http断点续传简单实现（java)

/* ees^O{ 8  
**SiteFileFetch.java IM2/(N.%  
*/ Bzwx0c2VY8  
package NetFox; t-a`.y  
import java.io.*; *@=fq|6l 2  
import java.net.*; @YbZ8Uc  
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public class SiteFileFetch extends Thread { 4jPwL|#  
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SiteInfoBean siteInfoBean = null; //文件信息Bean %!#rrt,F  
long[] nStartPos; //开始位置 MgSp.<!  
long[] nEndPos; //结束位置 ~|J*E38  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 FW5*_%J  
long nFileLength; //文件长度 G-ZrM  
boolean bFirst = true; //是否第一次取文件 Ed8U;U b  
boolean bStop = false; //停止标志 FK?mS>G6  
File tmpFile; //文件下载的临时信息 +KYxw^k}"7  
DataOutputStream output; //输出到文件的输出流 Ig='a"%  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） yg.\^C  
public SiteFileFetch(SiteInfoBean bean) throws IOException 6Eij>{v  
{ ,5`."-0}  
siteInfoBean = bean; 20S9/9ll  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); #.RG1-L  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Kn3YI9  
if(tmpFile.exists ()) zT2F&y q  
{ 3/yt*cr  
bFirst = false; `mh-pBVD1  
read_nPos(); `,hW;p>-  
} /[p?_EX@  
else ZJ)3GF}4  
{ []sB^UT  
nStartPos = new long[bean.getNSplitter()]; jcT{ugpq  
nEndPos = new long[bean.getNSplitter()]; M^!C?(Hx^x  
} I%.jc2kK  
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} nEeQL~:  
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public void run() ^\Ue7,H-  
{ EIy]qAE:f  
//获得文件长度 U4 go8  
//分割文件 G "c&C
 
//实例FileSplitterFetch %N?W]vbra  
//启动FileSplitterFetch线程 *FI5z[8,  
//等待子线程返回 Xs.$2  
try{ /*mFP.en  
if(bFirst) GgZEg ?@  
{ 4w?]dDyc%  
nFileLength = getFileSize(); E.WNykF-  
if(nFileLength == -1) i`ZHjW~`  
{ ly[\mGr  
System.err.println("File Length is not known!"); {d*qlztO  
} 5Xq.=/eX  
else if(nFileLength == -2) 5 O{Ip-  
{ 0k.#  
System.err.println("File is not access!"); `% #zMS  
} ouu-wQ|(mM  
else 7><* 9iOW  
{ Ot4;,UZ  
for(int i=0;i<nStartPos.length;i++) *cI6&;y  
{ ?fqkM  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); K
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} |P[D2R}  
for(int i=0;i<nEndPos.length-1;i++) \M3NasZ  
{ _z"ci$[  
nEndPos = nStartPos[i+1];
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} y<Z#my$`|n  
nEndPos[nEndPos.length-1] = nFileLength; -h^} jP8  
} k8t Na@H  
} X<@y*?D9D  
:g]HB,78  
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//启动子线程 =^%Pwkz  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; eiNk]KXAYX  
for(int i=0;i<nStartPos.length;i++) :n%sU*'T  
{ qkR,<"C|`  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *9U4^lJjn  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), uq#h\p|  
nStartPos,nEndPos,i); 51FK~5  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "8j;k5<  
fileSplitterFetch.start();  xhVq  
} s+\qie  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), l2KxZteXY0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); g`f6gxc  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", QWQ6j#`  
nEndPos = " + nFileLength); Kt&$Si  
// fileSplitterFetch[nPos.length-1].start(); GXvo't@N  
9rvxp;  
V n!az}  
//等待子线程结束 :QhEu%e  
//int count = 0; u
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//是否结束while循环 ;0_J7  
boolean breakWhile = false; %`uRUex  
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while(!bStop) 3M:B?2  
{ x2IU PM  
write_nPos(); _F$t#.o  
Utility.sleep(500); m^u&g&^  
breakWhile = true; lO[jf6gB  
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for(int i=0;i<nStartPos.length;i++) )k%drdY{J'  
{ JU,RO
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if(!fileSplitterFetch.bDownOver) CCvBE, ux  
{ `/j|Rb|eow  
breakWhile = false; ,8-_=*  
break; 'jlXLb  
} [ BC%$Sj  
} 1AkHig,  
if(breakWhile) N(/<q
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break; 8&[<pbN)  
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//count++; ua>~$`@gX  
//if(count>4) 3V!&y/c<  
// siteStop(); F^
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} 5z mHb  
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System.err.println("文件下载结束！"); Vwg|?sG_  
} cb&In<q  
catch(Exception e){e.printStackTrace ();} kITmo"$K  
} _eeX]x
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//获得文件长度 Gqb-3ngH  
public long getFileSize() i1\ /\^  
{ QN8Hz/}\  
int nFileLength = -1; W_n.V" hN  
try{ 72.IhBNtT  
URL url = new URL(siteInfoBean.getSSiteURL()); 4zDAfi#0  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9NXiCP9A  
httpConnection.setRequestProperty("User-Agent","NetFox"); _llaH  
l0 :xQV`  
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int responseCode=httpConnection.getResponseCode(); BcO2* 3  
if(responseCode>=400) i4Cb&h^  
{ KKJ[  
processErrorCode(responseCode); t|"d#5'  
return -2; //-2 represent access is error ghR]$SG  
} PBnn,#  
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String sHeader; *fX)=?h56  
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for(int i=1;;i++) (pNng"/  
{ FLOJ  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); u<2sb;a  
//Utility.log(in.readLine()); 5E(P,!-.  
