http断点续传简单实现（java)

/* "
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**SiteFileFetch.java %3B0s?,I  
*/ #l kv&.)x  
package NetFox; IbFS8 *a\  
import java.io.*; JQCQpn/  
import java.net.*; H+UA  
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public class SiteFileFetch extends Thread { 9V5}%4k%+  
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SiteInfoBean siteInfoBean = null; //文件信息Bean rr/0pa$  
long[] nStartPos; //开始位置 iYwzdW1  
long[] nEndPos; //结束位置 <Sm@ !yx  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 F Xbf7G)H  
long nFileLength; //文件长度 F
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boolean bFirst = true; //是否第一次取文件 .EJo9s'  
boolean bStop = false; //停止标志 DbRq,T  
File tmpFile; //文件下载的临时信息 WCc7 MK  
DataOutputStream output; //输出到文件的输出流 1D3{\v  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 6_KO6O7g  
public SiteFileFetch(SiteInfoBean bean) throws IOException {9>LF  
{ p%;n4*b2  
siteInfoBean = bean; E0 ~\ A;  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); g\;&Z  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !Zf< j  
if(tmpFile.exists ()) J]|Zh  
{ oC"1{ybyl  
bFirst = false; :m~R<BQ"  
read_nPos(); i8CO+Iv*{  
} 4hRc,Vq  
else *}mk$bA  
{ cj=6_
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nStartPos = new long[bean.getNSplitter()]; /_yJ;l/K  
nEndPos = new long[bean.getNSplitter()]; :Fe}.* t  
} ]iP  +Y  
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} OsQB` D  
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 Rd|#-7  
public void run() KmUH([#  
{ 2y"]rUS`  
//获得文件长度 ;8!L*uMI  
//分割文件 &-l(nr]h]  
//实例FileSplitterFetch A.`) 0dV  
//启动FileSplitterFetch线程 -u!{8S~wA  
//等待子线程返回 ZdcG6IG+  
try{ "n,?)  
if(bFirst) y2nwDw(xF  
{ Pe-1o#7~W  
nFileLength = getFileSize(); ElBpF8xJ|o  
if(nFileLength == -1) QQ1|]/)  
{ CF|4, K)  
System.err.println("File Length is not known!"); &x= PAu  
} )SJ18 no|l  
else if(nFileLength == -2) Ft} h&aYP  
{ ?4G/f<ou  
System.err.println("File is not access!"); >fX_zowX  
} IYZ$a/{P  
else 3m2hB%SNb  
{ $F^p5EXkc6  
for(int i=0;i<nStartPos.length;i++) H_ecb;|mP  
{ ix.I)  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); |2ttdc.  
} 6;JlA})  
for(int i=0;i<nEndPos.length-1;i++) >St]MS
 
{ #`kLU:  
nEndPos = nStartPos[i+1]; {:peArO  
} (g>8!Gl  
nEndPos[nEndPos.length-1] = nFileLength; 
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} c-?2>%;(V  
} luPj'd?  
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1/hk3m(C  
//启动子线程 tN-U,6c]  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; *3A`7usU  
for(int i=0;i<nStartPos.length;i++) BH@b]bEJ  
{ Hu4\4x$?  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), M.*3qWM  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 5!tiu4LU  
nStartPos,nEndPos,i); at(oepq  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;s$bVGHr  
fileSplitterFetch.start(); 9/LnO'&-  
} -FxE!K  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), JZc"4qf@OT  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); d z-  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", RxeyMNd  
nEndPos = " + nFileLength); -c_}^j  
// fileSplitterFetch[nPos.length-1].start(); xzI?'?duC  
mmf}6ABYT  
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//等待子线程结束 ZSs)AB_Pe/  
//int count = 0; /8$*{ay  
//是否结束while循环 pb`!_GmB  
boolean breakWhile = false; mrc% 6Ri  
cq?&edjP  
0P?\eoB@8  
while(!bStop) ggP#2I\  
{ T?!D?YV  
write_nPos(); |mHxkd  
Utility.sleep(500); [H-r0Ah  
breakWhile = true; G/y@`A)  
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for(int i=0;i<nStartPos.length;i++) jE.yT(+lW  
{ q>n0'`q   
if(!fileSplitterFetch.bDownOver) EKr#i}(x<  
{ FF}A_ZFY  
breakWhile = false; j1Ng[  
break; xllk hD4F  
} CLn}BxgD  
} K0YUN^St  
if(breakWhile) @0v%5@  
break; 4fuKpLA  
7UVhyrl  
#<4/ *< 5  
//count++; GM{J3O=  
//if(count>4) FxK2 1  
// siteStop(); D on8x
k  
} >sfH[b  
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AhNy+p{  
System.err.println("文件下载结束！"); M~o\K'  
} 'K8emt$d+  
catch(Exception e){e.printStackTrace ();} C{5^UCJkg  
} |1rKGDc  
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//获得文件长度 S2!$  
