http断点续传简单实现（java)

/* mcpM<vY/H  
**SiteFileFetch.java xQ^zX7  
*/ P< O[S  
package NetFox; bh3}[O,L A  
import java.io.*; q*mNVBy  
import java.net.*; 2u*o/L+  
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public class SiteFileFetch extends Thread { # 0dN!l;  
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SiteInfoBean siteInfoBean = null; //文件信息Bean GTeFDm;T^  
long[] nStartPos; //开始位置 O!\P]W4r$  
long[] nEndPos; //结束位置 (w-z~#<  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 o(u&n3Q'  
long nFileLength; //文件长度 4=%Uv^M  
boolean bFirst = true; //是否第一次取文件  .]k+hc`  
boolean bStop = false; //停止标志 .MXznz  
File tmpFile; //文件下载的临时信息 |Eu_K`  
DataOutputStream output; //输出到文件的输出流 9.!6wd4mw  
*rXESw]BR  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Wr a W  
public SiteFileFetch(SiteInfoBean bean) throws IOException (I IPrW;>  
{ gG>1  
siteInfoBean = bean; m$NBGw  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); o )G'._  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); +%OINMo.A  
if(tmpFile.exists ()) t>)iC)^u
 
{ 'nz;|6uC  
bFirst = false; 1`^l8V(  
read_nPos(); o+4/L)h  
} ] QGYEjW  
else wc*5s7_  
{ j&6,%s-M`a  
nStartPos = new long[bean.getNSplitter()]; mSp-  
nEndPos = new long[bean.getNSplitter()]; *`mPPts}  
} zH0%; o}  
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} o]t6u .L  
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public void run() OL4I}^*,  
{ ! @{rkp  
//获得文件长度 1P. W 34  
//分割文件 ^VK-[Sz&  
//实例FileSplitterFetch Nwr.mtvh  
//启动FileSplitterFetch线程 :3^b>(W.  
//等待子线程返回 11glFe  
try{ %<lfe<;^t  
if(bFirst) (%}T\~`1z#  
{ 0#pjfc `:  
nFileLength = getFileSize(); kTb.I;S  
if(nFileLength == -1) <W~5;m  
{ (o~f6pNB,  
System.err.println("File Length is not known!"); M#LQz~E  
} }S<2({GI  
else if(nFileLength == -2) LZch7Xe3  
{ jJkM:iR  
System.err.println("File is not access!"); D9zw' RY  
} rlT[tOVAY  
else XSyCT0f08  
{ lhw]?\  
for(int i=0;i<nStartPos.length;i++) gh=s#DQsFw  
{ F1JSf&8  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); %Koc^ pb)  
} 4:q<<vCJv  
for(int i=0;i<nEndPos.length-1;i++) kMWu%,s4  
{ bj\v0NKN4  
nEndPos = nStartPos[i+1]; {_0Efc=7  
} WMnR+?q  
nEndPos[nEndPos.length-1] = nFileLength; JZQkr  
} ] e!CH <N  
} c9-$td&  
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//启动子线程 7F;"=DarOE  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; bN$`&fC
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for(int i=0;i<nStartPos.length;i++) )67_yHW  
{ `au(' xi<  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), z`qBs  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), hLPg=8nJ_  
nStartPos,nEndPos,i); ; Xrx>( n  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); RIOR%~U  
fileSplitterFetch.start(); 79U Th@r}  
} +M
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), vpcHJ^19  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); wUWSW<  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", u 'DM?mV:-  
nEndPos = " + nFileLength); ]as_7  
// fileSplitterFetch[nPos.length-1].start(); #t:]a<3Y2  
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//等待子线程结束 Zx,R6@l  
//int count = 0; E{kh)-  
//是否结束while循环 AWHB^}!}  
boolean breakWhile = false; aehGT|  
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while(!bStop) 4o8uWS{`  
{ 5W"nn  
write_nPos(); mA}-hR%  
Utility.sleep(500); ^29w
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breakWhile = true;
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 Q];gC{I  
for(int i=0;i<nStartPos.length;i++) ,C2qP3yg  
{ "u5Hm ^H  
if(!fileSplitterFetch.bDownOver) }$!bD  
{ Ni*f1[sI<  
breakWhile = false; o"~ODN"L  
break; @/*{8UBP  
} [RCUP.  
} LWHP31{R  
if(breakWhile) [?x9NQ{  
break; WLW'.  
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//count++; 0h-holUf}~  
//if(count>4) biG=4?Xl  
// siteStop(); Tl5K'3  
} zqfv|3-!}  
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System.err.println("文件下载结束！"); :b
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} }3:DJ(Y  
catch(Exception e){e.printStackTrace ();} *#1&IJPI  
} >Z?fX  
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//获得文件长度 WXu:mv,'e  
public long getFileSize() eT1b88_  
{ *vv<@+gA  
int nFileLength = -1; aSd$;t~  
try{ | qtdmm  
URL url = new URL(siteInfoBean.getSSiteURL()); KY H*5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); X).UvPZ/  
httpConnection.setRequestProperty("User-Agent","NetFox"); l%\3'N]  
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int responseCode=httpConnection.getResponseCode(); r \H+=2E'  
if(responseCode>=400) o6sL~*hQ  
{ Mm`jk%:%]  
processErrorCode(responseCode); au7%K5  
return -2; //-2 represent access is error g]85[xz  
} 
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String sHeader; r)Ts(#Z  
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for(int i=1;;i++) BM=`zGh"  
{ `?LQd2p  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); c_c]0Tm  
//Utility.log(in.readLine()); ;tTM3W-h  
sHeader=httpConnection.getHeaderFieldKey(i); ,!t1( H  
if(sHeader!=null) B04%4N.g"X  
{ %41dVnWB^4  
if(sHeader.equals("Content-Length")) UgDai?b1  
{ -q' np0H  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); DfwxPt#
 
