http断点续传简单实现（java)

/* '[V}]Z>-  
**SiteFileFetch.java *c9/ I  
*/ jzt$  
package NetFox; aAJ'0xnj  
import java.io.*; :!Ea.v  
import java.net.*; 5'*v-l,[  
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public class SiteFileFetch extends Thread { S&N[@G  
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SiteInfoBean siteInfoBean = null; //文件信息Bean x=]PE}<E  
long[] nStartPos; //开始位置 2?J[D7  
long[] nEndPos; //结束位置 T-S6`^_L  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Qv4g#jX{  
long nFileLength; //文件长度 D_VAtz  
boolean bFirst = true; //是否第一次取文件 Twl>Pn>  
boolean bStop = false; //停止标志 *PEk+e  
File tmpFile; //文件下载的临时信息 0@ccXFE  
DataOutputStream output; //输出到文件的输出流 4K{<R!2I  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） <e)5$Aj  
public SiteFileFetch(SiteInfoBean bean) throws IOException <?h
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{ (^,4{;YQ5  
siteInfoBean = bean; u6tD5Y  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); !5FZxmUup  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ;]/>n:[E  
if(tmpFile.exists ()) "kHFt|%@  
{ A|Z'\D0  
bFirst = false; o$disJ  
read_nPos(); CI%4!K;{  
} TX/Ng+v S  
else n_ORD@$]  
{ p{c+ +P5  
nStartPos = new long[bean.getNSplitter()]; N!RkV\:X  
nEndPos = new long[bean.getNSplitter()]; U5_1-wV  
} c:>&iB-Yu  
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} JrZ"AId2  
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public void run() b3$aPwv  
{ [ QHSCF5  
//获得文件长度 %#g9d  
//分割文件 9#C hn~ \  
//实例FileSplitterFetch e(t,~(  
//启动FileSplitterFetch线程 8~q%H1[I\N  
//等待子线程返回 ;}/@ar7s3  
try{ KNH.4A ,  
if(bFirst) r0 mXRZC  
{ vbXZZ  
nFileLength = getFileSize(); +*Um:}&  
if(nFileLength == -1) pzL !42  
{ ctqXzM `  
System.err.println("File Length is not known!"); iobL6SUZ  
} 0H<&*U_V  
else if(nFileLength == -2) qQzf&"  
{ +aa( YGL  
System.err.println("File is not access!"); {Vg8pt  
} Yr7%C  
else io8c[#"uU  
{ ?uiQ'}
 
for(int i=0;i<nStartPos.length;i++) e<Pbsj  
{ $]H^?  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); \(m_3 H  
} aDXdr\C6  
for(int i=0;i<nEndPos.length-1;i++) H?ZlJ|/c  
{ 7F=Xn@ _  
nEndPos = nStartPos[i+1]; EKwA1,Xz  
} : 5=E>!  
nEndPos[nEndPos.length-1] = nFileLength; e7fA-,DV  
} A$w0+&*=  
} $8kQM  
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//启动子线程 X[F<sxw  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; / /ty]j  
for(int i=0;i<nStartPos.length;i++) O^tH43C  
{ !kzC1U  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 86.LkwlqoH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), )@%wj;>a  
nStartPos,nEndPos,i); A>SXc%K  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,<,ige  
fileSplitterFetch.start(); $M `%A  
} iGCA>5UE  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), a-P'h1hbH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); "ZuhN(-`  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", -85]x)JE  
nEndPos = " + nFileLength); Z @:5vo  
// fileSplitterFetch[nPos.length-1].start(); u!iBAr5  
,}9G|$  
 rkp 1tv  
//等待子线程结束 bC[TLsh7{2  
//int count = 0; 'eKvt5&@  
//是否结束while循环 N{lj"C]L  
boolean breakWhile = false; /hC[>t<  
st8=1}:&\  
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while(!bStop) cyR K&J  
{ a,B2;4"  
write_nPos(); 1-HL#y*7$  
Utility.sleep(500); a{?`yO/ 2  
breakWhile = true; _.Ey_K_1  
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for(int i=0;i<nStartPos.length;i++) lu]Z2xSv  
{ }Pu|%\  
if(!fileSplitterFetch.bDownOver) gH{X?  
{ &) '5_#S  
breakWhile = false; yQ^k%hHa  
break; I=N;F6  
} bu;3Ib3\  
} ,&wTUS\  
if(breakWhile) D][e u
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break; M7$ h  
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//count++; Jd].e=]pN  
//if(count>4) {I/|7b>@r  
// siteStop(); lnXb]t
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} s_`PPl_D$K  
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System.err.println("文件下载结束！"); 2r3]DrpJ  
} /}_OCuJJ,  
catch(Exception e){e.printStackTrace ();}  -jBk  
} fS( )F*J  
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//获得文件长度 n?@3+wG  
public long getFileSize() UfE41
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{ @<GVY))R8  
int nFileLength = -1; ?q}XDc  
try{ LGxQ>f[V  
URL url = new URL(siteInfoBean.getSSiteURL()); ?DAW~+,!7o  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); P'4oI0Bw  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1|_8+)i;  
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int responseCode=httpConnection.getResponseCode(); aFI?^"L  
if(responseCode>=400) ,bv?c@  
{ 3 cd5g  
processErrorCode(responseCode); ##%R|P3  
return -2; //-2 represent access is error R]oi&"H@r)  
} u )'l|Y  
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String sHeader; Tk9/1C{8  
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for(int i=1;;i++) In-W,   
{ 9fWr{fx  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); N9W\>hKaeh  
//Utility.log(in.readLine()); D,aJ`PK~  
sHeader=httpConnection.getHeaderFieldKey(i); Z;/"-.i  
if(sHeader!=null) C:$12{I?*  
{ QK+s}ny  
if(sHeader.equals("Content-Length")) 'O#,;n  
{  eRlJ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); &"V%
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break; Jm%hb,  
} ^1&xt(G  
} .x$!
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else (qE*z  
break; $,vZX u|Qw  
} {H$F!}a  
} !fFmQ\|)4S  
catch(IOException e){e.printStackTrace ();} )~hsd+ 0t
 
