http断点续传简单实现（java)

/* w  
**SiteFileFetch.java 8D6rShx =  
*/ \:D"#s%x  
package NetFox; HGl.dO7NU  
import java.io.*; A#KfG1K>  
import java.net.*; \zx$]|AQ  
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public class SiteFileFetch extends Thread { ['jr+gIfQ  
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SiteInfoBean siteInfoBean = null; //文件信息Bean $ n"*scyI  
long[] nStartPos; //开始位置 r%412#  
long[] nEndPos; //结束位置 `|WEz
W~  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 SBh"^q  
long nFileLength; //文件长度 Q]hl+C$d"/  
boolean bFirst = true; //是否第一次取文件 <tto8Y j  
boolean bStop = false; //停止标志 G;Py%8  
File tmpFile; //文件下载的临时信息 Y4Y~ep  
DataOutputStream output; //输出到文件的输出流 6'45c1e   
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） $L"h|>b\o  
public SiteFileFetch(SiteInfoBean bean) throws IOException X;7hy0Y  
{ (d>}Fp  
siteInfoBean = bean; _bn "c@s  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); )18C(V-x  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); O b'Br
  
if(tmpFile.exists ()) M2pFXU?]  
{ Z]08gH  
bFirst = false; X+kgx!u'y  
read_nPos(); ?Sr7c|a2  
} W^YaC (I  
else H*HL:o-[  
{ zvK'j"Wq=  
nStartPos = new long[bean.getNSplitter()]; sf"vii,1A  
nEndPos = new long[bean.getNSplitter()]; -CLBf'a  
} %U6A"?To  
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} kgh0  
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public void run() @Yn+ir0>O  
{ K5!OvqzG  
//获得文件长度 '<{Jlz(u9  
//分割文件 `j8pgnY>5~  
//实例FileSplitterFetch |]5`T9K@b#  
//启动FileSplitterFetch线程 b/?)_pg  
//等待子线程返回 "!ks7:}v  
try{ +{0v@6<(02  
if(bFirst)
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{ ?Wc+ J4  
nFileLength = getFileSize(); X0Wx\xDg[  
if(nFileLength == -1) ?j&ZzK'#^  
{ SY.ZEJcv  
System.err.println("File Length is not known!"); ! (Q[[M  
} |DYgc$2pN  
else if(nFileLength == -2) cn: L]%<  
{ ?dPr HSy  
System.err.println("File is not access!"); C\4d.~C:w3  
} >gDeuye  
else k~F;G=
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{ n?;h-KKO:  
for(int i=0;i<nStartPos.length;i++) `<{LW>Lb  
{
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); W-*HAS  
} {Fqwr>e  
for(int i=0;i<nEndPos.length-1;i++) C^;>HAK|F  
{ &u~Pp=kv  
nEndPos = nStartPos[i+1]; "j&'R#$&d  
} S+"Bq:u"  
nEndPos[nEndPos.length-1] = nFileLength; N<ux4tz  
} H32o7]lT  
} ]&N>F8.L+  
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//启动子线程 o".,JnbXl  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; YUHiD*  
for(int i=0;i<nStartPos.length;i++) ~KRS0^  
{ @v#,SF{  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &>B"/z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), z(>QGzyc  
nStartPos,nEndPos,i); +xvn n  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^Ua6.RH8  
fileSplitterFetch.start(); bLSc=f&  
} \Z,{De%  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), w$Fg0JS  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); { 0-on"o  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", M9""(`U  
nEndPos = " + nFileLength); m"'}{3$%  
// fileSplitterFetch[nPos.length-1].start(); $8xb|S[  
9K#3JyW*  
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//等待子线程结束 SZyORN  
//int count = 0; % P Ex  
//是否结束while循环 #]6{>n1*+w  
boolean breakWhile = false; J8i,[,KcE  
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while(!bStop) JSi0-S[Y{  
{ +'-.c"  
write_nPos(); Mn/@?K?y  
Utility.sleep(500); hl7 z1h  
breakWhile = true; NPS*
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for(int i=0;i<nStartPos.length;i++) g&y^r/  
{ dzBP<Xyh  
if(!fileSplitterFetch.bDownOver) as|w} $  
{ gFKJbjT|  
breakWhile = false; `d$@1  
break; ~!5=o{wy  
} #XA`n@2Uoo  
} !{(Bc8 hT  
if(breakWhile) tV
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break; RG""/x;  
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//count++; giX[2`^NG  
//if(count>4) R-j*fO}  
// siteStop(); eF22 ~P  
} .= ?*Wp  
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System.err.println("文件下载结束！"); ]5c(:T F  
} +IWH7qRtp  
catch(Exception e){e.printStackTrace ();} {V2"Pym?  
