http断点续传简单实现（java)

/* *XbEiMJ  
**SiteFileFetch.java 9s$CA4?HP  
*/ 1A G<$d5U|  
package NetFox; $ig0j`  
import java.io.*; D"rK(  
import java.net.*; T)TfB(  
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public class SiteFileFetch extends Thread { "(z5{z
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SiteInfoBean siteInfoBean = null; //文件信息Bean Et/\xL  
long[] nStartPos; //开始位置 D rHVG  
long[] nEndPos; //结束位置 *%fi/bimG  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 vMt/u?oB  
long nFileLength; //文件长度 [~#WG/!:  
boolean bFirst = true; //是否第一次取文件 _R13f@NWB:  
boolean bStop = false; //停止标志 Y^7
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File tmpFile; //文件下载的临时信息 ]X5 9  
DataOutputStream output; //输出到文件的输出流 Vjp1RWb  
W~~7C,!  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ;HJLs2bP  
public SiteFileFetch(SiteInfoBean bean) throws IOException I]<_rN8~o  
{ B!_mC<*4`X  
siteInfoBean = bean; (#Gw1  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); MLje4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ke]Lw  
if(tmpFile.exists ()) rrqR}}l  
{ LO khjHR  
bFirst = false; ,p2s:&"  
read_nPos(); (ehK?6[  
} X
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else iAa.}CI,zB  
{ 4C-jlm)V  
nStartPos = new long[bean.getNSplitter()]; E2@65b$  
nEndPos = new long[bean.getNSplitter()]; Q<'nE  
} Ba*,-i3ZK  
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} WEQ1 Seq  
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public void run() NI#:|}CYS  
{ ,5kKimTt  
//获得文件长度 G!W[8UG  
//分割文件 =K{"{5Wb  
//实例FileSplitterFetch Wm"4Ae:B  
//启动FileSplitterFetch线程 Hl/ QnI!  
//等待子线程返回 BuWHX>H  
try{ C8e !H  
if(bFirst) 9S7kUl{  
{ cc&axc7I  
nFileLength = getFileSize(); ^xHTWg%9  
if(nFileLength == -1) v'qG26
  
{ jR22t`4  
System.err.println("File Length is not known!"); %Bn?n{/  
} V
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else if(nFileLength == -2) ') gi%  
{ :xD=`ib  
System.err.println("File is not access!"); *-q"3D`  
} Nq` C.&  
else 8x8uo  
{ V9(@Y  
for(int i=0;i<nStartPos.length;i++) =aj/,Q]  
{
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); feNdMR7eM  
} zj`v?#ET  
for(int i=0;i<nEndPos.length-1;i++) 7_Z#m (  
{ F\AX:  
nEndPos = nStartPos[i+1]; 04'~ta(t  
} OCJnjlV%  
nEndPos[nEndPos.length-1] = nFileLength; LbG_z =A  
} J'fQW<T4wU  
} jbu8~\"  
U.XNv-M  
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//启动子线程 R_68-WO  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ]Nl=wZ#`  
for(int i=0;i<nStartPos.length;i++) 2viM)+  
{ mc_ch$r!  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), C] 9p5Hs  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), *R3f{/DK  
nStartPos,nEndPos,i); *@Y3oh}S  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6s\Kt3=  
fileSplitterFetch.start(); M^iU;vo  
} RIE5KCrGB  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), iz?tu: \v&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); &)vC;$vD`  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", jhu&&==\f  
nEndPos = " + nFileLength); CkD#/  
// fileSplitterFetch[nPos.length-1].start(); GXjfQ~<]  
C;`XlQG `  
Bj}^\Pc;}  
//等待子线程结束 {>,V\J0p  
//int count = 0; !V\Q<So<  
//是否结束while循环 T G{k0cdOT  
boolean breakWhile = false; t{FlB!jv  
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while(!bStop) )\be2^p  
{ ks97k8B  
write_nPos(); 80&.JP.
 
Utility.sleep(500); YoLx>8  
breakWhile = true; D3^7y.u<)  
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for(int i=0;i<nStartPos.length;i++) vab@-=%k  
{ tBT<EV{ G  
if(!fileSplitterFetch.bDownOver) C,NxE5?h  
{ d&u]WVU  
breakWhile = false; S.Ma$KL~'^  
break; OY5OJ*  
} Wg0g/  
} Ns0cgCrhX  
if(breakWhile) vRxM4O~"  
break; |t)}VM%
 