break; (1H_V(  
} L;/#D>U(  
} %F-/|x1#Q  
else T
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break; fv$Y&_,5  
} cnvxTI<  
}  A]R7H1  
catch(IOException e){e.printStackTrace ();} ^tX+<X  
catch(Exception e){e.printStackTrace ();} / U1VE|T  
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Utility.log(nFileLength); " ] 0ER  
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return nFileLength; @QI]P{  
} k1Zu&4C\  
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//保存下载信息（文件指针位置） vR`-iRQ?_  
private void write_nPos() &&$/>[0=.  
{ zrk/}b0j  
try{ !e@G[%k  
output = new DataOutputStream(new FileOutputStream(tmpFile)); rubqk4  
output.writeInt(nStartPos.length); }'$6EgX  
for(int i=0;i<nStartPos.length;i++) I8HUH*|)n  
{ {:m5<6?x)  
// output.writeLong(nPos);
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output.writeLong(fileSplitterFetch.nStartPos); uA=6 HpDB  
output.writeLong(fileSplitterFetch.nEndPos); oc'#sE  
} 2+"=i/8  
output.close(); .O @bX)  
} 1<A+.W  
catch(IOException e){e.printStackTrace ();} fHvQ9*T  
catch(Exception e){e.printStackTrace ();} YS=|y}Q|7d  
} [W=%L:Ea  
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//读取保存的下载信息（文件指针位置） d='z^vHK  
private void read_nPos() piJ/e  
{ *cCr0\Z`  
try{ pC(AM=RY!  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); *LcLYxWo  
int nCount = input.readInt(); zr@Bf!VG:  
nStartPos = new long[nCount]; i0/gyK  
nEndPos = new long[nCount]; s([9/ED  
for(int i=0;i<nStartPos.length;i++) %(;jx  
{ C&D]!ZvF  
nStartPos = input.readLong(); ]W<E#^  
nEndPos = input.readLong(); I=D{(%+^d  
} -cyJjLL*  
input.close(); ;d G.oUk=  
} 5Zs"CDU  
catch(IOException e){e.printStackTrace ();} RI w6i?/I  
catch(Exception e){e.printStackTrace ();} $t.N|b`'  
} }#zE`IT  
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private void processErrorCode(int nErrorCode) B) &BqZ&  
{ 0uzis09  
System.err.println("Error Code : " + nErrorCode); HP|,AmVLl  
} =sRd5aMs  
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. hHt+  
//停止文件下载 i_g="^
 
