http断点续传简单实现（java)

/* bz.sWBugR  
**SiteFileFetch.java @FF80U4'  
*/ Lcf?VV}  
package NetFox; U2CC#,b!(  
import java.io.*; 8fktk?|  
import java.net.*; q/ (h{cq  
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public class SiteFileFetch extends Thread {
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SiteInfoBean siteInfoBean = null; //文件信息Bean &.qLE  
long[] nStartPos; //开始位置 P)LOAe1'  
long[] nEndPos; //结束位置 oTrit_@3  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 mP's4  
long nFileLength; //文件长度 &h_Y?5kK  
boolean bFirst = true; //是否第一次取文件 t+
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boolean bStop = false; //停止标志 }pGjc_:']  
File tmpFile; //文件下载的临时信息 >pe!T aBN  
DataOutputStream output; //输出到文件的输出流 ;#mm_*L%@  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） g:@4/+TSt  
public SiteFileFetch(SiteInfoBean bean) throws IOException F>GPi!O  
{ [f}`reRlZ  
siteInfoBean = bean; 5.D0 1?k  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Pq@-`sw  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); sL;;'S&  
if(tmpFile.exists ()) <[u(il  
{ GVfRy@7n  
bFirst = false; ddd2w
  
read_nPos(); VTY #{  
} 1.TIUH1  
else &Pc.[k  
{ /1$u|Gs *  
nStartPos = new long[bean.getNSplitter()]; Yq4nmr4  
nEndPos = new long[bean.getNSplitter()]; cI/}rZ+  
} b"nkF\P@Fj  
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} OR37  
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public void run() &N]e pV>  
{ %~k
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//获得文件长度 P1Eg%Y6  
//分割文件 {u-J?(s}  
//实例FileSplitterFetch _dW#[TCF  
//启动FileSplitterFetch线程 #{
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//等待子线程返回 y&bZai8WlE  
try{ e+:X%a4\  
if(bFirst) _~*j=XRs  
{ v#`>  
nFileLength = getFileSize(); %9J:TH9E)  
if(nFileLength == -1) |_QpB?b  
{ 5NhAb$q2Y  
System.err.println("File Length is not known!"); qq3/K9 #y  
} W39J)~D^@  
else if(nFileLength == -2) 6q!Q(_  
{ R%q:].  
System.err.println("File is not access!"); salDGsW^  
} AEDBr<  
else 6y57m;JW/  
{ UZmo?&y  
for(int i=0;i<nStartPos.length;i++) d|)ARRW  
{ }RKsS3}   
nStartPos = (long)(i*(nFileLength/nStartPos.length)); n_k`L(8*  
} A (p^Q  
for(int i=0;i<nEndPos.length-1;i++) OW@"j;6 3`  
{ :$gs7<z{rm  
nEndPos = nStartPos[i+1]; p=#/H,2  
} E9Dy)f]#W  
nEndPos[nEndPos.length-1] = nFileLength; E7hs+Mh  
} wy{
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} :ln?PT  
R3.w")6  
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//启动子线程 :SWrx MT
 
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; HKJ^6|'  
for(int i=0;i<nStartPos.length;i++) l*huKSX}  
{ NU+PG`Vb  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), y>#kT  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), X.FoX  
nStartPos,nEndPos,i); ~4O3~Y_+GN  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _HjB'XNr(  
fileSplitterFetch.start(); SuNc&e#(  
} _MuzD&^qE  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), uXvE>VpJG  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ksOc,4A  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", R y(<6u0  
nEndPos = " + nFileLength); B&<5VjZ\  
// fileSplitterFetch[nPos.length-1].start(); m1X*I  
>[wB|V5  
lj:.}+]r  
//等待子线程结束 w=: c7Y+  
//int count = 0; cIC/3g}]  
//是否结束while循环 {'B(S/Z7  
boolean breakWhile = false; 5e1oxSU  
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while(!bStop) 1?3+>  
{ (w\|yPBB  
write_nPos(); VS_\bIC  
Utility.sleep(500); q?)5yukeF  
breakWhile = true; [O|c3;  
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for(int i=0;i<nStartPos.length;i++) !'IZr{Y>  
{ Da!vGr  
if(!fileSplitterFetch.bDownOver) qs= i+  
{ "u&7Y:)^wr  
breakWhile = false; v6|[p  
break; Z_<NUPE  
} RlU?F  
} R
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if(breakWhile) `ZO5-E  
break; i,%N#  
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//count++; ^k{/Yl  
//if(count>4) g>eWX*Pa|  
// siteStop(); m=/HUt3(&0  
} p_e x  
(n_.bSI  
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System.err.println("文件下载结束！"); }H saJ=1U  
} RBg2iG$8|  
catch(Exception e){e.printStackTrace ();} 4>H0a  
} U3v~R4  
=CS$c?  
*f{4_ts  
//获得文件长度 [D(JEO@ :  
public long getFileSize() V$;`#J$\b  
{ gp~-n7'~O  
int nFileLength = -1; O U9{Y9e  
try{ | z_av  
URL url = new URL(siteInfoBean.getSSiteURL()); Ol<LL#<j4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9&<c)sS&B  
httpConnection.setRequestProperty("User-Agent","NetFox"); YcR: _ac  
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int responseCode=httpConnection.getResponseCode(); 2`ERrh^i"  
if(responseCode>=400) Z![#Uz.z  
{ aHI~@  
processErrorCode(responseCode); \$t{K  
return -2; //-2 represent access is error 3[l\l5'm8  
} ";jAHGbO  
v&%W*M0q@  
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String sHeader; -;RAW1]}Y$  
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for(int i=1;;i++) ^h#A7 g  
{ +iQ~ Y2Gh  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); &hi
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//Utility.log(in.readLine()); IM[=]j.?  
sHeader=httpConnection.getHeaderFieldKey(i); pCa~:q
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if(sHeader!=null) rq1~%S  
{ K:Z,4Y  
if(sHeader.equals("Content-Length")) A)d0Z6G`  
{ )=aqj@v  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); */TO$ ^s  
break; C:bA:O  
} <S;YNHLC  
} LW("/  
else kI5LG6  
break; m}: X\G(6Q  
} d~QJ}a  
} IF//bgk-  
catch(IOException e){e.printStackTrace ();} -GQ.B{%G
 