sHeader=httpConnection.getHeaderFieldKey(i); L%Hm#eFx  
if(sHeader!=null) yKhzymS}T  
{ @= 9y5r  
if(sHeader.equals("Content-Length")) }#^F'%zf  
{ oIgj)AY<  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); tC~itU=V  
break; :|Ty 0>k  
} h"
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} l'f!za0  
else mmK_xu~f28  
break; q0<`XDD`  
} =Bx~'RYl1d  
} KPqI(  
catch(IOException e){e.printStackTrace ();} E/ )+hK&  
catch(Exception e){e.printStackTrace ();} IGQ8-#=  
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Utility.log(nFileLength); __npX_4%S  
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return nFileLength; ^Y |s^N  
} [i_x 1  
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//保存下载信息（文件指针位置） \)WjkhG<w#  
private void write_nPos() X2Mj|_#u  
{ n4,J#h/  
try{ | w -W=v  
output = new DataOutputStream(new FileOutputStream(tmpFile)); +(0eOO'\M  
output.writeInt(nStartPos.length); =G6@:h=  
for(int i=0;i<nStartPos.length;i++) %4J?xhd  
{ V:18]:  
// output.writeLong(nPos); :f:C*mYvu  
output.writeLong(fileSplitterFetch.nStartPos); RPwSo.c4
 
output.writeLong(fileSplitterFetch.nEndPos); `!N?#N:b)  
}
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output.close(); Y.J$f<[R  
} {wySH[V  
catch(IOException e){e.printStackTrace ();} vD t?N9  
catch(Exception e){e.printStackTrace ();} s]UeDZ<a  
} )1le-SC  
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//读取保存的下载信息（文件指针位置） T8LwDqio  
private void read_nPos() >E3OYa?G  
{ `N+ P,  
try{ u#<]>EtbB  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); PoZBiw@  
int nCount = input.readInt(); t|%ul6{gz  
nStartPos = new long[nCount]; A\>qoR!
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nEndPos = new long[nCount]; '1<QK  
for(int i=0;i<nStartPos.length;i++) gqd#rj
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{ 4j5plm=  
nStartPos = input.readLong(); XOMWqQr|  
nEndPos = input.readLong(); gC_U7aw  
} IV76#jL  
input.close(); ,O(uuq  
} %|Vq"MW,I  
catch(IOException e){e.printStackTrace ();}  OxRzKT  
catch(Exception e){e.printStackTrace ();} K9c:K/H  
} [/FIY!nC?  