public void siteStop() 9 U1)sPH;  
{ +A W6 >yV`  
bStop = true; QI~s~j  
for(int i=0;i<nStartPos.length;i++) \sHM[nF0  
fileSplitterFetch.splitterStop(); g_;5
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} -qfd)A6]  
} 9UOx~Ty  
//负责部分文件的抓取 1
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**FileSplitterFetch.java %_M B-  
*/ ~U*2h =]  
package NetFox; ']$ttfJB  
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import java.io.*; dDW],d}B;  
import java.net.*; RUf,)]Vvk  
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public class FileSplitterFetch extends Thread { v3S{dX<  
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String sURL; //File URL %xxe U  
long nStartPos; //File Snippet Start Position Bp^>R`,  
long nEndPos; //File Snippet End Position vtR<(tOu@  
int nThreadID; //Thread's ID T1PWFw\GH  
boolean bDownOver = false; //Downing is over <y*#[:i  
boolean bStop = false; //Stop identical 8/b_4!5c  
FileAccessI fileAccessI = null; //File Access interface 0'^? m$  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException )
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{ *bn9j>|iv  
this.sURL = sURL; A42At]  
this.nStartPos = nStart; \_@u"+,$W  
this.nEndPos = nEnd; =%Ut&6}sQ  
nThreadID = id; 5 W(iU  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 -iBu:WyY$  
} mwbkXy;8  
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public void run() 4TG|  
{ j /-p3#c  
while(nStartPos < nEndPos && !bStop) )t&|oQ3sVG  
{ C'n 9n!hR  
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try{ A40 -])'!  
URL url = new URL(sURL); PG<N\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ":]O3 D{r  
httpConnection.setRequestProperty("User-Agent","NetFox"); rorzxp{  
String sProperty = "bytes="+nStartPos+"-"; `<HY$PAe  
httpConnection.setRequestProperty("RANGE",sProperty); \Zoo9Wy  
Utility.log(sProperty); !"2OcDFx  
}E>2U/wpXY  
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InputStream input = httpConnection.getInputStream(); "T}J|28Z  
//logResponseHead(httpConnection); pe,c  
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byte[] b = new byte[1024]; ]Wd{4(b  
int nRead; 42z9N\ f  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ?N11R?8  
{ A*E4
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nStartPos += fileAccessI.write(b,0,nRead); ,z%F="@b9  
//if(nThreadID == 1) Crpkq/M  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); bs+KcY:N]  
} cR@z^  
s
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Utility.log("Thread " + nThreadID + " is over!"); J\;~(: ~  
bDownOver = true; M?nnpO  
//nPos = fileAccessI.write (b,0,nRead);  .)cOu>  
} &`>*3m(  
catch(Exception e){e.printStackTrace ();} 2vWkAC;   
} ` |]6<<'iW  
} 2"__jp:(  
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+\:I3nKs%  
//打印回应的头信息 N`iK1n4X  
public void logResponseHead(HttpURLConnection con) X]1ep  
{ X/7: *  
for(int i=1;;i++) ,\=u(Y\I[  
{ 1>1|>%  
String header=con.getHeaderFieldKey(i); {'!D2y.7g  
if(header!=null) Do_L  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); u'32nf?  
Utility.log(header+" : "+con.getHeaderField(header)); VwC,+B  
else jC\R8_  
break; ^<% w'*gR  
} uxh4nyE  
} k*M{?4  
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public void splitterStop() Ix *KL=MG  
{ 'HqAm$
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bStop = true; >_F&oA#  
} AOWI`  
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} uO^{+=;A=  
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/* %pwm34  
**FileAccess.java MfL q h  
*//文件访问(定位，写) ^k)f oD  
package NetFox; kW,
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import java.io.*; e.HN%LrhS  
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public class FileAccessI implements Serializable{ rg'? ?rq  
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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 3BSeZ:j7  
RandomAccessFile oSavedFile; s-C.+9  
long nPos; M?\)&2f[Z  
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public FileAccessI() throws IOException uj:w^t ][  
{ Y]Fq)-  
this("",0); Vy/g;ZPU1  
} +s S*EvF  
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public FileAccessI(String sName,long nPos) throws IOException 5#fLGXP  
{ C$(t`G  
oSavedFile = new RandomAccessFile(sName,"rw"); 6*LU+U=`  
this.nPos = nPos; Ha/\&Z(  
oSavedFile.seek(nPos); tTmFJ5  
} C$%QVcf  
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#|CG %w  
public synchronized int write(byte[] b,int nStart,int nLen) PO}Q8Q3  
{ h:GOcLYM@X  
int n = -1; 3] @<.  
try{ RB\WttI  
oSavedFile.write(b,nStart,nLen); W4#:_R,&,  
n = nLen; 1mjv~W  
} 9
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catch(IOException e) _*;cwMne-  
{ >WD^)W fa  
e.printStackTrace (); I{Kc{MXn  
} z)]EB6uRg  
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return n; lGM3?AN  
} BT#>b@Xub  
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} BsRas  
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/* ,Utw!]  
**SiteInfoBean.java SP*5 W)6  
*/ ,AD| u_pP  
package NetFox; M\<!m^~  
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public class SiteInfoBean { Mb9q<4  
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private String sSiteURL; //Site's URL H@3+K$|v  
private String sFilePath; //Saved File's Path #0P
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private String sFileName; //Saved File's Name 5\'%zZ,l  
private int nSplitter; //Count of Splited Downloading File 0F3>kp4u  
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public SiteInfoBean() i&30n#  
{//nSplitter的缺省值为5 1Efl|lV  
//default value of nSplitter is 5 "p;DQ-V  
this("","","",5); .{;!bw
 