public long getFileSize() 0r|mg::'  
{ 0/g 0=dW=  
int nFileLength = -1; )"]Nf6  
try{ p,cw-lN  
URL url = new URL(siteInfoBean.getSSiteURL()); Wwf],Ya  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Qr n^T  
httpConnection.setRequestProperty("User-Agent","NetFox"); hU]Gv)B  
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int responseCode=httpConnection.getResponseCode(); qh]ILE87(  
if(responseCode>=400) i^O(JC  
{ v})-:  
processErrorCode(responseCode); /-mo8]J#2~  
return -2; //-2 represent access is error E+tV7xa~  
} `g~T #U\>d  
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String sHeader; faqh }4
 
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for(int i=1;;i++) 'x{E#4A  
{ ;FI"N@z  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); kCuIEv@  
//Utility.log(in.readLine()); L
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sHeader=httpConnection.getHeaderFieldKey(i); BY&+fKae  
if(sHeader!=null) xGU~FU  
{ iuxS=3lT"K  
if(sHeader.equals("Content-Length")) r^jiK\*  
{ <O]
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); i_KAD U&mP  
break; ~Wox"h}(  
} .w@o%AO_  
} dh; L!  
else B0&W wa:  
break; /Ayo78Pi  
} >E:V7Fa  
} {dk%j~w8  
catch(IOException e){e.printStackTrace ();} I8%2tLVY  
catch(Exception e){e.printStackTrace ();} bt2`elH|  
L)!9+!PKD  
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Utility.log(nFileLength); "j<l=l!  
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return nFileLength; `1Cg)\&[e0  
} yM}Wg~:D:  
/3>5ex>PN  
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//保存下载信息（文件指针位置） iFi6,V*PRt  
private void write_nPos() 2X@|H  
{ 1X7tN2tQ  
try{ -*QxZiKD  
output = new DataOutputStream(new FileOutputStream(tmpFile)); o;#9$j7QP!  
output.writeInt(nStartPos.length); 4,yS7l  
for(int i=0;i<nStartPos.length;i++) lls-Nir%  
{ P*\h)F/3}t  
// output.writeLong(nPos); H`XE5Hk)P%  
output.writeLong(fileSplitterFetch.nStartPos); ^kElb;d  
output.writeLong(fileSplitterFetch.nEndPos); YgFmJ.1  
} Go8?8*  
output.close(); IeZgF>  
} MeSF,*lP  
catch(IOException e){e.printStackTrace ();} %xH2jf  
catch(Exception e){e.printStackTrace ();}
=HGC<#  
} js~?y|e8k  
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//读取保存的下载信息（文件指针位置） a'U}.w}  
private void read_nPos() ,$xV&w8f\"  
{ )T_o!/\*|*  
try{ Jh)x_&R&Q  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); e=yQFzQT)  
int nCount = input.readInt(); ?f{-
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nStartPos = new long[nCount]; &/}reE*  
nEndPos = new long[nCount]; p}r1@L s  
for(int i=0;i<nStartPos.length;i++) R}S@u@mOE  
{ MzWVsV  
nStartPos = input.readLong(); lebwGW,!  
nEndPos = input.readLong(); ?df*Y5I2  
} @'Y^
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input.close(); s_j ?L  
} m,TN%*U!  
catch(IOException e){e.printStackTrace ();} $}*bZ~  
catch(Exception e){e.printStackTrace ();} @Ft\~ +}  
} 
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private void processErrorCode(int nErrorCode) 1F*3K3T {  
{ ";PW#VHC  
System.err.println("Error Code : " + nErrorCode); .*3.47O  
} }K8W%h
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//停止文件下载 2D"n#O`y  
public void siteStop() )e1&[0  
{ \@3B%RW0  
bStop = true; ,y'E#_cTgQ  
for(int i=0;i<nStartPos.length;i++) 4~bbng  
fileSplitterFetch.splitterStop(); |lnMT)^D  
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} GO|1O|?  
} Uzx,aYo X  
//负责部分文件的抓取 -{^IT`  
**FileSplitterFetch.java S>! YBzm&X  
*/ KTQy pv  
package NetFox; &Ti:IC%M  
d[p-zn.  
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import java.io.*; dE`a1H%  
import java.net.*; )C@O7m*.4  
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public class FileSplitterFetch extends Thread { $P{|^ou3a#  
=.sg$VX  
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String sURL; //File URL 3t*e|Ih&j5  
long nStartPos; //File Snippet Start Position 1hz:AUH  
long nEndPos; //File Snippet End Position H;eGB
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int nThreadID; //Thread's ID g ss 3e&  
boolean bDownOver = false; //Downing is over O@Ro_sPG(  
boolean bStop = false; //Stop identical re$xeq\1P?  
