http断点续传简单实现（java)

/* yJx,4be  
**SiteFileFetch.java >>=zkPy  
*/ 25G~rklk  
package NetFox; VU\G49  
import java.io.*; NX8w(~r,:  
import java.net.*; Xe}I;sKrB  
1%@i4  
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public class SiteFileFetch extends Thread { h6Vd<sV\tf  
}lk9|U#6*`  
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SiteInfoBean siteInfoBean = null; //文件信息Bean %PVu>^  
long[] nStartPos; //开始位置 y]Q/(O  
long[] nEndPos; //结束位置 D
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 J^kSp  
long nFileLength; //文件长度 @$b7 eu  
boolean bFirst = true; //是否第一次取文件 b#(QZ  
boolean bStop = false; //停止标志 _J>Ik2EF  
File tmpFile; //文件下载的临时信息 :>y5'q@R  
DataOutputStream output; //输出到文件的输出流 98}l`J=i  
~LH).\V  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） @&h_+|:-  
public SiteFileFetch(SiteInfoBean bean) throws IOException L#V
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{ G$`hPNSh  
siteInfoBean = bean; Ornm3%p+e  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); lz).=N}m  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); *E@as  
if(tmpFile.exists ()) V2Z
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{ +5ql
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bFirst = false; nCldH|>5w  
read_nPos();
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} (!ud"A|ab4  
else * se),CP!s  
{ UuJ gB)  
nStartPos = new long[bean.getNSplitter()]; Dhft[mvo  
nEndPos = new long[bean.getNSplitter()]; 2J(,Xf  
} iA2TvP#  
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} 5N>L|J2  
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public void run() ?f6Fj  
{ _T^@,!&  
//获得文件长度 G!GGT?J  
//分割文件 }g.)%Bw!  
//实例FileSplitterFetch ovtZHq/  
//启动FileSplitterFetch线程
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//等待子线程返回 Xt
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try{ 9@(V!G  
if(bFirst) #1>c)_H  
{ ?cr^.LV|h^  
nFileLength = getFileSize(); xqVIw!J?/}  
if(nFileLength == -1) U,9=&"e b  
{ uoY]@.  
System.err.println("File Length is not known!"); Nrp1`qY  
} P= 26! b  
else if(nFileLength == -2) 6r5<uZ9w_X  
{ &-.2P!t  
System.err.println("File is not access!"); !"^//2N+,  
} 9(9\kQj{C  
else 7baQ4QY?n  
{ y#{> tC  
for(int i=0;i<nStartPos.length;i++) &W y9%  
{ 2)`4(38  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); l;JB;0<s"  
} "CQ:<$|$  
for(int i=0;i<nEndPos.length-1;i++) 3}?]G8iL?L  
{ |P=-m-W  
nEndPos = nStartPos[i+1]; C'z}jM`g  
} bq}o#d5p-_  
nEndPos[nEndPos.length-1] = nFileLength; ,3ivB8  
} d>Np; "  
} ]+78 "(  
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~p/1 9/  
//启动子线程 9
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; oGZ%w4T  
for(int i=0;i<nStartPos.length;i++) o7@81QA!e  
{ i\k>2df  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), GA)t!Xg^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), p?sC</R  
nStartPos,nEndPos,i); ]OA8H[U-eA  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); jTz~ V&^  
fileSplitterFetch.start(); %wux#"8  
} .{#J2}+[_}  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 20RISj  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); RC]-9gd3Q  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", #ruL+-8!<  
nEndPos = " + nFileLength); +,ZQ( ZW  
// fileSplitterFetch[nPos.length-1].start(); arj?U=zy  
)1!*N)$  
1O;q|p'9  
//等待子线程结束 |lf,3/*jDB  
//int count = 0; g)~"-uQQ  
//是否结束while循环 k| ,F/:  
boolean breakWhile = false; #ANbhHG  
~Wj. 4b*  
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while(!bStop) O9[Dae{i  
{ 0=KyupwXC  
write_nPos(); NXD
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Utility.sleep(500); PzDekyl  
breakWhile = true; [E|%  
/q>1X!Z  
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for(int i=0;i<nStartPos.length;i++) 7^Q4?(A  
{ S6Fn(%T+9  
if(!fileSplitterFetch.bDownOver) Vq<\ixRi  
{ J9*$@&@S  
breakWhile = false; BO)Q$*G~JD  
break; T4x%dg  
} etWCMR  
} IX)\z  
if(breakWhile) <mdHca  
break; aqzIMOAf  
RW04>oxVn  
S4FR=QuVQC  
//count++; -9z!fCu3  
//if(count>4) _B5v&#h(.  