} +q'1P}e  
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//获得文件长度 v={{$=/t  
public long getFileSize() ur\6~'l4  
{ 7>__ fQu  
int nFileLength = -1; 3@Mh* \;\b  
try{ Qk:Lo*!  
URL url = new URL(siteInfoBean.getSSiteURL()); &Y=0 0  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `a4&_`E,p  
httpConnection.setRequestProperty("User-Agent","NetFox"); {g<D:"Q  
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int responseCode=httpConnection.getResponseCode(); )*;Tt @'y  
if(responseCode>=400) &Mk!qE<:N  
{ %S^hqC  
processErrorCode(responseCode); #f2k*8"eAF  
return -2; //-2 represent access is error !%,7*F(  
} _|#abLh%  
*9EwZwE_K  
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String sHeader; i D IY|  
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74  
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for(int i=1;;i++) G+8)a$?v  
{ W^tD6H;  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 0\tac/  
//Utility.log(in.readLine()); S} m=|3%y  
sHeader=httpConnection.getHeaderFieldKey(i); -[7+g  
if(sHeader!=null) #cfiN b}GX  
{ Yub}AuU`v  
if(sHeader.equals("Content-Length")) #c^]p/  
{ iWf+wC|  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 1_]X  
break; .n]"vpWm[  
} Xxg|01  
} NZvgkci_(u  
else yxt"vm;  
break; o72r `2  
} kw#X,hP  
} ;'n%\*+fHH  
catch(IOException e){e.printStackTrace ();} Z!"-LQJ  
catch(Exception e){e.printStackTrace ();} 6dIPgie3w  
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Utility.log(nFileLength); w.?4}'DK  
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return nFileLength; >3uNh:|>/  
} |H?t+Dyn)q  
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//保存下载信息（文件指针位置） k
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private void write_nPos() 'Lrn<  
{ lmeTW0U@9(  
try{ =NF0E8O  
output = new DataOutputStream(new FileOutputStream(tmpFile)); fN&\8SPE  
output.writeInt(nStartPos.length); zZ=SAjT QP  
for(int i=0;i<nStartPos.length;i++) A(FnU:  
{ Z =+Z96  
// output.writeLong(nPos); JQ03om--(  
output.writeLong(fileSplitterFetch.nStartPos); qbv\uYow3k  
output.writeLong(fileSplitterFetch.nEndPos); '=_(fa,  
} EQm{qc;  
output.close(); ?\V#^q-  
} E_ns4k#uG  
catch(IOException e){e.printStackTrace ();} ;4rhhh&  
catch(Exception e){e.printStackTrace ();} s;VW %e  
} dCd~]CI  
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//读取保存的下载信息（文件指针位置） u} ot-!}Q  
private void read_nPos() :$k*y%Z*N&  
{ 7:jLZ!mgi  
try{ XY"b90  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ;{ifLI0#  
int nCount = input.readInt(); "-Q+!byh  
nStartPos = new long[nCount]; F/oqYk9`  
nEndPos = new long[nCount]; v;]rFc#Px[  
for(int i=0;i<nStartPos.length;i++) yvd)pH<a2  
{ K[z)ts-  
nStartPos = input.readLong(); rwP#Yj[BK+  
nEndPos = input.readLong(); |+nmOi,z  
} <z<>E1ZLI  
input.close(); \,#$,dUXD  
} .&^
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catch(IOException e){e.printStackTrace ();} ,2FK$:M\  
catch(Exception e){e.printStackTrace ();} gm9*z.S\'  
} |}=eY?iXo  
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private void processErrorCode(int nErrorCode) !..<_qfw  
{ MmT/J1zM  
System.err.println("Error Code : " + nErrorCode); Bj@>iw?g'  
} *vb"mB  
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8 .%0JJ.3  
//停止文件下载 w!f2~j~  
public void siteStop() V^_
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{ @Xo*TJB  
bStop = true; #mQ@4k9i  
for(int i=0;i<nStartPos.length;i++) 8['R D`O  
fileSplitterFetch.splitterStop(); ]oGd,v X  
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} (y9KO56.V&  
} TQ"XjbhU;X  
//负责部分文件的抓取 dtTn]}J  
**FileSplitterFetch.java noWF0+%  
*/ '/>Mr!H#  
package NetFox; $)M3fZ$#  
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import java.io.*; Dz}i-tw+  
import java.net.*; 2`=jKt  
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public class FileSplitterFetch extends Thread { $TUYxf0q  
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String sURL; //File URL bn*:Bn1  
long nStartPos; //File Snippet Start Position u zZ|0  
long nEndPos; //File Snippet End Position l(>6Yq  
int nThreadID; //Thread's ID Y|tHU'x  
boolean bDownOver = false; //Downing is over _o~ pVBl/  
boolean bStop = false; //Stop identical E+
