http断点续传简单实现（java)

/* 0qNk.1pv  
**SiteFileFetch.java -crMO57/  
*/ RI8*'~ix]  
package NetFox; VLm\PS   
import java.io.*; yJ!26  
import java.net.*; &UH0Tw4   
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public class SiteFileFetch extends Thread { L[2N zwO  
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SiteInfoBean siteInfoBean = null; //文件信息Bean }+m4(lpl  
long[] nStartPos; //开始位置 Ydrh+  
long[] nEndPos; //结束位置 2 %fcDEG/  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 # l9VTzi  
long nFileLength; //文件长度 m^XO77"  
boolean bFirst = true; //是否第一次取文件 yn!;Z._  
boolean bStop = false; //停止标志 s~Ivq+ipr;  
File tmpFile; //文件下载的临时信息 k-jFT3b$  
DataOutputStream output; //输出到文件的输出流 S6M7^_B4F  
^&&Wv'7XQ  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） yFk|8d-|  
public SiteFileFetch(SiteInfoBean bean) throws IOException _k]R6V:  
{ `5- ;'nX  
siteInfoBean = bean; <VD7(j]'^  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); C<teZz8/w  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ggPGKY-b=  
if(tmpFile.exists ()) &*/= `=:C8  
{ =b*GV6b  
bFirst = false; h'S0XU ;  
read_nPos(); TP#Ncqh  
} Io<T'K  
else bp'%UgA)1  
{ 5rLx b  
nStartPos = new long[bean.getNSplitter()]; fUf1G{4  
nEndPos = new long[bean.getNSplitter()]; 69$R.  
} ZhCd**  
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} OP+*%$wR  
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public void run() 3(K.:376  
{ 8!35 K  
//获得文件长度 Vp; `!+z"  
//分割文件 +mBS&FK  
//实例FileSplitterFetch to).PI?  
//启动FileSplitterFetch线程 r&xIVFPI[  
//等待子线程返回 O1jiD_Y!9  
try{ #m{(aa9;  
if(bFirst) C+t3a@&|  
{ K?,?.!ev
 
nFileLength = getFileSize(); EG^ rh;  
if(nFileLength == -1) #f(tzPD  
{ nW
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System.err.println("File Length is not known!"); 8Ys)qx>7'  
} }.D18bE(  
else if(nFileLength == -2) V?yQm4  
{ MPnMLUB$\  
System.err.println("File is not access!"); *PlKl_nP6  
} :j~4mb?$  
else ;Egl8Vhr  
{ 
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for(int i=0;i<nStartPos.length;i++) KW'nW  
{ >!Y#2]@}o  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ^7>~y(  
} 5q@s6_"{  
for(int i=0;i<nEndPos.length-1;i++) 00IW9B-  
{ PdVY tK%  
nEndPos = nStartPos[i+1]; f%n ;Z}=  
} ;\}dQsX  
nEndPos[nEndPos.length-1] = nFileLength; }>AA[ba"'  
} |8{ k,!P'K  
} HABUf^~-  
LsI@_,XW<  
+ R6X  
//启动子线程 CB9:53zK9  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; #\N8E-d  
for(int i=0;i<nStartPos.length;i++) %x,HQNRDU  
{ 1O,5bi>t7  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4E=QO!pVv  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Chl^LEN:  
nStartPos,nEndPos,i); dY.X/f  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); eN5F@isy  
fileSplitterFetch.start(); VWt=9D;  
} n&&C(#mBC  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :Nf(:D8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); unFm~rcf  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", U.Vn|s(`z  
nEndPos = " + nFileLength); xX<T5Ls  
// fileSplitterFetch[nPos.length-1].start(); |1H9,:*%  
n|WSnm,W  
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//等待子线程结束 eu)""l  
//int count = 0; H(Wiy@cJn  
//是否结束while循环 kLF3s#k  
boolean breakWhile = false; -4Dz98du  
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.KG9YGL#  
while(!bStop) cV1E<CM  
{ 2s,cyCw&  
write_nPos(); e/x 9@1s#  
Utility.sleep(500); Tt{X(I} J  
breakWhile = true; GMZ6 dK  
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for(int i=0;i<nStartPos.length;i++) ,>qtnwvlHP  
{ L Y4bn)Qf  
if(!fileSplitterFetch.bDownOver) $s ,g&7*-  
{ si~zg\uY  
breakWhile = false; Ui"$A/  
break; _IEbRVpb  
} ~x4]p|)</  
} ^^ SMr l  
if(breakWhile) ^o>WCU=  
break; OXZK|C;M}  
*C|*{!  
90F.9rh  
//count++; "+{2!  
//if(count>4) ?HOnDw.v1  
// siteStop(); U7/ =|Z  
} S
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System.err.println("文件下载结束！"); ;H8`^;  
} DfGq m-c  
catch(Exception e){e.printStackTrace ();} oP
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} =B+dhZ+#S$  
]!1HN3  
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//获得文件长度 ]X7_ji(l,  
public long getFileSize() .i?{h/9y  
{ B k\KG  
int nFileLength = -1; KCbOO8cQS  
try{ ('uUf!h?\  
URL url = new URL(siteInfoBean.getSSiteURL()); P!j*4t  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]C+PJ:CC  
httpConnection.setRequestProperty("User-Agent","NetFox"); kuLur)^
 
