e.printStackTrace ();} i50^%,  
} 8MPXrc,9-  
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//读取保存的下载信息（文件指针位置） s4c2  
private void read_nPos() _[.3I1kG  
{ [Y]\sF;J  
try{ y"SVZ} ;|  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); h"G#} C]  
int nCount = input.readInt(); u($y<Q)=  
nStartPos = new long[nCount]; K%A:W  
nEndPos = new long[nCount]; hK&/A+*  
for(int i=0;i<nStartPos.length;i++) <$'OSN`!  
{ GoNX\^A  
nStartPos = input.readLong(); ,0=:06l  
nEndPos = input.readLong(); "+V.Yue`R  
} @'EU\Y\l  
input.close(); n +z5;'my  
} vrD]o1F  
catch(IOException e){e.printStackTrace ();} $fA%_T_P'P  
catch(Exception e){e.printStackTrace ();} bO%bMZWB!y  
} RcH",*U  
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private void processErrorCode(int nErrorCode) rOu7r4  
{ bytAdS$3  
System.err.println("Error Code : " + nErrorCode); |};P"&  
} {1V~`1(w  
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//停止文件下载 |Tp>,\:5  
public void siteStop() #;6YADk2_  
{ g2v0!  
bStop = true; ?_9A`LC*  
for(int i=0;i<nStartPos.length;i++) kN*,3)T;}  
fileSplitterFetch.splitterStop(); 4c*?9r@  
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} Vn-y<*np  
} ;V~[kF=t0  
//负责部分文件的抓取 c_li.]P  
**FileSplitterFetch.java \ueo^p]_?  
*/ pAo5c4y!4  
package NetFox; c} GH|i  
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import java.io.*; -Fe))Y'=  
import java.net.*; 2R2ws.}  
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public class FileSplitterFetch extends Thread { 3U0>Y%m|,  
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String sURL; //File URL [wJM=`!W  
long nStartPos; //File Snippet Start Position MV<2x7S  
long nEndPos; //File Snippet End Position 1>1&NQ#}  
int nThreadID; //Thread's ID Ap{p_~~
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boolean bDownOver = false; //Downing is over a'zf8id  
boolean bStop = false; //Stop identical =Vv"\p8  
FileAccessI fileAccessI = null; //File Access interface >M\3tB2C  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Ccld;c&+  
{ ndn)}Z!0h  
this.sURL = sURL; _h2axXFhT  
this.nStartPos = nStart; WKib$(%f6  
this.nEndPos = nEnd; @Q;%hb  
nThreadID = id; \Q"j^4  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 k[0Gz  
} P".CZyI-i  
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public void run() 82.::J'e  
{ J|-X?V;ZW  
while(nStartPos < nEndPos && !bStop) x78`dX  
{ *UVo>;  
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try{ ]Z?y\L*M-  
URL url = new URL(sURL); E)l0`83~^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Nr?Z[6O|  
httpConnection.setRequestProperty("User-Agent","NetFox"); zrqQcnx9(m  
String sProperty = "bytes="+nStartPos+"-"; M<R3JzT  
httpConnection.setRequestProperty("RANGE",sProperty); _yi`relcq-  
Utility.log(sProperty); h\#\hx  
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InputStream input = httpConnection.getInputStream(); 7JvBzD42  
//logResponseHead(httpConnection); %l4LX~-:  
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byte[] b = new byte[1024]; 1 PL2[_2:  
int nRead; w\o?p.drp=  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) )YE3n-~7{  
{ !2-f%x]tO  
nStartPos += fileAccessI.write(b,0,nRead); _?"P<3/iF  
//if(nThreadID == 1) lxIoP  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); WC6yQSnY&  
} Id6H~;  
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Utility.log("Thread " + nThreadID + " is over!"); jlvh'y`  
bDownOver = true; iI|mFc|V  
//nPos = fileAccessI.write (b,0,nRead); @]v}&j7  
} (gY3?&Ok*  
catch(Exception e){e.printStackTrace ();} eD4D<\*  
} ws1io.  
} !6Sr*a*5  
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//打印回应的头信息 r%`g` It  
public void logResponseHead(HttpURLConnection con) h0m+u}oP_H  
{ z'=8U@P'#  
for(int i=1;;i++) lyY\P6 X  
{ e[<vVe!  
String header=con.getHeaderFieldKey(i); B2p/  
if(header!=null) gD}lDK6N  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); . V5Pr}"y  
Utility.log(header+" : "+con.getHeaderField(header)); <'n'>@  
else )ry7a .39b  
break; US5]@!  
} "DN0|%`M/  
} SlU?,)J}  
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public void splitterStop() ~s3X&!#   
{ L
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bStop = true; Q=YIAGK  
} *0vq+C  
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} t zn1|  
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> 2)@(f~g  
/* \9 ,a"g  
**FileAccess.java !3O8B0K)v  
*//文件访问(定位，写) O52B  
package NetFox; 73Zx`00  
import java.io.*; JWZG)I]r  
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public class FileAccessI implements Serializable{ z):LF<  
b/[$bZD5o  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 v2w|?26Lf  
RandomAccessFile oSavedFile; eILdq*  
long nPos; 4S%s
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public FileAccessI() throws IOException eELLnU{"  
{ 4d x4hBd  
this("",0); xG_LEk( zD  
} [TX1\*W  
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public FileAccessI(String sName,long nPos) throws IOException ()'yY^   
{ WiU-syNh  
oSavedFile = new RandomAccessFile(sName,"rw"); 0r_3:#Nn  
this.nPos = nPos; (
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oSavedFile.seek(nPos); @\*`rl]  
} .ZOG,h+8  
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public synchronized int write(byte[] b,int nStart,int nLen) 8'>yB  
{ As{Q9o5j/  
int n = -1; e w%rc.;  
try{  !n`9V^`  
oSavedFile.write(b,nStart,nLen); i'cGB5-j  
n = nLen; ]EN+^i1F[  
} j.]ln}b/'+  
catch(IOException e) AU$<W"%R  
{ nyoLrTs{  
e.printStackTrace (); '048Qykt;  
} t6q7w  
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return n; ;NoiH&  
} 7|@FN7]5NF  

