http断点续传简单实现（java)

/* \G &q[8F\  
**SiteFileFetch.java !fG`xZ~  
*/ V
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package NetFox; >oc&hT  
import java.io.*; KXga{]G:  
import java.net.*; =?- sazF&  
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public class SiteFileFetch extends Thread { STQ~mFs"  
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SiteInfoBean siteInfoBean = null; //文件信息Bean JQWW's}  
long[] nStartPos; //开始位置 vD4<G{  
long[] nEndPos; //结束位置 d9uT*5f  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 8\ WOss)al  
long nFileLength; //文件长度 Ol. rjz9  
boolean bFirst = true; //是否第一次取文件 de?lO;8  
boolean bStop = false; //停止标志 e.^Y4(  
File tmpFile; //文件下载的临时信息 DM@&=c  
DataOutputStream output; //输出到文件的输出流 QCk(qlN'h9  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） x<e-%HB*-  
public SiteFileFetch(SiteInfoBean bean) throws IOException IpMZ{kJlv`  
{ _79 ?,U]  
siteInfoBean = bean; Y=N; Bj  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); #o-CG PE  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ) _O
6_  
if(tmpFile.exists ()) qfzT8-Y  
{ db.E-@W.OI  
bFirst = false; s|=.L&"   
read_nPos(); * E3 c--  
} K=C).5=U  
else ]&/KAk  
{ 1)f~OL8o  
nStartPos = new long[bean.getNSplitter()]; y[@<goT  
nEndPos = new long[bean.getNSplitter()]; }8qsE  
} GCEq3 ^/  
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} Nd4!:.  
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public void run() y:+s*x6Vg  
{ %?WmWs0  
//获得文件长度 -'!%\E;5  
//分割文件 U1^R+ *yp  
//实例FileSplitterFetch tcxs%yWO
1  
//启动FileSplitterFetch线程 S4Vv _k-&  
//等待子线程返回 ku}I;k |  
try{ l6Q75i)eF  
if(bFirst) NTtRz(  
{ :+>:>$ao  
nFileLength = getFileSize(); S*1Km&  
if(nFileLength == -1) 2x*C1   
{ MO$dim>  
System.err.println("File Length is not known!"); s GP}>w-JZ  
} 1y5$  
else if(nFileLength == -2) h}_1cev?  
{ B:\TvWbu  
System.err.println("File is not access!"); /8` S}g+  
} |<ZkJR3B  
else grhwPnKl  
{ ;|LS$O1c  
for(int i=0;i<nStartPos.length;i++) $yx34=  
{ ,\K1cW~U5  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); /U%
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} S qQqG3F  
for(int i=0;i<nEndPos.length-1;i++) =Gq 'sy:h  
{ k(;c<Z{?1  
nEndPos = nStartPos[i+1]; _8'FI_E3  
} P2Ja*!K]  
nEndPos[nEndPos.length-1] = nFileLength; vK\;CSk  
} y[l19eU  
} RZ[r XV5  
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//启动子线程 ,{{uRs/  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; F W# S.<  
for(int i=0;i<nStartPos.length;i++) :oH"  
{ Z<#beT6
 
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .#b!#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), $bU|'}QR  
nStartPos,nEndPos,i); x6ig,N~AO  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \8!&XcA  
fileSplitterFetch.start(); .#;;pu7W  
} fodr1M4J  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?7cF_Zvve  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); M9
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 
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nEndPos = " + nFileLength); nD+vMG1~w  
// fileSplitterFetch[nPos.length-1].start(); uv2!][  
I^
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U!-|.N,  
//等待子线程结束 7 '@l?u/6  
//int count = 0; 1lNg} !)[K  
//是否结束while循环 9 0[gXj  
boolean breakWhile = false; e.0vh?{\  
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while(!bStop) 8fdK|l w  
{ F~ n}Ep~1  
write_nPos(); }q(IKH\&  
Utility.sleep(500); AX%9k  
breakWhile = true; OX?9 3AlG  
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for(int i=0;i<nStartPos.length;i++) -9U'yL90B  
{ 9b !+kJD  
if(!fileSplitterFetch.bDownOver) {cv,Tz[Q>  
{ [j5^Zb&0  
breakWhile = false; V&_5q`L  
break;

