http断点续传简单实现（java)

/* d.snD)X  
**SiteFileFetch.java nQw, /Lk  
*/ Vg7+G( ,  
package NetFox; AWZ4h,as{  
import java.io.*; 4YMUkwh  
import java.net.*; R<T5lkJ\/  
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public class SiteFileFetch extends Thread { 7n#Mh-vq  
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SiteInfoBean siteInfoBean = null; //文件信息Bean J<L"D/  
long[] nStartPos; //开始位置 o>M&C X+j$  
long[] nEndPos; //结束位置 `)jAdad-s  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 $nthMx$  
long nFileLength; //文件长度 mqQ//$Y   
boolean bFirst = true; //是否第一次取文件 <XpG5vV  
boolean bStop = false; //停止标志 AQ-R^kT  
File tmpFile; //文件下载的临时信息 O sIvW'$\  
DataOutputStream output; //输出到文件的输出流 &53LJlL Co  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Yu%ZwTvw  
public SiteFileFetch(SiteInfoBean bean) throws IOException A*{V%7hs&  
{ r2;+ACwWf_  
siteInfoBean = bean; `?"[u"*  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); *=QWx[K|  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); U_0"1+j
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if(tmpFile.exists ()) Yv;iduc('  
{ 6r5<uZ9w_X  
bFirst = false; &-.2P!t  
read_nPos(); !"^//2N+,  
} +_fxV|}P  
else kEdAt5/U{  
{ 62OZj%CXN  
nStartPos = new long[bean.getNSplitter()]; &ZPyZj  
nEndPos = new long[bean.getNSplitter()]; 
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} k8sjW!2  
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} 5 .bU2C  
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public void run() ^X?3e1om  
{ [M.!7+$o  
//获得文件长度 SQBe}FlktK  
//分割文件 #c1c%27cmm  
//实例FileSplitterFetch dBp)6ok#c  
//启动FileSplitterFetch线程 [%6"UH r  
//等待子线程返回 x_KJCU  
try{ v+2t;PJd2  
if(bFirst) 7gbu7"Qc  
{ Pu|3_3^  
nFileLength = getFileSize(); >^KO5N-:4  
if(nFileLength == -1) r7:4|6E  
{ xcl8q:  
System.err.println("File Length is not known!"); TqXB2`
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} t'Pn*  
else if(nFileLength == -2) =I9RM9O<  
{ 7pz #%Hf  
System.err.println("File is not access!"); sZPA(N?  
}  F| O  
else I.}E#f/A'  
{ lxD~[e  
for(int i=0;i<nStartPos.length;i++) LZ*ZXFIg  
{ 64-;| k4F  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); p#(5 ;  
} nJo6;_MI!  
for(int i=0;i<nEndPos.length-1;i++) Ut^ {4_EC  
{ V> @+&q  
nEndPos = nStartPos[i+1];  HO =\  
} 0=KyupwXC  
nEndPos[nEndPos.length-1] = nFileLength; t=(CCq_N,  
} 5XA{<)$  
} z0-`D.D@\  
s(Llz]E~ZX  
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//启动子线程 /aD3E"Op  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; sM'%apM#  
for(int i=0;i<nStartPos.length;i++) &,~Oi(SX5  
{ ]eZrb%B.  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), q'[q]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), =?gB@vS  
nStartPos,nEndPos,i); OB5`a,5dI  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >hmBV7nR  
fileSplitterFetch.start(); \$[S=&E  
} N1i%b,:3  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), etWCMR  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); iqPMCOPZ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", zU,Qph ,<  
nEndPos = " + nFileLength); K.K=\ Y2  
// fileSplitterFetch[nPos.length-1].start(); u
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//等待子线程结束 a
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//int count = 0; ?#P@N4Uw}y  
//是否结束while循环 {]6Pd`-  
boolean breakWhile = false; _B5v&#h(.  
u =%1%p,  
},LO
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while(!bStop) a"&Gs/QKSC  
{ w4e(p3  
write_nPos(); j>-O'CO
 