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private void processErrorCode(int nErrorCode) cVN|5Y  
{ qmhHHFjQ  
System.err.println("Error Code : " + nErrorCode); ?]S*=6  
} LvS`  
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//停止文件下载 Y&nY]VV  
public void siteStop() U<$|ET'  
{ -4.+
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bStop = true; {.v+ iSM  
for(int i=0;i<nStartPos.length;i++) h8Gp>b  
fileSplitterFetch.splitterStop(); YvonZ  
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} -O\`G<s%  
} 5Jd,]~KAP  
//负责部分文件的抓取 0oD?4gn  
**FileSplitterFetch.java 'Q# KjY
 
*/ /)N[tv2  
package NetFox; 72aj4k]^  
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import java.io.*; 278 6tZF,  
import java.net.*; ."${.BPn~  
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public class FileSplitterFetch extends Thread { _|3n h;-m  
}JS?42CTaV  
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String sURL; //File URL I%
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long nStartPos; //File Snippet Start Position >>p3#~/  
long nEndPos; //File Snippet End Position >k"/:g^t  
int nThreadID; //Thread's ID k z<We/  
boolean bDownOver = false; //Downing is over f5AK@]4G  
boolean bStop = false; //Stop identical e(cctC|l  
FileAccessI fileAccessI = null; //File Access interface Lf3:' n  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException -rUn4a  
{ 99vm7"5hQ  
this.sURL = sURL; {/N4/gu  
this.nStartPos = nStart; $Ad 5hkz  
this.nEndPos = nEnd; ~b*f2UVs  
nThreadID = id; VHJOj  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 in$Pk$ c  
} C,.$g>)MZK  
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public void run() jT%k{"+>+?  
{ r\Zz=~![<  
while(nStartPos < nEndPos && !bStop) vk&C'&uV9@  
{ ~]3y667  
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}sZme3*J[  
try{ Q u{#4qToA  
URL url = new URL(sURL); f3h^R20qmO  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 46Vx)xX  
httpConnection.setRequestProperty("User-Agent","NetFox"); qdWsP9}q  
String sProperty = "bytes="+nStartPos+"-"; q<dZy? f  
httpConnection.setRequestProperty("RANGE",sProperty); %&0_0BU  
Utility.log(sProperty); ND77(I$3s  
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InputStream input = httpConnection.getInputStream(); n]jZ2{g+   
//logResponseHead(httpConnection); D=i)AZqMPp  
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byte[] b = new byte[1024]; ?VmEbl
 
int nRead; 1--_E,Su>  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) -AWL :<  
{ Lj`MFZ  
nStartPos += fileAccessI.write(b,0,nRead); bdEc?  
//if(nThreadID == 1) NBU[>P  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); W{B)c?G]  
} k` cz$>  
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( E;!.=%  
Utility.log("Thread " + nThreadID + " is over!"); b;A(6^V  
bDownOver = true; C7:;<<"P  
//nPos = fileAccessI.write (b,0,nRead); R-5EztmLae  
} .93B@u  
catch(Exception e){e.printStackTrace ();} N{w)}me[YY  
} &]~Vft l  
} qRC-+k:  
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//打印回应的头信息 5'*v-l,[  
public void logResponseHead(HttpURLConnection con) `tZm  
{ h' #C$i  
for(int i=1;;i++) tj<a , l  
{ 2?J[D7  
String header=con.getHeaderFieldKey(i); tgz  
if(header!=null) 2vbm=~)$F  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); A"ApWJ3  
Utility.log(header+" : "+con.getHeaderField(header)); " b?1Yc-  
else MhT.Zg\  
break; _ljdo`j#N  
} 8y:c3jzP_  
} /-J12O  
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public void splitterStop() [R-&5 G!x  
{ J)yNp,V  
bStop = true; }fzv9$]$  
} !LDuCz -  
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}
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$;@LPE  
--X1oC52A  
/* @!;EW R]  
**FileAccess.java e(t,~(  
*//文件访问(定位，写) O:K={#Xj  
package NetFox; ~x}/>-d  
import java.io.*; #A&(b}#:o  
? dD<KCbP,  
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public class FileAccessI implements Serializable{ %(72+B70R  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ze5Hg'f  
RandomAccessFile oSavedFile; kaK0'l2%  
long nPos; P8Nzz(JF  
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public FileAccessI() throws IOException Y%1J[W  
{ +1`Zu$|  
this("",0); !%pY)69gv  
} X^pxu6nm-  
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public FileAccessI(String sName,long nPos) throws IOException Z33&FUU  
{ !`S`%\"  
oSavedFile = new RandomAccessFile(sName,"rw"); ,<,ige  
this.nPos = nPos; lP9XqQ(  
oSavedFile.seek(nPos); m%mA0r  
} >o\s'i[  
]{` 8C  
 rkp 1tv  
public synchronized int write(byte[] b,int nStart,int nLen) CTqAhL 4}  
{ !>%U8A  
int n = -1; m~upTQz  
try{ ?zypF 5a  
oSavedFile.write(b,nStart,nLen); Y6_%HYI$  
n = nLen; ,d^ze=  
} l?_h(Cq<  
catch(IOException e) c^N'g!on  
{ a{?`yO/ 2  
e.printStackTrace (); =N_7DT  
} "K.XoG4|  
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return n; XxN=vL&m  
} D][e u
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}
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/* w"-'  
**SiteInfoBean.java &e#>%0aS  
*/ 5&
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package NetFox; q>$[<TsE&}  
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public class SiteInfoBean { n?@3+wG  
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private String sSiteURL; //Site's URL "8pfLI  
private String sFilePath; //Saved File's Path Ch`nDIne  
private String sFileName; //Saved File's Name gq$]jWtCD  
private int nSplitter; //Count of Splited Downloading File k\:f2%!!  
