http断点续传简单实现（java)

/* )mj<{Td`  
**SiteFileFetch.java >cT
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*/ R^uc%onP  
package NetFox; \` &ej{  
import java.io.*; Bf/|{@  
import java.net.*; gUspGsfr  
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@Zj&`/  
public class SiteFileFetch extends Thread { HXyFj  
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SiteInfoBean siteInfoBean = null; //文件信息Bean !h?=Wv ==]  
long[] nStartPos; //开始位置 ,?I(/jI  
long[] nEndPos; //结束位置 uO"y`$C$_  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 /Ad6+cY  
long nFileLength; //文件长度 _nP)uU$  
boolean bFirst = true; //是否第一次取文件 w\p9J0  
boolean bStop = false; //停止标志 DDWp4`CS|  
File tmpFile; //文件下载的临时信息 |ebvx?\  
DataOutputStream output; //输出到文件的输出流 yYg   
$:(z}sYQ7  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 3Qa?\C&4  
public SiteFileFetch(SiteInfoBean bean) throws IOException 8+&gp$a$  
{ '\ XsTs#L  
siteInfoBean = bean; gXF.on4B  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); / xs9.w8-  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); #sS9vv7i  
if(tmpFile.exists ()) G#|Hu;C6"  
{ K0LbZMn,/  
bFirst = false; .5]{M\aA  
read_nPos(); 4'` C1a  
} X'jr|s^s  
else _%;M9Sg3  
{ 3hLqAj  
nStartPos = new long[bean.getNSplitter()]; Fk aXA.JE  
nEndPos = new long[bean.getNSplitter()]; v:?o3 S  
} 9Eu #lV  
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} Rh[Ibm56  
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public void run() =D}4X1l  
{ ~x\Cmu9`  
//获得文件长度 M.S s:ttj  
//分割文件 svqvG7  
//实例FileSplitterFetch -IbbPuRq  
//启动FileSplitterFetch线程 k},>^qE  
//等待子线程返回 lYP~3wp99  
try{ I.-v?1>,  
if(bFirst) UTvs |[  
{ :SK<2<8h  
nFileLength = getFileSize(); BD4`eiu"  
if(nFileLength == -1) #%4=)M>^  
{ &lq^dFP&Su  
System.err.println("File Length is not known!"); + LS3T^  
} p0Z:Wkz]  
else if(nFileLength == -2) #>XeR>T  
{ ]
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System.err.println("File is not access!"); %2}C'MqS  
} EDtCNqBS~2  
else #3.\j"b  
{ z(rK^RT  
for(int i=0;i<nStartPos.length;i++) h07eEg  
{ l^
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); JCNk\@0i*  
} >gnF]<  
for(int i=0;i<nEndPos.length-1;i++) qfa}3k8et  
{ ~o i)Lf1  
nEndPos = nStartPos[i+1];
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} j3{HkcjJG  
nEndPos[nEndPos.length-1] = nFileLength; mTJ"l(,3  
} jFG5)t<D  
} 3(C :X1  
_F^$aZt?e  
@UV{:]f~e  
//启动子线程 2uEhOi0I  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; bQ"N ;d)e  
for(int i=0;i<nStartPos.length;i++) 6< >SHw  
{ Ch7Egzl7?  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), i%MA"I\9  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), `zY!`G  
nStartPos,nEndPos,i); DRp&IP<  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); gvGi%gq  
fileSplitterFetch.start(); d@Q][7  
} r^Y~mq  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Ok*Z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); >T QZk4$  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", {\L|s5=yr  
nEndPos = " + nFileLength); @C=M UT-!  
// fileSplitterFetch[nPos.length-1].start(); +aj^Cs1$  
i5VG2S  