Utility.sleep(500); 7[?{wbq  
breakWhile = true; "nEfk{g  
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for(int i=0;i<nStartPos.length;i++) ii:E>O(0B  
{ ;XXB^,  
if(!fileSplitterFetch.bDownOver) of k@.TmO  
{ R9`37(c9+  
breakWhile = false; ' (1`iQ;  
break; iy\ 6e k1  
} qTUyax  
} {gwJ>]z"e  
if(breakWhile) Xe7/  
break; YA[\|I33  
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/f0*NNSat-  
//count++; ~dc~<hK  
//if(count>4) W2F*+M  
// siteStop(); R+y 9JE  
} )D"E]  
<UC_QPA\  
{WoS&eL  
System.err.println("文件下载结束！"); NP^j5|A*"  
} Oq3]ZUVa  
catch(Exception e){e.printStackTrace ();} KJ;;825?  
} `}Z`aK  
+<o}@hefY2  
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//获得文件长度 mxfmK +'_  
public long getFileSize() FLzC kzJ:6  
{ qPG>0 O  
int nFileLength = -1; 7uW=fkxT  
try{ LW '3m5  
URL url = new URL(siteInfoBean.getSSiteURL()); $zUHka  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Yg kd1uI.  
httpConnection.setRequestProperty("User-Agent","NetFox"); l" P3lKS  
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int responseCode=httpConnection.getResponseCode(); GLE/ 1  
if(responseCode>=400) 7`_`V&3s  
{ :[C"}mR1  
processErrorCode(responseCode); o!-kwtw`l  
return -2; //-2 represent access is error cA8A^Iv:0  
} 6A23H7  
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String sHeader; 9H#;i]t&  
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for(int i=1;;i++) 
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{ t#BQB<GI  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); UHT2a9rG  
//Utility.log(in.readLine()); o;5ns  
sHeader=httpConnection.getHeaderFieldKey(i); #<*=)[  
if(sHeader!=null) wFX>y^ 1  
{ mx3p/p  
if(sHeader.equals("Content-Length")) ZD;1{  
{ x@*!MC#  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); J=sj+:GS  
break; _ ,~D]JYE  
} O.Xhi+  
} O=;}VZ<9  
else _my!YS5n  
break; !}pvrBS  
} ews{0  
} A$o7<Hx  
catch(IOException e){e.printStackTrace ();} 0wnC"2GUX  
catch(Exception e){e.printStackTrace ();} eOUv#F  
,?/AIL]_  
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Utility.log(nFileLength); d;FOmo4  
{ d|lN:B  
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return nFileLength; p%ZOLoc)Y  
} 5BRZpCb  
' |Ia-RbX  
e` {F7rd:  
//保存下载信息（文件指针位置） }2+*E}g  
private void write_nPos() T7qE 2  
{ O'[r,|Q{  
try{ ;*[oi  
output = new DataOutputStream(new FileOutputStream(tmpFile)); *aaK_=w  
output.writeInt(nStartPos.length); &r0
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for(int i=0;i<nStartPos.length;i++) M>g%wg7Ah  
{ i8|0zI  
// output.writeLong(nPos); bTepTWv  
output.writeLong(fileSplitterFetch.nStartPos); .6HHUy  
output.writeLong(fileSplitterFetch.nEndPos); $3)Z>p  
} e.VR9O]G  
output.close(); -ztgi
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} _Qd CV`  
catch(IOException e){e.printStackTrace ();} &Fy})/F3v  
catch(Exception e){e.printStackTrace ();} E@[ZwTnJ  
} h"ZR`?h  
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//读取保存的下载信息（文件指针位置） h}&1 7M  
private void read_nPos() bSgdVP-  
{ $*q^7ME  
try{ S\<nCkE^  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); !>,XK!)  
int nCount = input.readInt(); N4rDe]JnPR  
nStartPos = new long[nCount]; /w "h'u  
nEndPos = new long[nCount]; b;jr;I  
for(int i=0;i<nStartPos.length;i++) hywy(b3  
{ )PCh;P0C  
nStartPos = input.readLong(); }=$>w@mJ  
nEndPos = input.readLong(); WlW7b.2.  
} Hkzx(yTi  
input.close(); '1vm]+oM
 
} 88g|(k/  
catch(IOException e){e.printStackTrace ();} 0f9*=c  
catch(Exception e){e.printStackTrace ();} Cc&SHG*R  
} Gc*p%2c  
|{V@t1`  
7&w$@zs87  
private void processErrorCode(int nErrorCode) /5N`Euw
 
{ p,K!'\  
System.err.println("Error Code : " + nErrorCode); G/4~_\YMq  
} D/&nEMp6  

