http断点续传简单实现（java)

/* 2[po~}2-0  
**SiteFileFetch.java 2-0cB$W+  
*/ )^H9C"7T  
package NetFox; HIm, "iYk  
import java.io.*; 1RbYPX  
import java.net.*; $0}bi:7  
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public class SiteFileFetch extends Thread { )F9r?5}v4x  
9/Dt:R3QU  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Ra5'x)m36)  
long[] nStartPos; //开始位置 ~ fEs!hl  
long[] nEndPos; //结束位置 sRQh~5kM  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ok[=1gA#h  
long nFileLength; //文件长度 SAh054/St  
boolean bFirst = true; //是否第一次取文件 TEyx((SK  
boolean bStop = false; //停止标志 }G+A_HF ^  
File tmpFile; //文件下载的临时信息 5Kj4!Ai  
DataOutputStream output; //输出到文件的输出流 ,,@`l\Pgd  
NCnId}
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） hxVM]e[  
public SiteFileFetch(SiteInfoBean bean) throws IOException WN+Jf  
{ _|3TC1N$n  
siteInfoBean = bean; ACO4u<M)  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); VtiqAh}4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");  IB{ZE/  
if(tmpFile.exists ()) WV1
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{ |HGb.^f?  
bFirst = false; Us,[xQ  
read_nPos();  |7zP8  
} _F@p53WE  
else "jO3Y/>S  
{ @O}j:b  
nStartPos = new long[bean.getNSplitter()]; sLdUrD%  
nEndPos = new long[bean.getNSplitter()]; o?K|[gNi  
} 6bKO;^0  
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} k(z<Bm  
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public void run() =
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{ ASZ5;N4u  
//获得文件长度 KM}4^Qc  
//分割文件 )]>G,.9C}  
//实例FileSplitterFetch 3 9{"T0  
//启动FileSplitterFetch线程 eM=)>zl  
//等待子线程返回 '0')6zW5s  
try{ c48J!,jCd'  
if(bFirst) S"TMsi  
{ OI_/7@L  
nFileLength = getFileSize(); U
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if(nFileLength == -1) BX(d"z b<  
{ ?ZHE8  
System.err.println("File Length is not known!"); ?h)3S7  
} 
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else if(nFileLength == -2) {L4>2rF  
{ t9n  
System.err.println("File is not access!"); j22#Bw  
} OZ!$%.?l  
else (_qBsng:  
{ gSr}p$N  
for(int i=0;i<nStartPos.length;i++) uxC   
{ S2ppKlVv  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); =HV-8C]  
} `)=A!x y  
for(int i=0;i<nEndPos.length-1;i++) f:[d]J|  
{ HS
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nEndPos = nStartPos[i+1]; NnLhJPh  
} .aismc`=  
nEndPos[nEndPos.length-1] = nFileLength; y|;8:b32  
}
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} %rDmW?T  
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O/Mz?$8J  
//启动子线程 J4[x,(iq(  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; x1:Pj  
for(int i=0;i<nStartPos.length;i++) 52MCUl  
{ r($_>TS&"  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), foz5D9sQ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), [pW1=tI  
nStartPos,nEndPos,i); $}^\=p}X  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); adO!Gs9f?  
fileSplitterFetch.start(); I,<>%Z|'  
} \'??  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Ztyv@z'/Z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); qBBYckS.  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", I
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nEndPos = " + nFileLength); n-y^7'v  
// fileSplitterFetch[nPos.length-1].start(); i
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//等待子线程结束 -.b Io  
//int count = 0; s0)qlm*  
//是否结束while循环 p&OJa$N$[  
boolean breakWhile = false; O,=Q1*c,&  
=tS[&6/  
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while(!bStop) xMSNrOc  
{ yL;o{ G  
write_nPos(); hINnb7o  
Utility.sleep(500); Q.9Ph ~  
breakWhile = true; jTd4H)  
;WvYzd9  
MJ>Qq[0  
for(int i=0;i<nStartPos.length;i++) of+phMev  
{ &ppE|[{  
if(!fileSplitterFetch.bDownOver) m
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{ -B*<Q[_  
breakWhile = false; XWUvP  
break; ^<>Jw%H  
} y\)G7 (  
} hi {2h04  
if(breakWhile) _H4$$  
break; \3Q:K|  
+EST58  
mmrW`~-  
//count++; "[Qb'9/Jc  
//if(count>4) h;EwkbDQg>  
// siteStop(); nE]~E xr  
} ;.nP%jD  
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POqRHuFq  
System.err.println("文件下载结束！"); u=@h`5-fp  
} j8[`~pb  
catch(Exception e){e.printStackTrace ();} z*M}=`M$  
} :]B% >*;}  
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VY+(,\)U  
//获得文件长度 \~gA+o}Q  
public long getFileSize() e;A^.\SP  
{ ;Cr_NP[8|j  
int nFileLength = -1; A*7Io4e!  
try{ L.09\1?.n  
URL url = new URL(siteInfoBean.getSSiteURL()); kyW6S+#-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +A8=R%&b)[  
httpConnection.setRequestProperty("User-Agent","NetFox"); c&7Do}  
%rpR-}j  
1<LC8?wt  
int responseCode=httpConnection.getResponseCode(); %_B:EMPd  
if(responseCode>=400) N,j>;x3xT  
{ s{(ehP.Dd  
processErrorCode(responseCode); -
1jjB1  
return -2; //-2 represent access is error `e'G.@  
} .k# N7[q=  
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CRZi;7`*1  
String sHeader; -`zG_]=-  
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do:QH.q8)  
for(int i=1;;i++) CS~=Z>6EjA  
{ *.kj]BoO  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); >DDQ
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//Utility.log(in.readLine()); !lR0w|  
sHeader=httpConnection.getHeaderFieldKey(i); E$]a?uA:  
if(sHeader!=null) m>]>$=%  
{ gCv"9j<j
 
