http断点续传简单实现（java)

/* Hz>_tA"^T  
**SiteFileFetch.java YXlaE=9bn  
*/ -U
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package NetFox; l:.q1UV  
import java.io.*; kM;}$*?  
import java.net.*; r+W;}nyf  
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 r .`&z  
public class SiteFileFetch extends Thread { Nf^6t1se  
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SiteInfoBean siteInfoBean = null; //文件信息Bean M/abd 7q  
long[] nStartPos; //开始位置 '3uN]-A>D  
long[] nEndPos; //结束位置 1G}\IK1+  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 x,fX mgE  
long nFileLength; //文件长度 @TraEBJGL  
boolean bFirst = true; //是否第一次取文件 KlGmO;k  
boolean bStop = false; //停止标志  84g8$~M  
File tmpFile; //文件下载的临时信息 B
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DataOutputStream output; //输出到文件的输出流 (^~0%1  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） }nK=~Wcu\  
public SiteFileFetch(SiteInfoBean bean) throws IOException Maw$^Tz,  
{ aJzyEb  
siteInfoBean = bean; n_/;j$h  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 5{|tE!  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); -%_vb6u  
if(tmpFile.exists ()) .P(Ax:g  
{ ~5;2ni8n  
bFirst = false; 9zD,z+  
read_nPos(); ,7n8_pU  
} f~R`RBZ]9  
else [NU@A>H  
{ ,opS)C$  
nStartPos = new long[bean.getNSplitter()]; rNl%I@
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nEndPos = new long[bean.getNSplitter()]; }08Sv=XM  
} 68()2v4X  
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} Yc-gJI*1  
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public void run() l H{~?x  
{ J93@\b  
//获得文件长度 tpn.\z%  
//分割文件 cq4sgQ?sW  
//实例FileSplitterFetch b~C^cM  
//启动FileSplitterFetch线程 iTVepYv4m  
//等待子线程返回 C5^9D  
try{ {wptOZ  
if(bFirst) BMH?BRi  
{ c{{RP6o/j=  
nFileLength = getFileSize(); [<JY[o=
 
if(nFileLength == -1) fD#!0^  
{ bqwn_=.  
System.err.println("File Length is not known!"); zxrbEE Q  
} T( CTU/a-,  
else if(nFileLength == -2) 'p&q}IO  
{ 5n1T7-QCL  
System.err.println("File is not access!"); D9r4oRkP*  
} >l=;6QL  
else :OD-L)Or  
{ h/NI5  
for(int i=0;i<nStartPos.length;i++) #^9a[ZLj0  
{ tKC
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); 2!nz>K  
} Id?2(Tg  
for(int i=0;i<nEndPos.length-1;i++) >@.:9}Z  
{ ^TqR0a-*  
nEndPos = nStartPos[i+1]; )P#xny2  
} xsRu~'f  
nEndPos[nEndPos.length-1] = nFileLength; Y.#:l<  
} Z"d21D~h9`  
} )E}eK-Yu  
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VX'G\Zz@h|  
//启动子线程 yUX<W'-Hev  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; @ 5V3I^  
for(int i=0;i<nStartPos.length;i++) ;edt["Eu  
{ ^o[(F<q  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "vo o!&<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), psAr>:\3  
nStartPos,nEndPos,i); S20E}bS:>  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); wT&P].5n  
fileSplitterFetch.start(); K{`3,U2Wx  
} DxzNg_E]  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "64D.c(r$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); hOr4C4  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", <(x!P=NM-  
nEndPos = " + nFileLength); nzl3<Ar  
// fileSplitterFetch[nPos.length-1].start(); xX\A&9m  
,H5o/qNU`{  
9@8)ZHf  
//等待子线程结束 GQ1m h*4$  
//int count = 0; _MzdbUb5,  
//是否结束while循环 gjPbhY=C[  
boolean breakWhile = false; gacE?bW'  
AxiCpAS;J  
^03M~SNCj  
while(!bStop) DX<xkS[P  
{ ;s w3MRJ  
write_nPos(); 'ExTnv ~  
Utility.sleep(500); pTE.,~-J^j  
breakWhile = true; B0ZLGB  
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for(int i=0;i<nStartPos.length;i++) M<3m/l%`Y  
{ r=ht:+m  
if(!fileSplitterFetch.bDownOver) cE3V0voSw1  
{ Y@'ahxF  
breakWhile = false; `E5vO1Pl  
break; KZI-/H+  
} 3.?B')  
} 7=@MnF`  
if(breakWhile) +KHk`2{y~  
break; Ov|Uux  
-"w&g0Z  
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//count++; W%P0X5YQ  
//if(count>4) Qh,Dcg2ZM"  
// siteStop(); RRJ
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} F!&_  
m^Rf6O^  
k4BiH5\hA  
System.err.println("文件下载结束！"); SkMBdkS9z[  
} $6yr:2Xvt  
catch(Exception e){e.printStackTrace ();} V>B*_J,z.  
