http断点续传简单实现（java)

/* 9@52Fg;mj  
**SiteFileFetch.java YZ7|K<   
*/ 6s\Kt3=  
package NetFox; .k9{Yv0  
import java.io.*; 7J|VD#DE$Y  
import java.net.*; 0-|byAh  
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public class SiteFileFetch extends Thread { !{)tSipd  
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SiteInfoBean siteInfoBean = null; //文件信息Bean w{uuSe  
long[] nStartPos; //开始位置 T2Y,U {  
long[] nEndPos; //结束位置 g'=B%eO$j:  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 .I'o  
long nFileLength; //文件长度 c`WHNky%j  
boolean bFirst = true; //是否第一次取文件 R~jHr )0.#  
boolean bStop = false; //停止标志 IS[thbzkZ  
File tmpFile; //文件下载的临时信息 ./
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DataOutputStream output; //输出到文件的输出流 IlE_@gS8  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） =gvBz| +  
public SiteFileFetch(SiteInfoBean bean) throws IOException r8&^>4  
{ OD 3f.fT  
siteInfoBean = bean;
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 4RV%Z!kcD!  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); * Y7jl#7  
if(tmpFile.exists ()) `|#Qx3n%  
{ 2aB^WY'tC  
bFirst = false; B`o]*"xkB  
read_nPos(); 0i|oYaC  
} rB
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else \nB8WSvk2W  
{ 4jBC9b}O  
nStartPos = new long[bean.getNSplitter()]; <~!Hx+j   
nEndPos = new long[bean.getNSplitter()]; eKz?"g/j  
} iNWo"=J  
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} T<@cd|`  
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public void run() ~$f;U  
{ E55t*^`  
//获得文件长度 !\#_Jw%y  
//分割文件 <b?!jV7  
//实例FileSplitterFetch u4neXYSy  
//启动FileSplitterFetch线程 bb`':3%  
//等待子线程返回 P<2+L|X?}  
try{ |vMpXiMxxT  
if(bFirst) saAxGG  
{ 4)4+M  
nFileLength = getFileSize(); wwoweztER  
if(nFileLength == -1) uy^   
{ V&|Ed  
System.err.println("File Length is not known!"); ?EpSC&S\  
} E)-r+ <l  
else if(nFileLength == -2) }KKY6D|d>  
{ #D9e$E(J^  
System.err.println("File is not access!"); 2gjGeM  
} zrv#Xa!O\  
else ^6P3%  
{ 6ubL1K  
for(int i=0;i<nStartPos.length;i++) fr}Eaa-{^  
{ X_G| hx  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); kctzNGF|  
} he-Ji  
for(int i=0;i<nEndPos.length-1;i++) +"}=d3E6  
{ q4$+H{xB  
nEndPos = nStartPos[i+1]; F3lw@b3])  
} xc:!cA{V  
nEndPos[nEndPos.length-1] = nFileLength; !W'Ui 9uX  
} ~!d/8?!  
} y}K\%;`[a  
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//启动子线程 (j"(  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Rek -`ki5F  
for(int i=0;i<nStartPos.length;i++) "ZHtR/;  
{ q
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), FvuGup`w  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), bo=ZM9  
nStartPos,nEndPos,i); !.<T"8BUpv  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); f8<o8*`7  
fileSplitterFetch.start(); R%H$%cnj  
} %F9{EXJy  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), o}'bv  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); $hVYTy~}  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ]PP:oriWl  
nEndPos = " + nFileLength); W Qzj[  
// fileSplitterFetch[nPos.length-1].start(); lhYn5d)DV  
q*AQq=  
#W2[  
//等待子线程结束 Y'3}G<'%  
//int count = 0; asgF1?r  
//是否结束while循环 FNQX7O52  
boolean breakWhile = false; {8EW)4Hf  
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while(!bStop) cj|*_}
 
{ u%dKig  
write_nPos(); %_aMl  
Utility.sleep(500); w$5A|%Y+V}  
breakWhile = true; PS" .R
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for(int i=0;i<nStartPos.length;i++) /<3<. ~  
{ geefnb  
if(!fileSplitterFetch.bDownOver) f
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{ xg{HQQ|TC  
breakWhile = false; j?|* LT$%7  
break; -(JUd4#  
} {,j6\Cj4  
} Pe~`16f  
if(breakWhile) k)FmDX  
break; &?p
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6Bm9?eU0  
6`"M
 
//count++; SnTDLa  
//if(count>4) ])#\_'fg  
// siteStop(); %im#ww L%  
} kao}(?x%  
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System.err.println("文件下载结束！"); =]Hs|{  
} }98>5%Uv  
catch(Exception e){e.printStackTrace ();} 3Gr&p6  
} D0]a\,aZ  
g#K'6VK{  
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//获得文件长度 iY/KSX^~O  
public long getFileSize() o8FXqTUcs4  
{ q
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int nFileLength = -1; qturd7  
try{ qq0?e0H  
URL url = new URL(siteInfoBean.getSSiteURL()); Y&r]lD
 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); h#Ce_,o  
httpConnection.setRequestProperty("User-Agent","NetFox"); Cw,D{  
h:Ndzp{  
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int responseCode=httpConnection.getResponseCode(); ;+I4&VieK  
if(responseCode>=400) v
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{ C;\VO)]t  
processErrorCode(responseCode); Y5!b)vke  
return -2; //-2 represent access is error cf[vf!vi  
} r<L#q)]  
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String sHeader; gw3NS8 A+  
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for(int i=1;;i++) +ydm,aKk  
{ WA.\*Nqze  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 4W\,y_Qo  
//Utility.log(in.readLine()); ]B
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sHeader=httpConnection.getHeaderFieldKey(i); mKg@W;0ML  
if(sHeader!=null) 02]xJo  
{ *"G8  
if(sHeader.equals("Content-Length")) JA
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{ ,R-Y~+!  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Q)Dwq?  
