http断点续传简单实现（java)

/* Fc~G*Gz~Z|  
**SiteFileFetch.java Hn|W3U  
*/ )4yP(6|lx  
package NetFox; 8dGsV5"*  
import java.io.*; BI1M(d#1L"  
import java.net.*; NJUKH1lIhR  
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public class SiteFileFetch extends Thread { b}[S+G-9W  
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SiteInfoBean siteInfoBean = null; //文件信息Bean k# [!; <  
long[] nStartPos; //开始位置 <LHhs<M'  
long[] nEndPos; //结束位置 S,#1^S  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 OW7  
long nFileLength; //文件长度 YKyno?m  
boolean bFirst = true; //是否第一次取文件 {w@qFE'b  
boolean bStop = false; //停止标志 o`bch?]  
File tmpFile; //文件下载的临时信息 xye-Z\-t  
DataOutputStream output; //输出到文件的输出流 g6GkA.!X$  
'!HTE`Aj  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） po| Ux`u  
public SiteFileFetch(SiteInfoBean bean) throws IOException `2l
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{ n6/Ous  
siteInfoBean = bean; (Ou%0 KW  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); GAz-yCJp  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); lA
^1}  
if(tmpFile.exists ()) b9bIvjm_  
{ M5dYcCDE  
bFirst = false; OUX7 *_  
read_nPos(); v=U<exM6%  
} 02;jeZ#z  
else /0s1;?  
{ a=z] tTs4  
nStartPos = new long[bean.getNSplitter()]; M(%H  
nEndPos = new long[bean.getNSplitter()]; >B BV/C'9  
} )(iv#;ByL  
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} RRL{a6(?  
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public void run() YF%gs{  
{ T &ZQie/  
//获得文件长度 n;g'?z=hy  
//分割文件 5ZCu6A  
//实例FileSplitterFetch CIudtY(:  
//启动FileSplitterFetch线程 Fr9/TI  
//等待子线程返回 w,UE0i9I  
try{ J4Gzp~{  
if(bFirst) b^o4Q[  
{ cgnNO&  
nFileLength = getFileSize(); )U/jD  
if(nFileLength == -1) R9J!}az'  
{ ZpTDM1ro  
System.err.println("File Length is not known!"); #Hw|P  
} ?CpVA  
else if(nFileLength == -2) YT\`R  
{ &g`&#IRz  
System.err.println("File is not access!"); TW|K.t@5#H  
} N/4E ~^2  
else 2+1ybOwb  
{ V9c.(QY|f  
for(int i=0;i<nStartPos.length;i++) Myq8`/_  
{ DT-VxF6h  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); `TrWtSwv  
} 9LR=>@Z  
for(int i=0;i<nEndPos.length-1;i++) K-RmB4WI  
{ Et=Pr+Q{c  
nEndPos = nStartPos[i+1]; %OQdUH4x  
} X9x`i  
nEndPos[nEndPos.length-1] = nFileLength; .-gJS-.c  
} D,#UJPyg  
} H$![]Ujq  
waMF~#PJlt  
}7 N6nZj`  
//启动子线程 NxP(&M(  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; &:&'70Ya  
for(int i=0;i<nStartPos.length;i++) lC<;Q*Y  
{ 'zyw-1  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), i|:!I)(lh  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), e3I""D{)[=  
nStartPos,nEndPos,i); /jv/qk3i  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5.rAxdP  
fileSplitterFetch.start(); D|uvgu2  
} -TUJ"ep]QJ  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), c_8&4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); <WXVUEea  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", x,B] J4  
nEndPos = " + nFileLength); 'uL4ezTtA  
// fileSplitterFetch[nPos.length-1].start(); (x=$b(I  
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//等待子线程结束 3j7FG%\  
//int count = 0; b8WtNVd  
//是否结束while循环 cu!%aM,/<-  
boolean breakWhile = false; jn(x-fj6R  
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while(!bStop) *22Vc2[i;  
{ xyL"U*  
write_nPos(); Z.VKG1e}  
Utility.sleep(500); tv#oEM9esl  
breakWhile = true; kK&w5'  
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for(int i=0;i<nStartPos.length;i++) 'a#lBzu\b  
{ BP/nK.  
if(!fileSplitterFetch.bDownOver) p2vN=[g9)  
{ J%"BCbxW~B  
breakWhile = false; 0|&@)`  
break; @MSmg3&  
} lQ8hY$  
} g'.OzD  
if(breakWhile) br I;}m  
break; rA~f68h|  
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7;jD>wp9D  
//count++; "O34 E?ql.  
