http断点续传简单实现（java)

/* *IY*yR6  
**SiteFileFetch.java "9^j.  
*/ )6Ny1x+  
package NetFox; k-HCeZ  
import java.io.*; :)_~w4&  
import java.net.*; l*kPOyB  
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public class SiteFileFetch extends Thread { PG_0\'X)/w  
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SiteInfoBean siteInfoBean = null; //文件信息Bean S`"LV $8  
long[] nStartPos; //开始位置 M\Z6$<H?U  
long[] nEndPos; //结束位置 bV8!"{  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 z6?)3'  
long nFileLength; //文件长度 lmxr oHE  
boolean bFirst = true; //是否第一次取文件 -t2+|J*  
boolean bStop = false; //停止标志 -#2)?NkeE  
File tmpFile; //文件下载的临时信息 @:U+9[  
DataOutputStream output; //输出到文件的输出流 YE=q:Bv  
+AHUp)  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） W0k0$\i
X  
public SiteFileFetch(SiteInfoBean bean) throws IOException <0QH<4  
{ =ZDAeVz3w  
siteInfoBean = bean; sm\f0P!rv  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); F^5?\  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); sp5eVAd  
if(tmpFile.exists ()) Tjl:|F8  
{ 8&Oa_{1+Q  
bFirst = false; -|Y(V5]  
read_nPos(); {iv<w8CU)  
} l411a9o  
else O=
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{ n< ud> JIb  
nStartPos = new long[bean.getNSplitter()]; ~<k,#^"}X  
nEndPos = new long[bean.getNSplitter()]; <%Ostqj  
} H'LD}\K l  
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+> WM[o^I  
AwTJJ0>  
} \uXcLhXN  
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public void run() y
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{ 1xbK'i:-S  
//获得文件长度 w7FW^6Zl  
//分割文件 lK4M.QV ?\  
//实例FileSplitterFetch t\ 7~S&z  
//启动FileSplitterFetch线程 g+ MdHn[  
//等待子线程返回
]6{*^4kX  
try{ W3;#fa:[L  
if(bFirst) @EDs~ lPv  
{ Nof3F/2 N&  
nFileLength = getFileSize(); 7\9>a  
if(nFileLength == -1) {qmdm`V[  
{ o.'g]Q<}UB  
System.err.println("File Length is not known!"); TP"1\O  
} %^8^yZz  
else if(nFileLength == -2) RtCkVxaEx  
{ 5e}A@GyC  
System.err.println("File is not access!"); K,e w>U  
} ]Lm9^q14m  
else 7yx$Nn`(  
{ >A<bBK#  
for(int i=0;i<nStartPos.length;i++) vk?sk
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{ 5i-Rglo  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); OI?K/rn  
} ph_4q@  
for(int i=0;i<nEndPos.length-1;i++) 7yz4'L  
{ Vm df8[5  
nEndPos = nStartPos[i+1]; n':!,a[  
} .p=sBLp8  
nEndPos[nEndPos.length-1] = nFileLength; *0}3t<5  
} ^kgBa27  
} .-IkL|M  
}4{fQ`HT  
l6~-8d+lfN  
//启动子线程 b L]erYm  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; MzP7Py 8.  
for(int i=0;i<nStartPos.length;i++) OZIW_'Wm/  
{ 24/XNSE,-  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), w,Lvt }  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), OKP9CLg9  
nStartPos,nEndPos,i); q-rB2  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %rF?dvb;?  