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} 2WIbu-"l  
} `\&qk)ZP  
if(breakWhile) 9`)NFy?  
break; w
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//count++; O;:8mm%(  
//if(count>4) ^
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// siteStop(); C/[2?[  
} OZ_'&CZ  
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System.err.println("文件下载结束！"); 'W$jHs  
} AdB5D_ Ir  
catch(Exception e){e.printStackTrace ();} .l*]W!L]  
} *kxk@(lT?  
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//获得文件长度 =?57*=]0M  
public long getFileSize() _-Aw`<_*-  
{ fZXJPy;n  
int nFileLength = -1; ?/{ qRz'C<  
try{ xGqe )M>8?  
URL url = new URL(siteInfoBean.getSSiteURL()); a'Qy]P}'Ug  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); LIVVb"V|,  
httpConnection.setRequestProperty("User-Agent","NetFox"); /PIU@$DV  
>.#uoW4ZV  
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int responseCode=httpConnection.getResponseCode(); k-T_,1l{  
if(responseCode>=400) \nx^=4*yk  
{ /v;g v[  
processErrorCode(responseCode); C did*hxJ  
return -2; //-2 represent access is error -b(:kAwStk  
} [/*854  
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String sHeader; sj`9O-?49  
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for(int i=1;;i++) A A<9XC  
{ "F|OJ@M  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); -NZj:N  
//Utility.log(in.readLine()); }<&g1x'pa  
sHeader=httpConnection.getHeaderFieldKey(i); Qkk~{OuC  
if(sHeader!=null) :H\6wJ  
{ _?@>S7-  
if(sHeader.equals("Content-Length")) &.o}(e:]  
{ {TdKS  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 6yTL7@V|B  
break; _>A])B ^  
} }k<b)I*A  
} A@_F ;4X  
else "`,PLC  
break; E] t:_v  
} J(M0t~RZ  
} rg_-gZl8&z  
catch(IOException e){e.printStackTrace ();} f8N  
catch(Exception e){e.printStackTrace ();} _ZD)#?  
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Utility.log(nFileLength); rQ*'2Zf'<  
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return nFileLength; 0} liK  
} ?GD{}f33  
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//保存下载信息（文件指针位置） .rG Rdb  
private void write_nPos() ERGDo=j  
{ v[r:1T@  
try{ 0V}vVAa(B  
output = new DataOutputStream(new FileOutputStream(tmpFile)); @w6^*Z_hQ  
output.writeInt(nStartPos.length); HC4ad0Gs+{  
for(int i=0;i<nStartPos.length;i++) >}u?{_s *0  
{ (LRv c!`"  
// output.writeLong(nPos); jfqWcX.X=  
output.writeLong(fileSplitterFetch.nStartPos); XT~JP
  
output.writeLong(fileSplitterFetch.nEndPos); * 2T&pX  
} C+r--"Z  
output.close(); :'Imz  
} Fdu0?H2TL  
catch(IOException e){e.printStackTrace ();} J%f5NSSU{6  
catch(Exception e){e.printStackTrace ();} ?8! 4!P%n  
} '/;#{("  
-1S+fUkiK/  
;-^WUf|
 
