http断点续传简单实现（java)

/* ;
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**SiteFileFetch.java =vd9mb-  
*/ B+8lp4V9%  
package NetFox; 1E1oy(\V  
import java.io.*; TzPG(f  
import java.net.*; [iT*L)R4  
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public class SiteFileFetch extends Thread { 2{-};
 
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SiteInfoBean siteInfoBean = null; //文件信息Bean vpnOc2 -  
long[] nStartPos; //开始位置 +>w %j&B  
long[] nEndPos; //结束位置 '@jP$6T&  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 D-v}@tS'  
long nFileLength; //文件长度 M,uQ8SZA[  
boolean bFirst = true; //是否第一次取文件 uR;m<wPH,f  
boolean bStop = false; //停止标志 d*M:PjG@  
File tmpFile; //文件下载的临时信息 C(4r>TNm  
DataOutputStream output; //输出到文件的输出流 /t4#-vz  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） vs*Q
{  
public SiteFileFetch(SiteInfoBean bean) throws IOException ##_`)/t,  
{ lhp.zl  
siteInfoBean = bean; ^V5VRGq  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); []\=(Uc;  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); dKG2f  
if(tmpFile.exists ()) q_J)68BR  
{ {.,-lFb\  
bFirst = false; >EVY,  
read_nPos(); pA~eGar_J  
} s<GR ?  
else j\/Rjn+:[  
{ UWf@(8  
nStartPos = new long[bean.getNSplitter()]; i_[nW  
nEndPos = new long[bean.getNSplitter()]; "\CUHr9k  
} eeOE\  
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} t XbMP  
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public void run() cBGR%w\t%  
{ {&I3qk2(  
//获得文件长度 6 _Cc+}W  
//分割文件 dXBXV>rbB  
//实例FileSplitterFetch t>Ot)d  
//启动FileSplitterFetch线程 V\2&?#GZ  
//等待子线程返回 qsUob  
try{ 40M/Gu:  
if(bFirst) $-J=UT2m  
{ P {8d.  
nFileLength = getFileSize(); '1f:8  
if(nFileLength == -1) #mFY?Zp)  
{ YXFUZ9a#e  
System.err.println("File Length is not known!"); fG`<L;wi  
} /XeCJxo8  
else if(nFileLength == -2) ws_/F  
{ FN>ns,  
System.err.println("File is not access!"); usFhcU  
} K+F]a]kld  
else yw
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{ ]ssX,1#Xh  
for(int i=0;i<nStartPos.length;i++) *~b}]M700  
{ $bho]~  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); "m'roU  
} KhWt9=9  
for(int i=0;i<nEndPos.length-1;i++) sf(2~BMQI  
{ U6sPJc<  
nEndPos = nStartPos[i+1]; bS2)L4MQY  
} $I$ B8  
nEndPos[nEndPos.length-1] = nFileLength; V=+wsc  
} k%-S7iQ  
} (&=gM  
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//启动子线程 V']{n7a-  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; J Gpy$T{t  
for(int i=0;i<nStartPos.length;i++) e5HHsR6  
{ '(.vB~m7*+  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `;\<Fr  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), dJYW8pcKT  
nStartPos,nEndPos,i); 9NPOdt:@  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^5,B6
  