break; `:
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} 1
}`LTPW9  
} abY0)t  
else cvAtwQ'  
break; }w!ps{*  
} ":d*dl  
} jgvh[@uB?  
catch(IOException e){e.printStackTrace ();} :?r*p>0$  
catch(Exception e){e.printStackTrace ();} (@ea|Fd#4  
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Utility.log(nFileLength); -%uy63LbHF  
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return nFileLength; <
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} dB|Te"6  
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//保存下载信息（文件指针位置） gB CC  
private void write_nPos() {>.>7{7  
{ m(3);)d  
try{ 4IGxI7~27#  
output = new DataOutputStream(new FileOutputStream(tmpFile)); T=? bdIl  
output.writeInt(nStartPos.length); .{N\<01  
for(int i=0;i<nStartPos.length;i++) )Ul&1UYA  
{ yer> x  
// output.writeLong(nPos); .g-3e"@  
output.writeLong(fileSplitterFetch.nStartPos); {u]CHN`%Z  
output.writeLong(fileSplitterFetch.nEndPos); TSyzdnMvz  
} o#d$[oa  
output.close(); L/k40cEI^z  
} WX*cICb5  
catch(IOException e){e.printStackTrace ();} mvf _@2^  
catch(Exception e){e.printStackTrace ();} hrlCKL&  
} O~Uw&Bq  
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//读取保存的下载信息（文件指针位置） >7FSH"8[,  
private void read_nPos() -g2{681`r  
{ G(i\'#5+  
try{ lZ~+u  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); t61'LCEis  
int nCount = input.readInt(); @c"yAy^t  
nStartPos = new long[nCount]; h2}am:%mC  
nEndPos = new long[nCount]; *Ypqq  
for(int i=0;i<nStartPos.length;i++) ~iT{8  
{ U3q5^{0d/  
nStartPos = input.readLong(); byj[u!{  
nEndPos = input.readLong(); z`9l<Q/  
} {dZ8;Fy4  
input.close(); 9XN~Ln@}  
} 2<.Vv\ =  
catch(IOException e){e.printStackTrace ();} 2?*1~ 5~I  
catch(Exception e){e.printStackTrace ();} `t\z   
} 2wOy}:  
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lWl-@*'  
private void processErrorCode(int nErrorCode) w})NmaT;YF  
{ `hF;$  
System.err.println("Error Code : " + nErrorCode); g Np-f  
} l_sg)Vr/b  
v=bv@c  
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//停止文件下载 }Ch[|D=Wd6  
public void siteStop() &x/k^p=  
{ Y=WR6!{  
bStop = true; NQ3|\<Wt  
for(int i=0;i<nStartPos.length;i++) i~AJ.@ #  
fileSplitterFetch.splitterStop(); AuM:2N2  
L(Rorf~V  
~g96o81V  
} E#~2wqK  
} Gm*Uv6?H?  