//读取保存的下载信息（文件指针位置） %'4dgk  
private void read_nPos() in#qV  
{ na $z\C\  
try{ YV{^S6M  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); p5)A"p8"9,  
int nCount = input.readInt(); y @Y@"y  
nStartPos = new long[nCount]; s.C-II?e  
nEndPos = new long[nCount]; !S%XIq}FX  
for(int i=0;i<nStartPos.length;i++) yql+N[  
{ og.dYs7W4  
nStartPos = input.readLong(); Zf]d'oW{/  
nEndPos = input.readLong(); A+Y>1-=JO  
} Lkk'y
})/  
input.close(); Ao`9fI#q  
} ;n7k_K#0z!  
catch(IOException e){e.printStackTrace ();} F2oY_mA  
catch(Exception e){e.printStackTrace ();} 'D\(p,(Mt  
} -Q 6W`*8  
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private void processErrorCode(int nErrorCode) X"iy.@7  
{ E;VW6[M  
System.err.println("Error Code : " + nErrorCode); N<Y-]xS  
} \)y5~te*  
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//停止文件下载 NqhRJa63  
public void siteStop() >4~{CXZ  
{ Xd|@w{.m*  
bStop = true; aKH\8O4L5  
for(int i=0;i<nStartPos.length;i++)  A{5k}  
fileSplitterFetch.splitterStop(); Ha)w*1&w"  
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} HEjV7g0E  
} D\j1`  
//负责部分文件的抓取 dHf_&X2A  
**FileSplitterFetch.java rS(693kb  
*/ nF A7@hsm  
package NetFox; _~L
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import java.io.*; Eto0>YyZ  
import java.net.*; u4z]6?,"e  
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public class FileSplitterFetch extends Thread { :Nc~rOC_  
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String sURL; //File URL YDjQ&EH  
long nStartPos; //File Snippet Start Position _k5KJKvr  
long nEndPos; //File Snippet End Position vuDp_p*]S  
int nThreadID; //Thread's ID ! ~&X1,l1*  
boolean bDownOver = false; //Downing is over gA~Ih  
boolean bStop = false; //Stop identical oPzt1Y  
FileAccessI fileAccessI = null; //File Access interface BR5$;-7W  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException kz,Nz09}W  
{ Ms^Y:,;Hi  
this.sURL = sURL; .o|Gk 5)  
this.nStartPos = nStart; Uy_`=JZ  
this.nEndPos = nEnd; |P5?0{  
nThreadID = id; r^*,eF  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 {_^sR}%]F  
} hs<7(+a  
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public void run() [uAfE3  
{ /:yKa=$  
while(nStartPos < nEndPos && !bStop) =\:YNP/  
{ <ezvz..g  
2!]':(8mR  
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try{ ut-UTW  
URL url = new URL(sURL); J"6_H =s   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =x/]2+ s  
httpConnection.setRequestProperty("User-Agent","NetFox"); Q*mPU=<  
String sProperty = "bytes="+nStartPos+"-"; [R A=M  
httpConnection.setRequestProperty("RANGE",sProperty); !i)?j@D  
Utility.log(sProperty); 3.R?=npA  
NwT3e&u%|  
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InputStream input = httpConnection.getInputStream(); @zd)]O]xH?  
//logResponseHead(httpConnection); dBobVT'  
?1OS%RBF  
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byte[] b = new byte[1024]; '7xmj:.==  
int nRead; A`X$jpAn&  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) h"wXmAf4%  
{ Eg  w?  
nStartPos += fileAccessI.write(b,0,nRead); 3ufUB^@4v  
//if(nThreadID == 1) bE]2:~  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); M5Pvc  
} uERc\TZ  
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Utility.log("Thread " + nThreadID + " is over!"); _5.7HEw>/  
bDownOver = true; 1S.nqOfx  
//nPos = fileAccessI.write (b,0,nRead); $stJ+uh  
} (q:L_zFj>"  
catch(Exception e){e.printStackTrace ();} mI"|^!L  
} 6"j
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} 42# rhgW  
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uiDR}   
//打印回应的头信息 4
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public void logResponseHead(HttpURLConnection con) Eer rIV  
{ -f Zm_FE  
for(int i=1;;i++) q ,}W.
 
{ v>7=T8  
String header=con.getHeaderFieldKey(i); EVRg/{X  
if(header!=null) kCN9`9XI{  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 7z F29gC  
Utility.log(header+" : "+con.getHeaderField(header)); 1[X+6viE  
else bS* "C,b~s  
break; K[T?--H  
} zbi[r  
} Du[$6  
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public void splitterStop() |3"'>* J  
{ BhdJ/C^  
bStop = true; FeSe^^dW  
} a8Ci 7<V  
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} u4#BD!W  
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/* c5]^jUB6  
**FileAccess.java XQlK}AK  
*//文件访问(定位，写) aSKI%<?xN  
package NetFox; 0[9A*  
import java.io.*; ":eHR}Hzx  
oryoGy=(yk  
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public class FileAccessI implements Serializable{ MH!'g7iK8  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ,Qj7wFZ  
RandomAccessFile oSavedFile; !:rQ@PSy9  
long nPos; "{L%5:H@  
AP/5,M<  
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public FileAccessI() throws IOException Wd&!##3$Q  
{ Ojie.+'SB  
this("",0); ]}KmT"vA  
} l_+s$c  
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public FileAccessI(String sName,long nPos) throws IOException hD # Yz<  
{ r-&4<=C/N  
oSavedFile = new RandomAccessFile(sName,"rw"); H%Q@DW8~@  
this.nPos = nPos; F/&Z1G.  
oSavedFile.seek(nPos); ",`fGu )  
} y\r8_rBo  
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public synchronized int write(byte[] b,int nStart,int nLen) 7P=1+2V  
{ 2-]gHAw%  
int n = -1; ihf5`mk/$  
try{ 0=L:8&m  
oSavedFile.write(b,nStart,nLen); l"b78n  
n = nLen; IqcPml{\  
} .CrahV1G  
catch(IOException e) :m^eNS6:  
{ C!RxMccTh  
e.printStackTrace (); GwW!Q|tVz=  
} im4V6 f;%  