fileSplitterFetch.start(); Mu>WS)1lS  
} &1(PS)s  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), E$?:^ausu  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); N Dg*8i  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", \ld{Z;e  
nEndPos = " + nFileLength); C3#mmiL-  
// fileSplitterFetch[nPos.length-1].start(); kH9fK80  
hp<NVST  
K[G=J  
//等待子线程结束 )RZ:\:c  
//int count = 0; .~L^h/)Gjy  
//是否结束while循环 !92zC._  
boolean breakWhile = false; c1CUG1i  
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while(!bStop) fdCN?p[_  
{ Ac,Qj`'V  
write_nPos(); x_eR/B>  
Utility.sleep(500); 0.4Q-?J  
breakWhile = true; &|j^?ro6  
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for(int i=0;i<nStartPos.length;i++) Pd^v-}[  
{ 0DIXd*oj&  
if(!fileSplitterFetch.bDownOver) B?|url6h  
{ ~ 6`Ha@  
breakWhile = false; {rE]y C^  
break; >i:hdcxe  
} G|,'6|$jE  
} E#I^D/0  
if(breakWhile) <lxE^M  
break; c7[+gc5}  
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^XbN&'^,HL  
//count++; }@'Zt6+tS  
//if(count>4) zK@DQ5  
// siteStop(); s+jL BY  
} 9bVPMq7}i  
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System.err.println("文件下载结束！"); ySXQn#}-,  
} `dpm{sn  
catch(Exception e){e.printStackTrace ();} OY?x'h  
} ]!=,8d
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k#Bq8d  
}c1?:8p  
//获得文件长度 r:QLO~l/  
public long getFileSize() %I 3D/!%  
{ 41'|~3\X  
int nFileLength = -1; gWZz
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try{ Ce%fz~*b  
URL url = new URL(siteInfoBean.getSSiteURL()); CPj8`kl  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0Ia8x?80V  
httpConnection.setRequestProperty("User-Agent","NetFox"); X$4MpXx  
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int responseCode=httpConnection.getResponseCode(); q8_8rp-@  
if(responseCode>=400) <JyF5  
{ d4]9oi{}  
processErrorCode(responseCode); kTQvMa-X9D  
return -2; //-2 represent access is error OU /=wpt  
} k:JlC(^h  
cI
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9R6]OL)p  
String sHeader; y~ZYI]` J  
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for(int i=1;;i++) y))) {X  
{ BWHH:c
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); "F3M  m  
//Utility.log(in.readLine()); vXP+*5d/ K  
sHeader=httpConnection.getHeaderFieldKey(i); y {PUklq  
if(sHeader!=null) 2U Q&n`A  
{ i;GF/pi  
if(sHeader.equals("Content-Length")) %Uz 5Ve  
{ l2lyi  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); TODTR7yGo  
break; m+ww  
} ; wpX  
} ]?$eBbt  
else PAUepO_  
break; {"x>ewAf  
} 4U1!SR]s  
} 9BA*e-[  
catch(IOException e){e.printStackTrace ();} [IgB78_$  
catch(Exception e){e.printStackTrace ();} ^ rB7&96C,  
2[;4D/`*  
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Utility.log(nFileLength); !9/1_Bjv  
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return nFileLength; C72!::o  
} EG|fGkv"  
d77->FX2  
N;A#K7A[@  
//保存下载信息（文件指针位置） 5,,b>Z<  
private void write_nPos() !pMp n%r<]  
{ k ='c*`IE  
try{ 2Kg+SLU[~  
output = new DataOutputStream(new FileOutputStream(tmpFile)); G+$A|'<`z  
output.writeInt(nStartPos.length); 13X\PO'9  
for(int i=0;i<nStartPos.length;i++) l^$8;$Rq  
{ d;-/F b{4  
// output.writeLong(nPos); 7 z#Xf  
output.writeLong(fileSplitterFetch.nStartPos); Zc<fopih  
output.writeLong(fileSplitterFetch.nEndPos); 0<{zW%w  
} a0]n>C`~  
output.close(); a1 I
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} wACx}'+M  
catch(IOException e){e.printStackTrace ();} M]RbaXZ9  
catch(Exception e){e.printStackTrace ();} 9t1aR*b&@  
} rpZ^R}B%*v  
vj?6,Ae  
x^J}]5{0  
//读取保存的下载信息（文件指针位置） |1@/gqa  
private void read_nPos() Bn5O;I13  
{ \en}8r9cy  
try{ 
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); I\|x0D  
int nCount = input.readInt(); !&ly :v!  
nStartPos = new long[nCount]; =DT7]fU
 
nEndPos = new long[nCount]; ,vnHEY&  
for(int i=0;i<nStartPos.length;i++) 4%]wd}'#Un  
{ +frkC| .  
nStartPos = input.readLong(); mqx#N%  
nEndPos = input.readLong(); .8O.  
} DAPbFY9  
input.close(); %e71BZo~^s  
} jYv`kt  
catch(IOException e){e.printStackTrace ();} 7a4b,-93  
catch(Exception e){e.printStackTrace ();} aIA
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} Eed5sm$H  
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private void processErrorCode(int nErrorCode) S5W*,?  
{ '|9fDzW"]  
System.err.println("Error Code : " + nErrorCode); rerl-T<3  
} J'%  
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//停止文件下载 ')8c  
public void siteStop() ir-= @@  
{ |K H&,  
bStop = true; is2OJ,  
for(int i=0;i<nStartPos.length;i++) $jL{l8x  
fileSplitterFetch.splitterStop(); yd-r7iq  
+a{P,fRl@  
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} Mu>GgQSZ  
} y7s:Buyc  
//负责部分文件的抓取 p7\}X.L  
**FileSplitterFetch.java  bK7j"  
*/ sI7<rI.t){  
package NetFox; K)z!e;r  