fileSplitterFetch.start(); {XWZ<OjG  
} k~/>b~.c  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), RiTa \  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); t(+)#  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Ik[s  
nEndPos = " + nFileLength); _9?I A  
// fileSplitterFetch[nPos.length-1].start(); sU!6hk  
d)[;e()  
TeWMp6u,r  
//等待子线程结束 x+h~gckLb  
//int count = 0;
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//是否结束while循环 X5]TY]  
boolean breakWhile = false; \y88d4zX  
a3VM'  
8NU`^L:1  
while(!bStop) $rhgzpZ!X_  
{ uu/+.9  
write_nPos(); d @*GUmJ  
Utility.sleep(500); [F*4EGB  
breakWhile = true; [ G e=kFB  
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for(int i=0;i<nStartPos.length;i++) gxT4PQDy  
{ $&=p+  
if(!fileSplitterFetch.bDownOver) yR~R:  
{ LT~YFS  
breakWhile = false; Y'u7 IX}  
break; Hh4 n  
} Ic{F*nnM  
} `g_"GE  
if(breakWhile) 2o9$4{}rG  
break; S8l1"/?aHE  
{66fG53x  
sjM;s{gy  
//count++; ;),BW
g  
//if(count>4) e }*0ghKI  
// siteStop(); ~=wCwA|1  
} Dgql?+2$  
9M /SH$Qy  
`s]4AKBO  
System.err.println("文件下载结束！"); =rd|0K"(r  
} 4#(ZNP  
catch(Exception e){e.printStackTrace ();} 9~0^PzTA  
} ;ml 3  
)%X;^(zKM  
#$1og=  
//获得文件长度 kip`Myw+  
public long getFileSize() W{5:'9,  
{ @<@SMK)  
int nFileLength = -1; #-Z8Z i"44  
try{ kJAn4I.l  
URL url = new URL(siteInfoBean.getSSiteURL()); ;@nFVy>U  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $LHa?3  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;oNhEB:F  
gUR]{dq^'  
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int responseCode=httpConnection.getResponseCode(); '&FjW-`" G  
if(responseCode>=400) r{sebE\ ;  
{ @[6,6:h|  
processErrorCode(responseCode); ,zQOZ'^  
return -2; //-2 represent access is error M('d-Q{B7L  
} `Ci4YDaz;k  
H2r8,|XL  
@-)tM.8~  
String sHeader; T'#!~GpB  
T%F0B`  
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for(int i=1;;i++) @+Y8*Rj\3  
{ =9G;PVk|  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); -.<k~71  
//Utility.log(in.readLine()); f&x0@Q/eON  
sHeader=httpConnection.getHeaderFieldKey(i); W0zbxJKjd  
if(sHeader!=null) }K(o9$V ^!  
{ UzKFf&-:;K  
if(sHeader.equals("Content-Length")) .la&P,j_L  
{ `aqrSH5^h  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); MqKye8h9f  
break; kJ(A,s|  
} qUo-Dq>  
} @4!x>q$3  
else e9^2,:wLB  
break; 1P]de'-`j  
} J.RAmU<  
} '(#g1H3  
catch(IOException e){e.printStackTrace ();} S:8OQI  
catch(Exception e){e.printStackTrace ();} v8I{XU@%  
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'+*-s7o{  
Utility.log(nFileLength); &*&?0ov^"  
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return nFileLength; . -"E^f  
} (shK  
>?YNW   
{6d b{ ay_  
//保存下载信息（文件指针位置） -Y:ROoFOZ  
private void write_nPos() [rreFSy#@  
{ ^*^/]vM  
try{ cUK\x2  
output = new DataOutputStream(new FileOutputStream(tmpFile)); bO<0qM~  
output.writeInt(nStartPos.length); S^cH}-+  
for(int i=0;i<nStartPos.length;i++) fA^7^0![  
{ HhkN^S,  
// output.writeLong(nPos); D6Y6^eS-  
output.writeLong(fileSplitterFetch.nStartPos); {BO
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output.writeLong(fileSplitterFetch.nEndPos); W3Ulewa  
} b>~RSO*  
output.close(); XNH4==4  
} >!9h6BoGV  
catch(IOException e){e.printStackTrace ();} ;t]|15]u  
catch(Exception e){e.printStackTrace ();} ?A7Yk4Y.?N  
} c[0oh.  