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//停止文件下载 KvY1bMU!  
public void siteStop() *|B
t!  
{ Ju"K"  
bStop = true; Lpv,6#m`)  
for(int i=0;i<nStartPos.length;i++) ')zf8>,  
fileSplitterFetch.splitterStop(); S'}pUGDO  
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} e+O502]  
} :R1F\FT*  
//负责部分文件的抓取 12LGWhDp  
**FileSplitterFetch.java nxhn|v  
*/ ^?R8>97_?  
package NetFox; 8fWk C<f}  
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import java.io.*; <_3OiU=w  
import java.net.*; [ XBVES8  
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@  
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public class FileSplitterFetch extends Thread { ?.Lq`~T`  
}s@vN8C  
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String sURL; //File URL #u/5 nm  
long nStartPos; //File Snippet Start Position s`I]>e  
long nEndPos; //File Snippet End Position Btyp=wfN[  
int nThreadID; //Thread's ID t7 +U!  
boolean bDownOver = false; //Downing is over ?!a8'jfs  
boolean bStop = false; //Stop identical d7P'c!@+  
FileAccessI fileAccessI = null; //File Access interface BI6]{ZC"  
|32uC3?o  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException -(JBgM"  
{ g27)$0&0  
this.sURL = sURL; RYZM_@5$t  
this.nStartPos = nStart; s_ %LU:WC  
this.nEndPos = nEnd; a_(T9pr  
nThreadID = id; iyTKy+3A  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 'cPE7uNT  
} !EOYqD  
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]/[$3rPwZ  
public void run() wo5fGQJ
 
{ ~nRbb;M  
while(nStartPos < nEndPos && !bStop) i;fU],aK!  
{ nO `R++  
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try{ #tN!^LLi  
URL url = new URL(sURL); 8;$zD]{D1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); B\\M%!a>  
httpConnection.setRequestProperty("User-Agent","NetFox"); O&evv8 6L  
String sProperty = "bytes="+nStartPos+"-"; {4>N2mP{M  
httpConnection.setRequestProperty("RANGE",sProperty); COH9E
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Utility.log(sProperty); o?/fObV@(  
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InputStream input = httpConnection.getInputStream(); v,Uu)Z  
//logResponseHead(httpConnection); UTVqoCHA  
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#n.XOet<\  
byte[] b = new byte[1024]; ",pd 9  
int nRead; *:"p*qV*  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 4uE|$  
{ iC4rzgq  
nStartPos += fileAccessI.write(b,0,nRead); 0aa&13!5  
//if(nThreadID == 1) \{.c0  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Vc!'=&*  
} wxE'h~+  
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Utility.log("Thread " + nThreadID + " is over!"); A7R
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bDownOver = true; PYyT#AcW2  
//nPos = fileAccessI.write (b,0,nRead); AHet,N  
} -=GmI1:=$4  
catch(Exception e){e.printStackTrace ();} @umn#*  
} 4P?R "Lk  
} YQ`88z  
r<!/!}fE,  
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//打印回应的头信息 C&f{Lp
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public void logResponseHead(HttpURLConnection con) q"VC#97`  
{ jqQGn"!  
for(int i=1;;i++) m[<z/D  
{ G2w0r,[  
String header=con.getHeaderFieldKey(i); -u~AY#*  
if(header!=null) n!h952"  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); d,E2l~s  
Utility.log(header+" : "+con.getHeaderField(header)); #D^(dz*  
else VJS1{n=;k  
break; ~\u~>mtchu  
} 9#1
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} iQvqifDmh  
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public void splitterStop() ]F srk  
{ Q*8efzgs|  
bStop = true; ZM_-g4[H  
} FDTC?Ii O  
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} ^C~t)U  
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/* mV.26D<c  
**FileAccess.java \RmU6(;IQ  
*//文件访问(定位，写) &W%fsy<  
package NetFox; ~|&To>  
import java.io.*; ]uXmug  
@5{h+^  
-# /'^O+%  
public class FileAccessI implements Serializable{ 9>ML;$T&  
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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 P(B&*1X  
RandomAccessFile oSavedFile; EO\- J-nM  
long nPos; & sgzSX  
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public FileAccessI() throws IOException t:%u4\nZ;  
{ gM&4Ur  
this("",0); ?3do-tTp  
} s[%@3bY!7  
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/gP"X1.  
public FileAccessI(String sName,long nPos) throws IOException UVD*GsBk  
{ yH(%*-S  
oSavedFile = new RandomAccessFile(sName,"rw"); y-_IMu.J`  
this.nPos = nPos; 4YA1~7R  
oSavedFile.seek(nPos); !-tVt D  
} !=]cASPGD  
/U=?D(>x  
*/j[n$K>~`  
public synchronized int write(byte[] b,int nStart,int nLen) +K48c,gt?  
{ 5 ~YaXh^  
int n = -1; HjT-5>I7f  
try{ iz2;xa*  
oSavedFile.write(b,nStart,nLen); 9n;6;K#  
n = nLen; v K!vA-7  
} \xX'SB#.l  
catch(IOException e) K}tC8D  
{ A[H"(E#k  
e.printStackTrace (); @VnK/5opS  
} rhC x&L  
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return n; >+Y@rj2  
} +m1*ou'K  
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} 4#ZZwa]y  
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EO"G(v  
/* (#rhD}  
**SiteInfoBean.java U?j[ 8z  
*/ c Sktm&SP  
package NetFox; 5 &s<&h  
):nC&M\W~  
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public class SiteInfoBean { {=,+;/0  
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private String sSiteURL; //Site's URL nQd~i0`vB  
private String sFilePath; //Saved File's Path gqDSHFm:  
private String sFileName; //Saved File's Name ZQ[s/  
private int nSplitter; //Count of Splited Downloading File /H*n(d  
a[RqK#  
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public SiteInfoBean() -qpe;=g&f  
{//nSplitter的缺省值为5 .<Jq8J  
//default value of nSplitter is 5 U)D}J_Zi(  
this("","","",5); v8\pOI}c  
} uOb}R   
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) m,r>E%;Cj  
{ }M &hcw<  
sSiteURL= sURL; h/7_IuD  
sFilePath = sPath; a4eE/1  
sFileName = sName; ) -@Dh6F  
this.nSplitter = nSpiltter; #g]eDU-[  
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} BHDd^bd  
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g]U!]  
public String getSSiteURL() <Gz*2i  
{ +{cCKR
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return sSiteURL; F`5
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} I GB)  
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public void setSSiteURL(String value) (w?W
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{ zI'c'X1,  
sSiteURL = value; A&:~dZ:%w  
} V0y_c^x  
x_#'6H\1ga  
bOK0^$k  
public String getSFilePath() #w;%{C[D  
{ fU'[lZ  
return sFilePath; B)s%B'  
} :{~TG]4M  
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public void setSFilePath(String value) ~4M?[E&  
{ d*Kg_He-  
sFilePath = value; =p&uQ6.i+  
} e# KP3Lp  
:jGgX>GG  
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public String getSFileName() [+b&)jN*2  
{ %^bN^Sq -  
return sFileName; $%"~.L4  
} JvM:xy9  
E 7"`D\*  
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public void setSFileName(String value) @T~~aQFk  
{ r8Z} mvLM  
sFileName = value; e%KCcU  
} Kj*$'('  
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lVS.XQ2<  
public int getNSplitter() 'E%+ O  
{ ;a`I8Fj  
return nSplitter; ]SNcL[U  
} w'<"5F`  
)
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public void setNSplitter(int nCount) I=&Kn
@^  
{ 9l}G{u9a  
nSplitter = nCount; nrCr9#  
} 2w>yW]  
} YfVZ59l4y6  
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/* 8J8@0  
**Utility.java N@\`DO  
*/ io*iA<@Gx  
package NetFox; Dh .<&ri
 