} Y%YPR=j~ &  
|3uE"\nfA  
e(EXQP2P>  
//获得文件长度 Jk=d5B  
public long getFileSize() E@S5|CM  
{ #)28ESj  
int nFileLength = -1; 0?\d%J!"S  
try{ /rmm@  
URL url = new URL(siteInfoBean.getSSiteURL()); \I~9%QJ>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); gTqtTd~L  
httpConnection.setRequestProperty("User-Agent","NetFox"); N0']t Gh2  
=ms o1  
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int responseCode=httpConnection.getResponseCode(); ~0ZLaiJ  
if(responseCode>=400) ,?>:Cdz4  
{ te8lF{R  
processErrorCode(responseCode); t?cO>4*|  
return -2; //-2 represent access is error A]mXV4RmI  
} jBnvu@K"  
x#&%lJT  
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String sHeader; "T'?Ah6  
2_#Vw&v  
h?2:'Vu]  
for(int i=1;;i++) D"+xF&  
{ 8A3!XA  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); yct^AN|%  
//Utility.log(in.readLine()); B;mt11M  
sHeader=httpConnection.getHeaderFieldKey(i); ^q ?xi5w  
if(sHeader!=null) RB `
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{ )a'c_ 2[  
if(sHeader.equals("Content-Length")) $l!+SLK  
{ ~R
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 97n@HL1  
break; YJEL'k<l  
} f;PvXq<7"  
} ;~5w`F)  
else *1fZcw'C.  
break; 7L\kna<  
} KZ}F1Mr  
} ^6[o$eY3  
catch(IOException e){e.printStackTrace ();} |6}:n,KA.  
catch(Exception e){e.printStackTrace ();} k4ijWo{:0  
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Utility.log(nFileLength); 09>lx$  
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return nFileLength; ]C me)&hX  
} ZT;:Hxv0N  
l;gj],*  
ZHku3)V=o  
//保存下载信息（文件指针位置） "|:I]ZB  
private void write_nPos() $2j?Z.yEG  
{ VD*xhuy$k  
try{ /6%<97/d  
output = new DataOutputStream(new FileOutputStream(tmpFile)); I3ZbHb-)_,  
output.writeInt(nStartPos.length); uBe1{Z  
for(int i=0;i<nStartPos.length;i++) xe
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{ "T_OLegdK  
// output.writeLong(nPos); "/-T{p;.  
output.writeLong(fileSplitterFetch.nStartPos); TdAHw @(  
output.writeLong(fileSplitterFetch.nEndPos); -UM5&R+o  
} !Y3 *\  
output.close(); K{)YnY_E;  
} E"P5rT  
catch(IOException e){e.printStackTrace ();} 0bQm:J[(#  
catch(Exception e){e.printStackTrace ();} 75pz' Cb  
} H8}}R~ZO  
)@]Y1r4U  
<2Qh5umQ  
//读取保存的下载信息（文件指针位置） +I+7@XiZ  
private void read_nPos() *\i<+~I@
l  
{ /}Z0\,  
try{ nPj+mg  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 8'(|1  
int nCount = input.readInt(); |H)WJ/`  
nStartPos = new long[nCount]; N8>;BHBV!  
nEndPos = new long[nCount]; ktr l|  
for(int i=0;i<nStartPos.length;i++) Hlw0ia  
{ ,DT=(  
nStartPos = input.readLong(); cQaEh1n  
nEndPos = input.readLong(); !:[kS1s>M  
} (!nhU  
input.close(); 8\~IwtSk  
} btC.EmX  
catch(IOException e){e.printStackTrace ();} m_7)r  
catch(Exception e){e.printStackTrace ();} IJ%S[>  
}
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private void processErrorCode(int nErrorCode) psg}sl/  
{ ZR3x;$I~4  
System.err.println("Error Code : " + nErrorCode); S;"7d  
} o6$Q>g`]  
fU+A~oL%I  
.g7ebh6D  
//停止文件下载 "Iy @PR?>  
public void siteStop() FshQ OFW  
{ z90=,wd  
bStop = true; !Z7 ~Rsdm  
for(int i=0;i<nStartPos.length;i++) ql%>)k /x  
fileSplitterFetch.splitterStop(); VvwQz#S  
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} x0])&':!  