06jMj26!  
//等待子线程结束 SY|Ez!tU:N  
//int count = 0; uOre,AQR  
//是否结束while循环 6"+8M 3M l  
boolean breakWhile = false; /BT1oWi1y  
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-;U3w.-  
while(!bStop) EX+,:l\^  
{ gB >pd?d  
write_nPos(); H]]c9`ayt  
Utility.sleep(500); ;iQ
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breakWhile = true; 5
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for(int i=0;i<nStartPos.length;i++) ;NP[_2|-,  
{ B4^`Sw  
if(!fileSplitterFetch.bDownOver) >(3'Tnu  
{ F"[3c6yF  
breakWhile = false; ABZ06S/  
break; T .
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} /
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} ]4o?BkL  
if(breakWhile) oq. r\r  
break; ??(Kwtx{  
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//count++; # 66e@  
//if(count>4) >XnO&h
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// siteStop(); Um\0i;7 ~4  
} 8U=A{{0p  
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System.err.println("文件下载结束！"); b2s~%}T  
} s7"i.A  
catch(Exception e){e.printStackTrace ();} Z/7dg-$?'0  
} I="oxf#q  
${>DhfF  
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//获得文件长度 fI]bzv;  
public long getFileSize() qtY m!g  
{ \8>oJR 6  
int nFileLength = -1; 6c&Y  
try{ Yf=FeH7"  
URL url = new URL(siteInfoBean.getSSiteURL()); h)@InYwu7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); nB&j   
httpConnection.setRequestProperty("User-Agent","NetFox"); R04J3D|  
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int responseCode=httpConnection.getResponseCode(); H(&Z:{L  
if(responseCode>=400) t!t=|JNf{  
{ 6v>z h  
processErrorCode(responseCode); \igaQ\~  
return -2; //-2 represent access is error oCuV9dA
.  
} Hm4bN
\%  
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String sHeader; v ):V  
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for(int i=1;;i++) l;0y-m1  
{ _Ex|f5+  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); J*K<FFp3<  
//Utility.log(in.readLine()); wDw<KU1UK  
sHeader=httpConnection.getHeaderFieldKey(i); IT&i,`cJ~F  
if(sHeader!=null) no|Gq>Xp  
{ ?wCs&tM  
if(sHeader.equals("Content-Length")) |[LE9Lq/  
{ jyQVSQs  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); K(OaW)j
 
break; Y
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} l#xw.2bo  
} Xm@aYNV  
else }N]!0Ka  
break; eEP( ).
 
} SH=:p^J  
} =~JfVozU  
catch(IOException e){e.printStackTrace ();} JO}?.4B  
catch(Exception e){e.printStackTrace ();} ,]q%/yxi  
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Utility.log(nFileLength); =:/>6H1x  
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Q  
return nFileLength; mPG7Zy$z  
} lD3)TAW@o  
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//保存下载信息（文件指针位置） u>o<tw%Y  
private void write_nPos() zt?H~0$LB  
{ #HG&[Ywi  
try{ W>$BF[x!{  
output = new DataOutputStream(new FileOutputStream(tmpFile)); [pR)@$"k'  
output.writeInt(nStartPos.length); "teyi"U+  
for(int i=0;i<nStartPos.length;i++) 
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{ '=#5(O%pp  
// output.writeLong(nPos); O9e.
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output.writeLong(fileSplitterFetch.nStartPos); Abf1"#YImy  
output.writeLong(fileSplitterFetch.nEndPos); >[Rz <yv  
} VDa|U9N  
output.close(); T V;BNCg  
} TvM24Orct  
catch(IOException e){e.printStackTrace ();} ! TDD^  
catch(Exception e){e.printStackTrace ();} KZ )Ys  
} i~8DSshA  
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&CUC{t$VHX  
//读取保存的下载信息（文件指针位置） 0'@u!m?  
private void read_nPos() >?V<$>12  
{ )&z4_l8`=  
try{ g ;LVECk  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); PG"@A  
int nCount = input.readInt(); =ybGb7?  
nStartPos = new long[nCount]; zX~}]?|9  
nEndPos = new long[nCount]; WW6yFriuW  
for(int i=0;i<nStartPos.length;i++) _:%U_U  
{ ^#w{/C/n  
nStartPos = input.readLong(); }4vjKSV  
nEndPos = input.readLong(); =GTD"*vwr  
} u>|"28y  
input.close(); 4=s9A  
} {MxnIg7'  
catch(IOException e){e.printStackTrace ();} `p1DaV  
catch(Exception e){e.printStackTrace ();} :x+ig5  
} \xeVDKJH+n  
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private void processErrorCode(int nErrorCode) L=m:/qQL  
{  "l2bx  
System.err.println("Error Code : " + nErrorCode); ]#5^&w)'  
} 2&x7W*  
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GA ik;R  
//停止文件下载 8}z3CuM  
public void siteStop() 4 l1 i>_R  
{ @G(xaU'u  
bStop = true; &-4 ?!  
for(int i=0;i<nStartPos.length;i++) ~},~c:fF?  
fileSplitterFetch.splitterStop(); 9FNwpL'C  
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} 5m`[MBt2g  
} ^W}MM8 '  
//负责部分文件的抓取 J[r^T&o  
**FileSplitterFetch.java <A{y
($  
*/ pns+y  
package NetFox; B@-"1m~la?  
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import java.io.*; ?[|hGR2L  
import java.net.*; `#U ]iwW!  
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}!=U^A)  
public class FileSplitterFetch extends Thread { 97S? ;T  
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String sURL; //File URL 5&*zY)UL  
long nStartPos; //File Snippet Start Position +;6)  
long nEndPos; //File Snippet End Position <tW:LU(!  
int nThreadID; //Thread's ID t9Vb~ Ubdb  
boolean bDownOver = false; //Downing is over K%PxA#P}  
boolean bStop = false; //Stop identical jE*Ff&]%m  
FileAccessI fileAccessI = null; //File Access interface ]9@X?q  
kXEtuO5FUM  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException esteFLm`6  
{ $l#{_~ "m7  
this.sURL = sURL; '%ebcL  
this.nStartPos = nStart; VWD.J  
this.nEndPos = nEnd; CrO`=\  
nThreadID = id; ]hKgA~;  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 6}STp_x  
} C d|W#.6  
eQ\jZ0s;p  
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public void run() u?Z <n:  
{ `I{tZ$iD  
while(nStartPos < nEndPos && !bStop) yp?w3|`4;  
{ >|(%2Zl  
pX^=be_  
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try{ 6W:1>,xS  
URL url = new URL(sURL); k#?|yP:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); P{Lg{I_w.B  
httpConnection.setRequestProperty("User-Agent","NetFox"); SXh?U,5u  
String sProperty = "bytes="+nStartPos+"-"; {=6)SBjf  
httpConnection.setRequestProperty("RANGE",sProperty); x,f>X;
04  
Utility.log(sProperty); Mlwdha0  
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%i3{TL  
InputStream input = httpConnection.getInputStream(); (:l(_-O  
//logResponseHead(httpConnection); 5pmQp}}R  
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!pl_Ao~(  
byte[] b = new byte[1024]; "4RQ`.SR  
int nRead; }>,CUz  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) .8x@IWJD
 