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FileAccessI fileAccessI = null; //File Access interface j<^!"_G]*?  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Z '5itN^  
{ @ m`C%7<  
this.sURL = sURL; L.;b(bFe  
this.nStartPos = nStart; Myc-lCE  
this.nEndPos = nEnd; Clf$EX;~  
nThreadID = id; 3fOOT7!FL  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 5:@b
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} | Y:`>2ev  
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public void run() //@6w;P  
{ j7!u;K^c  
while(nStartPos < nEndPos && !bStop) e'mF1al  
{ uEgR>X>  
?+}Su'pv}  
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try{ 9B~&d(Bm  
URL url = new URL(sURL); ~(GvjB/C8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); aImzK/  
httpConnection.setRequestProperty("User-Agent","NetFox"); Zfs-M)  
String sProperty = "bytes="+nStartPos+"-"; ~gX1n9_n  
httpConnection.setRequestProperty("RANGE",sProperty); ~<k>07  
Utility.log(sProperty); aR2N,<Cp5  
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b`e_}
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InputStream input = httpConnection.getInputStream(); `n>/MY  
//logResponseHead(httpConnection); s_ZPo6p  
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byte[] b = new byte[1024]; hk !=ZE3  
int nRead; 56C8)?  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) th{J;a  
{ #ed|0  
nStartPos += fileAccessI.write(b,0,nRead); !w7/G  
//if(nThreadID == 1) $z!G%PO1%  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); RZ
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} |k~AGc  
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Utility.log("Thread " + nThreadID + " is over!"); wXQu%F3  
bDownOver = true; i?^L",[  
//nPos = fileAccessI.write (b,0,nRead); 3?E7\\/R  
} ]O;*Y{:Y  
catch(Exception e){e.printStackTrace ();} EUSM4djL  
} \zU<o~gs  
} }wo:1v8J  
?Nt(sZ-  
jA"}\^%3  
//打印回应的头信息 \(LD<-a  
public void logResponseHead(HttpURLConnection con) j~_iv~[  
{ `NhG|g  
for(int i=1;;i++) 0$Tb5+H5  
{ DWtITO>  
String header=con.getHeaderFieldKey(i); >!5RY8+  
if(header!=null) 9{(q[C5m  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); zgFL/a<  
Utility.log(header+" : "+con.getHeaderField(header)); [%^0L~:  
else & *tL)qKDc  
break; XR]bd  
} `Fcr`[  
} Uic  
*& w/*h$!  

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public void splitterStop() 1E$\&*(  
{ ,|O6<u9  
bStop = true; 7zzFM  
} ~_i=hx  
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} 4Kt0}W  
nt"\FZ*;3  
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/* L_T+KaQCH  
**FileAccess.java A1;'S<a  
*//文件访问(定位，写) "%Ief4  
package NetFox; f#Ud=& >j  
import java.io.*; i<$?rB!i<1  
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public class FileAccessI implements Serializable{ QeT~s5 H  
cjtcEW  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 L{1[:a)']B  
RandomAccessFile oSavedFile; !r6Yq,3  
long nPos; 4h?@
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public FileAccessI() throws IOException &hZ.K"@7{  
{ 8LF=l1=~  
this("",0); +BM[@?"hrh  
} 45BpZ~-  
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public FileAccessI(String sName,long nPos) throws IOException g`Q!5WK*  
{ $mf O:%  
oSavedFile = new RandomAccessFile(sName,"rw"); QxbG-B^)=  
this.nPos = nPos; x8c>2w;6x^  
oSavedFile.seek(nPos); PYNY1|3  
} vo:h"ti  
*6][[)(  
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public synchronized int write(byte[] b,int nStart,int nLen) Myn51pczl  
{
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int n = -1; X]2x0  
try{ ,*9gy$  
oSavedFile.write(b,nStart,nLen); zgGJ<=G.  
n = nLen; YADXXQ"
 
} xEq?[M  
catch(IOException e) O`!XW8  
{ ml)\RL  
e.printStackTrace (); #N|JC d_  
} ,y-!h@(  
? 47"$=G  
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return n; f6\4,()  
} (+xT5 2  
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} !M)] 1Y
 
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/* (["V( $  
**SiteInfoBean.java oO7)7$|1  
*/ SY:ISzB}  
package NetFox; }Q\+w,pJgN  
YUTh*`1k<  
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public class SiteInfoBean { BW3Q03SW6  
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private String sSiteURL; //Site's URL K:VZ#U(_  
private String sFilePath; //Saved File's Path h3GUFiZ.  
