http断点续传简单实现（java)

/* re,.@${H  
**SiteFileFetch.java JK~ m(oQ  
*/ DcV<y-`'1  
package NetFox; af+}S9To  
import java.io.*; 8h?X!2Nq  
import java.net.*; 26:evid  
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public class SiteFileFetch extends Thread { WY)^1Gb$ux  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 2neRJ  
long[] nStartPos; //开始位置 ]?9[l76O7  
long[] nEndPos; //结束位置 ^^$vR[7  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 #Y,A[Y5jX  
long nFileLength; //文件长度 >e8JK*Blz  
boolean bFirst = true; //是否第一次取文件 bv\ A,+  
boolean bStop = false; //停止标志 0B0G2t&hr  
File tmpFile; //文件下载的临时信息 ?SUQk55w  
DataOutputStream output; //输出到文件的输出流 ,\hYEup  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） hD 46@  
public SiteFileFetch(SiteInfoBean bean) throws IOException ! VRI_c  
{ g^o_
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siteInfoBean = bean; `.k5v7!o  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); o|287S|$  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 5&4F,v[zp  
if(tmpFile.exists ()) yCM{M  
{ <
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bFirst = false; dB|Te"6  
read_nPos(); u2`xC4>c  
} NR
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else |Odu4 Q  
{ +6%7CC6  
nStartPos = new long[bean.getNSplitter()]; GMFc K=  
nEndPos = new long[bean.getNSplitter()]; s%dF~DSK  
} ehc<|O9tY  
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} mMxHR$2  
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public void run() ( ji_o^  
{ 8)Tj
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//获得文件长度 1e$[p[  
//分割文件 mvf _@2^  
//实例FileSplitterFetch hrlCKL&  
//启动FileSplitterFetch线程 O~Uw&Bq  
//等待子线程返回 VA]ZR+m  
try{ @bQ!zCI  
if(bFirst) F|]rA*2u  
{ 9c5!\m1  
nFileLength = getFileSize(); >1XL;)IL>  
if(nFileLength == -1) C
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{ *!u?  
System.err.println("File Length is not known!"); <jL#>L%%  
} gLCz]D.'  
else if(nFileLength == -2) "=`~iXT{e  
{ A[Cg/ +Z  
System.err.println("File is not access!"); w:tGPort  
} DM/hcY$MW  
else dt.-C_MO  
{ zlX!xqHj  
for(int i=0;i<nStartPos.length;i++) p[P[#IeL  
{ GHrBK&  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); |2UauTp5yK  
} mSj76'L#  
for(int i=0;i<nEndPos.length-1;i++) /lUk5g^j  
{ J:W'cH$cR  
nEndPos = nStartPos[i+1]; 0N1' $K$\  
} VEo^ :o)r  
nEndPos[nEndPos.length-1] = nFileLength; `1p?*9Ssn  
} &(\@sxAyZ  
} $WD +Q@6  
?hSha)1:  
@5*xw1B  
//启动子线程 ZmO'IT=Ye  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; }Ch[|D=Wd6  
for(int i=0;i<nStartPos.length;i++) wL|7mMM,  
{ hd=j56P5P  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), I! ITM<Z$l  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), &.*T\3UO  
nStartPos,nEndPos,i); <\xQ7|e  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /kb$p8!C".  
fileSplitterFetch.start(); \1khyF'  
} ]*h&hsS0  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), h=wf>^l  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); `QAh5r"  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 7#/|VQX<A  
nEndPos = " + nFileLength); Oylp:_<aT  
// fileSplitterFetch[nPos.length-1].start(); )ldUayJ  
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?ZM^%]/+  
//等待子线程结束 Kk56/(_S  
//int count = 0; u> In(7\  
//是否结束while循环 ^"/Dih\_  
boolean breakWhile = false; 4}PeP^pj  
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VG#$fRrZ  
while(!bStop) :EaiM J_=  
{ :=B[yD!  