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public class Utility { o7v,:e:  
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public Utility() pFwhvw  
{ CF/8d6}Vf  
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} \Wf1b8FW  
![{0Yw D  
//线程睡眠 S"Drg m.  
public static void sleep(int nSecond) ]McDN[h:  
{ g5~wdhpb  
try{ u51Lp  
Thread.sleep(nSecond); 7/6%92T/B  
}
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catch(Exception e) JI|MR#_u  
{ td(4Fw||1y  
e.printStackTrace (); 2q%vd
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} MLt'tzgl  
} n{xL1A=9  
;7N~d TBQ  
//日志 &9\8IR>  
public static void log(String sMsg) R9O1#s^  
{ Mt%=z9OLq9  
System.err.println(sMsg); hbE~.[Y2r  
} 3V@!}@y,F6  
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T#-U\C~o  
public static void log(int sMsg) E<L6/rG  
{ 3}2a3)  
System.err.println(sMsg); B"2#}HM  
} ,")/R/d  
} T:!Re*=JJ  
n@y*~sG]  
}TwSSF|}3  
/* vs(x;zpJ  
**TestMethod.java Hjc *WTu  
*/ cUc:^wvLS  
package NetFox; "&
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8d8GYTl b)  
KN"<f:u  
public class TestMethod { ZMmf!cKY:'  
~?uch8H  
qt4^e7o  
public TestMethod() 0M|Jvw'n|  
{ ///xx/weblogic60b2_win.exe )P #
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try{ eWTbHF  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Qs;MEt1  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); : 5<u!-}  
SiteFileFetch fileFetch = new SiteFileFetch(bean);
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fileFetch.start(); W4n(6esO  
} L3y`*&e>  
catch(Exception e){e.printStackTrace ();} n$y@a?al  
::8c pUc`f  
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} |!"qz$8fB  
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public static void main(String[] args) _X]S`e1F  
{ w~}.c:B  
new TestMethod(); 6'qu[~}Q  
} OmAa$L,'w  
} AIw<5lW  
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