private String sFileName; //Saved File's Name zmu+un"\j  
private int nSplitter; //Count of Splited Downloading File u|\?6fz  
\J#&]o)Y  
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public SiteInfoBean() egr"og{  
{//nSplitter的缺省值为5 ?|_i"*]l  
//default value of nSplitter is 5 oLq N  
this("","","",5);  V_
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} j B1ZF#  
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{6
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)  8}AWU  
{ =HV${+K=~  
sSiteURL= sURL; 0`v-pL0|  
sFilePath = sPath; #Jp|Cb<qx  
sFileName = sName; n{{"+;oR  
this.nSplitter = nSpiltter; rXBCM  
c4Q9foE   
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} xTH3g^E  
}7xcHVO8-  
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public String getSSiteURL() Wl+spWqW  
{ W1LR ,:$  
return sSiteURL; 5G`fVsb  
} R>5Xv%R  
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0S&J=2D!  
public void setSSiteURL(String value) [}l 90
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{ FJKlqM
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sSiteURL = value; Jf#-OlEQ  
} 0V86]zSo  
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public String getSFilePath() /?b{*<TK  
{ o=Mm=;H  
return sFilePath; \P"Ol\@  
} *XYp~b  
Z( "-7_  
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public void setSFilePath(String value) 5'V-Ly)*%  
{ \MdieO*  
sFilePath = value; Eht8~"fj  
} ][#|5UK8L  
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public String getSFileName() 6hcK%0z  
{ @o#Yq n3Y  
return sFileName; Nz*,m'-1e  
} -II03 S1  
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C?W}/r[  
public void setSFileName(String value) 1{a4zGE?[  
{ p8?"}  
sFileName = value; nqTOAL9FF  
} z[O*f#t  
vCK+v r!  
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public int getNSplitter() a0PU&o1EF  
{ \[)SK`cwd  
return nSplitter; VeY&pPQ  
} l]Ym)QP  
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public void setNSplitter(int nCount) Gxxz4   
{ B(} 'yY@%u  
nSplitter = nCount; e"{"g[b/7  
} {^:NII]  
} EQw7(r|v:  
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/* e{XzUY6  
**Utility.java Rh$+9w  
*/ y7rT[f/J  
package NetFox; s aHY9{)  
BgDWl{pm  
x%[NK[^&  
public class Utility { hsYE&Np_Q  
(ov&iNx  
"!eq~/nk  
public Utility() `CBXz!v!O  
{ ?2\oi*$  
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D/;[x{;E  
} YTTij|(  
sX*L[3!vN  
//线程睡眠 8|L@-F  
public static void sleep(int nSecond) pjoyMHWK  
{ loE;q}^  
try{ esQ`6i  
Thread.sleep(nSecond); UWK|_RT6SA  
} kCoE;)y$  
catch(Exception e) ]
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{ q"DHMZB  
e.printStackTrace (); dxH\H?NO  
} x
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} b353+7"|  
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//日志 ._<, Eodv  
public static void log(String sMsg) bKzG5|Qu  
{ D&G?Klq  
System.err.println(sMsg); Uq{$j5p8  
} 1wdc4>  
~Eb:AC5  
v<<ATs%w  
public static void log(int sMsg) _g( aO70Zu  
{ wi+L4v  
System.err.println(sMsg); Yo=$@~vN]  
} o~L(;A]yN  
} ~Lg ;7i1L  
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F#RNm5  
/* x2r.4  
**TestMethod.java W\5 -Yg(@  
*/ mpVD;)?JmM  
package NetFox; G`Z<a  
PlK3;  
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public class TestMethod { mO(Y>|mm  
so/0f1R?~  
J|^z>gP(  
public TestMethod() mh`uvqY  
{ ///xx/weblogic60b2_win.exe ur=:Ha  
try{ mW+5I-~  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); XzqB=iX  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); YktZXc?iI<  
SiteFileFetch fileFetch = new SiteFileFetch(bean); }A;YM1^$  
fileFetch.start(); F< 5kcu#iL  
} ;T8(byH ?  
catch(Exception e){e.printStackTrace ();} S#HeOPRL  
)PYh./_2  
%|^,Q
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} ?9!9lSH6%  
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public static void main(String[] args) L
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{ 5JK'2J&  
new TestMethod(); %g89eaEZ  
} B!8X?8D  
} 8faT@J'e;  
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