if(sHeader.equals("Content-Length")) Dk)@>l:gI,  
{ `fQM  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); :D"@6PC]  
break; ;Y Dv.I  
} Ms.PO{wb  
} R#Y50hzT  
else IXGW2z;  
break; [ 3$.*   
} =E;=+eqt  
} jA4PDHf+  
catch(IOException e){e.printStackTrace ();} 2Ryp@c&r^  
catch(Exception e){e.printStackTrace ();} xK$}QZ)  
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Utility.log(nFileLength); iKg75%;t  
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return nFileLength; Px'R`1^  
} !+m@AQ:,  
~k9O5S{  
V-[2jC{  
//保存下载信息（文件指针位置） ^[ET&"  
private void write_nPos() ;LHDh_.pX  
{ pU M&"V  
try{ VVs{l\$=ZV  
output = new DataOutputStream(new FileOutputStream(tmpFile)); HDyQzCG,  
output.writeInt(nStartPos.length); %/P=m-K  
for(int i=0;i<nStartPos.length;i++) 0;}Aj8Fle  
{ ?sV[MsOsC  
// output.writeLong(nPos); Kn']n91m  
output.writeLong(fileSplitterFetch.nStartPos); bX7EO 8  
output.writeLong(fileSplitterFetch.nEndPos); Xa4GqV9M/-  
} FI\IY R  
output.close(); '4$lL6ly>  
} R"NGJu9  
catch(IOException e){e.printStackTrace ();} >OT\~C  
catch(Exception e){e.printStackTrace ();} S,lxM,DL&  
} doLkrEm&
 
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//读取保存的下载信息（文件指针位置） Zotz?jVVr  
private void read_nPos() uii7b7[w  
{ YZ0en1ly  
try{ *yrnK3  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); y $:yz;  
int nCount = input.readInt(); e{5,'(1]  
nStartPos = new long[nCount];  7krh4  
nEndPos = new long[nCount]; EY]a6@;  
for(int i=0;i<nStartPos.length;i++) |Z d]=tue  
{ moCK-:  
nStartPos = input.readLong(); m)r]F#@/  
nEndPos = input.readLong(); pqJ)G;%9  
} 5)mVy?Z
  
input.close(); `"B^{o  
} Y=9j2 ]t  
catch(IOException e){e.printStackTrace ();} 4KE)g  
catch(Exception e){e.printStackTrace ();} ai4PM b$p  
} 7UnzIe  
5lO^;.cS,  
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private void processErrorCode(int nErrorCode) q'.;W@m  
{ (]OFS;%  
System.err.println("Error Code : " + nErrorCode); f7Zf}1|  
} 3)y{n%
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(Q'U@{s  
//停止文件下载 L7m`HVCt&  
public void siteStop() ovz#  
{ +I&J7ICV0  
bStop = true; r]0(qg  
for(int i=0;i<nStartPos.length;i++) e[}],W  
fileSplitterFetch.splitterStop(); t~ -J %$  
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} 0vDg8i\  
} >&1um5K  
//负责部分文件的抓取 ?s%v 3T  
**FileSplitterFetch.java dsK/6yu  
*/ +lKrj\Xj  
package NetFox; +5-]iKh  
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:Dayv6g  
import java.io.*; }C_
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import java.net.*; ~Zmi(Ra  
)=Zsv40O  
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public class FileSplitterFetch extends Thread { uWTN2jr
 