// siteStop(); z<9wh2*M  
} 3=~0m  
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System.err.println("文件下载结束！"); (^).$g5Hg  
} e${Cf  
catch(Exception e){e.printStackTrace ();} WvJidz?5  
} ij+)U`  
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05gdVa,  
//获得文件长度 Y<0R5rO  
public long getFileSize() .8EaFEd  
{ XIJW$CY  
int nFileLength = -1; Doj>Irj?7  
try{ nL@(|nJ[  
URL url = new URL(siteInfoBean.getSSiteURL()); 9d_ Zdc  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); f,}9~r#  
httpConnection.setRequestProperty("User-Agent","NetFox"); rsgTd\b  
#
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int responseCode=httpConnection.getResponseCode(); +=N#6#1  
if(responseCode>=400) "MNI_C#{  
{ sV`!4 u7%}  
processErrorCode(responseCode); S)$iHBx{  
return -2; //-2 represent access is error ?(d<n   
} oi:!YVc  
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String sHeader; yz7X7mAo  
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for(int i=1;;i++) 2jiH&'@  
{ =AIeY
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); M6o"|\  
//Utility.log(in.readLine()); 7lH3)9G;  
sHeader=httpConnection.getHeaderFieldKey(i); +XP9=U*g  
if(sHeader!=null) EAPjQA-B?  
{ ]n9gnE  
if(sHeader.equals("Content-Length")) 6=o'.03\f  
{ zt|DHVy  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 
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break; |)}&:xA%  
} Ufr,6IX  
} g`9`/  
else ev"f@y9Do  
break; J70r`   
} |b'}.(/3i  
} iVe"iH  
catch(IOException e){e.printStackTrace ();} ?|NMJQsa7  
catch(Exception e){e.printStackTrace ();} 'NYW`,  
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9H#;i]t&  
Utility.log(nFileLength); J':x]_;  
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return nFileLength; d,d ohi  
} zD,K_HicI  
8%EauwAx  
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//保存下载信息（文件指针位置） a 0+W-#G  
private void write_nPos() sRkPXzK  
{ x=%wPVJ  
try{ e=u?-8  
output = new DataOutputStream(new FileOutputStream(tmpFile)); > t~2  
output.writeInt(nStartPos.length); |Jpi|'  
for(int i=0;i<nStartPos.length;i++) T1[B*RwC  
{ w1J%%//(h  
// output.writeLong(nPos); <A
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output.writeLong(fileSplitterFetch.nStartPos); Mj5&vs~n;  
output.writeLong(fileSplitterFetch.nEndPos); fDD^?/^  
} P4{!
/&/  
output.close(); 3s B9t X  
} VSLi{
=#  
catch(IOException e){e.printStackTrace ();} /=IBK`  
catch(Exception e){e.printStackTrace ();} &~{0@/
 
}
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//读取保存的下载信息（文件指针位置） V3v/hV:  
private void read_nPos() J-d>#'Wb|  
{ mP[ZlS~"  
try{ /JbO$A  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Zv&<r+<g  
int nCount = input.readInt(); Mv\]uAT`  
nStartPos = new long[nCount]; jWNF3\  
nEndPos = new long[nCount]; &r0
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for(int i=0;i<nStartPos.length;i++) M>g%wg7Ah  
{ X 3q2XU  
nStartPos = input.readLong(); ~A$y-Dt'  
nEndPos = input.readLong(); ~;/}D0k$x  
} ^={s(B2  
input.close(); "l[ c/q[  
} +b_o2''  
catch(IOException e){e.printStackTrace ();} 4RyQ^vL  
catch(Exception e){e.printStackTrace ();} >1S39n5z.  
} U]}f]GK  
>#[,OU}N  
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private void processErrorCode(int nErrorCode) uG,*m'x']  
{ Cr>YpWm  
System.err.println("Error Code : " + nErrorCode); 9AP."RV  
} ![Ll$Lr  
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//停止文件下载 7;r Jr&.)  
public void siteStop() ly( LMr  
{ \9N )71n(  
bStop = true; )PCh;P0C  
for(int i=0;i<nStartPos.length;i++) }=$>w@mJ  
fileSplitterFetch.splitterStop(); i)=dp!Bx^  
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} <:ptNGR  
} B:rzM:BQ  
//负责部分文件的抓取  4"~F  
**FileSplitterFetch.java Zg=jDPt}  
*/ pKNrEq  
package NetFox; *iiyU}x  
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import java.io.*; XpIl-o&re  
import java.net.*; ocPM zq-  
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public class FileSplitterFetch extends Thread { 05s{Z.aK  
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String sURL; //File URL ')zf8>,  
long nStartPos; //File Snippet Start Position U^ ;H{S  
long nEndPos; //File Snippet End Position vR*p1Kq:  
int nThreadID; //Thread's ID aW*8t'm;m'  
boolean bDownOver = false; //Downing is over {n 4W3  
boolean bStop = false; //Stop identical Ng|c13A=  
FileAccessI fileAccessI = null; //File Access interface 'LMMo4o3  
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<*[D30<  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException +<rWYF(ii/  
{ Gc,6;!+(  
this.sURL = sURL; Ex-?[Hq  
this.nStartPos = nStart; 1+v!)Y>Z&  
this.nEndPos = nEnd; bwyj[:6l  
nThreadID = id; N}CeQ'l[R  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 uy rS6e0  
} w^E$R  
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 RxO!