//if(count>4) 6bm7^e(  
// siteStop(); ,#Z%0NLe  
} [LoQYDku  
HP# SR';E  
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System.err.println("文件下载结束！"); WZQ2Mi<&1'  
} c'oiW)8;A  
catch(Exception e){e.printStackTrace ();} $ XjijD9R  
} :ld~9  
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//获得文件长度 )/RG-L  
public long getFileSize() 4'QX1
p  
{ q G%Y& P  
int nFileLength = -1; x|O7}oj  
try{ v,w af`)J  
URL url = new URL(siteInfoBean.getSSiteURL()); Giyh( DL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {&5lZ<nu8A  
httpConnection.setRequestProperty("User-Agent","NetFox"); m8s
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int responseCode=httpConnection.getResponseCode(); \jfK']P/H  
if(responseCode>=400) (/:m*x*6  
{ {JE [  
processErrorCode(responseCode); IkCuw./  
return -2; //-2 represent access is error "6B@V=d  
} %8*:VR  
P
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String sHeader; 8t!jo.g  
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 ?eS;Yc  
for(int i=1;;i++) YBt=8`r  
{ 64B.7S88  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); =B}IsBn'J  
//Utility.log(in.readLine()); ng}C$d . I  
sHeader=httpConnection.getHeaderFieldKey(i); +?J N_aR  
if(sHeader!=null) )Zq'r L<  
{ A@V$~&JCL5  
if(sHeader.equals("Content-Length")) g,,wG k  
{ #9,8{ O"  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); g+#<;Gbpe  
break; Xm#W}Y'  
} Xg dBLb  
} /4x\}qvU  
else [F6)Z[uG  
break; 'K7\[if{  
} M%E<]H2;S  
} M<-Q8a~  
catch(IOException e){e.printStackTrace ();} D ,kxB~  
catch(Exception e){e.printStackTrace ();} #`iEbiSq  
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Utility.log(nFileLength); {$8+n::  
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return nFileLength; >7W)iwF  
} ]IV{;{E)  
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//保存下载信息（文件指针位置） }#ink4dK:  
private void write_nPos() 
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{ )Cy>'l*Og7  
try{ hF'VqJS  
output = new DataOutputStream(new FileOutputStream(tmpFile)); u@Hz7Q} P  
output.writeInt(nStartPos.length); $_S-R 3L\  
for(int i=0;i<nStartPos.length;i++) #)'Iqaq7  
{ ^yW['H6V  
// output.writeLong(nPos); d6n_Hpxw^  
output.writeLong(fileSplitterFetch.nStartPos); :E9pdx+  
output.writeLong(fileSplitterFetch.nEndPos); /EjXyrn2  
} )Rn\6ka  
output.close(); gX"-3w  
} \c2x udU  
catch(IOException e){e.printStackTrace ();} #D9.A7fCc5  
catch(Exception e){e.printStackTrace ();} \,13mB6  
} i^DMnvV.  
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//读取保存的下载信息（文件指针位置） 7r;16"  
private void read_nPos() J4+K
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{ 'V]C.`9c  
try{ (WHgB0{  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); OlT8pG5Oa  
int nCount = input.readInt(); L\#YFf  
nStartPos = new long[nCount]; >6S7#)0T  
nEndPos = new long[nCount]; %`i*SF(gV  
for(int i=0;i<nStartPos.length;i++) 8\s#law  
{ p7QZn.,=u  
nStartPos = input.readLong(); /?;'y,(Q  
nEndPos = input.readLong(); fXMY.X>f  
} p_I^7 $  
input.close(); Gazva/e  
} P*KIk~J  
catch(IOException e){e.printStackTrace ();} t+v%%N_  
catch(Exception e){e.printStackTrace ();} o< @![P  
} rd7p$e=i  
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private void processErrorCode(int nErrorCode) O}i+1  
{ ,8r?C!m]  
System.err.println("Error Code : " + nErrorCode); Jg$<2CR&  
} LDQ
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//停止文件下载 {&+M.Xn  
public void siteStop() {D[6=\F  
{
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bStop = true; t`B@01;8A  
for(int i=0;i<nStartPos.length;i++) T +vo)9w  
fileSplitterFetch.splitterStop(); 0si1:+t-[+  
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} NK qIx  
} 4s7 RB  
//负责部分文件的抓取 wQG?)aaM  
**FileSplitterFetch.java ,ayEZ#4.m  
*/ glLVT i  
package NetFox; V8/4:Va7s  
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import java.io.*; x*H#?.E  