{ -tMA  
nStartPos += fileAccessI.write(b,0,nRead); b@!:=_Mr  
//if(nThreadID == 1) jJc07r']  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); F:,#?  
} aH  
^6#-yDZC@  
. wmkj  
Utility.log("Thread " + nThreadID + " is over!"); jNIUsM8e  
bDownOver = true; ]Ly8s#<g]N  
//nPos = fileAccessI.write (b,0,nRead); D Kq-C%  
} ? osfL  
catch(Exception e){e.printStackTrace ();} %b9fW  
} ]xYayN!n  
} q#|r  
+NT:<(;|i5  
fQ1 0O(`g,  
//打印回应的头信息 j<@fT ewZ  
public void logResponseHead(HttpURLConnection con) W.p66IQwL&  
{ 58PKx5`D  
for(int i=1;;i++) _)q4I(s*  
{ HGb.656r  
String header=con.getHeaderFieldKey(i); V>r j$Nc]  
if(header!=null) 5)8.  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 0NrTJ R`  
Utility.log(header+" : "+con.getHeaderField(header)); &<@%{h@=  
else SKW;MVC  
break; {<r`5  
} G_0)oC@Jl:  
} `;e^2  
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public void splitterStop() g&XhQ.aa  
{
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bStop = true; ,.h$&QFj;  
} ~n8F7  
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} l%@dE7<&#Z  
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/* 4V1|jy3  
**FileAccess.java &62`Wr0C  
*//文件访问(定位，写) p#z;cjfSt  
package NetFox; }pt-q[s>  
import java.io.*; J7_8
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c9|I4=_K  
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public class FileAccessI implements Serializable{ jXtLo,km  
o;%n,S8J|^  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 unpfA#&!"  
RandomAccessFile oSavedFile; O4n8MM|`  
long nPos; ]2P/G5C3tU  
#c:9V2  
b6]e4DL:R  
public FileAccessI() throws IOException f7S^yA[[  
{ L+uOBW_  
this("",0); -GK'V  
} 5vYsA1Z
 