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2 Y|D'^  
//读取保存的下载信息（文件指针位置） ,vG<*|pn  
private void read_nPos() :+,st&(E  
{ d<@Mdo<;?g  
try{ T+RZ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 3SARr>HRyI  
int nCount = input.readInt(); T 4|jz<iK]  
nStartPos = new long[nCount]; agd)ag4"[u  
nEndPos = new long[nCount]; F* #h9 Y  
for(int i=0;i<nStartPos.length;i++) PM4>ThQ  
{ bj"z8kP  
nStartPos = input.readLong(); m1.B\~S3  
nEndPos = input.readLong(); .yVnw^gu  
} 2W3W/> 2h  
input.close(); dALK0U  
} 4VIg>EL*  
catch(IOException e){e.printStackTrace ();} b Dg9P^<n  
catch(Exception e){e.printStackTrace ();} G^Xd-7 GQ  
} P Tnac  
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private void processErrorCode(int nErrorCode) C=VIT*=  
{ 00M`%c/  
System.err.println("Error Code : " + nErrorCode); p\U*;'hv  
} DMkhbo&+  
{TL +7kiX/  
Z~3u:[x";  
//停止文件下载 (L|}`  
public void siteStop() 
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{ "E>t, D  
bStop = true; ):bu;3E  
for(int i=0;i<nStartPos.length;i++) ,deUsc  
fileSplitterFetch.splitterStop(); 3#Y3Dz`  
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V_;9TC  
} `)[dVfxA  
} DuF7HTN[K  
//负责部分文件的抓取 
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**FileSplitterFetch.java w3#`1T`N  
*/ V:\]cGA{  
package NetFox; 8Inx/>eOI  
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import java.io.*; pN$;!  
import java.net.*; \$;~74}  
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<F=Dj*]  
public class FileSplitterFetch extends Thread { Lp~^*j(  
b~W)S/wF$P  
8^w/HCC8O  
String sURL; //File URL \|Qb[{<:,  
long nStartPos; //File Snippet Start Position p^8JLC  
long nEndPos; //File Snippet End Position ] C,1%(  
int nThreadID; //Thread's ID 6wpU6NU  
boolean bDownOver = false; //Downing is over ;i9>}]6  
boolean bStop = false; //Stop identical >Me]m<$E;  
FileAccessI fileAccessI = null; //File Access interface B~_Spp  
>Zdi5') 5  
UE)fUTS  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 99KVtgPm  
{ g+9v$[!  
this.sURL = sURL; !BRcq~-.  
this.nStartPos = nStart; @*_ZoO7{  
this.nEndPos = nEnd; & zgPN8u  
nThreadID = id; q2!'==h2i  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 d
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} )nnCCRS6  
L*O>IQh2  
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public void run() !~d'{sy6  
{ Yzd2G,kZ=  
while(nStartPos < nEndPos && !bStop) 
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{ =yh3Nd:u
 
( 2zeG`  
&A"e,h(^  
try{ p1 4d,}4W  
URL url = new URL(sURL); b8HE."*t  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); tzNaw %\  
httpConnection.setRequestProperty("User-Agent","NetFox"); t{=i=K3  
String sProperty = "bytes="+nStartPos+"-"; M@~o6^  
httpConnection.setRequestProperty("RANGE",sProperty); 7O461$4v  
Utility.log(sProperty); 4OEKx|:5n  
=
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A|C_np^z2  
InputStream input = httpConnection.getInputStream(); M*H< n*  
//logResponseHead(httpConnection); E&9!1!B
 
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byte[] b = new byte[1024]; XSl!T/d  
int nRead; "<*nZ~nE)  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 8;8YA1@w  
{ {,F/KL^u  
nStartPos += fileAccessI.write(b,0,nRead); +',^((o  
//if(nThreadID == 1) `x4E
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |1i]L@&  
} |>@-grs  
mo*'"/  
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Utility.log("Thread " + nThreadID + " is over!"); 4 iKR{P6  
bDownOver = true; @%H8"A  
//nPos = fileAccessI.write (b,0,nRead); qM*S*,s  
} IW]*i?L  
catch(Exception e){e.printStackTrace ();} *) } :l  
} bHJoEYY^  
} m8u=u4z("  
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Dh?vU~v(6  
//打印回应的头信息 W[GQ[h  
public void logResponseHead(HttpURLConnection con) _^b@>C>O  
{ +]_nbWL(%  
for(int i=1;;i++) u x#.:C|  
{ [NZ-WU&&LP  
String header=con.getHeaderFieldKey(i); WzlS^bZ  
if(header!=null) -^Rb7g-  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); iz$FcA]  
Utility.log(header+" : "+con.getHeaderField(header)); + lP5XY{  
else t5n2eOy~T  
break; qf)C%3gXI  
} U
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}  'X|v+?  