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5i{J0/'Xu)  
int responseCode=httpConnection.getResponseCode(); sm[zE/2b  
if(responseCode>=400) FncP,F$8   
{ wj'fdrY5h  
processErrorCode(responseCode); X-bM`7'H  
return -2; //-2 represent access is error bs% RWwn  
} FB,rQ9D  
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String sHeader; 6W]C`  
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for(int i=1;;i++) w .M  
{ i*4v!(E  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); e50xcf1u  
//Utility.log(in.readLine()); 8eh3K8tL#  
sHeader=httpConnection.getHeaderFieldKey(i); yO
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if(sHeader!=null) #jxPh!%9  
{ p}I\H ^"8+  
if(sHeader.equals("Content-Length")) D'D IC  
{ *>EV4Hl  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); L`Ys`7  
break; 2.@IfBF6  
} Z6WNMQ1:  
} #U3q +d+^  
else  RZqMpW  
break; Xa"I  
} C[
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} &0ymAf5R  
catch(IOException e){e.printStackTrace ();} }a UQ#x  
catch(Exception e){e.printStackTrace ();} y'oH>l+n  
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Utility.log(nFileLength); f/.f08  
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return nFileLength; 1B 0[dK2N  
} n#?y;Y\  
#IqRu:csp  
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//保存下载信息（文件指针位置） FSkX95  
private void write_nPos() SuV3$-);z  
{ x=\W TC  
try{ hSps9*y  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 0;w 4WJJ  
output.writeInt(nStartPos.length); siV]NI':|  
for(int i=0;i<nStartPos.length;i++) sQrM"i0Y>  
{ gCL}Ba  
// output.writeLong(nPos); 4`V&Yqwl  
output.writeLong(fileSplitterFetch.nStartPos); wYS r.T8Q  
output.writeLong(fileSplitterFetch.nEndPos); BG4TUt  
} l\m7~  
output.close(); YiL^KK  
} Kj?hcGl[  
catch(IOException e){e.printStackTrace ();} D~Q-:G$x  
catch(Exception e){e.printStackTrace ();} j@UE#I|h  
} 8{&.[SC7  
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//读取保存的下载信息（文件指针位置） @,G\`;Ma  
private void read_nPos() .M[t5I'\  
{ xA*6Z)Y  
try{ AS4oz:B  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); CqX*.j{  
int nCount = input.readInt(); m("KLp8  
nStartPos = new long[nCount]; x>J(3I5_b  
nEndPos = new long[nCount]; Cnu])R  
for(int i=0;i<nStartPos.length;i++) p~(STHDe#  
{ `oO*ORq&  
nStartPos = input.readLong(); (2 hI  
nEndPos = input.readLong(); N /;Vg^Wx  
} ~xJr|_,gp  
input.close(); AOqL&z
 