##%R|P3  
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public SiteInfoBean() x]({Po4  
{//nSplitter的缺省值为5 ya+eGD@N':  
//default value of nSplitter is 5 \\j98(i  
this("","","",5); fO!S^<9,-  
} N9W\>hKaeh  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) QlbhQkn  
{ !PCw-&  
sSiteURL= sURL; X%S9H^9  
sFilePath = sPath; 8}Pd- .se  
sFileName = sName; $(2c0S{1  
this.nSplitter = nSpiltter; w|6;Pf~1y)  
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} YF{KSGq  
;pU#3e+P8  
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public String getSSiteURL() 'E/vE0nN?  
{ <{C oM  
return sSiteURL; 4|+6a6  
} 8aCa(Xu(H  
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public void setSSiteURL(String value) >\Qyg>Md]  
{ =rj5 q
  
sSiteURL = value; c;,jb  
} *iSsGb\M%  
[CH%(#>i~  
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public String getSFilePath() ~o:lh],~  
{ ArBgg[i  
return sFilePath; cad%:%p  
} f"h{se8C  
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public void setSFilePath(String value) 89F^I"Im(  
{ 2Y&QJon)  
sFilePath = value; #vhxW=L`=  
} @?_<A%hz  
JLT^0wBB  
i(q%E
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public String getSFileName() #vJDb |z  
{ zBWn*A[4  
return sFileName;  MD~03  
} wU_e/+0h  
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public void setSFileName(String value) y\Z7]LHCqw  
{ V7u;"vD  
sFileName = value; \p"`!n  
} *]
%{ttR~  
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)*N]Q  
public int getNSplitter() /jih;J|  
{ XGZ1a/x;s  
return nSplitter; ;4of7d  
} z.{T`Pn  
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G S-@drZp_  
public void setNSplitter(int nCount) }6}Gj8Nb  
{ v\ggFrG]  
nSplitter = nCount; [E_6n$w  
} :
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} %fMK^H8{  
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/* ]ERPWW;^  
**Utility.java [gFpFz|b<  
*/ kpi)uGvGUA  
package NetFox; YC4S,fY`  
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public class Utility { s"`uE$6N  
^R\0<\'  
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public Utility() Qjh5m5e  
{ {E!ie{~  
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} TYW$=p|  
M >Yx_)<U  
//线程睡眠 N~g@  
public static void sleep(int nSecond) :P<} bGN  
{ B<(v\=xZ  
try{ ?UnOi1"v9  
Thread.sleep(nSecond); =Y>_b 2  
} @ae;&  
catch(Exception e) IQxY]0\uf6  
{ ,TaaXI  
e.printStackTrace ();
w
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} .%;UP7g  
} ^yg`U(  
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//日志 Se+sgw_"  
public static void log(String sMsg) hu.c&Q>  
{ %k @"*  
System.err.println(sMsg); szN`"Yi){  
} jd
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public static void log(int sMsg) $EHAHNL?Lx  
{ p*E_Po  
System.err.println(sMsg); |&lAt\  
} )3PQ|r'  
} &NiDv   
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pB;)Hii\  
/* J(F]?H  
**TestMethod.java `G
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*/ YqwDvJWX  
package NetFox;  *e{d^  
fl>*>)6pm  
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public class TestMethod { [ah%>&u  
{t`UV,  
>:%YAR`  
public TestMethod() W#!![JDc  
{ ///xx/weblogic60b2_win.exe ZOvMA]Rf  
try{ v[WbQ5AND  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 7@al)G;~  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 6n37R#(  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8"l9W=  
fileFetch.start(); 1V(tt{  
} 6O2
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catch(Exception e){e.printStackTrace ();} o!EPF-:  
Tx"}]AyB6  
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} l}B,SkP^  
$$8xdv#  
w A<JJ_R  
public static void main(String[] args) =+`I%>wc  
{ S?*pCJ0  
new TestMethod(); 99
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} >v^Bn|_/  
} H)aeSF5  
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