write_nPos(); nR#a)et  
Utility.sleep(500); =1&}t%<X  
breakWhile = true; OUKj@~T  
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for(int i=0;i<nStartPos.length;i++) kt5YgW  
{ $/
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if(!fileSplitterFetch.bDownOver) v,@E}F~-f1  
{ zh hGqz[K  
breakWhile = false; iPJ9Gh7  
break; ^$?7H>=_ha  
} d<)s@Ntgm  
} -<12~HKK::  
if(breakWhile) gtl;P_  
break; 5D>BV*"  
@<%oIE~]F  
{K6Kx36  
//count++; z4nou>  
//if(count>4) \Z8Y(]6*  
// siteStop(); L)=8mF.  
} 1pl2;!  
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u<J2p?`\&`  
System.err.println("文件下载结束！"); QDl)92z  
} ge@reGfsB1  
catch(Exception e){e.printStackTrace ();} 'II vub#q  
} vJzxPy|  
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V=Ww>  
//获得文件长度 +,:nm_kQU  
public long getFileSize() " Tw0a!  
{ e*6U |+kJ  
int nFileLength = -1; )62q|c9F  
try{ eF*TLI<[^I  
URL url = new URL(siteInfoBean.getSSiteURL()); L)j]~^P$-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8p3ZF@c~t  
httpConnection.setRequestProperty("User-Agent","NetFox"); aslNlH6  
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int responseCode=httpConnection.getResponseCode(); x*k65WO\  
if(responseCode>=400) FDZeIj9uF  
{ -+`az)lrp  
processErrorCode(responseCode); /,-h%gj  
return -2; //-2 represent access is error knI*-  
} #.RG1-L  
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String sHeader; fB@K'JQG  
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Jq=X!mTd.  
for(int i=1;;i++) A;b=E[iv  
{ h,Y{t?Of  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); k,yc>3P;U  
//Utility.log(in.readLine()); c g3Cl[s  
sHeader=httpConnection.getHeaderFieldKey(i); vEX|Q\b6'  
if(sHeader!=null) wGZ>iLe:  
{ oR!n bm  
if(sHeader.equals("Content-Length")) &! 5CwEIF  
{ ?nj"Ptzs  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); +6i7,U  
break; {IF
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} V7Vbl?*n  
} 
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else n$}R/*  
break; I 0x`H)DA  
} ;Hz`0V  
} |SwZi'p  
catch(IOException e){e.printStackTrace ();} A8CIP:Z  
catch(Exception e){e.printStackTrace ();} V!jK3vc  
"P>$=X~Zi  
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Utility.log(nFileLength); YqK+F=0  
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return nFileLength; 60.[t9pk6  
} d;*OO xQV  
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|*/uN~[  
//保存下载信息（文件指针位置） -k|g04Q?  
private void write_nPos() wC4AVJJ^>  
{ G "c&C
 
try{ )Gu0i7iN  
output = new DataOutputStream(new FileOutputStream(tmpFile)); F}VS)  
output.writeInt(nStartPos.length); \#IJ=+z  
for(int i=0;i<nStartPos.length;i++) Y`E{E|J  
{ Xs.$2  
// output.writeLong(nPos); &mO/u
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output.writeLong(fileSplitterFetch.nStartPos); 6&/ Ew4 e  
output.writeLong(fileSplitterFetch.nEndPos); J7 Oa})-+'  
} %M4XbSN|  
output.close(); 24.7S LXO  
} <s59OdzP  
catch(IOException e){e.printStackTrace ();} @ ~0G$  
catch(Exception e){e.printStackTrace ();} $;KQY7  
} ;%3thm7+  
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//读取保存的下载信息（文件指针位置） YFC0KU  
private void read_nPos() ]k3GFPw  
{ 6KZ8 .m}:  
try{ 5 O{Ip-  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ePPp)=
 
int nCount = input.readInt(); 2\$WP-)%  
nStartPos = new long[nCount]; l>[QrRXiSN  
nEndPos = new long[nCount]; LRqw\fKk[  
for(int i=0;i<nStartPos.length;i++) -=v/p*v0o  
{ "'&>g4F`o  
nStartPos = input.readLong(); jN5} 2 p*  
nEndPos = input.readLong(); ;OT#V,}r  
} 2:6Y83  
input.close(); _dJVnC1 !  