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//count++; lGk{LO)  
//if(count>4) pY~,(s|Qb  
// siteStop(); n;p:=\uN  
} Fxqp-}:  
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System.err.println("文件下载结束！"); !\#_Jw%y  
} a/U2xq{x  
catch(Exception e){e.printStackTrace ();}
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} bb`':3%  
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;?~$h-9)  
//获得文件长度 1q3( @D5~+  
public long getFileSize() R:AA,^Z  
{ *"98L+  
int nFileLength = -1; >,gvb5  
try{ =rQP[ICs!  
URL url = new URL(siteInfoBean.getSSiteURL()); k({\/t3i  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); c.f"Gv  
httpConnection.setRequestProperty("User-Agent","NetFox"); { "xln/  
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int responseCode=httpConnection.getResponseCode(); lR`'e0Lq  
if(responseCode>=400) qdG~!h7j  
{ h:)Ci!D;  
processErrorCode(responseCode); l?DJJ|>O  
return -2; //-2 represent access is error ,\d6VBP&  
} 2Nm>5l  
kctzNGF|  
1s*.A6EP"  
String sHeader; je4w=]JV  
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for(int i=1;;i++) ]cC[-F[  
{ 7
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); {d%&zvJnD  
//Utility.log(in.readLine()); 'snn~{hG  
sHeader=httpConnection.getHeaderFieldKey(i); 5,;`$'?a%  
if(sHeader!=null) G"59cv8z4R  
{ a7/-wk  
if(sHeader.equals("Content-Length")) \WrFqm#  
{ gx:;&4AD  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); lvpc*d|K  
break; *tX{MSYW  
} 9Sq%s&  
} %q322->
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else hv$m4,0WB  
break; H,<7G;FPT  
} g3sUl&K  
} b7\ cxgRq  
catch(IOException e){e.printStackTrace ();} &G>(9  
catch(Exception e){e.printStackTrace ();} NHgjRPz"  
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Utility.log(nFileLength); ZC4*{  
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return nFileLength; "SoHt]%#  
} 5ZPzPUa8~  
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//保存下载信息（文件指针位置） !lmWb-v%36  
private void write_nPos() qxJQPz  
{ 9H]Lpi^OH  
try{ =}fd6ea(o  
output = new DataOutputStream(new FileOutputStream(tmpFile)); h2;z4  
output.writeInt(nStartPos.length); Dli^2hD  
for(int i=0;i<nStartPos.length;i++) Ld,5iBiO:  
{ B 2.q3T  
// output.writeLong(nPos); ;#)mLsl  
output.writeLong(fileSplitterFetch.nStartPos); JH]K/sC>  
output.writeLong(fileSplitterFetch.nEndPos);
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} 2~p[7?sp'  
output.close(); }5O>EXE0R  
} "?
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catch(IOException e){e.printStackTrace ();} ZDYJhJ.  
catch(Exception e){e.printStackTrace ();} Zz |MIGHm  
} Bl1Z4` 3  
9kY[j2,+  
8g7,2f/ }  
//读取保存的下载信息（文件指针位置） kK~IwA  
private void read_nPos() ?vGffMm  
{ 5lJ)(|_  
try{ ?68uS;  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); :Ze+%d=  
int nCount = input.readInt(); :y,v&Kk#T  
nStartPos = new long[nCount]; 8Chu"PM%-J  
nEndPos = new long[nCount]; W {.78Zi9K  
for(int i=0;i<nStartPos.length;i++) hvt@XZT  
{ m>e3vu  
nStartPos = input.readLong(); dYojm1MQ  
nEndPos = input.readLong(); ;}.Kb
 
} pY^9l3y^  
input.close(); F[7x*-NO-  
} f|aDTWF  
catch(IOException e){e.printStackTrace ();} <<|H=![  
catch(Exception e){e.printStackTrace ();} qq0?e0H  
} Y&r]lD
 