} <s2l*mc  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) S]o  
{ ?dmMGm0T9  
sSiteURL= sURL; \}Wkj~IX  
sFilePath = sPath; I[`2MKh  
sFileName = sName; !Q3Snu=  
this.nSplitter = nSpiltter; %zD-gw>  
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} KALg6DZe:  
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public String getSSiteURL() iR_Syk`G*A  
{
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return sSiteURL; _l,Z38  
} P3yiJ|vP  
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1;xw)65  
public void setSSiteURL(String value) =5/;h+bk+3  
{ PHK#b.B>a8  
sSiteURL = value; 0;H6b=  
} t?
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public String getSFilePath() ^sOm7S{  
{ Fp6Y Y  
return sFilePath; {l11WiqQH  
} =zjUd 5  

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public void setSFilePath(String value) sKuTG93sr@  
{ 9v F2aLPk  
sFilePath = value; JAb?u.,Ns_  
} PM.SEzhm  
)c'>E4>  
{e%abr_B  
public String getSFileName() ThlJhTh<%4  
{ >a7(A#3@d
 
return sFileName; ]18ygqt  
} pu:D/2R2;k  
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public void setSFileName(String value) 5y3TlR  
{ Crhi+D  
sFileName = value; /8MQqZ C  
} #VV.
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KYu(H[a  
public int getNSplitter() Y+ Z9IiS7  
{ $ tNhwF  
return nSplitter; "k<:a2R  
} 1(i>Vt.+  
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public void setNSplitter(int nCount) U+"=  
{ `zp2;]W  
nSplitter = nCount;
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} {&#~t4  
} y<1$^Y1/
)  
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/* e^NEj1  
**Utility.java  ;Zq~w
 
*/ V0Z7o\-J  
package NetFox; Hm VTfH'  
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public class Utility { "x;k'{S  
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public Utility() =_=Z;#`cXk  
{ 06^1#M$'  
j 3MciQ`  
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} Dum`o^l#  
bfJ`}xl
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//线程睡眠 3EVC8ue  
public static void sleep(int nSecond) Ke?gz:9j  
{ KKjxg7{K  
try{ +z=%89GJ  
Thread.sleep(nSecond); Dsj|~J3  
} ~y
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catch(Exception e) S[~O')  
{ cN WcNMm  
e.printStackTrace (); =/g$bZ  
} Ydh<TF4!  
} 9V;$v  
uUz`=4%A  
//日志 ! F <] T
 
public static void log(String sMsg) =*g$#l4  
{ |R;l5ZKvV  
System.err.println(sMsg); ^Y7/Ow  
}
}utNZhJ  
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public static void log(int sMsg) E ;!<Z4  
{ *?bk?*?s  
System.err.println(sMsg); =kb6xmB^t  
} #t@x6Vt  
} d{yIy'+0/  
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/* XalJo@%-  
**TestMethod.java 9c6GYWIFt&  
*/ h ??C4z  
package NetFox; A!{.|x[S44  
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public class TestMethod { *NW QmC~  
;4G\]%c)E{  
t@(9ga(  
public TestMethod() /> 3  
{ ///xx/weblogic60b2_win.exe KR=d"t Qw  
try{ 2]D$|M?$~  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); /c@*eU  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); >7nV$.5S  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 5e)6ua,  
fileFetch.start(); 2{e dW+  
} 7-d}pgVK  
catch(Exception e){e.printStackTrace ();} {OO*iZ.O  
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} `z}vONXpAX  
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public static void main(String[] args) +9zJlL^A%  
{ 1l+kO,X]  
new TestMethod(); DD!MGf/  
} d&|z=%9xl  
} v7;J%9=0D`  
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