FileAccessI fileAccessI = null; //File Access interface (iT?uMRz  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 7;wx,7CUq  
{ OIqisQ7ZB  
this.sURL = sURL; CXe2G5  
this.nStartPos = nStart; )37.H^7  
this.nEndPos = nEnd; ['*{f(AI  
nThreadID = id; sv g`s,g  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 3>+9Rru  
} TN+iv8sT  
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r
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public void run() swfcA\7R  
{  3Y L  
while(nStartPos < nEndPos && !bStop) ?bq S{KF  
{ us_o{  
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try{ 5Dhpcgq<<  
URL url = new URL(sURL); {D6E@a  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); kwcH$w<I  
httpConnection.setRequestProperty("User-Agent","NetFox"); h0=Q.Yz6  
String sProperty = "bytes="+nStartPos+"-"; (F<VcB  
httpConnection.setRequestProperty("RANGE",sProperty); HkP')= sa  
Utility.log(sProperty); ib3u:  
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InputStream input = httpConnection.getInputStream(); o)(N*tC  
//logResponseHead(httpConnection); P?zPb'UVqa  
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byte[] b = new byte[1024]; iPD5 KsAOA  
int nRead; `Wes!>Vh!  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) mr4W2Z@L  
{ lJ'.1Z&  
nStartPos += fileAccessI.write(b,0,nRead); "M GX(SQ  
//if(nThreadID == 1) 2i~tzo  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); H(JgqbFB*  
} &sbKN[xM  
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Utility.log("Thread " + nThreadID + " is over!"); =u*\P!$  
bDownOver = true; |>Q]q  
//nPos = fileAccessI.write (b,0,nRead); }k`-n32)|  
} *tWZ.I<<  
catch(Exception e){e.printStackTrace ();} Y`O"+Jr  
} |#&{`3$CG[  
} X J+y5at  
/uh?F  
/|kR=
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//打印回应的头信息 !vaS fL*]  
public void logResponseHead(HttpURLConnection con) z vM=k-Ec  
{ 015 ;'V#we  
for(int i=1;;i++) dTE(+M- Gr  
{ <~%e{F:[#  
String header=con.getHeaderFieldKey(i);

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if(header!=null) sULCYiT|Hn  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); :jJ;&t^^  
Utility.log(header+" : "+con.getHeaderField(header)); #[Z1W8e  
else (P+TOu-y\  
break; sQ)D.9\~  
} jo7`DDb  
} ;2NJkn9t  
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public void splitterStop() a5)<roWQ  
{ up# R9 d|  
bStop = true; \),DW)  
} CQ4MQ<BJ.  
#:~MtV  
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} I3ZlKI  
}!&Vcf  
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/* Ih&rXQ$  
**FileAccess.java /K@_O\+;Q
 
*//文件访问(定位，写) q&:UP  
package NetFox; y1oQ4|KSI  
import java.io.*; " hD6Z  
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2j*+^&M/  
public class FileAccessI implements Serializable{ E#0_y4  
3pV^Oe^9  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 aX)k(*|  
RandomAccessFile oSavedFile; aJ4y%Gy?  
long nPos; SY[7<BUZ  
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public FileAccessI() throws IOException 0LjF$3GpZ  
{ g }%$VUSA  
this("",0); +K@wh  
} bm</qF'T6  
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public FileAccessI(String sName,long nPos) throws IOException vFz#A/1  
{ /OX;3" +1  
oSavedFile = new RandomAccessFile(sName,"rw"); vC# *w,  
this.nPos = nPos; PsV1btq]  
oSavedFile.seek(nPos); y{?wxg9  
} |5;:3K+
 
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public synchronized int write(byte[] b,int nStart,int nLen) 6JCq?:#ab  
{ Xf"B\%,(`  
int n = -1; THOXs; k0  
try{ ^L,Uz:[J  
oSavedFile.write(b,nStart,nLen); 0m,3''Q5lO  
n = nLen; RRasX;
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} 0sQt+_Dl%L  
catch(IOException e) S260h,(,  
{ ;RElG>#$  
e.printStackTrace (); ;b-d2R  
} 0-=PP@W  
6AA"JX  
++d%D9*V<  
return n; jNC@b>E?~  
} ~8j4IO(  
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} FxkxV GZ"  
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/* U#X6KRZ~g  
**SiteInfoBean.java G2,9$8qE  
*/
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package NetFox; q_R^Q>ZIe  
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public class SiteInfoBean { ` 465 H  
T2%{pcdV/  
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private String sSiteURL; //Site's URL $#HPwmd  
private String sFilePath; //Saved File's Path N!TC}#}l  
private String sFileName; //Saved File's Name gQ0W>\xz  
private int nSplitter; //Count of Splited Downloading File O 8\wH  
l>J>?b=x"[  
Q|CLis-  
public SiteInfoBean() uQ_s$@b
rI  
{//nSplitter的缺省值为5 _'.YC<;  
//default value of nSplitter is 5 *oW^P~m/  
this("","","",5); mDG=h6y"V  
}  hb,G'IU  
#\{j/{VZ  
G'dN_6ho3  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) c:@lR/oe"  
{ 8etNS~^  
sSiteURL= sURL; !