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private void processErrorCode(int nErrorCode) h:Ndzp{  
{ ;<G<1+  
System.err.println("Error Code : " + nErrorCode); ;+I4&VieK  
} TQ1WVq }*  
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, Ut Hc]  
//停止文件下载 [ij,RE7,T  
public void siteStop() g>7Y~_}  
{ {lzG*4?  
bStop = true; jV7&Y.$zF]  
for(int i=0;i<nStartPos.length;i++) >n7["7HHk  
fileSplitterFetch.splitterStop(); z]$j7dp  
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} azb=(l-  
} oBlzHBn>0  
//负责部分文件的抓取 8!h'j  
**FileSplitterFetch.java ._p""'Sa  
*/ \w)?SVp  
package NetFox; 76#.F  
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import java.io.*; }Pg' vJW  
import java.net.*; 0v"&G<J  
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public class FileSplitterFetch extends Thread { 1 2]fQkp  
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String sURL; //File URL IB7tAG8  
long nStartPos; //File Snippet Start Position T }uE0Z,  
long nEndPos; //File Snippet End Position <e6=% 9  
int nThreadID; //Thread's ID {=At#*=A  
boolean bDownOver = false; //Downing is over G79C {|c\  
boolean bStop = false; //Stop identical J/4y|8T/y  
FileAccessI fileAccessI = null; //File Access interface Q.(51]'  
u5gZxO1J5  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException VvgN3e[  
{ $M]%vG  
this.sURL = sURL; A"/aGCG0z  
this.nStartPos = nStart; \kwe51MQ  
this.nEndPos = nEnd; +|nsu4t,<  
nThreadID = id; gB CC  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 {>.>7{7  
} S+*cbA{J|  
4IGxI7~27#  
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public void run() TJ2/?p\x  
{ iiwpSGFl]  
while(nStartPos < nEndPos && !bStop) uaQ&&5%%J  
{ h1%y:[_  
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try{ p\txlT  
URL url = new URL(sURL); W:ixzpQ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); pa] TeH  
httpConnection.setRequestProperty("User-Agent","NetFox"); <J#R3{  
String sProperty = "bytes="+nStartPos+"-"; gv` h-b  
httpConnection.setRequestProperty("RANGE",sProperty); |z7dRDU}]  
Utility.log(sProperty); q lY\*{x4  
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InputStream input = httpConnection.getInputStream(); *Pb.f  
//logResponseHead(httpConnection); tq E>Zx=X  
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byte[] b = new byte[1024]; UIw?;:Y  
int nRead; s4IKSX  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ip5u_Xj?  
{ "X?LAo  
nStartPos += fileAccessI.write(b,0,nRead); !\w\ ]7ls  
//if(nThreadID == 1) M-91 JOt~  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~M[>m~8  
} ],V kp  
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Utility.log("Thread " + nThreadID + " is over!"); lIy/;hIc  
bDownOver = true; cJ4S!  
//nPos = fileAccessI.write (b,0,nRead); `t\z   
} pFH?/D/q  
catch(Exception e){e.printStackTrace ();} L9'-  
} cd"wNH-  
} [xS5z1;  
.%hQJ{vf-^  
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//打印回应的头信息 k*9%8yi_ U  
public void logResponseHead(HttpURLConnection con) {1HB!@%,(  
{ xfUhSt  
for(int i=1;;i++) o(SuUGW  
{ <
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String header=con.getHeaderFieldKey(i); 9_`
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if(header!=null) :,=Fx</H  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); '!j(u@&!  
Utility.log(header+" : "+con.getHeaderField(header)); >?Qxpqf2  
else +wjlAqMQ  
break; ]J~g'">  
} 0eaUorm)  
} ^AH-+#5  
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public void splitterStop() *%f3rvt7@)  
{ 'v`~(9'Rcj  
bStop = true; G32_FQ$b  
} n=SzF(S[M  
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} _PdAN= C3  
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c; d"XiA  
/* zrTY1Asw;4  
**FileAccess.java n K0hTQ  
*//文件访问(定位，写) X!?wL0n  
package NetFox; yL4 -4  
import java.io.*; ?-M)54b\  
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public class FileAccessI implements Serializable{ BfEx'C  
k4*! Q_A  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 v,@E}F~-f1  
RandomAccessFile oSavedFile; zh hGqz[K  
long nPos; j?d!}v  
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public FileAccessI() throws IOException s=}~Q&8  
{ %!W6<ioW  
this("",0); 6;[1Jz]?i  
} rGAFp,}-f  
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public FileAccessI(String sName,long nPos) throws IOException cEtZ}2,j  
{ (O<abB(  
oSavedFile = new RandomAccessFile(sName,"rw"); 1pl2;!  
this.nPos = nPos; :0|Hcg  
oSavedFile.seek(nPos); u<J2p?`\&`  
} QDl)92z  
%j!z\pa  
cKSfqqPm$"  
public synchronized int write(byte[] b,int nStart,int nLen) ^$ZI>L0+  
{ "&s9cO.H  
int n = -1; -!JlM@  
try{ " -<}C%C  
oSavedFile.write(b,nStart,nLen); tzP@3+.w  
n = nLen; </2,2AV4q*  
} 1XC*|  
catch(IOException e) +EQpD.  
{ YGi/]^Nba  
e.printStackTrace (); 23,%=U  
} 1@s^$fvW  
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return n; X~`.}
 