} fCO<-L9k$  
catch(IOException e){e.printStackTrace ();}  Lo)T  
catch(Exception e){e.printStackTrace ();} h]Gvt 5  
} PyQ\O*  
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private void processErrorCode(int nErrorCode) \mt Y_O  
{ `Xi)';p  
System.err.println("Error Code : " + nErrorCode); Iy4REP|  
} OzTR#`oey  
( pCU:'"  
mZnsr@KF  
//停止文件下载 >V%.=})K  
public void siteStop() NXS$w{^  
{ h>z5m  
bStop = true; tC/+  
for(int i=0;i<nStartPos.length;i++) )2jH&}K  
fileSplitterFetch.splitterStop(); wr>6Go%  
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} ^>fr+3a"P  
} x%dVD  
//负责部分文件的抓取 eQfXUpk3@I  
**FileSplitterFetch.java T&<ee|t@{  
*/ y"_rDj`  
package NetFox; O^3XhTW^\~  
aOUTKyR ~  
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import java.io.*; $>wN:uN(  
import java.net.*; + :b"0pu-H  
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public class FileSplitterFetch extends Thread { $9G".T  
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String sURL; //File URL ?'t
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long nStartPos; //File Snippet Start Position Pn?gB}l  
long nEndPos; //File Snippet End Position vXak5iq>X  
int nThreadID; //Thread's ID {s2eOL5I|%  
boolean bDownOver = false; //Downing is over I3ugBLxVC3  
boolean bStop = false; //Stop identical iqWkhJphv  
FileAccessI fileAccessI = null; //File Access interface _Qb].~  
lI9|"^n7F  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 7VLn$q]:  
{ +Q:)zE  
this.sURL = sURL; +\.0Pr  
this.nStartPos = nStart; JFkx=![  
this.nEndPos = nEnd; P;IM -]  
nThreadID = id; l5enlYH  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 k/Q8:qA  
} DKNcp8<J  
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&5%~Qw..  
public void run() {Bpu-R&T  
{ @G|z_  
while(nStartPos < nEndPos && !bStop) 8K\S]SZ  
{ E6?
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}C JK9*Z  
try{ "2"2qZ*h}  
URL url = new URL(sURL); 8&7zV:=
  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); AbX#wpp!  
httpConnection.setRequestProperty("User-Agent","NetFox"); @[TSJi  
String sProperty = "bytes="+nStartPos+"-"; !]8QOn7=  
httpConnection.setRequestProperty("RANGE",sProperty); DeQZDY //  
Utility.log(sProperty);
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InputStream input = httpConnection.getInputStream(); ?:7$c  
//logResponseHead(httpConnection); OHH\sA  
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byte[] b = new byte[1024]; y@ c[S;  
int nRead; {@tO9pc`8  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) t+Qx-sW  
{ ;"NW=P&  
nStartPos += fileAccessI.write(b,0,nRead); * YLpC^&  
//if(nThreadID == 1) d(,M  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); c
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} ypTH=]y  
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Utility.log("Thread " + nThreadID + " is over!"); iu`B8yI  
bDownOver = true; 87R$Y> V  
//nPos = fileAccessI.write (b,0,nRead); =o[H2o y  
} {t('`z  
catch(Exception e){e.printStackTrace ();} |O*?[|`H  
} ,
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} h0-CTPQ7A  
6
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//打印回应的头信息 EB p(^rj  
public void logResponseHead(HttpURLConnection con) 2=n,{rkmj%  
{ $N4i)>&T2  
for(int i=1;;i++)
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{ af=lzKt*  
String header=con.getHeaderFieldKey(i); |u[@g`Z  
if(header!=null) "l(<<Ha/  
//responseHeaders.put(header,httpConnection.getHeaderField(header));
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Utility.log(header+" : "+con.getHeaderField(header)); *nHkK!d<N  
else R`%O=S*]  
break; 0BP=SCi  
} Co:Rg@i(F  
} r<$"T  
;4*mUD6  
W"D>>]$|u  
public void splitterStop() &M#}?@!C  
{ p7,dl*'  
bStop = true; +GNXV-S  
} [XD3}'Aa  
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} 8HDI]  
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/,+&O#SX  
/* cXt]55"  
**FileAccess.java TcH7!fUj  
*//文件访问(定位，写)  YS>VQl  
package NetFox; &[[Hfs2:-]  
import java.io.*; r@G34QC+  
GOX2'N\h^  

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public class FileAccessI implements Serializable{ 5Qxm\?0J
  
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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 xsx0Zo
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RandomAccessFile oSavedFile; *,Sa*-7(  
long nPos; `m-7L  
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public FileAccessI() throws IOException ]KQBek#DD  
{ ]fU0;jzX  
this("",0); ,veI'WHMB  
} Bv^5L>JZ/  
.QDeS|l  
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public FileAccessI(String sName,long nPos) throws IOException Y5
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{ f}Uf*Bp  
oSavedFile = new RandomAccessFile(sName,"rw"); v.>95|8  
this.nPos = nPos; [9~6, ;6  
oSavedFile.seek(nPos); nOU.=N v`  
} *YP;HL  
H) q_9<;  
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public synchronized int write(byte[] b,int nStart,int nLen) x,QXOh\a  
{ sE\Cv2Gx  
int n = -1; Tuy5h5  
try{ OJ<V<=MYZ  
oSavedFile.write(b,nStart,nLen); l'Uj"9r,  
n = nLen; {\n?IGP?wd  
} u
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catch(IOException e) P:m6:F@hO  
{ p9~$}!ua  
e.printStackTrace (); dU|&- .rG  
} #9q ]jjH E  
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p^ )iC&*0  
return n; DP!~WkU~  
} h:<?)g~U  
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} qyR}|<F8*  
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=dY!-#yg!  
/* KKNQ+'?  
**SiteInfoBean.java 8]l(D  
*/ \s,~|0_V  
package NetFox; $u::(s} x<  
mN1n/LNi  
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public class SiteInfoBean { hfRxZ>O2  
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i: VMCNH  
private String sSiteURL; //Site's URL IkgRZ{Y  
private String sFilePath; //Saved File's Path Lwkl*  
private String sFileName; //Saved File's Name ^NFL3v8  
private int nSplitter; //Count of Splited Downloading File {,e-;2q  
J{PNB{v  
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public SiteInfoBean() W]M Fq5.  
{//nSplitter的缺省值为5 4ms"mIt  
//default value of nSplitter is 5 o}y(T07n  
this("","","",5); {z |+.D  
} (E7C9U*  
sQMfU{S /  
,
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) h|OWtf4  
{ `"y:/F"{
 