//负责部分文件的抓取 ht$ WF  
**FileSplitterFetch.java D1~^\)*  
*/ 3\9][S-B  
package NetFox; pgfu+K7?w  
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import java.io.*; S%
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import java.net.*; `w(sXkeaI  
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public class FileSplitterFetch extends Thread { <W9) Bq4  
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String sURL; //File URL :EaiM J_=  
long nStartPos; //File Snippet Start Position {C, #rj  
long nEndPos; //File Snippet End Position ^8U6"O6|X  
int nThreadID; //Thread's ID ma`w\8a  
boolean bDownOver = false; //Downing is over A9.;>8!u  
boolean bStop = false; //Stop identical 92NC]_jw  
FileAccessI fileAccessI = null; //File Access interface -q|*M:R  
| )S{(#k  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException >T$7{ ~  
{ 3# :EK M~!  
this.sURL = sURL; <X9T-b"$h  
this.nStartPos = nStart; dR%q1Y&`  
this.nEndPos = nEnd; o|BFvhg  
nThreadID = id; ="=#5C  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 k@lXXII ?  
} f>b!-|  
5]Z]j[8Y  
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public void run() k.h^ $f  
{ olslzXn7o  
while(nStartPos < nEndPos && !bStop) +&zb^C`J  
{ !cv6 #:  
=NI.d>kvC  
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try{ ~|J*E38  
URL url = new URL(sURL); @b>YkJDk  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); q8tP29  
httpConnection.setRequestProperty("User-Agent","NetFox"); {!>E9Px  
String sProperty = "bytes="+nStartPos+"-"; =54Vs8.  
httpConnection.setRequestProperty("RANGE",sProperty); )OS>9 kFH  
Utility.log(sProperty); ENpaaW@!Y  
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InputStream input = httpConnection.getInputStream(); c@)pKi#W  
//logResponseHead(httpConnection); L)j]~^P$-  
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byte[] b = new byte[1024]; ejDCmD  
int nRead; wZ}n3R,   
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) u_hE7#i  
{ D'Jm!Ap  
nStartPos += fileAccessI.write(b,0,nRead); `8qT['`#R  
//if(nThreadID == 1) 20S9/9ll  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;N9n'Sq4  
} _-YL!oP  
@5JL
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Utility.log("Thread " + nThreadID + " is over!"); o x03c  
bDownOver = true; -(|7`U  
//nPos = fileAccessI.write (b,0,nRead); Qj{$dqmDN  
} `mh-pBVD1  
catch(Exception e){e.printStackTrace ();} Q;d+]xj  
} H,01o5J  
} j P{:A9T\  
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{  
//打印回应的头信息 i,C0o  
public void logResponseHead(HttpURLConnection con) ?nj"Ptzs  
{ +6i7,U  
for(int i=1;;i++) -d\AiT  
{ {yul.m  
String header=con.getHeaderFieldKey(i); iDyMWlV  
if(header!=null) yd{Y}.  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); K*J4&5?/  
Utility.log(header+" : "+con.getHeaderField(header)); dVjcK/T<  
else 8N</Yi|n  
break; \pT^Zhp)  
} $l0eI  
} 58a)&s[+  
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public void splitterStop() 401/33yBJ  
{ HMl!?%%  
bStop = true; i
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} )M&I)In'  
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} tIc0S!H#  
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8YT_DM5iI  
/* .x\/XlM  
**FileAccess.java P'FPe55F  
*//文件访问(定位，写) t1*BWY  
package NetFox; !HT>  
import java.io.*; %B*<BgJ;4F  
gdkLPZ<<  
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public class FileAccessI implements Serializable{ y^0HCp{  
4w?]dDyc%  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 fwar8 i1  
RandomAccessFile oSavedFile; C.Wms}XA  
long nPos; i`ZHjW~`  
?[NTw./'7A  
QI :/,w  
public FileAccessI() throws IOException mfp`Iy"}+  
{ ~{3o(gzl  
this("",0); n9mM5H47  
} ImT+8pa  

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public FileAccessI(String sName,long nPos) throws IOException 7>c 0V&  
{ Q
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oSavedFile = new RandomAccessFile(sName,"rw"); c)n0D=  
this.nPos = nPos; 6@,'m  
oSavedFile.seek(nPos); Q T0IW(A  
} 6cgpg+-a  
)\:lYI}Wpm  
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public synchronized int write(byte[] b,int nStart,int nLen) !z"a_  
{ m;$F@JJ  
int n = -1; k=d%.kg  
try{ 6@ (k8<3  
oSavedFile.write(b,nStart,nLen); nEZ-h7lzl(  
n = nLen; q:D0$YY0  
} o q'J*6r  
catch(IOException e) 5Qm.ECXV  
{ y:^>
(l#;  
e.printStackTrace (); sEgeS9a{  
} Fh3Dc 83~  
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return n; OJC*|kN-#^  
} E-7a`S  
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} cr=FMfhB  
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66Cj=n5  
/* L3hxe]mr  
**SiteInfoBean.java =^%Pwkz  
*/ hjm.Ath  
package NetFox; d q+7K  

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HnKF#<  
public class SiteInfoBean { >R'VY "\  
19YJ`(L`x  
VgC9'"|  
private String sSiteURL; //Site's URL ;29XvhS8  
private String sFilePath; //Saved File's Path D+vl%(g  
private String sFileName; //Saved File's Name $M8>SLd  
private int nSplitter; //Count of Splited Downloading File ^w.(*;/  
#mz,HK0|aC  
Ws}kb@5  
public SiteInfoBean() q[,R%6&'  
{//nSplitter的缺省值为5 f4\p1MYQ  
//default value of nSplitter is 5 *M\i4FO8  
this("","","",5); 88+\mX;A#  
} j}x O34  
e>i8=U`;  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) =QxE-)v  
{ +h\W~muR  
sSiteURL= sURL; kAe-d  
sFilePath = sPath; I!i#=  
sFileName = sName; `sp'Cl!  