} ,5`."-0}  
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} MJpP!a^Q  
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O>kXysMv>  
/* :tg@HyY)  
**SiteInfoBean.java Cw@k.{*7,  
*/ P<TpG0~(  
package NetFox; V%VrAi.  
8-W"4)@b  
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public class SiteInfoBean { H,01o5J  
j P{:A9T\  
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private String sSiteURL; //Site's URL uVoF<=
{  
private String sFilePath; //Saved File's Path i,C0o  
private String sFileName; //Saved File's Name )<m=YI ;<  
private int nSplitter; //Count of Splited Downloading File ~t1O]aO(  
{IF
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V7Vbl?*n  
public SiteInfoBean() n$}R/*  
{//nSplitter的缺省值为5 ~m009  
//default value of nSplitter is 5 |8&\
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this("","","",5); >F_qa=t%[  
} g>d7%FFn}  
1 P(&GYc  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) &/z
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{ Z{8exy
m  
sSiteURL= sURL; 60.[t9pk6  
sFilePath = sPath; d;*OO xQV  
sFileName = sName; jb#1&L14  
this.nSplitter = nSpiltter;
5#N"WHz!  
w%%6[<3%  
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} ~4p]E'b  
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public String getSSiteURL() e3oYy#QNk  
{ G!> iqG  
return sSiteURL; /ynKKJx<Y  
} >llwNT  
&Sa_%:*D(  
ZQgxrZx3  
public void setSSiteURL(String value) GgZEg ?@  
{ >b/k|?xP  
sSiteURL = value; fwar8 i1  
} C.Wms}XA  
i`ZHjW~`  
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public String getSFilePath() XSL t;zL:  
{ +S:u[x  
return sFilePath; dvrvpDoE.  
} 5Xq.=/eX  
75^)Ni  
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public void setSFilePath(String value) 5Tcl<Y6l  
{ [TpA26#TTO  
sFilePath = value; `% #zMS  
} gz)wUQ|W  
[E..VesrM  
945 |MQPn  
public String getSFileName() E@'CU9Fo  
{ d=.n|rS4 W  
return sFileName; jN5} 2 p*  
} ;OT#V,}r  
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public void setSFileName(String value) eKU@>5  
{ ,/[dmoe  
sFileName = value; /o}0oo5B  
} %i]uW\~U  
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public int getNSplitter() ,~ia$vI}R  
{ "\R@lUx.Y  
return nSplitter; ]w&?k:y>  
} tSh}0N)  
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public void setNSplitter(int nCount) B[U.CAUn  
{ <or>bo^  
nSplitter = nCount; >8Yrmq  
} jP6oJcZ  
} VK@i#/jm  
k:HSB</}  
ys"mP*wD  
/* X=!n,=xI  
**Utility.java .k!k-QO5La  
*/  c
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package NetFox; l5N\>q  
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public class Utility { 41+E UMc  
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<EMLiiNY  
public Utility() ?'8MI|*l%  
{ aaa#/OWQZ  
/9vMGef@  
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} f>, Qhl  
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//线程睡眠
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public static void sleep(int nSecond) ]@j"0F/`  
{ =[tls^  
try{ a?Qcf;o  
Thread.sleep(nSecond); O]4 x;`)  
} 0Ts_"p  
catch(Exception e) 9rvxp;  
{ \"sSS.'  
e.printStackTrace (); *"9)a6T t+  
} jP7+s.j>  
} 6O|\4c;  
u
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//日志 (k2J{6]  
public static void log(String sMsg) 7<C~D,x6  
{ WU4vb  
System.err.println(sMsg); i6\!7D]  
} odT7G
q  
/>j+7ts  
BNKo6:wy  
public static void log(int sMsg) fKK-c9F  
{ B,na  
System.err.println(sMsg); x2IU PM  
} JI#Enh!Lv  
} @W5hrei  
a^)4q\E  
:tS>D5dz(  
/* @xM!:  
**TestMethod.java d}B_ll#j-  
*/ :$Di.|l@7  
package NetFox; iJj?~\zp  
i(cb&;Xx:A  
V;+$/>J`vB  
public class TestMethod { GyXs{*  
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.)pRB7O3  
public TestMethod() -D^y)  
{ ///xx/weblogic60b2_win.exe EvardUB)  
try{ ~b<4>"7y.  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); X]^E:'E!  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); >b"z`{tE  
SiteFileFetch fileFetch = new SiteFileFetch(bean); {O,M
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fileFetch.start();  F3
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} lp%.n= '\  
catch(Exception e){e.printStackTrace ();} :g:h 0'G  
1AkHig,  
Y
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} rOf  
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F p=Q$J|  
public static void main(String[] args) YKxA2`3v%  
{ tVh4v#@+  
new TestMethod(); dcTM02kEh  
} Am`A[rV0  
} >]08".ajS  
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