http断点续传简单实现（java)

/* i-<1M|f  
**SiteFileFetch.java -E$(<Pow~\  
*/ =T?:b8yV  
package NetFox; 3.t j%
+  
import java.io.*; k%|Sl>{Ir  
import java.net.*; a_GnN\kX^Z  
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public class SiteFileFetch extends Thread { ,cesQ ou  
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SiteInfoBean siteInfoBean = null; //文件信息Bean N<$dbqoT|  
long[] nStartPos; //开始位置 V,*<E&+  
long[] nEndPos; //结束位置 RZ6[+Ygn  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 b-`=
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long nFileLength; //文件长度 sa7F-X
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boolean bFirst = true; //是否第一次取文件 '[Ue0r<jn  
boolean bStop = false; //停止标志 c SV`?[a  
File tmpFile; //文件下载的临时信息 7K5D,"D;1  
DataOutputStream output; //输出到文件的输出流 9GV1@'<Y]  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） (2SmB`g  
public SiteFileFetch(SiteInfoBean bean) throws IOException \~r`2p-K  
{ Mur)'  
siteInfoBean = bean; o4zX 41W  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 1Zh4)6x  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); L/[b~D>T%  
if(tmpFile.exists ()) =(3Yj[>st  
{ PXx:JZsju  
bFirst = false; +n)_\@aQ  
read_nPos(); !jySID?q  
} ZNKopA(=|%  
else r*r3QsO  
{ js$L<^7  
nStartPos = new long[bean.getNSplitter()]; _,ki/7{  
nEndPos = new long[bean.getNSplitter()];  s-Z<  
} >,9ah"K_x  

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} tQ@%3`  
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public void run() -5 Q gJ  
{ B&M-em=  
//获得文件长度 Jn#05Z
 
//分割文件 Z)7|m  
//实例FileSplitterFetch C3]"y7  
//启动FileSplitterFetch线程 YAc~,N
 
//等待子线程返回 dPm_jX  
try{ G2[?b2)8  
if(bFirst) t|5T,YFG  
{ WXj iKW(  
nFileLength = getFileSize(); \{@n>Mh  
if(nFileLength == -1) $!ATj`}kb  
{ V?zCON  
System.err.println("File Length is not known!"); T[L7-5U0  
} I&Z4?K  
else if(nFileLength == -2) )&") J}@  
{ -Gyj]v5y`c  
System.err.println("File is not access!"); Cd7imj  
} n|M~C\*  
else {tDH !sX  
{ \Qgc7ev  
for(int i=0;i<nStartPos.length;i++) ;k=&ZV  
{ om1@;u8u  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); %FhUjHm  
} nn?h;KzB  
for(int i=0;i<nEndPos.length-1;i++) y!kU0  
{ %`# HGji)  
nEndPos = nStartPos[i+1]; kR !O-@GJ]  
} %@~;PS3kd  
nEndPos[nEndPos.length-1] = nFileLength; TpH-_ft  
} MV?#g-5  
} SqosJ}K  
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//启动子线程 L>>RboR}  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Tp[-,3L  
for(int i=0;i<nStartPos.length;i++) z#|tcHVFT  
{ /)-OK7x  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), y(fJ{k   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 2gM/".|{  
nStartPos,nEndPos,i); tYk!Y/O}  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2N}UB=J  
fileSplitterFetch.start(); t8?$q})RL  
} ^D5+S`V  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `Q!#v{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Oj,v88=  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", iU/v;T(  
nEndPos = " + nFileLength); f =MP1q[  
// fileSplitterFetch[nPos.length-1].start(); O,[9E  
_)%Sz"g^Ix  
.ED8b5t|  
//等待子线程结束 ?glK~G!i  
//int count = 0; hR+\,P#G[  
//是否结束while循环 Re<@.d  
boolean breakWhile = false; |6O7_U#q  
uf/4vz,  
2CY4nSKW  
while(!bStop) &~K4I  
{ #7r13$>!  
write_nPos(); ]5',`~jkF  
Utility.sleep(500); _g2"D[I%  
breakWhile = true; G&z^AV  
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}Sr=|j  
for(int i=0;i<nStartPos.length;i++) ak"W/"2:  
{ ?e#bq]  
if(!fileSplitterFetch.bDownOver) \n>7T*iM&  
{ PY76;D*`  
breakWhile = false; 0Lx,qZ'  
break; E'cI}q  
} o6/"IIso3  
} <5]ufv  
if(breakWhile) gjL+8Rk  
break; L6 IIk  
9q]n&5  
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//count++; % 4Gt^:J"  
//if(count>4) d^+0=_[PmK  
// siteStop(); $z[@DB[  
} ^5n#hSqZ=M  
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System.err.println("文件下载结束！"); ey@{Ng#  
} E;rS"'D:  
catch(Exception e){e.printStackTrace ();} `V2doV)  
} HJ+Q7)  
-~Chf4?<4  
' +f(9/  
//获得文件长度 dJF3]h Y  
public long getFileSize() 1}Th@Vq
 