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import java.io.*; |@rPd=G^(/  
import java.net.*; O!3MXmaO  
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public class FileSplitterFetch extends Thread { 7AE
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|fJpX5W-l  
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String sURL; //File URL Ed(6%kd  
long nStartPos; //File Snippet Start Position Oc51|[ Wj  
long nEndPos; //File Snippet End Position W[dK{?RB  
int nThreadID; //Thread's ID 4FWb5b!A=  
boolean bDownOver = false; //Downing is over XJs*DK  
boolean bStop = false; //Stop identical \5MW65  
FileAccessI fileAccessI = null; //File Access interface @F+zME   
7u9]BhcFv?  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Vm
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{ U^ecg{  
this.sURL = sURL; M[C9P.O%w  
this.nStartPos = nStart; E%?X-$a  
this.nEndPos = nEnd; .5i\L OTd  
nThreadID = id; J<<Ph  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 XtJ_po  
} v*Fr#I0U  
* mzJ)4A  

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public void run() Z|8oD*,  
{ P|>pm]>C  
while(nStartPos < nEndPos && !bStop) 4H<@da}  
{ |6M:JI8  
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try{ yBd#*3K1  
URL url = new URL(sURL); U]aH4N  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &vDK6w,  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?"d25LyN  
String sProperty = "bytes="+nStartPos+"-";
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httpConnection.setRequestProperty("RANGE",sProperty); {hS9FdWA;  
Utility.log(sProperty); -2{NIF^H  
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InputStream input = httpConnection.getInputStream(); rv75R}.6R^  
//logResponseHead(httpConnection); 0Y%u[i/  
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byte[] b = new byte[1024]; P6n9yJ$,cb  
int nRead; pyW&`
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) D*Cn!v$  
{ 7Vn;LW  
nStartPos += fileAccessI.write(b,0,nRead); <B }4}-}  
//if(nThreadID == 1)  !e+^}s  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); X^?M4  
} M<4tjVQ6  
$jpAnZR- /  
{0&'XA=j  
Utility.log("Thread " + nThreadID + " is over!"); :y>$N(.8f  
bDownOver = true; z1
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//nPos = fileAccessI.write (b,0,nRead); TqvgCk-  
} [>rX/a%c  
catch(Exception e){e.printStackTrace ();} x&ngCB@O  
} pj~Ao+  
} kw%vO6"q(  
aBBTcN%'  
}mZsK>  
//打印回应的头信息 7Fg-}lJAC  
public void logResponseHead(HttpURLConnection con) bJ~@ k,'  
{ p\"WX  
for(int i=1;;i++) lURL;h  
{ 6X2~30pdE  
String header=con.getHeaderFieldKey(i); 5IwQ<V  
if(header!=null) WOv m%sX  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); )I
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Utility.log(header+" : "+con.getHeaderField(header)); 8Pkw'.r  
else $KmhG1*s  
break; 
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} 4axc05  
} ceW,A`J  
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public void splitterStop() 1x"S^j   
{ I6q]bQ="  
bStop = true; (jV_L1D  
} "@!B"'xg  
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Cwb}$=p'  
} )kBN]>&R  

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/* ^lt;K{  
**FileAccess.java A6D@#(D  
*//文件访问(定位，写) f vAF0 a  
package NetFox; \Y>!vh X  
import java.io.*; 3I" <\M4x  
yY3Mv/R  
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public class FileAccessI implements Serializable{ ~h:/9q  
g[#4`Q<.  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Zx1I&K\Cd  
RandomAccessFile oSavedFile; (_9cL,v  
long nPos; nVO|*Bnf)  
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public FileAccessI() throws IOException ^Hdru]A$2  
{ &fIx2ZM[  
this("",0); /+11`B0
9  
} )\!-n]+A  
na%DF@Rt#  
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public FileAccessI(String sName,long nPos) throws IOException 'ot,6@~x>  
{ OYj4G?c  
oSavedFile = new RandomAccessFile(sName,"rw"); |%i|P)]  
this.nPos = nPos; Ot^<:\<`G  
oSavedFile.seek(nPos); NV[_XXTv7  
} l6AG!8H  
U&(TqRi,  
uTX0lu;  
public synchronized int write(byte[] b,int nStart,int nLen) Nydhal00  
{ GC<zL}  
int n = -1; FtEmSKD  
try{ 7jf%-X  
oSavedFile.write(b,nStart,nLen); DKvNQ:fI>9  
n = nLen; 6G6B!x  
} f19~B[a  
catch(IOException e) b{Qg$ZJeR  
{ x}c%8dO#J  
e.printStackTrace (); F1q a`j^'  
} *<5zMSZO  
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return n; #nzVgV]  
}  .Lvg $d  
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} ,pg\5b  
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/* ]Zj6W9]m  
**SiteInfoBean.java r=`]L-}V  
*/ >_<J=8|E  
package NetFox; iJr 1w&GL$  
GOzV#  
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public class SiteInfoBean { f:).wi Ld  
v4YY6?4  
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private String sSiteURL; //Site's URL y{`aM(&  
private String sFilePath; //Saved File's Path Wl4T}j  
private String sFileName; //Saved File's Name c^$+=-G{fd  
private int nSplitter; //Count of Splited Downloading File (I) e-1  
E>|xv#:~DV  
}+" N '  
public SiteInfoBean() ?11\@d  
{//nSplitter的缺省值为5 4raKhN"  
//default value of nSplitter is 5 CQ(;L{}  
this("","","",5); xIrRFK9[Q  
} (ohza<X;6  
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3 E~d  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 3XOf-v:~  
{ L'*P;z7<  
sSiteURL= sURL; l$:.bwXXO  
sFilePath = sPath; h /.^iT  
sFileName = sName; 5z$>M3  
this.nSplitter = nSpiltter; %U4w@jp  
Ga%x(1U[&  
7n_'2qY  
} ZgXn8O[a  
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Ao%;!(\I%  
public String getSSiteURL() `2j \(N,  
{ nCj_4,O  
return sSiteURL; ~MgU"P>  
} e/h2E dY  
?;//%c8,.  
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public void setSSiteURL(String value) f\Fk+)e@  
{ :=<0Z1S  
sSiteURL = value; e2onR~Cf  
} H"_]Hq  
9
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{
  