catch(Exception e){e.printStackTrace ();} 2(e;pM2Dq  
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Utility.log(nFileLength); {4p7r7n'  
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return nFileLength; YYkgm:[  
} d)XT> &  
7ruWmy;j  
>Yv#t.!  
//保存下载信息（文件指针位置） c\tw#;\9  
private void write_nPos()
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{ BCd0X. m(  
try{ I>-}ys`[  
output = new DataOutputStream(new FileOutputStream(tmpFile)); *]kE3  
output.writeInt(nStartPos.length); a<+Rw{  
for(int i=0;i<nStartPos.length;i++) ,p\*cHB9  
{ AP=SCq;  
// output.writeLong(nPos); cmah
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output.writeLong(fileSplitterFetch.nStartPos); qPhVc9D#  
output.writeLong(fileSplitterFetch.nEndPos); K+yi_n L  
} p{SIGpbR&  
output.close(); Esg:  
} T).}~i;!  
catch(IOException e){e.printStackTrace ();} {c&9}u$e  
catch(Exception e){e.printStackTrace ();} P5"B7>L:  
} "e29j'u!*  
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//读取保存的下载信息（文件指针位置） +OB&PE  
private void read_nPos() [!ZYtp?Hf  
{ L9whgXD  
try{ 8-K4*(-dL
 