'6X%=f'^b  
<PioQ>~  
String sURL; //File URL z>|)ieL  
long nStartPos; //File Snippet Start Position "c,!vc4  
long nEndPos; //File Snippet End Position tn{8u7  
int nThreadID; //Thread's ID }'TTtV:Q  
boolean bDownOver = false; //Downing is over =5Wp
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boolean bStop = false; //Stop identical |YRY!V_w  
FileAccessI fileAccessI = null; //File Access interface 2A>C+Y[7\  
y^G>{?Tha  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException PPj[;(A  
{ xZyeX34{M;  
this.sURL = sURL; /$Z m~Mp  
this.nStartPos = nStart; \6:>
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this.nEndPos = nEnd; 2h<U  
nThreadID = id; y@
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 8?1o<8hV  
} Ft) lp>3gv  
xg} ug[  
<BPRV> 0X  
public void run() 4>YU8/Rw  
{ ]~8v^A7u  
while(nStartPos < nEndPos && !bStop) U*qNix  
{ sMm/4AY]  
7@IFp~6<qK  
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try{ .'/l'>  
URL url = new URL(sURL); b_=8!Q.:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); IA2GUnUhu  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7]s%rya  
String sProperty = "bytes="+nStartPos+"-"; Fu%X  
httpConnection.setRequestProperty("RANGE",sProperty); :+:6_x  
Utility.log(sProperty); 5B{k\H;  
l4 "\) ];  
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InputStream input = httpConnection.getInputStream(); SdxY>;  
//logResponseHead(httpConnection); l{5O5%\,  
4\6:\  
%
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byte[] b = new byte[1024]; ej52AK7  
int nRead; ?/'}JS(Sm  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) <0
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{
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nStartPos += fileAccessI.write(b,0,nRead); Me/\z
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//if(nThreadID == 1) Us-A+)r*!  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Q]rqD83((  
} 8;#AO8+U7)  
6IP$n($2  
!
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Utility.log("Thread " + nThreadID + " is over!"); X>t3|
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bDownOver = true; 9P.(^SD][z  
//nPos = fileAccessI.write (b,0,nRead); Z>2]Xx% \  
} HabzCH  
catch(Exception e){e.printStackTrace ();} @Tr&`Hi  
} M
3(k'q7&:  
} +9[SVw8  
'9J*6uXf.  
6^E`Sa!s  
//打印回应的头信息 o@/xPo|  
public void logResponseHead(HttpURLConnection con) gvyT-XI  
{ >'`Sf ?+|  
for(int i=1;;i++) j[XYj6*d  
{ n+;vjVS%  
String header=con.getHeaderFieldKey(i); P+Z\3re  
if(header!=null) JMlV@t7y<  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); n3ZAF'  
Utility.log(header+" : "+con.getHeaderField(header)); cJ
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else //.>>-~1m  
break; }1U*A#aN7K  
} `f)(Y1%.  
} ,w2WS\`%  
@B`Md3$7
 
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public void splitterStop()  AmcC:5  
{ NfwYDY  
bStop = true; wqy^8N[K]  
} %{C)1*M7  
>SDpuG&>  
_ 08];M|  
} 2a`J%A  
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/* nbmc[!PwG  
**FileAccess.java <9ifPSvJ  
*//文件访问(定位，写) B4yh3cf  
package NetFox; N:x0w+Ca  
import java.io.*; {DBIonY];  
>F3.c%VU]w  
>"("*3AO  
public class FileAccessI implements Serializable{ I:$"E% >=  
{QQl$ys/  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 #$'FSy#  
RandomAccessFile oSavedFile; Wx]d $_  
long nPos; |!LnAh  
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public FileAccessI() throws IOException 6y Wc1  
{ @6&JR<g*t  
this("",0); 3t(c_:[%  
} V1<`%=%
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public FileAccessI(String sName,long nPos) throws IOException mhz
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{ CWlW/>yF B  
oSavedFile = new RandomAccessFile(sName,"rw"); :a3xvN-l  
this.nPos = nPos; - k`.j  
oSavedFile.seek(nPos); "C
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} =|SdVv  
4#)6.f~  
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public synchronized int write(byte[] b,int nStart,int nLen) [uR/M
 