sSiteURL= sURL; M^.>UZKyl  
sFilePath = sPath; {EyWS
f"  
sFileName = sName; ?I;PJj  
this.nSplitter = nSpiltter; B1b9 JS(>  
M,oRi;V  
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} }hS$F  
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public String getSSiteURL() 8_T9[]7V8  
{ \n^;r|J7k  
return sSiteURL; mQ^SpK #  
} xtzkgb,0[  
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P5&8^YV`N  
public void setSSiteURL(String value) {ukQBu#}<  
{ !twYjOryH[  
sSiteURL = value; N;i\.oY  
} |P7FP
mn  
=JN{j2xY  
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public String getSFilePath() +3]V>Mv  
{ ln_[@K[oX  
return sFilePath; D|IS@gWa  
} '8;'V%[+  
Pdk#"H-j  
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public void setSFilePath(String value) Qn)AS1pL+  
{ Nu@dMG<5  
sFilePath = value; | &/_{T  
} e;9x%kNs!  
Mt&n|']`8  
@nIoIz D~  
public String getSFileName() gPIl:, d(  
{ !EGpI@  
return sFileName; E_Fm5zb?X  
} K7wU tg  
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public void setSFileName(String value) - #-Bo  
{ 6dhzx; A  
sFileName = value; HSEz20s  
} ku
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=4gPoS  
|2Uw8M7.E  
public int getNSplitter() 3e)$<e  
{ {2U3   
return nSplitter; y-mjfW`n  
} ;Swy5z0=ro  
\Yh*ywwP#  
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public void setNSplitter(int nCount) ^ LVKXr  
{ me$nP}%C&  
nSplitter = nCount; wxy@XN"/i+  
} -Sa-eWP  
} z-h?Q4;  
h;):TFiC  
2Q;rSe._`  
/* C=JS]2W2  
**Utility.java x|)pZa  
*/ A[uB)wWsn  
package NetFox; Jv?EV,S/e  
S{N=9934_  
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public class Utility { gnw">H  
9(lcQuE9  
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public Utility() vb3hDy  
{ ?0+N  
svtqX-Vj"  
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} yYdh+x  
d '\^S}  
//线程睡眠 0 gR_1~3  
public static void sleep(int nSecond) S}qGf%  
{ ijKQ`}JA  
try{ ]d.e(yCuE  
Thread.sleep(nSecond); (6&"(}Pai  
} O)D$
UG\<  
catch(Exception e) Xh}G=1}  
{ C9*[/|T  
e.printStackTrace (); ,h<xY>  
} pUa\YO1J  
} yatZAl(B  
M5 ^qc  
//日志 }:(;mW8 D  
public static void log(String sMsg) z>)lp$  
{ `nY.&YT  
System.err.println(sMsg); 1'|g
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} NdrR+t^#  
yQf(/Uxk*x  
N_d{E/  
public static void log(int sMsg) 2Sk"S/4}Z  
{ k106fT]eX  
System.err.println(sMsg); #Y'ewu;qJ  
} 5F#FC89Kk  
} yT[=!M  
-Ua&/Yd/}  
Z/d {v:)  
/* ^ 4*#QtO  
**TestMethod.java s"p\-Z  
*/ z<gII~%  
package NetFox; G!o6Y:1!  
~i!I6d~  
}$LnjwM;,  
public class TestMethod { dV
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KyBtt47\  
8Wgzca Q*  
public TestMethod() /T+%q#4  
{ ///xx/weblogic60b2_win.exe uvJ&qd8M  
try{ dA<_`GFR  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); JL>DRIR%NV  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); uPE Ab2u="  
SiteFileFetch fileFetch = new SiteFileFetch(bean); p{+F{e  
fileFetch.start(); 8C@6 b4VK  
} .9?GKD  
catch(Exception e){e.printStackTrace ();} M{SJ8+G  
6C\WX(@4  
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} U>@AE  
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BCtKxtbS  
public static void main(String[] args) [Y j:H  
{ HDaeJk  
new TestMethod(); 6C/Pu!Sx?  
} }<&?t;  
} Wevd6)\  
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