mHHzCKE,  
s1Okoxh/!V  
public void splitterStop() m'SmN{(t  
{ y3IA '  
bStop = true; RE*WM3QK~  
} o|+E+l9\  
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} Dw*Arc+3V  
-}<d(c  
:;q>31:h  
/* BL0|\&*1  
**FileAccess.java 2J)74SeH  
*//文件访问(定位，写) /<6ywLD  
package NetFox; \U Ax(;  
import java.io.*; 6{ C Fe|XN  
Et)920  
QTeFR&q8  
public class FileAccessI implements Serializable{ yS+(<  
^g-Fg>&M  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 C(xqvK~p  
RandomAccessFile oSavedFile; =zz+<!!  
long nPos; A"0wvk)UcY  
J &{q
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_IC
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public FileAccessI() throws IOException 'xQna+%h  
{ K/Sq2:  
this("",0); .|U4N/XN%q  
} L>0!B8X2  
kpl~/i`4  
=?wMESU  
public FileAccessI(String sName,long nPos) throws IOException Gee~>:_Q{J  
{ lD9%xCo9(  
oSavedFile = new RandomAccessFile(sName,"rw"); g)X7FxS,z  
this.nPos = nPos; HgYc@P*b  
oSavedFile.seek(nPos); B'<!k7Ewy  
} v'h3CaA9j  
7Nd*,DV_  
T=^jCH &  
public synchronized int write(byte[] b,int nStart,int nLen) c]e`m6  
{ vlAO z  
int n = -1; 4}+xeGA$  
try{ zjea4>!A2  
oSavedFile.write(b,nStart,nLen); E!dz/.  
n = nLen; )\0Ug7]?  
} ^WmGo]<B_  
catch(IOException e) \5t`p67Ve_  
{ ESn6D@"  
e.printStackTrace (); p(~Y" H  
} yI3Q|731)  
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`  
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return n; t8t}7XD   
} u82h6s<'W  
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} @bc[ eas  
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O~${&(  
/* P/C&R-{')  
**SiteInfoBean.java S&5Q~}{,  
*/ mfu*o0   
package NetFox; P4hZB_.=  
fL(':W&n-  
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public class SiteInfoBean { ay=KfY5  
&7$,<9.  
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private String sSiteURL; //Site's URL kuWK/6l4  
private String sFilePath; //Saved File's Path IRlN++I!  
private String sFileName; //Saved File's Name 6e-#XCR{  
private int nSplitter; //Count of Splited Downloading File $dlnmNP+  
{9h`$e=  
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public SiteInfoBean() Fl B, (Cm  
{//nSplitter的缺省值为5 ;3 G~["DA  
//default value of nSplitter is 5 $?[1#%  
this("","","",5);
<P|`7wfxE  
} Ko1AaX(I'+  
Oyi;bb<#  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 7k'=Fm6za  
{ >Y,/dyT Zm  
sSiteURL= sURL; eFt\D\XOW  
sFilePath = sPath; Z[a
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sFileName = sName; 8T8pAs0 p  
this.nSplitter = nSpiltter; A)hq0FPp  
4}.WhE|h  
u^}7Vs .  