catch(Exception e){e.printStackTrace ();} !Ua74C
 
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Utility.log(nFileLength); e`1,jt'  
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return nFileLength; |51z&dG  
} )^&,[Q=i  
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//保存下载信息（文件指针位置）  b;!oPT  
private void write_nPos() st;.Po[h  
{
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try{ Dh*>361y-  
output = new DataOutputStream(new FileOutputStream(tmpFile)); y{Wtm7fnA  
output.writeInt(nStartPos.length); #S[:Q.0 ;  
for(int i=0;i<nStartPos.length;i++) G0sg\]  
{ C[j'0@~V:B  
// output.writeLong(nPos);  T)o)%Yv  
output.writeLong(fileSplitterFetch.nStartPos); ;SBM
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output.writeLong(fileSplitterFetch.nEndPos); @Q"%a`mKH  
} ^s@?\v  
output.close(); ~lx5RTkp  
} wW4/]soM  
catch(IOException e){e.printStackTrace ();} S.o@95M  
catch(Exception e){e.printStackTrace ();} opz.kP[e,  
} H6<\7W89y  
\ H#zRSbZ  
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//读取保存的下载信息（文件指针位置） "FC;k >m  
private void read_nPos() T-=sC=sS,  
{ -I1Ne^DZn4  
try{ )Cuc]>SC  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); j)Z3m @Ii5  
int nCount = input.readInt(); ~+VIELU<%  
nStartPos = new long[nCount]; (rcH\   
nEndPos = new long[nCount]; &~ g||rq  
for(int i=0;i<nStartPos.length;i++) l?_Iu_Qp  
{ saOXbt(&  
nStartPos = input.readLong(); ;0V{^  
nEndPos = input.readLong(); XVi?-/2  
} GgH=w`;_  
input.close(); f=v+D0K$n  
} N|eus3\E  
catch(IOException e){e.printStackTrace ();} ~4th;#'  
catch(Exception e){e.printStackTrace ();} @?_<A%hz  
} qyMR
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private void processErrorCode(int nErrorCode) Y_&D W4  
{ zJWh  
System.err.println("Error Code : " + nErrorCode); I:s#,!>  
} TY"=8}X1  
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//停止文件下载 3_(fisvx  
public void siteStop() %WrUu|xj>_  
{ be`\O  
bStop = true; ,R=Mr}@u
 