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public void run() QE4TvnhK  
{ ?!a8'jfs  
while(nStartPos < nEndPos && !bStop) |"aop|  
{ BI6]{ZC"  
"@(Sw>*o  
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try{ -(JBgM"  
URL url = new URL(sURL); :CGh$d] +  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Ci$?Hm9n  
httpConnection.setRequestProperty("User-Agent","NetFox"); bsv!z\}  
String sProperty = "bytes="+nStartPos+"-"; a/TeBx#yG  
httpConnection.setRequestProperty("RANGE",sProperty); 8iUYZF  
Utility.log(sProperty); '#NDR:J"  
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InputStream input = httpConnection.getInputStream(); qQp;i{X  
//logResponseHead(httpConnection); bY}:!aR<mK  
w`
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byte[] b = new byte[1024]; L "5;<  
int nRead; 
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) qZYh^\  
{ a\*_b2 ^n  
nStartPos += fileAccessI.write(b,0,nRead); G'{*guYU  
//if(nThreadID == 1) ]PQ6 em  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); o}e]W,  
} &~V6g(9  
MuF{STE>->  
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Utility.log("Thread " + nThreadID + " is over!"); o?/fObV@(  
bDownOver = true; cCv@fks  
//nPos = fileAccessI.write (b,0,nRead); "R^0eNv$  
} v,Uu)Z  
catch(Exception e){e.printStackTrace ();} 1eOQ;#OV  
} )-^[;:B\k"  
} W%@0Ym`7  
Xq%ijo  
"@UyU
L  
//打印回应的头信息 Dd'J"|jF38  
public void logResponseHead(HttpURLConnection con) ^\g?uH6k U  
{ >l^[73,]L  
for(int i=1;;i++) &0RKNpwg  
{ .f9&.H#  
String header=con.getHeaderFieldKey(i); n8Rsle`a  
if(header!=null) `%_(_%K  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); h~5gHx/a  
Utility.log(header+" : "+con.getHeaderField(header)); r1[#_A`Yn  
else Odr<fvV,>  
break; AHet,N  
} @umn#*  
} 4P?R "Lk  
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public void splitterStop() +2,EK   
{ t
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bStop = true; >0S(se
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} Le2rc*T  
7`
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} ]23+ d/  
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/* 9a]JQ  
**FileAccess.java h@@q:I=  
*//文件访问(定位，写) wRu\9H}  
package NetFox; 8=-#LVo~c  
import java.io.*; " nLWvV1  
SI/3Dz[  
5`)
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public class FileAccessI implements Serializable{ )j}v3@EM5  
-IS$1  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 !SThK8j$7  
RandomAccessFile oSavedFile; $|VD+[jSV  
long nPos; '5\?l:z  
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public FileAccessI() throws IOException ;aDYw [  
{ Q|7;Zsd:  
this("",0); mV.26D<c  
} \RmU6(;IQ  
%<\tN^rP  
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public FileAccessI(String sName,long nPos) throws IOException ~;@\9oPpz%  
{ yAQ)/u[|  
oSavedFile = new RandomAccessFile(sName,"rw"); QeQ
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this.nPos = nPos; B~`:?f9ny5  
oSavedFile.seek(nPos); :.crES7<[X  
} e#^vA$d  
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@6VkNe9  
public synchronized int write(byte[] b,int nStart,int nLen) X4/3
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{ Kza5_7p`L  
int n = -1; _uZVlu@  
try{ {cmV{ 4Yx  
oSavedFile.write(b,nStart,nLen); {4r }jH  
n = nLen; OQ+kOE&  
} lh-zE5;  
catch(IOException e) nQ;M@k&9eV  
{ IYe,VL  
e.printStackTrace (); scyv]5Hm!  
} !_?#f|  
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R]NCD*~  
return n; &?^"m\K4J*  
} LT:8/&\  
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} A>rN.XW  
@+Anp4%;Y  
@!B%ynrG  
/* h%] D[g  
**SiteInfoBean.java BrsBB"<o,  
*/ oT9qd@uQ0:  
package NetFox; \xX'SB#.l  
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a.up&g_$  
public class SiteInfoBean { &,'CHBM  
1WAps#b.  
|fPR7-  
private String sSiteURL; //Site's URL  )OZ  
private String sFilePath; //Saved File's Path w%~Mg3|  
private String sFileName; //Saved File's Name O7yIFqI=/  
private int nSplitter; //Count of Splited Downloading File in2m/q?  