} o0-fUCmC  
catch(IOException e){e.printStackTrace ();} t2!$IH
E:  
catch(Exception e){e.printStackTrace ();} h~^qG2TYWq  
} ;_Of`C+  
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private void processErrorCode(int nErrorCode) -?2&5YB  
{ p8}5x 2F  
System.err.println("Error Code : " + nErrorCode); f6aT[Nw<  
} 1,*Z_ F=y  
1Q2k>q8  
EFT02#F_f  
//停止文件下载 CoKj'jA  
public void siteStop() B[U.CAUn  
{ #4|i@0n}D  
bStop = true; ?@,f[U-  
for(int i=0;i<nStartPos.length;i++) PL$(
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fileSplitterFetch.splitterStop(); !m/Dd0  
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} 1_dMe%53  
} BW(DaNt^  
//负责部分文件的抓取 tp,
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**FileSplitterFetch.java "*H'bzK  
*/ c?3F9w#  
package NetFox; ck4T#g;=  
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import java.io.*; [gg7Z|Hu  
import java.net.*; 51FK~5  
?'8MI|*l%  
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m  
public class FileSplitterFetch extends Thread { +%cr?g  
8d*<Aki?;  
KWuj_.;  
String sURL; //File URL *M\i4FO8  
long nStartPos; //File Snippet Start Position 88+\mX;A#  
long nEndPos; //File Snippet End Position ]@j"0F/`  
int nThreadID; //Thread's ID =[tls^  
boolean bDownOver = false; //Downing is over `QyALcO  
boolean bStop = false; //Stop identical J1v0 \  
FileAccessI fileAccessI = null; //File Access interface 0z<]\a4  
5M.n'*   
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException @gVyLefS6g  
{ ~sU! 1  
this.sURL = sURL; V n!az}  
this.nStartPos = nStart; w _6Y+  
this.nEndPos = nEnd; 1{fwr1b  
nThreadID = id; 6w`}+3  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 pmpn^ZR  
} sR0e&Y  
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/j5- "<;.  
public void run() ;hRpAN  
{ owS@dbO  
while(nStartPos < nEndPos && !bStop) d_?Zr`:  
{ }rAN2D]"}  
3~1lVU:  
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try{ p/^\(/\])  
URL url = new URL(sURL); kBQenMm  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); a^)4q\E  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]bU'G$Qm&s  
String sProperty = "bytes="+nStartPos+"-"; x)qHeS  
httpConnection.setRequestProperty("RANGE",sProperty); \5pAG mgD  
Utility.log(sProperty); uP'w.nA&2  
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InputStream input = httpConnection.getInputStream(); Hn'2'Vu  
//logResponseHead(httpConnection); y2hFUq
  
hm} :Me$[)  
v
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byte[] b = new byte[1024]; r+.4|u  
int nRead; x%?*]*W  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >b"z`{tE  
{ {O,M
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nStartPos += fileAccessI.write(b,0,nRead);  F3
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//if(nThreadID == 1) Ru\Lr=9  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); JX,#W!d  
} nm|m1Z+U  
3Os3=Ix  
NCpn^m)Q}  
Utility.log("Thread " + nThreadID + " is over!"); 4a50w:Jy]  
bDownOver = true; Mh/>qyS*2  
//nPos = fileAccessI.write (b,0,nRead); "Ohpb!J9  
} x]01j4HJ  
catch(Exception e){e.printStackTrace ();} ~ z&A  
} E#F9<=mA)  
} H5MAN,`  
#yRA.;  
?)QBJ9F  
//打印回应的头信息 W[Ew6)1T  
public void logResponseHead(HttpURLConnection con) yt#;3  
{ sTstc+w  
for(int i=1;;i++) 6rCP]YnF  
{ nXaX=  
String header=con.getHeaderFieldKey(i); (<~
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if(header!=null) >oaEG5%d  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); L<>NL$CrN  
Utility.log(header+" : "+con.getHeaderField(header)); {gHscj;SM  
else |DS@90}  
break; cb&In<q  
} 6f9<&dCK  
} I=Dk'M  
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4bjp*1*]  
public void splitterStop() EKJ4_kkjM  
{ E/-Kd!|"  
bStop = true; , p=8tf#  
} IMw)X0z  
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} tZ24}~d
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T@.m^|~  
/* t>u9NZt G  
**FileAccess.java z"C(#Y56 x  
*//文件访问(定位，写) ij5=f0^4.  