} IUluJ.sXIf  
\Pw8wayr%  
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public String getSSiteURL() Zx}NFcn  
{ Gojl0?  
return sSiteURL; x?%rx}h  
} rFKo E%  
AeNyZ[40T  
v(qV\:s}m  
public void setSSiteURL(String value) `V]egdO  
{ u&1j>`~qJ  
sSiteURL = value; r{pI-$  
} UiJ^~rn  
*Gg1h@&  
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public String getSFilePath() Aivu%}_|  
{ _ff=B  
return sFilePath; DCEvr"(  
} ]NaMZ  
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c'4>D,?1  
public void setSFilePath(String value) @?<N +qdH>  
{ &/B2)l6a  
sFilePath = value; F3kC"H  
} S% JNxT7'  
&,W_#l{  
D}zOuB,S  
public String getSFileName() ^m6k@VM  
{ Gl?P.BCW.&  
return sFileName; k)H[XpM  
} v+xgxQGYH  
K!IF?iell  
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public void setSFileName(String value) q`/amI0  
{ %k/ k]:s  
sFileName = value; iYO wB'z  
} (t]lP/  
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public int getNSplitter() >uBV  
{ |y{;|K  
return nSplitter; ~[d
=s  
} '+o:,6  
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public void setNSplitter(int nCount) K^!e-Xi6  
{ ,^MW)Gf<  
nSplitter = nCount; 7,V!Iv^X  
} tz\+'6NpOb  
} 7&;[an^w  
<Dt/Rad  
s,UN'~e1  
/* l|@/?GaH  
**Utility.java GibggOj2Q,  
*/ ^}i50SG:y  
package NetFox; xZ9}8*Q&:  
:GwSs'$O  
;kyL>mV{  
public class Utility { }S~ysQwT  
9#Aipu\  
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public Utility() s T :tFK\  
{ GL;x:2XA  
mV:RmA  
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} nZ`2Z7!  
LyJTK1]#  
//线程睡眠 a@5xz
)  
public static void sleep(int nSecond) 877EKvsiC  
{ 1jUhG2y  
try{ rZ8Y=) e  
Thread.sleep(nSecond); (n":]8}  
} WuP([8  
catch(Exception e) X/`#5<x  
{ :/yr(V{  
e.printStackTrace (); [6,]9|~  
} J'G`=m"-'  
} .R$+#_  
s0XRL1kWr  
//日志 5CY@R  
public static void log(String sMsg) YA^wUx  
{ <FcP
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System.err.println(sMsg); *f0.=?  
} )AnlFO+V  

zbIwH6  
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public static void log(int sMsg) .WL\:{G8;  
{  =BqaGXr  
System.err.println(sMsg); 5I8FD".i  
} [x$eF~Kp  
} F9u:8;\@`  
rB.=f[aX[  
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/* >?G|Yz*kEJ  
**TestMethod.java F653[[eQ  
*/ L6[rvM|9_  
package NetFox; L5zG0mC8  
DK@w^ZW6JA  
e~t}z_>F  
public class TestMethod { :"<B@Z  
6PzN>+t^y  
7/^TwNsv  
public TestMethod() ~q8V<@?  
{ ///xx/weblogic60b2_win.exe Zv1Bju*y  
try{ 7'{Yz  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); "x:)$@  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); o/x5  
SiteFileFetch fileFetch = new SiteFileFetch(bean);
wQdW lon  
fileFetch.start(); aCUV[CPw  
} /,rF$5G,  
catch(Exception e){e.printStackTrace ();} #5ohmp,u  
SQ^^1.V&/Y  
'&pf  
} g6@NPQ  
+/@ZnE9s  
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public static void main(String[] args) R@7GCj  
{ JR a*;_  
new TestMethod(); (}~eD  
} wCq)w=,  
} w371.84
 
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