{ };S0 G!  
int n = -1; (Uk,  
try{ n%$ &=-Fk  
oSavedFile.write(b,nStart,nLen); [ee30ELn  
n = nLen; mX\ ;
oV!  
} B9M>e'H%<  
catch(IOException e) nP
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{ {gU&%j  
e.printStackTrace (); ;dQAV\  
} #H5=a6E+q  
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return n; V3.t;.@  
} zxKCVRJ  
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} Zdn!qyR`  
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S>f&6ZDNY(  
/* W`L!N&fB  
**SiteInfoBean.java l\Xd.H" j,  
*/ 36$[  
package NetFox; "2hh-L7ql  
u\g,.C0  
.\)A@ua^  
public class SiteInfoBean { qO()w  
{-WTV"L5*2  
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private String sSiteURL; //Site's URL C1fyV]  
private String sFilePath; //Saved File's Path v?j!&d>  
private String sFileName; //Saved File's Name :&yDqoQKJ  
private int nSplitter; //Count of Splited Downloading File b{&FuvQg2  
FFzH!=7T?  
12(wj6Q  
public SiteInfoBean() ]~jN^"o_B  
{//nSplitter的缺省值为5 )bDnbO$s_  
//default value of nSplitter is 5 r@$ w*%  
this("","","",5); 8cdsToF(e.  
} (:sZ b?*  
ZkWL_ H)  
b^Cfhy^RTq  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) OhwF )p=  
{ U^_D|$6  
sSiteURL= sURL; _gV8aH ZyM  
sFilePath = sPath; G[z .&l  
sFileName = sName; '%7 Bxof  
this.nSplitter = nSpiltter; X")|Uw8Kl/  
Y25uU%6t_  
/A07s[L  
} LmLGki$w  
HL8eD^  
VKuAO$s$  
public String getSSiteURL() e7k%6'@  
{ O<N#M{kc.  
return sSiteURL; KIus/S5 RC  
} (S9f/i^  
|g_g8[@`}  
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public void setSSiteURL(String value) Iti0qnBN5  
{ 7"Mk+'   
sSiteURL = value; >^SEWZ_[  
} 9&  
#oV+@D`  
4 I@p%g&  
public String getSFilePath() ,8VU&?`<}  
{ a!,r46>$H  
return sFilePath; oF|N O^H  
} 3W&S.$l  
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public void setSFilePath(String value) b?VV'{4  
{ H3O@9YU  
sFilePath = value; =8JB8ZFP  
} ~]fJ
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public String getSFileName() ..qd,9H  
{ A Y9 9!p  
return sFileName; f)NHM'  
} K+d2m9C=  
jRj=Awy  
97`WMs
  
public void setSFileName(String value) JUt7En;XE  
{ M+Uyb7  
sFileName = value; %1}6q`:w  
} "(TkJbwC[  
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public int getNSplitter() X0$@Ik  
{ kgW @RD|  
return nSplitter; !1Y&Y@ze  
} b"CAKl  
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public void setNSplitter(int nCount) YT-=;uK^S  
{ #&Is GyU  
nSplitter = nCount; 2F+gF~znQ  
} w*!wQ,o  
}
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/* p]&j;H.  
**Utility.java wij,N(,H  
*/ GjT#%GBF  
package NetFox; FN87^.^2S  
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PuCc2'#  
public class Utility { )&W**!(C  
'Pd(\$ZY
 
,.mBJSE3  
public Utility() u$*>`Xe6  
{ S2^>6/[xM  
{qpi?oY  
ZxHJ<2oD  
} w#y2_  
(Tvcq  
//线程睡眠 SNY (*  
public static void sleep(int nSecond) $dg9z}D  
{ c:hK$C)T  
try{ Gt-UJ-RR y  
Thread.sleep(nSecond); $:bih4@>  
} 3Qn!y\#  
catch(Exception e) mY-hN|  
{ eph)=F$  
e.printStackTrace (); LR&_2e^[  
} "8<K'zeS8  
} m#5_%3T  
B#l?IB~  
//日志 = !2NU  
public static void log(String sMsg) QwWW!8  
{ &0 \ ci9o  
System.err.println(sMsg); ~)X[(T{  
} %w}gzxN^  
wSXVyg{  
nb,2,H  
public static void log(int sMsg) 3MBN:dbQ  
{ !]koSw}  
System.err.println(sMsg); @F5f"8!.\  
} <nHkg<O6Y  
} f@ `*>"  
U~f4e7x*O  
i!H!;z#  
/* I-@?guZ r  
**TestMethod.java S\x=&Rz  
*/ p9[6^rjx8  
package NetFox; >s EjR!  
ql{_%x?  
L8$1K&!  
public class TestMethod { Ib`-pRU;  
#bnb': f  
a\5FAkI  
public TestMethod() {E_{JB~`  
{ ///xx/weblogic60b2_win.exe 2KJ1V+g@a6  
try{ `N87h"  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); blt'={Z?.x  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 8*a), 3aK  
SiteFileFetch fileFetch = new SiteFileFetch(bean); @w9{5D4  
fileFetch.start(); q!lP"J  
} P,xwSvO#M  
catch(Exception e){e.printStackTrace ();} '+y_\  
9U_ks[Qa  
%&blJ6b  
} eVz#7vqv  
</~ 6f(mg  
c0- ;VZ'  
public static void main(String[] args) d IB }_L  
{ Kuw^qX"  
new TestMethod(); ocRdbmS  
} @cvP0A  
} `}gbc69  
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