package NetFox; v7u}nx  
import java.io.*; ew ,edU  
mqc Z3lsv  
@[Qg}'i  
public class FileAccessI implements Serializable{ T.N7`  
1gK3=Ys  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 !fjU?_[S  
RandomAccessFile oSavedFile; MQMy Z:  
long nPos; >gLyz2  
i4Cb&h^  
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public FileAccessI() throws IOException vX24W*7  
{ t|"d#5'  
this("",0); 3t6'5{  
} Nmq5Tv  
mzR @P$:36  
=zGz|YI*?  
public FileAccessI(String sName,long nPos) throws IOException 7%}}m&A7h  
{ uy\+#:44d  
oSavedFile = new RandomAccessFile(sName,"rw"); :2d9ZDyD  
this.nPos = nPos; 5F?g6?j{  
oSavedFile.seek(nPos); U4pvQE.m<  
} < l ^ Z;.  
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}H^
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public synchronized int write(byte[] b,int nStart,int nLen) y+x>{!pw  
{ +6-!o,(  
int n = -1; =qQQ^`^F'~  
try{ ^Exq=oV  
oSavedFile.write(b,nStart,nLen); R6.#gb8^oS  
n = nLen; +34jot.!  
} )BrqE uX@"  
catch(IOException e) Gnq~1p5^  
{ 2b` M(QL  
e.printStackTrace ();  `.-C6!  
} 5-po>1g'  
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\{mJO>x  
return n; &<b7T$c  
} =D$r5D/xd  
->{WO+6(  
/T'nY{  
} bG?[":k  
t!C-G+It  
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/* 2p[3Ap  
**SiteInfoBean.java {
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*/ = F<`-6  
package NetFox; %/C[\wp81  
'FXZ`+r|  
_/\H3  
public class SiteInfoBean { Y>~zt -  
cK@K\AE  
#<3\}*/  
private String sSiteURL; //Site's URL l!'iLq"K(  
private String sFilePath; //Saved File's Path )j*qGsOg  
private String sFileName; //Saved File's Name 7QFEQ}  
private int nSplitter; //Count of Splited Downloading File ,FO|'l  
"G(/MT^C  
=?aB@&  
public SiteInfoBean() __npX_4%S  
{//nSplitter的缺省值为5 #O ]IXo(5z  
//default value of nSplitter is 5 aoX$,~oI5  
this("","","",5); 4!|ar?Zy  
} @SXgaWr  
^Y |s^N  
=c4U%d2  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) mg]dKp  
{ /Qy0vAvJ  
sSiteURL= sURL; np(<Ap r  
sFilePath = sPath; $ 7!GA9Bn  
sFileName = sName; 5}ah
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this.nSplitter = nSpiltter; Dh<e9s:  
T]`" Xl8  
(5 hu W7v  
} XPKcF I=  
58,mu#yq6  
;zODp+4@Q  
public String getSSiteURL() "(GeW286k  
{ w ?aLWySYT  
return sSiteURL; IgJC>;]u  
} %4J?xhd  
UPF=X)!M  
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public void setSSiteURL(String value) &|eQLY #l  
{ 2ra4t]f6  
sSiteURL = value; hI0l2OE  
} qMOD TM~+  
`!N?#N:b)  
zZ-*/THB@R  
public String getSFilePath() $la,_Sr  
{ iYkNtqn/  
return sFilePath; <KX#;v!I  
} oef(i}8O@  
M:E#}(
 
;{RQ+ZX'[  
public void setSFilePath(String value) db|$7]!w  
{ IZLX[
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sFilePath = value; O8%/Id  
} KW\`&ki  
\)*qW[C$a  
H#K|SSqY?  