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Xa&:Hg<  
int nCount = input.readInt(); AJzm/,
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nStartPos = new long[nCount]; lWf(!=0m  
nEndPos = new long[nCount]; ?:zMrlX  
for(int i=0;i<nStartPos.length;i++) /T6Te<68^  
{ 'XSHl?+q  
nStartPos = input.readLong(); )
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nEndPos = input.readLong(); d{C8}U  
} U
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input.close(); mj9]M?]  
} X<1ymb3  
catch(IOException e){e.printStackTrace ();} \D[~54  
catch(Exception e){e.printStackTrace ();} L;KL
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} 9@*4^Ks p  
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private void processErrorCode(int nErrorCode) xlW>3'uHfa  
{ Me;Nn$'%  
System.err.println("Error Code : " + nErrorCode); H"2,Q T  
} HI)U6.'  
i l%9j  
_b=})**  
//停止文件下载 o%Qn%gaX  
public void siteStop() wo^1%:@/2  
{ ^$lsmF]^  
bStop = true; o`}8ZtD  
for(int i=0;i<nStartPos.length;i++) 2TaHWw<A  
fileSplitterFetch.splitterStop(); hrOp9|!m  
[|HQfTp$  
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} hDEZq>&  
} ]08
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//负责部分文件的抓取 "xD5>(|^+Q  
**FileSplitterFetch.java r1$x}I#Zv  
*/
? 5hwz  
package NetFox; "n<u(m8E  
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import java.io.*; ^}GR!990  
import java.net.*; H329P*P  
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public class FileSplitterFetch extends Thread { uRw%`J4H  
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7|?Ht]  
String sURL; //File URL jH4Wu`r;m  
long nStartPos; //File Snippet Start Position 9p"';*{=  
long nEndPos; //File Snippet End Position m$q*  
int nThreadID; //Thread's ID u #7AB>wi{  
boolean bDownOver = false; //Downing is over /B  
boolean bStop = false; //Stop identical jbTyM"Y  
FileAccessI fileAccessI = null; //File Access interface j!`2Z@  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException VU|Cct&)  
{ I~c}&'V  
this.sURL = sURL; e?-LB  
this.nStartPos = nStart; G@S'_  
this.nEndPos = nEnd; 11yS2D   
nThreadID = id; u+8?'ZT,  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 2l4`h)_q  
} *Kw/ilI  
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+;;pM[U  
public void run() m^,3jssdA  
{ HM\gO
z  
while(nStartPos < nEndPos && !bStop) %w6lNl  
{ e9?y0vT//  
rHgrCMW  
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try{ o/\z4Ri)$  
URL url = new URL(sURL); h$fC/Juit  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,Onu%  
httpConnection.setRequestProperty("User-Agent","NetFox"); F?TmOa0  
String sProperty = "bytes="+nStartPos+"-"; 6~q"#94  
httpConnection.setRequestProperty("RANGE",sProperty); 2VS#=i(B^  
Utility.log(sProperty); /ec~^S8X  
rkWW)h(e  
k\M">K0E  
InputStream input = httpConnection.getInputStream(); BH=CoD.  
//logResponseHead(httpConnection); z3-AYQ.H  
u\G\KASUK%  
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byte[] b = new byte[1024]; NW;wy;;  
int nRead; w2`j&]D6  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) aw/5#(1R  
{ n 6|\  
nStartPos += fileAccessI.write(b,0,nRead); R2[!h1nZ  
//if(nThreadID == 1) zX/9^+p:  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 38
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} Cqk6Igw  
t\C[mw  
L"!BN/i_  
Utility.log("Thread " + nThreadID + " is over!"); yh Ymbu  
bDownOver = true; gG=E2+=uy  
//nPos = fileAccessI.write (b,0,nRead); bDPT1A`F  
} _Msaub!N  
catch(Exception e){e.printStackTrace ();} \Tj(]  
}  Z@`HFZJ  
} E^. =^bR  
m,]M_y\u  

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//打印回应的头信息 K&noA  
public void logResponseHead(HttpURLConnection con) b}r3x&)  
{ ~UJ_Rr54  
for(int i=1;;i++) KcjP39@I  
{ I*K~GXWs#  
String header=con.getHeaderFieldKey(i); DavG=kvd  
if(header!=null) th*E"@  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); JEes'H}Y  
Utility.log(header+" : "+con.getHeaderField(header)); z '%Vy  
else ?5 d3k%  
break; 5ERycC y  
} SLc'1{  
} 07+Qai-]  
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public void splitterStop() `4 A%BKYB  
{ KmkPq]  
bStop = true; ),)]gw71QW  
} [e'Ts#($A  
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} oa|nQ`[  
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/* pJ5Sxgv{;  
**FileAccess.java &u_f:Pog  
*//文件访问(定位，写) 6]^}GyM!  
package NetFox; l8hOryB&  
import java.io.*; [?hc.COE  
o3l_&?^  
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public class FileAccessI implements Serializable{ !}^{W)h[  
?J~(qaa;  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 7m=tu?@  
RandomAccessFile oSavedFile; puz~Rfn#*  
long nPos; Y m|zM1qc  
>%.6n:\rG  
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'  
public FileAccessI() throws IOException }ya9 +?I  
{ pRj1b^F5y  
this("",0); D[)g-_3f6<  
} Dw^d!%Ala  
]|[oL6"  
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public FileAccessI(String sName,long nPos) throws IOException ]J C}il_b  
{ T0Q)}%L  
oSavedFile = new RandomAccessFile(sName,"rw"); yA!#>u%g  
this.nPos = nPos; |,Y(YSg.  
oSavedFile.seek(nPos); A@EeX4N  
} a<M<) {$u  
:d-+Z%Y  
Nd*zSsVlq  
public synchronized int write(byte[] b,int nStart,int nLen) N$H0o+9-Y  
{ AjK'P<:/  
int n = -1; g#1_`gK  
try{ Jn.WbS  
oSavedFile.write(b,nStart,nLen); g~Zel}h#  
n = nLen; ,\f!e#d  
} ^~2GhveBV  
catch(IOException e) 0t1WvW  
{ )sVz;rF<  
e.printStackTrace (); 5/Q^p"  
} <ok/2v
 