public String getSFilePath() nhUL{ER  
{ o`!7~n  
return sFilePath; #ilU(39e  
} _QhB0/C  
][b2Q>  
X1P_IB  
public void setSFilePath(String value) LPOZA`  
{ \[-z4Fxg|'  
sFilePath = value; LEUD6 M+~t  
} !*U
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xyoh B#'W  
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public String getSFileName() ~4{E0om@  
{ LGOeBEAMV^  
return sFileName; T}?vp~./   
} w'Kc#2  
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7\q_^  
public void setSFileName(String value) s 4Mi9h_  
{ 05|,-S  
sFileName = value; =h083|y>  
} (,J`!Y hS  
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public int getNSplitter() 'm;M+:l 6  
{ lO+<T[  
return nSplitter; "/EE$eU  
} Lnk!zj  
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pY3N7&m\:  
public void setNSplitter(int nCount) Ozygr?*X  
{ %7_c|G1  
nSplitter = nCount; #$vef  
} CKAs3",  
} Kp|#04]  
. k6)  
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/* yrDWIU(8;6  
**Utility.java Z
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*/ m-SP#?3  
package NetFox; u%^Lu.l_c  
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=
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public class Utility { a?+Ni|+  
!f(aWrw7e6  
IZm_/  
public Utility() iwHy!Vi-5  
{ _HT
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/12D >OK  
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} g5EdW=Dt,  
0d-w<lg9  
//线程睡眠 b}G4eXkuj  
public static void sleep(int nSecond) a<.7q1F  
{ >.D0McQg  
try{ ;w(]z  
Thread.sleep(nSecond); <JA`e+Bi  
} hIj[#M&6  
catch(Exception e) q2I;Ly\3o  
{ ${$XJs4  
e.printStackTrace (); 2$D *~~  
} 7k<4/|CQ{  
} 6~b~[gA  
)e)@_0  
//日志 o:\RJig<  
public static void log(String sMsg) ZCQ7xQD  
{ Jmb [d\ /D  
System.err.println(sMsg); q%4l!gzF3  
} 4>4*4!KR}  
v-85`h  
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public static void log(int sMsg) VV(>e@Bc4  
{ 9o.WJ  
System.err.println(sMsg); n6gYZd  
} S7Xr~5>X  
} J&{qe@
^
 
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/* @<]xbWhuw  
**TestMethod.java XpzdvR1  
*/ w;.'>ORC  
package NetFox; Z
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public class TestMethod { z8bDBoD6  
q+{-p?;;  
I/bED~Z:a  
public TestMethod() ,jBd3GdlZ  
{ ///xx/weblogic60b2_win.exe H_'i.t 'SS  
try{ Sf}>~z2  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); oZ1#.o{  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); %$j)?e  
SiteFileFetch fileFetch = new SiteFileFetch(bean); j.$#10*:  
fileFetch.start(); lz!F{mR  
} s-eC')w~E  
catch(Exception e){e.printStackTrace ();} 0s = h*"[  
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JMu|$"o&{  
} %S8e:kc6  
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public static void main(String[] args) 1<
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{ ,ZcW+!  
new TestMethod(); zCD?5*7  
} 07"dU  
} \5^#5_<  
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