import java.net.*; +j{Cfv$do  
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public class FileSplitterFetch extends Thread { ~vz%I^xW  
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String sURL; //File URL :(]fC~G~  
long nStartPos; //File Snippet Start Position pq`uB  
long nEndPos; //File Snippet End Position ,NQ!d4~D  
int nThreadID; //Thread's ID F`7v  
boolean bDownOver = false; //Downing is over g `s|]VNt  
boolean bStop = false; //Stop identical 0!,uo\`  
FileAccessI fileAccessI = null; //File Access interface =.z;:0]'n  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException %M`48TW)  
{ fHd[8{;P:  
this.sURL = sURL; :|n[zjK/S  
this.nStartPos = nStart; {.2\}7.c  
this.nEndPos = nEnd; JaUzu3*=  
nThreadID = id; '^TeV=  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 *b>RUESF  
} `,6|6.8#  
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public void run() ;mEn@@{  
{ O q$_ q  
while(nStartPos < nEndPos && !bStop) UF7h{V})  
{ f|,Kh1{e  
{_N9<i{T  
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try{ P7F"#R0QB  
URL url = new URL(sURL); kBZ1)?  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Q3WI@4  
httpConnection.setRequestProperty("User-Agent","NetFox"); d1/WUKmbZ  
String sProperty = "bytes="+nStartPos+"-"; by<@\n2B:U  
httpConnection.setRequestProperty("RANGE",sProperty); ir<e^a  
Utility.log(sProperty); "`ftcJUd  
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InputStream input = httpConnection.getInputStream(); =sk[I0W  
//logResponseHead(httpConnection); ~1+6gG  
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byte[] b = new byte[1024]; 5hm
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int nRead; K
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 0Ncpi=6  
{ |^l_F1+w  
nStartPos += fileAccessI.write(b,0,nRead); {V/>5pz4e  
//if(nThreadID == 1) \Wfw\x0.  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [uU!\xe  
} AY5iTbL1  
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Utility.log("Thread " + nThreadID + " is over!"); ^7yt>  
bDownOver = true; 3'.@aMA@  
//nPos = fileAccessI.write (b,0,nRead); bVUIeX'  
} n/skDx TE  
catch(Exception e){e.printStackTrace ();} #B5,k|"/,M  
} o{y}c->  
} ?)1Y|W'Rv  
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//打印回应的头信息 I Id4w~|  
public void logResponseHead(HttpURLConnection con) FL{?W(M  
{ 5Rl\& G\  
for(int i=1;;i++) f7a4E+}  
{ gbuh04#~  
String header=con.getHeaderFieldKey(i); Jx5`0?  
if(header!=null) J
>  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); esJ7#Gxt  
Utility.log(header+" : "+con.getHeaderField(header)); i#V(oSx  
else tq59w  
break; sA,bR|  
} 1x|3|snz)  
} &MSU<S?1  
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nq{/fD(2  
public void splitterStop() dO82T3T  
{ LJ[zF~4#  
bStop = true; B)Y[~4o  
} cR3d&/_,U  
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} F_*']:p  
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/* CI{2(.n4  
**FileAccess.java S-Y{Vi"2  
*//文件访问(定位，写) P{9:XSa%  
package NetFox; R->x_9y-
R  
import java.io.*; |4mvB2r  
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public class FileAccessI implements Serializable{ #zl1#TC{(  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 `2 <:$]  
RandomAccessFile oSavedFile; itzUq,T  
long nPos; FC1rwXL(  
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public FileAccessI() throws IOException 6nk}k]Ji  
{ ^f,4=-  
this("",0); !Axe}RD'  
} !
}!KT(%%  
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public FileAccessI(String sName,long nPos) throws IOException 1(Is 7  
{ nNCR5&,q  
oSavedFile = new RandomAccessFile(sName,"rw"); zgGysjV  
this.nPos = nPos; w80
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oSavedFile.seek(nPos); K(?V]Mxl6  
} Q("m*eMRt  
uU 7 <8G  
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public synchronized int write(byte[] b,int nStart,int nLen) ;JkIZ8!  