public String getSFileName() ,H8Pmn?  
{ 7 pV3#fQ  
return sFileName; C.O-iBVe#  
} TzJN,]F!M  
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!WXSrICX[  
public void setSFileName(String value) /2(F  
{ C4,W[L]4"  
sFileName = value; =9-c*bL  
} vr$[  
'"Gi&:*nQ<  
ko$R%W&T  
public int getNSplitter() =8-e1R/  
{ -L@=j  
return nSplitter; 9L,T@#7  
} qM'5cxe  
ifUgj8i_  
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public void setNSplitter(int nCount) LJ?7W,?  
{ I6+5mv\  
nSplitter = nCount; "\ m
d  
} , {^g}d8  
} %|Vq"MW,I  
1ARIZ;H  
^
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/* uP:'e8  
**Utility.java f|!
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*/ 7-)KTBFL  
package NetFox; ?~"RCZ[;.f  
u-,=C/iU  
^)WGc/  
public class Utility { cVN|5Y  
|yr
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JXrMtSp\  
public Utility() Nsb13mlY  
{ kq+L63fZ  
HUH=Y;  
;IyQqP#,<  
} q-'zZ#  
8l6R.l  
//线程睡眠 j1)w1WY0@  
public static void sleep(int nSecond) :7gIm|2"]  
{ {8
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try{ sqhM[u k  
Thread.sleep(nSecond); q4{ 6@q  
} 6B=J*8 Hs  
catch(Exception e) sHNt>5p  
{ cOSUe_S0w[  
e.printStackTrace (); TeHR,GB  
} ^VD14V3  
} ;-59#S&?tB  
M%m$5[;n  
//日志 &12.
|  
public static void log(String sMsg) 92EvCtf  
{ R"jX9~3Ln  
System.err.println(sMsg); $4m{g"xL  
} yo5|~"yZY  
t2>Vj>U  
BO^e.iB/  
public static void log(int sMsg) c8h 9  
{ /)N[tv2  
System.err.println(sMsg); ;tO(,^  
} IsI\T8yfc  
} xGjEEBL  
[dL#0~CL$  
Gmc
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/* /J^yOR9  
**TestMethod.java O3S_P]{*ny  
*/ mU;TB%#)  
package NetFox; yA~W|q(/V  
N7XRk=J  
Y:O%x
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public class TestMethod { {=TD^>?  
"~tEmMz  
L49`=p<  
public TestMethod() }JS?42CTaV  
{ ///xx/weblogic60b2_win.exe xRb-m$B}L  
try{ E=7~\7TE  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); J^U#dYd  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); *g7dB2{  
SiteFileFetch fileFetch = new SiteFileFetch(bean); $%LjIeVA5  
fileFetch.start(); X=lOwPvP  
} |VIBSty2d  
catch(Exception e){e.printStackTrace ();} mhL,:UE  
)tB mSVprl  
R4{2+q=0  
} ;L|%H/SH  
13Q|p,^R  
^$VOC>>9  
public static void main(String[] args) WL<Cj_N_{H  
{ H13|bM<  
new TestMethod(); 2%QY~Ku~  
} J?HYN%  
} }{s<!b  
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