for(int i=0;i<nStartPos.length;i++) C?Dztkz  
fileSplitterFetch.splitterStop(); 4oLrCQZ\  
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} %n`wU-?lK  
} z65|NO6JW.  
//负责部分文件的抓取 SP9_s7LL  
**FileSplitterFetch.java lz 
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*/ f>
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package NetFox; _X{ihf  
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import java.io.*; Ip]-OVg  
import java.net.*; 8>G3KZ3  
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public class FileSplitterFetch extends Thread { #_{3W-35*  
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String sURL; //File URL c@)k#/[[b  
long nStartPos; //File Snippet Start Position ^-T!(P:  
long nEndPos; //File Snippet End Position IbQ3*  
int nThreadID; //Thread's ID ~4o2!!^tI  
boolean bDownOver = false; //Downing is over Q9)/INh  
boolean bStop = false; //Stop identical ,qJ/Jt$A  
FileAccessI fileAccessI = null; //File Access interface
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException W[A;VOj0$  
{ fB[I1Z  
this.sURL = sURL; O<l_2?S1  
this.nStartPos = nStart; M(o?I}  
this.nEndPos = nEnd; l)`bm/k]V  
nThreadID = id; j,QeL  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ~a&s5E {  
} F!jYkDY  
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public void run() tUl#sqN_{  
{ G8OLx+!0e  
while(nStartPos < nEndPos && !bStop) u|ia  
{ xlF$PpRNM  
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try{ 8D[P*?O  
URL url = new URL(sURL); &;5QB  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6rMGlzuRo  
httpConnection.setRequestProperty("User-Agent","NetFox"); D]v=/43  
String sProperty = "bytes="+nStartPos+"-"; }s{RW<A  
httpConnection.setRequestProperty("RANGE",sProperty); )s1W)J?8  
Utility.log(sProperty); tsR\cO~/  
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InputStream input = httpConnection.getInputStream(); t8 g^W K  
//logResponseHead(httpConnection); hv te)  
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byte[] b = new byte[1024]; a)GLz  
int nRead; *A.E?9pL\  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) %CJgJ,p
k>  
{ TO.?h!  
nStartPos += fileAccessI.write(b,0,nRead); W4
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//if(nThreadID == 1) #+V-65v  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <SmXMruU  
} mR:G,XytxM  
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Utility.log("Thread " + nThreadID + " is over!");  UN[rW0*  
bDownOver = true; {\ vj":  
//nPos = fileAccessI.write (b,0,nRead); i>i@r ;:|  
} Ss+e*e5Ht  
catch(Exception e){e.printStackTrace ();} bIt%KG{PY6  
} ~|kre:j9  
} &yN@(P)  
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% \Nfj)9  
//打印回应的头信息 2,?4'0Z@R  
public void logResponseHead(HttpURLConnection con) j#r|t
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{ 74hGk
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for(int i=1;;i++) 0TK+R43_  
{ 2[: *0 DV#  
String header=con.getHeaderFieldKey(i); / 2>\Z(  
if(header!=null) znv2
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); XNkw9*IT  
Utility.log(header+" : "+con.getHeaderField(header)); )?RR1P-ID  
else o,(MB[|hQ  
break; WgPpW!`  
} K4NB#
 