} 8u::f`vi  
//负责部分文件的抓取 nD\X3g`V  
**FileSplitterFetch.java S-8O9  
*/ [`^x;*C  
package NetFox; b|c?xHF}K  
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import java.io.*; R{r0dK"_  
import java.net.*; -IR9^)  
f
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public class FileSplitterFetch extends Thread { ms=Ilz  
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String sURL; //File URL =;{v
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long nStartPos; //File Snippet Start Position n_@YKz;8  
long nEndPos; //File Snippet End Position ?o h3t  
int nThreadID; //Thread's ID ChLU(IPo6  
boolean bDownOver = false; //Downing is over V(3udB@K  
boolean bStop = false; //Stop identical ku*|?uF  
FileAccessI fileAccessI = null; //File Access interface C!SB5G>OH  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException "[=Ee[/  
{ 2-| oN/FD  
this.sURL = sURL; #gOITXKs  
this.nStartPos = nStart; 0\AYUa?RM  
this.nEndPos = nEnd; B@]( ,  
nThreadID = id; L4aT=of-  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 I\sCH  
} (r,RwWYm  
#jV6w=I  
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public void run() apUV6h-v  
{ mp~\ioI*d  
while(nStartPos < nEndPos && !bStop) ushQWP)  
{ t=~5I>  
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try{ EOV<|WF>  
URL url = new URL(sURL); =o=)EU{~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =,I,K=+_x  
httpConnection.setRequestProperty("User-Agent","NetFox"); vKDPg p<j  
String sProperty = "bytes="+nStartPos+"-"; 8oY0?|_Bx  
httpConnection.setRequestProperty("RANGE",sProperty); {S\cpCI`  
Utility.log(sProperty); C+}uH:I'L  
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InputStream input = httpConnection.getInputStream(); Dw{C_e  
//logResponseHead(httpConnection); VLtb16|  
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byte[] b = new byte[1024]; _y`'T;~OY  
int nRead; A0S6 4(  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 1K,bmb xRt  
{ qO>BF/)a(  
nStartPos += fileAccessI.write(b,0,nRead); 2:i`,  
//if(nThreadID == 1) *D]/V U  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kaUH#;c>_  
} =#1iio&  
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33couAP#  
Utility.log("Thread " + nThreadID + " is over!"); }?>30+42:  
bDownOver = true; z]\0]i  
//nPos = fileAccessI.write (b,0,nRead); lbg!B4,  
} |U$oS2U\m  
catch(Exception e){e.printStackTrace ();} ,Mc}U9)F  
} &nj@t>5Bs$  
} $|z8WCJ  
=bf-+gZD  
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//打印回应的头信息 a&ZH  
public void logResponseHead(HttpURLConnection con) oHu0] XA  
{ 2NsI3M4$8  
for(int i=1;;i++) (a`z:dz}  
{ k`.-PU  
String header=con.getHeaderFieldKey(i); fYx$3a.  
if(header!=null) m+DkO{8F  
//responseHeaders.put(header,httpConnection.getHeaderField(header));  2c!?!:s  
Utility.log(header+" : "+con.getHeaderField(header)); W32mAz;  
else Ik=KEOz  
break; I2|iqbX40Q  
} ~oT0h[<  
} "S#0QH%5  
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public void splitterStop() nb'],({:9  
{ Qo)>i0  
bStop = true; ^5u}   
} L !yl^c  
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._  
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} VILzx+v M  
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/* 5H==m~  
**FileAccess.java 8Z/P<u  
*//文件访问(定位，写) kHX- AsRc  
package NetFox; 5@O
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import java.io.*; !K(0)~u  
]_|qv1K6  
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public class FileAccessI implements Serializable{ u Dm=W36  
&bs/a]?Z7  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ?
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RandomAccessFile oSavedFile; 6/s#'#jh  
long nPos; G+^HZ4jg  
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@(Ou
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public FileAccessI() throws IOException j3IxcG}f  
{ }I,]"0b  
this("",0); }#'O b  
} X!"ltNd  
f]%$HfF@  
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public FileAccessI(String sName,long nPos) throws IOException lkFv5^%  
{ 1/6G&RB  
oSavedFile = new RandomAccessFile(sName,"rw"); vy1:>N?#5  
this.nPos = nPos; JL`n12$m  
oSavedFile.seek(nPos); *8,]fBUq  
} MBXumc_g  
sh:sPzQ%Jv  
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public synchronized int write(byte[] b,int nStart,int nLen) ~e ]83?  