3/:LYvM<  
]yw_n^@  
public FileAccessI(String sName,long nPos) throws IOException `9:v*KuM#R  
{ xTGP  
oSavedFile = new RandomAccessFile(sName,"rw"); cK/PQs
MP  
this.nPos = nPos; G;Us-IRZ  
oSavedFile.seek(nPos); HuK Aj  
} O.dux5lfBd  
|b,zw^!e['  
Dxz5NW4  
public synchronized int write(byte[] b,int nStart,int nLen) Gi;9 S  
{ RsR] T]4  
int n = -1; 7L1\1E:!  
try{ 0@:Y>qVa  
oSavedFile.write(b,nStart,nLen); O~nBz):2  
n = nLen; v]l&dgoT  
} \l>qY(gu  
catch(IOException e) G[y&`Qc)G  
{ ]<Z&=0i#9  
e.printStackTrace (); -aC!0O y`  
} t7sUtmq  
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return n; 5c*p2:]  
} r*c82}tc  
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-,
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} _!|=AIX  
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[8xeQKp4  
/* c9 gz!NE  
**SiteInfoBean.java W<Bxm|  
*/ :v|r=#OI  
package NetFox; Qfwwh`;  
yLV2>kq  
zojuH8  
public class SiteInfoBean { |2WxcW]U.%  
Q9Q!9B@  
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private String sSiteURL; //Site's URL c1gz#,  
private String sFilePath; //Saved File's Path YK(XS"Kl  
private String sFileName; //Saved File's Name 0F-mROC=F  
private int nSplitter; //Count of Splited Downloading File ]JkpRaP$  
07~pf}  
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public SiteInfoBean() 0G+L1a-  
{//nSplitter的缺省值为5 v+|@}9|Z  
//default value of nSplitter is 5 |`N$>9qN  
this("","","",5); ?
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} XfD z #  
';i"?D?NAk  
\=HfO?$ Ro  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 4`?sE*P@`  
{ ~)WfJ  
sSiteURL= sURL; #L|JkBia  
sFilePath = sPath;
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sFileName = sName; ~e,f)?  
this.nSplitter = nSpiltter; >DSNKU+j  
~gSF@tz@  
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} /zChdjz  
t;Fbt("]:  
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public String getSSiteURL() @n5;|`)\  
{ *[XN.sb8E  
return sSiteURL; xCDA1y;j  
} AH"g^ gw~T  
XhJP87A  
]1YYrgi7  
public void setSSiteURL(String value) gOBj0P8s|}  
{ ;m2"cL>{l  
sSiteURL = value; P_:?}h\  
} zsR  wF  
hX{g]KE>  
+?4*,8Tmmz  
public String getSFilePath() +ZD[[+
 
{ Eg287B  
return sFilePath; +MOe{:/6  
} CuV=C Ay>  
4\ uZKv@,  
<lg"M;&Ht  
public void setSFilePath(String value) luP'JUq  
{ {9m!UlTtw  
sFilePath = value; ~@)-qV^~  
} Vz=j)[  
\N'hbT=  
XL"v21X  
public String getSFileName() es*_Oo1  
{ s>9z+;~!  
return sFileName; %l9WZ*yZ`2  
} F3H:I"4  
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5JXzfc9rL  
public void setSFileName(String value) u"Hd55"&  
{ / y":/"h  
sFileName = value; :$X4#k<  
} A{{q'zb!  
q\z=z$VR  
v4Fnh`{  
public int getNSplitter() Gdc~Lh  
{ &VZmP5Gv  
return nSplitter; !h`cXY~w  
} _{Fdw  
w<I5@)i|  
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public void setNSplitter(int nCount) D>"{H7mY  
{ Qw{\sCH>  
nSplitter = nCount; zBrWm_R5T  
} >%jEo'0;_  
} 3;-@<9  
Jnu}{^~  
@wAr[.lZ  
/* %$9)1"T0Y  
**Utility.java +r#=n7t  
*/ 5Xy^I^J  
package NetFox; K{r1&O>W  
dwf #~7h_  
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public class Utility { MK!]y8+Z  
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public Utility() 5@r_<J<>  
{ ]C!Y~  
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} .9[8H:Fe  
xTksF?u)  
//线程睡眠 
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public static void sleep(int nSecond) 8wH41v67F  
{ zDGg\cPj9  
try{ k_|v)\4B  
Thread.sleep(nSecond); \4`saM /x  
} 7}iewtdy,  
catch(Exception e) ixI5Xd<  
{ _sf0{/< )  
e.printStackTrace (); 6{Cu~G{]N  
} ,P; a/{U  
} [/fwt!  
{pQ@0b  
//日志 u;'<- _
 
public static void log(String sMsg) *nUpO]  
{ c|;|%"Mk  
System.err.println(sMsg); _QOOx+%*5  
} Ymk
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<>
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OV@h$fg  
public static void log(int sMsg) 1l`s1C  
{ J9$]]\52s.  
System.err.println(sMsg); ~jRk10T(B  
} UV *tO15i  
} uX5--o=C  
PE6u8ZAb"  
a*n%SUP  
/* :x*|lz[  
**TestMethod.java ]rX?n  
*/ >-tH&X^  
package NetFox; 'i h  
3{#pd6e5  
g$^qQs)^N  
public class TestMethod { WNlSve)]ie  
lh(+X-}D  
J^+$L"K  
public TestMethod() T~ q'y~9o  
{ ///xx/weblogic60b2_win.exe >-@{vyoOy  
try{ %OfDTs  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); b]qfcV  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); />2$ XwP  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ??e#E[bI  
fileFetch.start(); OTtanJ?  
} YI\Cs=T/  
catch(Exception e){e.printStackTrace ();} 1n5e^'z  
p7=^m>Z6  
[,szx1  
} t[yD8h  
;x0KaFk  
H7XxME  
public static void main(String[] args) +Tc(z{;  
{ )}9}"jrDlx  
new TestMethod(); 3=L1HZH  
} F>_lp,G  
} E#X!*q&  
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