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sFilePath = sPath; 1pDL()t  
sFileName = sName; G(*7hs  
this.nSplitter = nSpiltter; S+LS!b  
L+]|-L`S  
9P)28\4  
} W,53|9b@  
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k/`WfSM\.  
public String getSSiteURL() <jk.9$\$A  
{ 0c,)T1NG>  
return sSiteURL; Vi5&%/Y  
} R|,F C'  
%z_L}L  
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public void setSSiteURL(String value) XSv)=]{  
{ M#5*gWfq9  
sSiteURL = value; ?!{nNJ  
} w%NT 0J  
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public String getSFilePath() O\5q_>]  
{ ?04$1n:  
return sFilePath; WNa#X]*E)  
} /DC\F5 G  
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h88IP:bo  
public void setSFilePath(String value) +'!4kwTR  
{ :VvJx]  
sFilePath = value; x$WdW+glZ-  
} o<f#Zi  
~Bi{k'A9  
MB#KLTwnT  
public String getSFileName() A:JWUx  
{ C>0='@LB@r  
return sFileName; 'C")X  
} n?EL\B   
@XSx
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public void setSFileName(String value) Kd%>:E*  
{ D,<#pNO_  
sFileName = value; `(dRb  
} }w
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sP` k{xG  
$mF(6<w  
public int getNSplitter() F# a)"$j;  
{ E~| XY9U36  
return nSplitter; ,iYKtS3  
} ;A3aUN;"I  
Cjn)`Q8  
5"cYZvGkJ  
public void setNSplitter(int nCount) >_m4 idq1  
{ RO9oO7S  
nSplitter = nCount; iJsa;|2/  
} ^;xO-;q  
} (46S^*  
(d@ =   
1 xu2$x.b  
/* &qP@WFl  
**Utility.java J ;e/S6l  
*/ gL-\@4\wc  
package NetFox; d O'apey  
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public class Utility { 8g!C'5  
]B'H(o R<|  
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public Utility() H{4/~Z  
{ d J;y>_  
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} ZR|cZH1}C  
=nTNL.SX  
//线程睡眠 |vLlEN/S  
public static void sleep(int nSecond) u}L;/1,B  
{ &
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try{ GSh~j-C'  
Thread.sleep(nSecond); 4-dV%DgC  
} {k#RWDespy  
catch(Exception e) 4\?GA`@  
{ -?K?P=B;X  
e.printStackTrace (); ?{bAyh/  
} *wY { ~zh  
} e52y}'L  
$sTvXf:g  
//日志 k
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public static void log(String sMsg) |n_es)A  
{ ^^m3 11=  
System.err.println(sMsg); k"V@9q;*  
} #VA8a=t  
3|FZ!8D  
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public static void log(int sMsg) $kM8E@x2  
{ >FRJvZ6  
System.err.println(sMsg); HcKZmL.wp  
} sIZ|N"2]A*  
} 6'^Gh B  
UVIR P#  
+#/`4EnI  
/* my|UlZ(qg  
**TestMethod.java DwLl}{r'  
*/ >dTJ  
package NetFox; Fm3f/]>k#_  
6x_tX  
[Tq\K ^!^  
public class TestMethod { VIi/=mO]  
, 7kS#`P  
\;%DDw  
public TestMethod() UFED*al#  
{ ///xx/weblogic60b2_win.exe t'F_1P^*
/  
try{ Wxxnc#;lv  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); " ~X;u8m  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); vMQvq9T}  
SiteFileFetch fileFetch = new SiteFileFetch(bean); >10pk  
fileFetch.start(); 2'8$
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} YyZ>w2_MTi  
catch(Exception e){e.printStackTrace ();} 3X,SCG  
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} r,`59  
>cEB,@~  
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public static void main(String[] args) [9
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{ xzRs;AXOp  
new TestMethod(); 2EdKxw3$]  
} ^6Std x_  
} *Y@)t* -a  
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