{ m}Kn!21  
int n = -1; 5RI"gf  
try{ !95ZK.UT  
oSavedFile.write(b,nStart,nLen); 5R/k -h^`  
n = nLen; ~WehG<p v[  
} vkASp&a  
catch(IOException e) HeNg<5v%Y  
{ vM1f-I-  
e.printStackTrace (); . sgV  
} 4mQ:i7~  
29 Yg>R!/  
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return n; p_)V@7  
} +VI2i~  
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} ,g6w2y7 ]  
/b@8#px  
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/* z6A
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**SiteInfoBean.java EUu"H` E+  
*/ x=5k74  
package NetFox; V[5-A $ft  
xWU0Ev)4U  
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public class SiteInfoBean { &^{HD }/{b  
|t!kD(~r  
Vqb4 MWW  
private String sSiteURL; //Site's URL b Zn:q[7  
private String sFilePath; //Saved File's Path 8uchp  
private String sFileName; //Saved File's Name xCEEv5(5  
private int nSplitter; //Count of Splited Downloading File jL6u#0  
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B'lWs;  
public SiteInfoBean() co|jUDu>W  
{//nSplitter的缺省值为5 @vCPX=c  
//default value of nSplitter is 5 4=%Uv^M  
this("","","",5); #78p#E  
} .`)\GjDv  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) py]m^)yc  
{ 9.!6wd4mw  
sSiteURL= sURL; O1ofN#u  
sFilePath = sPath; %kxq"=3  
sFileName = sName; Wr a W  
this.nSplitter = nSpiltter; i"_)91RA  
#Ne<=ayS  
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} SWNi@  
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{W)Kz_  
public String getSSiteURL() " 2Dz5L1v  
{ dpDVEEs84  
return sSiteURL; 26G2. /**<  
} SsIy;l  
1y2D]h/'  
{Uz@`QO3  
public void setSSiteURL(String value) 9gZMfP  
{ C\ZL*,%}  
sSiteURL = value; Vl%AN;o  
} rr>QG<i;G  
o8-BTq8  
{KxeH7S
 
public String getSFilePath() w4Qqo(  
{ j&6,%s-M`a  
return sFilePath; GvF8S MO[x  
} '_lyoVP  
L'B
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puF'w:I(  
public void setSFilePath(String value) 9z$]hl  
{ >XcbNZV  
sFilePath = value; "o2p|2c  
} GpMKOjVm|  
`MAee8u'  
HgvgO\`]  
public String getSFileName() gbsRf&4h  
{ OL4I}^*,  
return sFileName; ! @{rkp  
} 1P. W 34  
W=c7>s0>  
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public void setSFileName(String value) :3^b>(W.  
{ 11glFe  
sFileName = value; \V  /s  
} p(QB5at  
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Jkzt=6WZ0  
public int getNSplitter() X6kB R  
{ rbiNp6AdL  
return nSplitter; |s-q+q{|  
} r(y1^S9!8  
!rZO~a0  
|R8=yO%(  
public void setNSplitter(int nCount) (~:k70V5  
{ T]Gxf"mK  
nSplitter = nCount; C)~YWx@v  
} x%23oPM  
} `zGK
$,[%  
Tf7$PSupP  
gcqcY  
/* .;yy= Rj  
**Utility.java d)1)/Emyj  
*/ jb~a z  
package NetFox; q>/# P5V  
8Y*SZTzV  
Fh9%5-t:J  
public class Utility { '@>FtF[Gu  
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public Utility() 7F;"=DarOE  
{ U_v{Vs  
/+l3 BeL  
S+
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} %Fig`qX  
)^7Y^ue  
//线程睡眠 sDT(3{)L7  
public static void sleep(int nSecond) 0,)B~|+  
{ W{O:j  
try{ 8J{I6nPF  
Thread.sleep(nSecond); CP_ ?DyWU  
} cTu7U=%  
catch(Exception e) xT70Rp(2po  
{ k$UgTZ  
e.printStackTrace (); !4GGq  
} P
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} }hrLM[  
s\i=-`  
//日志 G;_QE<V~_  
public static void log(String sMsg) iwWy]V m7  
{ |-4C[5rM  
System.err.println(sMsg); `,i'vb`W#b  
} fZL%H0&  
x|i"x+o  
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public static void log(int sMsg) Uhfm@1 cz&  
{ 'bGL@H  
System.err.println(sMsg); i#$9>X  
} -FytkM^]6  
} +5H9mk  
u +q}9  
_+g5;S5  
/* "'h?O*V]u{  
**TestMethod.java $gT+Ue|7  
*/ jXvGL  
package NetFox; 3p{N7/z(  
)k01K,%#)  
<9 lZ%j;  
public class TestMethod { WJ=DTON
 
&I:[ 'l!  
/tl/%:U*.  
public TestMethod() 1RM;"b/  
{ ///xx/weblogic60b2_win.exe vA@Kb3,  
try{ s:lar4>kM  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ^0"NcOzzxl  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); sY+U$BYB>  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Kdh(vNB>  
fileFetch.start(); TJ[C,ic=D  
} Y,RED5]t  
catch(Exception e){e.printStackTrace ();} v39`ct=e  
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} Cbm  
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: Q X~bq  
public static void main(String[] args) `fh^[Q|4n0  
{ -QjdL9\[c7  
new TestMethod(); J_YbeZ]  
} }[}u5T`w>  
} "}Kvx{L8  
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