this.nSplitter = nSpiltter; ,h)T
(  
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6@_@nlA<1  
} 0g*r!aa  
;?L[]Ezzt  
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public String getSSiteURL() 4`'BaUU(  
{ %`uRUex  
return sSiteURL; /IQ-|Qkg  
} `b'|FKc]  
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public void setSSiteURL(String value) YC,.Y{oY{  
{ tEs[zo+DR-  
sSiteURL = value; X-) ]lAP  
} kBQenMm  
: 1f5;]%N  
V/wc[p ~  
public String getSFilePath() C9;X6  
{ $\J9F=<a  
return sFilePath; jX8C2}j  
} ,knI26Jh  
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>*Z{@1*h  
public void setSFilePath(String value) )k%drdY{J'  
{ z%gtV'  
sFilePath = value; c+K=pp@  
} uJ5%JB("E  
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public String getSFileName() Dqcu$V]  
{ e.Q K%  
return sFileName; 'jlXLb  
} a>jI_)L  
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public void setSFileName(String value) 3Os3=Ix  
{ O.8m%ZjD  
sFileName = value; )Ai%wCzw*  
} YH+\rb_  
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public int getNSplitter() Y>!W&Gtu  
{ R~c vml  
return nSplitter; o0+BQ&A)s*  
} oX~$'/2v  
%-p{?=:K  
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public void setNSplitter(int nCount) ^9f`3~!#bc  
{ xgw)`>p,W  
nSplitter = nCount; Bst>9V&R  
} 7a_n\]t465  
} d"`
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+6Fdi*:  
&)}:Y!qiu  
/* >xMhA`
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**Utility.java t }C ^E  
*/ >(4S `}K  
package NetFox; r@ *A  
92ww[+RQ@  
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public class Utility { 2_~XjwKE  
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public Utility() Z/UVKJm>:  
{ |a:Vp
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]~eWr2uG?  
} GYmBxX87  
}u
j'BO2?  
//线程睡眠 d3J_IW+8R$  
public static void sleep(int nSecond) 2*DS_=6o  
{ V~"d`j  
try{ Z8n%=(He  
Thread.sleep(nSecond); W$&Ets8zo  
} /;m!>{({)  
catch(Exception e) >w#3fTJ  
{ .vF<3p|  
e.printStackTrace (); ]=VI"v<X  
} >w;W&[  
} 0$Db@  
*(.^$Iq4  
//日志 s-S"\zX\D  
public static void log(String sMsg)
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{ BQ)43Rr>  
System.err.println(sMsg); Jl9TMu!1]  
} _rh.z_a7w  
BCB/cBE  
<a}|G1 h  
public static void log(int sMsg) zd]L9 _  
{ ^G<M+RF2J  
System.err.println(sMsg); !0+Ex F  
} ,/U9v~  
} ri V/wN9C  
{!bJ.O l  
t[ocp
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/* T mE4p  
**TestMethod.java !h(0b*FUJ  
*/ Ui
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package NetFox; pg`;)@  
g7yHhF>%X  
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public class TestMethod { +6-!o,(  
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public TestMethod() )yAPYC
 
{ ///xx/weblogic60b2_win.exe zXPj7K*  
try{ w'>v@`y  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 5E(P,!-.  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 3goJ(XI  
SiteFileFetch fileFetch = new SiteFileFetch(bean); _j tS-CnO  
fileFetch.start(); aJ@qB9(ZBe  
} IKpx~  
catch(Exception e){e.printStackTrace ();} N Uml"  
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$^ 3 f}IzA  
} j"=jK^  
e-t`\5b
;  
{<BK@U  
public static void main(String[] args) ,gD i)]  
{ e@VRdhb  
new TestMethod(); ^/,yZ:  
} mmK_xu~f28  
} U<gw<[>f  
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