,&!Txyye  
n9Z|69W6>  
return n; ZO+c-!%[(  
} &gZ5dTj>  
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#!KbqRt  
} .Kr?vD^nG  
v*1UNXU\  
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/* [C)-=.Xx)j  
**SiteInfoBean.java Be+vC=\K  
*/ d:6?miMH]t  
package NetFox; g#;w)-Zj  
l-"$
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<Vr"  
public class SiteInfoBean { h\b]>q@  
VAF+\Cea=  
t7("geN]  
private String sSiteURL; //Site's URL DQd~!21\|  
private String sFilePath; //Saved File's Path HKCMK
HR  
private String sFileName; //Saved File's Name BM#cosV7%h  
private int nSplitter; //Count of Splited Downloading File
"8aw=3A  
iNgHx[*?  
XS]=sfN  
public SiteInfoBean() M& GA:`  
{//nSplitter的缺省值为5 cTFyF)  
//default value of nSplitter is 5 rE-Xv. |
 
this("","","",5); CEE`nn  
} ;Id%{1  
6)kF!/J  
b/
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) %<JjftNQ  
{ P7(+{d{  
sSiteURL= sURL; JG
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sFilePath = sPath; &+=A;Y)  
sFileName = sName; EUU9JnQhBJ  
this.nSplitter = nSpiltter; C+$dm)M/q  
iK1<4
)  
1K&z64Q5J  
} [J0L7p*6  
Y!v `0z  
tB4- of3+  
public String getSSiteURL() a5:Q%F<!  
{ %lAJ]$m  
return sSiteURL; ? r=cLC  
} )R+@vh#Q<$  
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eP$0TDZ  
public void setSSiteURL(String value) xXM`f0s@+]  
{ agN`) F!  
sSiteURL = value; )Fk%,H-1  
} {=j!2v#8~  
a0Cf.[L  

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public String getSFilePath() iV[g.sP-  
{ s(J,TS#I]  
return sFilePath; B0NK
av  
} #Na3eHT  
tWD~|<\. )  
 d>}pz  
public void setSFilePath(String value) W`K XO|'p@  
{ xxgS!J  
sFilePath = value; f2B?Zn  
} G*ZHLLO4S\  
J{Ei+@^/9  
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public String getSFileName() abU
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{ )V%xbDdS  
return sFileName; (Sr&
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} +.&#whEw(i  
=xWZJ:UnU  
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public void setSFileName(String value) {3]g3mj  
{ hWwh`Vw%  
sFileName = value; 1+v&SU  
} *<#jr  
4:=']C  
h}i /u  
public int getNSplitter() Pfu2=2Ra  
{ }x`W+r  
return nSplitter; K?,eIZ{.S  
} \@vR*E  
")"VQ|$y  
2@@OjeANsX  
public void setNSplitter(int nCount) LX'.up11X5  
{ kMAQHpDD  
nSplitter = nCount; rY_)N^B|nF  
} O E0w/{  
} T>e!DOW;  
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/* '+N!3r{G  
**Utility.java 1w/1k6`0  
*/ }$s#H{T!  
package NetFox; \dTX%<5D  
@*e|{;X]hy  
S)of.Nq.;  
public class Utility { 3t5`,R1@t  
k{(R.gLZG  
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public Utility() $As;Tvw.  
{ I?LJXo\O  
eTemRNz  
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} 7T9m@  
hJ\IE?+  
//线程睡眠 a7s
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public static void sleep(int nSecond) :0x,%V74_!  
{ 'd4I/  
try{
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Thread.sleep(nSecond); D*BZp0x  
} >UvLeS2h:y  
catch(Exception e) \B) a57  
{ _^;+_6&[  
e.printStackTrace (); YyEW}2  
} PnkJWl<S  
} EITA[Ba B`  
ivDmPHj{  
//日志 ^F2OTz4n  
public static void log(String sMsg) a3D''Ra  
{ JoeU J3N  
System.err.println(sMsg); @zo}#.g  
} 07 [%RG  
1.*VliY  
Agt6G\n  
public static void log(int sMsg) zmd,uhNc:  
{ gv)F`uRWA  
System.err.println(sMsg); z-};.!L^  
} h!.#r*vV  
} !wP|t#Sc9  
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QcQ
QQM  
/* ,{DZvif   
**TestMethod.java ETU.v*HT]  
*/ {p3VHd#  
package NetFox; W*?mc2;/  
Tj5G /H>   
JHQc)@E}  
public class TestMethod { =P'33) \ )  
Sc!]M 5  
]gHxvT\E  
public TestMethod() K5l#dl_T  
{ ///xx/weblogic60b2_win.exe .G-F5`2I  
try{ PL vz1}ts  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); FyD^\6/x  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); }#0MJ6L  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 4HXqRFUD  
fileFetch.start(); |]=. ^  
} i T* !3  
catch(Exception e){e.printStackTrace ();} ]j.=zQP?'  
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%f??O|O3  
} h M{&
if
 
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public static void main(String[] args) 5WhR|  
{ :(IPrQ  
new TestMethod(); BC!n;IAe  
} MV8Lk/zd?A  
} WH:[Y7D  
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