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/* g+j\wvx0  
**SiteInfoBean.java S4S}go*G[  
*/ 8l>7=~Egp  
package NetFox; Nf5zQ@o_y  
i}L*PCP  
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public class SiteInfoBean { $6l^::U  
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private String sSiteURL; //Site's URL " k0gZb  
private String sFilePath; //Saved File's Path Y=?Tm,z4  
private String sFileName; //Saved File's Name Cl8S_Bz  
private int nSplitter; //Count of Splited Downloading File o$p] p9  
x%yzhIRR  
 ^:^  
public SiteInfoBean() Vl^p3f[  
{//nSplitter的缺省值为5 3^Q;On|  
//default value of nSplitter is 5 |jI|},I  
this("","","",5); gJH^f3  
} HIqe~Vc  

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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) :IX_|8e ^  
{ ^\oMsU5(  
sSiteURL= sURL; &
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sFilePath = sPath; kp-`_sDg  
sFileName = sName; g_3Ozy  
this.nSplitter = nSpiltter; 3dx.%~c  
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} <CcSChCg  
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public String getSSiteURL() b:PzqMh{G  
{ Bun^EJ)  
return sSiteURL; Bdcs}Ga  
} &s{d r  
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public void setSSiteURL(String value) c;,-I  
{ P\y ZcL  
sSiteURL = value; 0Of6$`  
} C';Dc4j  
2c'<rkA  
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public String getSFilePath() \Ez&?yb/  
{ L=@8Zi!2<  
return sFilePath; )+Yu7
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} |&MOus#v  
z
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98maQQWD  
public void setSFilePath(String value) ,z01*Yx  
{ x21XzGLY|}  
sFilePath = value; GMY[Gd  
} <Zo{D |hW  
n0FzDQt26  
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public String getSFileName() 6"9(ce KX  
{ K}
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return sFileName; \8)FVpS  
} (~NR."s;
 
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public void setSFileName(String value) ck$>  
{ :7*9W|e  
sFileName = value; UJuz  
} ezA&cZ5  
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public int getNSplitter() A>frf[fAW  
{ *|^|| bd  
return nSplitter; @zJiR{Je-U  
} wn.UjxX.  
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@ %o'  
public void setNSplitter(int nCount) !Ld[`d.|R!  
{ 
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nSplitter = nCount; DB0?H+8t  
} ^SbxClUfw!  
} s)+] pxV0-  
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`[h&Q0Du6  
/* {Q)sR*d  
**Utility.java W!|l_/L'   
*/ sT,*<^  
package NetFox; "g/UpnH  
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public class Utility { NAO0b5-h  
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public Utility() )1g\v8XT  
{ #
@F  
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} BnG{)\s  
d>0 j!+s  
//线程睡眠 HP=5a.  
public static void sleep(int nSecond) O4!!*0(+91  
{ _y:aPn  
try{ \okvL2:!  
Thread.sleep(nSecond); Z ?ATWCa  
} a
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catch(Exception e) u~!Pzz3"  
{ \Hu?K\SWs  
e.printStackTrace (); bV:MOj^  
} (e32oP"  
} of'H]IZ  
U%KgLg#  
//日志 [4-u{Tu  
public static void log(String sMsg) JmuoYlf|  
{ S-79
uo  
System.err.println(sMsg); (\4YBaGd  
} \*#E4`Y  
]{AHKyA{:  
~7H?tp.Dw  
public static void log(int sMsg) {D
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{ o}Zl/&(  
System.err.println(sMsg); u"(2Xer  
} KssIoP
 
} Pu}PE-b  
7'7o^> !  
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/* ,]4.|A_[Rq  
**TestMethod.java 1#x@  
*/ l
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package NetFox; n*hRlL
  
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_:Ov-HIR  
public class TestMethod { scZ'/(b-E  
$oIGlKc:L  
iJk/fvi  
public TestMethod() Mvk#$:8e  
{ ///xx/weblogic60b2_win.exe _mDvRFq  
try{ R/&C}6Gn  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); |99Z& <8f  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); (N{  
SiteFileFetch fileFetch = new SiteFileFetch(bean); HqA3.<=F,  
fileFetch.start(); ?e23[  
} _p| KaT``  
catch(Exception e){e.printStackTrace ();} {'Gu@l  
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?D]T|=EZY  
} P,n:u'Iwy  
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public static void main(String[] args) cx4'rK.  
{ "HbrYYRb'  
new TestMethod(); s`,.&  
} fQ,(,^!;  
} jqy?Od)  
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