{ DKS1Sm6d0  
int n = -1; 3 ZOD2:(  
try{ A1p~K*[[  
oSavedFile.write(b,nStart,nLen); %f'pAc|#  
n = nLen; f![] :L  
} dT0W8oL  
catch(IOException e) sLA.bp.O  
{ 4<($ZN8  
e.printStackTrace (); ^^v3iCT  
} J,Ki2'=  
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return n; rT`sY  
} xq;>||B
 
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} E.*hY+kGZ  
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/* GUu8 N  
**SiteInfoBean.java 9^!.!%6O$  
*/ f4p*!e  
package NetFox; 'KjH|u  
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8~(,qU8-N  
public class SiteInfoBean { \r IOnZ.WK  
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private String sSiteURL; //Site's URL 1R}9k)JQ  
private String sFilePath; //Saved File's Path n=-vOa%  
private String sFileName; //Saved File's Name ]izHn;+  
private int nSplitter; //Count of Splited Downloading File )r.Wge  
m^oG9&";  
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public SiteInfoBean() 1vq2`lWpx  
{//nSplitter的缺省值为5 9C \}bT  
//default value of nSplitter is 5 ]lA}5  
this("","","",5); 2@MpWj4  
} rS>.!DiYr,  
1#N`elm  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) _t-6m2A  
{ 3YLK?X8  
sSiteURL= sURL; P1
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sFilePath = sPath; drAJ-ii  
sFileName = sName; :W
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this.nSplitter = nSpiltter; h.?<(I  
jlb8<xIC]  
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} p8 S~`fjV  
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public String getSSiteURL() Vb?wwx7=  
{ /HUT6B  
return sSiteURL; 2(!W 9#]  
} fP<==DK  
,$!fyi[;C  
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public void setSSiteURL(String value) U>kaQ54/  
{ (A2ga):Pk  
sSiteURL = value; jk`U7G*  
} IsT}T}p,t  
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public String getSFilePath() >0SG]er@  
{ z>+CMH5L)  
return sFilePath; F lVG,Z  
} M5*Ln-qt(a  
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public void setSFilePath(String value) )r
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{ Z<|x6%  
sFilePath = value; B[mZQ&Gz`a  
} vV"YgN:  
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public String getSFileName() rui
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{ BT(eU*m-  
return sFileName; ,r3`u2)  
} EQoK\.; G~  
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public void setSFileName(String value) ,MHK|8!  
{ [6K[P3UZx  
sFileName = value; |9i[*]  
} 9k93:#{WE  
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public int getNSplitter() M`7lYw\Or!  
{ @
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return nSplitter; N\s-{7K  
} k3LHLJZ#  
YO.ddy*59  
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public void setNSplitter(int nCount) `+."X1  
{ Q-iBK*-w  
nSplitter = nCount; I<W<;A  
} kN*I_#  
} ?w'03lr%  
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/* Le-t<6i-V#  
**Utility.java wg k[_i  
*/ 3 q
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package NetFox; ^Et^,I:`  
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N:KM8PZ&~  
public class Utility { hw`pi6  
w$]wd`N}  
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public Utility() PXl%"O%d  
{ !mVq+_7]  
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} 7#&Q-3\:  
J}-e9vK-#  
//线程睡眠 4F -<j!  
public static void sleep(int nSecond) $Ups9pQ  
{ i6FJG\d  
try{ /Aw@26  
Thread.sleep(nSecond); =yRv*C  
} x'G_z_<V  
catch(Exception e) Q`O~f<a  
{ bO('y@)X  
e.printStackTrace (); r|z B?9Q  
} G `eU   
} >,Zn~8&Z  
RP 6<#tq,  
//日志 j:8Pcx  
public static void log(String sMsg) k8+U0J_{'  
{ SEWdhthP  
System.err.println(sMsg); k:mW ,s|a  
} :"nh76xg<  
 Ew;AYZX  
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public static void log(int sMsg) /,<s9 :  
{ p? w^|V  
System.err.println(sMsg); Ai:,cY5%  
} -U7,~z  
} |rgPHRX^Hn  
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/* _K!)0p  
**TestMethod.java 1'\s7P  
*/ -) +B!"1  
package NetFox; t,A=B(W  
g^#,!e  
J_<6;#  
public class TestMethod { X_3hh}=  
oZL# *Z(h  
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public TestMethod() 2J)  
{ ///xx/weblogic60b2_win.exe 6@:<62!;  
try{ D)[(  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); pOB<Bx5t  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); E8lq2r=  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ^@Qc!(P  
fileFetch.start(); W%MS,zkAE  
} +T,0,^*  
catch(Exception e){e.printStackTrace ();} LOwd mj  
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L|'B*  
} 05jjLM'e  
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public static void main(String[] args) ssH[\i  
{ IO2@^jup  
new TestMethod(); oe=1[9T"  
} s=K?-O  
} u{sb^cmy  
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