{ k!"6mo@rd  
int nFileLength = -1; [:gp_Z&  
try{ U62Z ?nge%  
URL url = new URL(siteInfoBean.getSSiteURL()); {HtW`r1)Tt  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4Ifz-t/  
httpConnection.setRequestProperty("User-Agent","NetFox"); .x'?&7#(  
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int responseCode=httpConnection.getResponseCode(); f=IF_|@
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if(responseCode>=400) ):]5WHYg  
{ @+7CfvM  
processErrorCode(responseCode); ~5>k_\G8  
return -2; //-2 represent access is error T"/dn%21  
} ] B?NDxU  
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)W/
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String sHeader; k![oJ.vHD  
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for(int i=1;;i++) #Q"04'g  
{ ( TJGJY  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Jb6)U]  
//Utility.log(in.readLine()); wv  
sHeader=httpConnection.getHeaderFieldKey(i); 8[H bg  
if(sHeader!=null) @:}la  
{ ! NJGW  
if(sHeader.equals("Content-Length")) TDX~?>P  
{ +45.fo  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); +y^'\KN  
break; #x6EZnG  
} #wZbG|%  
} 0|6Y%a\U  
else aZ8f>t1Q  
break; Vy6~O|68=  
} ^"iJ  
} q)3QmA~  
catch(IOException e){e.printStackTrace ();} T>|Y_3YO_a  
catch(Exception e){e.printStackTrace ();} D67z6jep(  
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Utility.log(nFileLength); E BSjU8  
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i_:#]
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return nFileLength; {^?:-#~h  
} 2O
}X-/H  
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//保存下载信息（文件指针位置） Te`MIR  
private void write_nPos() NNMn
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{ LRR)T: e}q  
try{ kP1cwmZ7F  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ( 6ucA  
output.writeInt(nStartPos.length); |-TxX:O-  
for(int i=0;i<nStartPos.length;i++) WidLUv
 