DYTC2  
bl[2VM7P  
public SiteInfoBean() _@O.EksY3r  
{//nSplitter的缺省值为5 90">l^HX=  
//default value of nSplitter is 5 \'+P5,  
this("","","",5); uM2 .?>`X  
} Q$x 3uH\@  
Nx<fj=VJ  
43
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) PDpDkcy|QM  
{ k.wm{d]J  
sSiteURL= sURL; {=,+;/0  
sFilePath = sPath; ^@;P-0Sy  
sFileName = sName; R?8/qGSVqJ  
this.nSplitter = nSpiltter; ^TAf+C^Ry  
3e1^r_YI  
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} J"Nn.iVq  
3PEW0b*]Pf  
]EEac  
public String getSSiteURL() &J,&>CFc  
{ 8YO` TgW  
return sSiteURL; +[Q`I*C  
} GhW{6.^  
K&up1nZ@(  
h%!,|[|  
public void setSSiteURL(String value) ~/;shs<9EM  
{ gCM(h[7A  
sSiteURL = value; YRU#/TP  
} _s+_M+
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cfL:#IM  
3H`ES_JL  
public String getSFilePath() .|GnTC q  
{ #g]eDU-[  
return sFilePath; Rzxkz  
} 2 5Ia  
=HHb ]JE  
}XfRKGQw  
public void setSFilePath(String value) Fr1OzS^&(  
{ gk4DoOj#P  
sFilePath = value; .}3K9.hkr  
} :CG;:( |  
43N=OFU  
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public String getSFileName() DhT8Kh{
 
{ #<yKG\X?  
return sFileName; jNW/Biy4u  
} TlJ'pG 4^  
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Y|aaZ|+  
public void setSFileName(String value) |],ocAN{  
{ 92M_Z1_w[  
sFileName = value; j\2q2_f  
} K<fB]44Y  
'V}4_3#q  
9tIE+RD  
public int getNSplitter() j_}f6d/h  
{ ,pa=OF  
return nSplitter;
#A^(
1  
} J;Eg"8x]  
g>-u9%aa  
q[%SF=~<k{  
public void setNSplitter(int nCount) $i$Z+-W4'  
{ U9h@1:  
nSplitter = nCount; Sxcp [g;  
} pGsu#`t  
} mh8)yy5\  
k Hh0&~(  
^Dys#
^  
/* ]gmkajCzD  
**Utility.java xd^9R<  
*/ e%KCcU  
package NetFox; Kj*$'('  
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public class Utility { D*!9K8<o  
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public Utility() m]/sR3yF  
{ =xM:8 hm  
n4/Jx*  
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} }M~[8f ]  
>\Ml\CyL  
//线程睡眠 2E0$R%\  
public static void sleep(int nSecond) Hs(U|BXU  
{ M[?0 ^ FBx  
try{ dU#}Tk  
Thread.sleep(nSecond); ,5P tB]8&3  
} ^(1S`z$  
catch(Exception e) 7aeyddpM  
{ B#[.
c$  
e.printStackTrace (); BS+=*3J  
} fk(h*L|sI  
} YFs!,fw'  
{S5j;  
//日志 ,\D*=5  
public static void log(String sMsg) IeGVLC
  
{ 2g%p9-MO]I  
System.err.println(sMsg); 8o!LgT5  
} "%K[kA6  
FuFA/R=x/  
9v(k<('_  
public static void log(int sMsg) 01vKx)f  
{ "[\),7&03  
System.err.println(sMsg); I=K|1  
} 6|]e}I@<2  
} WXCZ }l  
| gP%8nh'C  
Oi\,clR^[o  
/* Vi<F@ji  
**TestMethod.java ]BY<D`$$P  
*/ dR >hb*kJ  
package NetFox; ]xN)>A2  
wak'L5GQE  
9M1UkS$`@  
public class TestMethod { Q ;$NDYV1  
zfm#yDf  
?T
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public TestMethod() @;h$!w<  
{ ///xx/weblogic60b2_win.exe YB"=eld  
try{ ,")/R/d  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); z9HUI5ns  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 7aJ:kumDZ  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Hjc *WTu  
fileFetch.start(); 287)\FU;3  
} 8d8GYTl b)  
catch(Exception e){e.printStackTrace ();} = K3NKPUI  
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d^^EfWU  
} Qs;MEt1  
\Ea(f**2B  
+<w\K*  
public static void main(String[] args) XcM.<Dn3  
{ HiTj-O  
new TestMethod(); |!"qz$8fB  
} #qg(DgH 7  
} .|<+-Rsj  
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