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return n; 1&Nk  
} Vk@u|6U'  
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} 2+ >.Z.pX  
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/* .5KRi6  
**SiteInfoBean.java osPX%k!yw  
*/ Xk(c2s&  
package NetFox;  V:F)m!   
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public class SiteInfoBean { Y -
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private String sSiteURL; //Site's URL pbR84g^p.S  
private String sFilePath; //Saved File's Path K=+w,H#`C  
private String sFileName; //Saved File's Name GkaIqBS  
private int nSplitter; //Count of Splited Downloading File 2O`uzT$  
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public SiteInfoBean() (9fqUbG  
{//nSplitter的缺省值为5 V5qvH"^  
//default value of nSplitter is 5 +%$!sp?  
this("","","",5); m"X0Owx  
} :}o0Eb  
)?I1*(1{A  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) o^d(mJZ.F~  
{ }g5h"N\$o  
sSiteURL= sURL; o24`5Jdh  
sFilePath = sPath; X.%Xi'H  
sFileName = sName; y3c]zDjV  
this.nSplitter = nSpiltter; .oN<c]iqE  
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} @,pO%,E6  
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public String getSSiteURL() _I3j7
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{ 9\R:J"X  
return sSiteURL; 2AzF@Pi^z  
} O&E1(M|*>  
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public void setSSiteURL(String value) r-H~MisL  
{ E6y/,s^~S_  
sSiteURL = value; gB71~A{J  
} Xe:B*  
6V*@ {  
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public String getSFilePath() V0c*M>V  
{ k2,n:7  
return sFilePath; V.:a6>]  
} = 14'R4:  
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public void setSFilePath(String value) {~[H"h537t  
{ KFCuv15w,3  
sFilePath = value; "|.>pD#0&  
} f|w+}z
 
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public String getSFileName()  Pb+oV  
{ xXp\U'Ad~~  
return sFileName; * j:  
} 
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public void setSFileName(String value) [/6$P[  
{ eP(%+[g  
sFileName = value; lVARe3#  
} 2:&8FdU  
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public int getNSplitter() N@58R9P<p  
{ `IFt;Ja\6  
return nSplitter; v}+axu/?  
} #fzvK+  
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public void setNSplitter(int nCount) G0^23j  
{ Y^2`)':  
nSplitter = nCount; {!o-
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} Qh? E*9  
} hG2btmBh
t  
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Q`,D#V${D  
/* DN&ZRA  
**Utility.java 7iLm_#M  
*/ gt';_
  
package NetFox; U@ALo  
}rn}r4_a  
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public class Utility { y@nWa\iG  
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public Utility() 4)]g=-3  
{ Olj]A]v}  
n
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} (=QaAn,,R  
7I&7YhFI  
//线程睡眠 {QM;%f  
public static void sleep(int nSecond) DcQ^V4_  
{ oZA|IF8U0  
try{ A0V"5syY  
Thread.sleep(nSecond); _B8e1an  
} 2t< dCw  
catch(Exception e) f"k?Ix\ e  
{ lqF{Y<l  
e.printStackTrace (); o~NeS|a  
} 7B"J x^  
} 0`h[|FYV  
KQJn\#>  
//日志 Jk}L+Xvv  
public static void log(String sMsg) P qagep d  
{ 69dFd!G\  
System.err.println(sMsg); [{}9"zB$x0  
} E,c~.jYc  
f8#WT$Ewy  
-E2[PW4$  
public static void log(int sMsg) J.$<Lnt>u  
{ 7. G  
System.err.println(sMsg); Ua5m2&U1  
} /JEH%)  
} (|'w$  
xp)#a_}  
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/* lE?e1mz{  
**TestMethod.java JjfNH ~  
*/ yD#w@yG  
package NetFox; { )'D<:T  
d#ya"e>  
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public class TestMethod { F}H!vh[  
p$?c>lim  
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public TestMethod() yz9`1R2c  
{ ///xx/weblogic60b2_win.exe KfG%#2\G_  
try{ @Sq=#f/=  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 7@fd[  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); \#LKsQa  
SiteFileFetch fileFetch = new SiteFileFetch(bean); >,@Fz)\:{'  
fileFetch.start(); <j ;HRm  
} nKu`Ta*fX  
catch(Exception e){e.printStackTrace ();} ,H22;UV9  
?9H
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**_VNDK+  
} |GdA0y\v*}  
iJ?8)}  
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public static void main(String[] args) 'x+0 yd  
{ Pu/0<Orp7  
new TestMethod(); }td+F&l($V  
} UM|GX  
} >B8)Wb:  
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