{ y!T
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// output.writeLong(nPos); j_.tg7X  
output.writeLong(fileSplitterFetch.nStartPos); R5xV_;wD  
output.writeLong(fileSplitterFetch.nEndPos); CIVV"p`}  
} oA8A @,-L  
output.close(); g"N&*V2  
} P?@o?  
catch(IOException e){e.printStackTrace ();} I#'yy7J  
catch(Exception e){e.printStackTrace ();} DiskGq@T  
} BKV:U\QZ  
!AGoI7W}  
d4)0G-|  
//读取保存的下载信息（文件指针位置） MkWbPm)  
private void read_nPos() p^w_-(p  
{ H`,t"I  
try{ o1k+dJUd  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ==S^IBG  
int nCount = input.readInt();  `)>}b 3  
nStartPos = new long[nCount]; 0./Rdf=-1j  
nEndPos = new long[nCount]; iI;np+uYk  
for(int i=0;i<nStartPos.length;i++) hW`o-'  
{ _p?s[r*  
nStartPos = input.readLong(); ,BR W=  
nEndPos = input.readLong(); rH'|$~a  
} B>[myx  
input.close(); jhkXU+4  
} tF\_AvL_8  
catch(IOException e){e.printStackTrace ();} BY':
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catch(Exception e){e.printStackTrace ();} %~M#3Ywa  
} &x$ps  
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^O}J',Fm%f  
private void processErrorCode(int nErrorCode) qC3PKlhv6  
{ u4'B  
System.err.println("Error Code : " + nErrorCode); eIOMW9Ivt  
} xZ(d*/6E  
53?Ati\Y)  
iba8G]2  
//停止文件下载 z/nW;ow  
public void siteStop() gGx<k3W^  
{ `XM0Mm%  
bStop = true; cYBjsN(!A|  
for(int i=0;i<nStartPos.length;i++) :(
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fileSplitterFetch.splitterStop(); !r9rTS]  
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} Oc-ia)v1G  
} _:FD#5BZ1  
//负责部分文件的抓取 E,fbIyX  
**FileSplitterFetch.java qTN30(x2  
*/ +O)ZB$w4  
package NetFox; a5&[O  
?O"zp65d(  
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import java.io.*; Ec^2tx"=  
import java.net.*; +11oVW  
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public class FileSplitterFetch extends Thread { {1+me
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,c 0]r;u!  
String sURL; //File URL 5bd4
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long nStartPos; //File Snippet Start Position VV sE]7P ]  
long nEndPos; //File Snippet End Position %cJdVDW`L  
int nThreadID; //Thread's ID q29d=  
boolean bDownOver = false; //Downing is over J4s`U/F  
boolean bStop = false; //Stop identical (j(9'DjP  
FileAccessI fileAccessI = null; //File Access interface 1~j,A[&|<  
y'n<oSB}  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException @!|h!p;  
{ J% ZM V  
this.sURL = sURL; F5OQM?J  
this.nStartPos = nStart; N34bB>_  
this.nEndPos = nEnd; d[*NDMO  
nThreadID = id; :&LV^A  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 rbs&A{i  
} uo*lW2&U  
?j
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public void run() kWs:7jiiu  
{ tK `A_hC  
while(nStartPos < nEndPos && !bStop) R]RLy#j  
{ l@]Fzl  
d*=qqe H  
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try{ \Ym!5,^o  
URL url = new URL(sURL); AP8J28I  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ylDfr){  
httpConnection.setRequestProperty("User-Agent","NetFox"); @}uo:b:Q  
String sProperty = "bytes="+nStartPos+"-"; 44KWS~  
httpConnection.setRequestProperty("RANGE",sProperty); Cv/3-&5S  
Utility.log(sProperty); Ns#L9T#  
]\]mwvLT  
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InputStream input = httpConnection.getInputStream(); .'4@Yp{=  
//logResponseHead(httpConnection);  A7eYKo q  
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byte[] b = new byte[1024]; lTFo#p_(  
int nRead; "{d[V(lE"  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 7M_GGjP  
{ \jS^+Xf?^  
nStartPos += fileAccessI.write(b,0,nRead); YG)7+94  
//if(nThreadID == 1) '#~Sb8   
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); E.-2 /'i  
} - s2Yhf  
Q5IN1 ^=HF  
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Utility.log("Thread " + nThreadID + " is over!"); " LhXR  
bDownOver = true; |/Y!R>El  
//nPos = fileAccessI.write (b,0,nRead); }:1qK67S  
} I*mBU^<9V  
catch(Exception e){e.printStackTrace ();} =/4}!B/  
} /b6
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} \lyHQ-gWhc  
= N:5#A  
W9bpKmc  
//打印回应的头信息 6)FM83zk)K  
public void logResponseHead(HttpURLConnection con) pBn;:  
{ P(3$XMx  
for(int i=1;;i++) n@S|^cH  
{ ^,[gO#hgz  
String header=con.getHeaderFieldKey(i); %WYveY  
if(header!=null) A-eCc#I  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); =,&{ &m)  
Utility.log(header+" : "+con.getHeaderField(header)); e'=#G$S?g  
else `qZ@eGZ z  
break; Rn{X+b.  
} B0gs<E  
} $cLZ,N24  
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j.  
d ;,C[&  
public void splitterStop() =H^~"16  
{ (: mF+%(  
bStop = true; JqEo~]E]  
} `[x'EJp#  
2#'"<n,G
 