} 2i`N26On  
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public void splitterStop() y)o!F^  
{ TcA+ov>TD  
bStop = true; Y,z15i3j?  
} pB;)Hii\  
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} LM}0QL m?  
*&{M,  
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/* JnE
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**FileAccess.java .q#2 op  
*//文件访问(定位，写) hGyi@0  
package NetFox; c<)C3v  
import java.io.*; :J` *@cDn  
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public class FileAccessI implements Serializable{ {t`UV,  
(cJb/|?3  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 GY 4?}T^s  
RandomAccessFile oSavedFile; MB;<F  
long nPos; m~ :W$x1+  
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public FileAccessI() throws IOException JVE]Qb_  
{ Ex^|[iV  
this("",0); 1~NXCIdF  
} ) '"@L7U  
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public FileAccessI(String sName,long nPos) throws IOException }3 NGMGu$  
{ ]X/1u"  
oSavedFile = new RandomAccessFile(sName,"rw"); (NrH)+)J!a  
this.nPos = nPos; Ld6j;ZJ';  
oSavedFile.seek(nPos); uSp=,2)  
} gK7j~.bb"  
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public synchronized int write(byte[] b,int nStart,int nLen) l}B,SkP^  
{ 2ijw g~_@  
int n = -1; !/O c)Yk  
try{ qYZ\<h^  
oSavedFile.write(b,nStart,nLen); j;@7
V4'  
n = nLen; l<0BMwS8  
} LQ pUyqR  
catch(IOException e) *+TIF"|1  
{ U&#1qRm\h  
e.printStackTrace (); +*-u_L\'  
} Q?rb(u(  
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return n; w.exLC  
} v{9< ATi  
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} +V*FFv  
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/* 0kP,Z
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**SiteInfoBean.java &qqS'G*  
*/ Uv'.]#H<  
package NetFox; GWa_^  
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public class SiteInfoBean { sxcpWSGA^  
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/pzEL  
private String sSiteURL; //Site's URL 3#vhQ*xU  
private String sFilePath; //Saved File's Path fhlhlOg  
private String sFileName; //Saved File's Name H@Dj$U  
private int nSplitter; //Count of Splited Downloading File ;,GE!9HW  
\2,7fy'  
|NFX"wv:c<  
public SiteInfoBean() aV`4M VWOz  
{//nSplitter的缺省值为5 \v.16obH  
//default value of nSplitter is 5 o<2H~2/  
this("","","",5); DP`$gd  
} rQgRD)_%w  
6+HpN"?e  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) X]d["  
{ l%@>)%LA  
sSiteURL= sURL; >(+g:p  
sFilePath = sPath; g@]G [(  
sFileName = sName; +4U?*:n  
this.nSplitter = nSpiltter; T.nY>Q8  
{X$8yy2zC5  
!X721lNP  
} .z7%74p  
j<w";I&Diz  
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public String getSSiteURL() A\J|eSG'$  
{ !DFT}eu  
return sSiteURL; yAOYe"d  
} @Q~Oc_z  
"1P8[  
#:"F-3A0  
public void setSSiteURL(String value) 7+';&2M)n~  
{ c0M=T  
sSiteURL = value; X=]FVHV;  
} )+
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6c-y<J+&s  
public String getSFilePath() f%ude@E3  
{ 2VaQxctk  
return sFilePath; =y.!Ny5A  
} y)N57#e  
o#Q0J17i?  
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public void setSFilePath(String value) td{M%D,R"  
{  9')  
sFilePath = value; :X7"fX  
} D4WvRxki  
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public String getSFileName() pX3Q@3,$  
{ 8/cD7O  
return sFileName; Y(QLlJ*)/  
} Ia-`x/r*m  
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public void setSFileName(String value) CC,_I>t  
{ :^".cs?g  
sFileName = value; luD.3&0n  
} *|S.[i_7  
%:rct  
4L}i`)CmB  
public int getNSplitter() 1j7^2Y|UT`  
{  meQ>mW  
return nSplitter; }& ;49k  
} YSi[s*.G  
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public void setNSplitter(int nCount) rMkoE7n  
{ !#P|2>>u  
nSplitter = nCount; 63R?=u@  
} _kR);\V.8  
} yxq+<A4,a  
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/* K^0cL%dB  
**Utility.java KICy! "af  
*/ aq/'2U 7  
package NetFox; tHgn-Dhzr  
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public class Utility { r9[{0y!4  
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public Utility() CSF-2lS
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{ FJ]BB4 K  
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} z3RD*3b  
U1zcJl^  
//线程睡眠 m]t`;lr<  
public static void sleep(int nSecond) P~Ss\
PT  
{ 4LY kK/:  
try{ nk8jXZ"w  
Thread.sleep(nSecond); Ubtu?wRBW  
} Y"J' 'K  
catch(Exception e) q)S70M_1  
{ x;d*?69f]  
e.printStackTrace (); Uu
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} [k)xn3[  
} 78'HE(*  
w
@ 1g_dy  
//日志 C>\0 "}iD  
public static void log(String sMsg) h>>KH*dQ  
{ " sh%8 <N  
System.err.println(sMsg); 9X<o8^V  
} Z!\xVCG"q  
8}9B*m  
?"oW1a\  
public static void log(int sMsg) ;2lKo="  
{ 'F3cvpc`  
System.err.println(sMsg); D vG9(Eh  
} QU0FeGtz  
} ]&l.-0jt  
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2M`]nAk2a  
/* ?LE\pk R  
**TestMethod.java $$my,:nH  
*/ <_X`D4g]XO  
package NetFox; !V|%n(O"  
v X=zqV  

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public class TestMethod { 34k}7k~n  
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kxp  
cBxBIC  
public TestMethod() /]pBcb|<  
{ ///xx/weblogic60b2_win.exe .Pz( 0Y  
try{ .Z[Bz7  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 3]Jl\<0  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); VXr'Z  
SiteFileFetch fileFetch = new SiteFileFetch(bean); (N63k1M  
fileFetch.start(); =b\k$WQ_(  
} }6YD5?4  
catch(Exception e){e.printStackTrace ();} !nX}\lw  
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} ~nul[>z  
!VNLjbee.  
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public static void main(String[] args) P3[!-sv  
{ QL_~E;U  
new TestMethod();  {@XzY>  
} 5v1f?btc  
} kJ
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