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} 6']WOM#  
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/* cO-^#di  
**FileAccess.java 0_t9;;y :  
*//文件访问(定位，写) u0$}VO5/a  
package NetFox; s##XC^;p[  
import java.io.*; T'N/A9{q  
gpCWXz')i  
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public class FileAccessI implements Serializable{ pz.fZV  
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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 a JQ_V  
RandomAccessFile oSavedFile; 2}5@:cwR+  
long nPos; YCyh+%Q(  
mH'om SCz  
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public FileAccessI() throws IOException s]xn&rd_  
{ `>0(N.'T  
this("",0); }IKU^0M9<T  
} =':B  
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}w)wW1&  
public FileAccessI(String sName,long nPos) throws IOException 6O'Y@9#  
{ }jg,[jw_"X  
oSavedFile = new RandomAccessFile(sName,"rw"); >E>'9@Uh  
this.nPos = nPos; qi8~bQ{rH  
oSavedFile.seek(nPos); sT91>'&  
} 5J3K3  
t\\<+^[%  
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public synchronized int write(byte[] b,int nStart,int nLen) ^K^rl9  
{ ?jnbm'~S  
int n = -1; \K:?#07Wj4  
try{ "}uV=y  
oSavedFile.write(b,nStart,nLen); Ul|htB<1:  
n = nLen; K!gocNOf  
} P_M!h~  
catch(IOException e)  Lvn+EM  
{ _,*QJ  
e.printStackTrace (); #?bOAWAwLh  
} S#\Cyn2(t  
59(} D'lw>  
>< Qp%yT  
return n; IpVtbDW  
} =Unu>p}2V  
_14
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} }`uq:y  
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/* [ _&z+  
**SiteInfoBean.java 2c5)pIVEy  
*/ 8ZDWaq8^2N  
package NetFox; Qs_]U  
|PLWF[+t8  
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public class SiteInfoBean { p%e/>N.P  
#LG<o3An  
N\x<'P4q  
private String sSiteURL; //Site's URL P)UpUMt;k  
private String sFilePath; //Saved File's Path l,j0n0h.  
private String sFileName; //Saved File's Name J8DKia|h(  
private int nSplitter; //Count of Splited Downloading File smuQ1.b  
byJ[1UK  
,L8(Vo`-  
public SiteInfoBean() Ewo6Q){X  
{//nSplitter的缺省值为5 vH]2
t.\  
//default value of nSplitter is 5 R78lV-};Q  
this("","","",5); ;-kg3fGB1Q  
} alZ83^YN'  
YU1z\pK  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) aOW$H:b  
{ 5K$d4KT  
sSiteURL= sURL; sHHu<[psM  
sFilePath = sPath; vNAQ/Q  
sFileName = sName; FX/f0C3CK  
this.nSplitter = nSpiltter; #vT~D>zj  
R"e533  
;x4yidb6  
} s%)>O{{)  
4zf(  
n*N`].r#{=  
public String getSSiteURL() d?=r:TBU  
{ D(M^%z2N  
return sSiteURL; QeD ;GzG  
} ]U5/!e  
qApf\o3[0  
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public void setSSiteURL(String value) v?S3G-r  
{ 4-q8:5  
sSiteURL = value; i7xBi:Si  
} /U"3LX  
2sT\+C&H  
@5TJ]=  
public String getSFilePath() 2Xp?O+b#"O  
{ A)D1 #,0  
return sFilePath; Us8nOr>5  
} ?rgtbiSW-  
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6"jV>CNc@  
public void setSFilePath(String value) p}-B>v  
{ mbO.Kyfen  
sFilePath = value; RMBPm*H  
} hdxq@%Vs  
7By&cdl  
oF(|NS^  
public String getSFileName() UN`O*(k[  
{ rs:a^W5t  
return sFileName; SR {KL#NC  
} Blv@u?  
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hN.{H:skL)  
public void setSFileName(String value) hxsW9  
{ <qCfw>%2F  
sFileName = value; 3[iHe+U(  
} ~_"/\;
1  
UoKXo*W2  
Wj31mV  
public int getNSplitter() _9"%;:t  
{ $oH?7sj  
return nSplitter; +:m'  
} ?h'd\.j{  
FFID<Lf/2  
?-9It|R  
public void setNSplitter(int nCount) _w49@9?  
{ b)@b63P_  
nSplitter = nCount; p ^Dm w0y  
} r7n-Xe  
} u6~/" _FwY  
K1^x+I7%U[  
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/* x)^t5"F  
**Utility.java f hr QJ  
*/ ;TG<$4N  
package NetFox; yX|0R H  
+(J{~A~  
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public class Utility { Ce_
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44(l1xEN+  
public Utility() \*6Ld%:h$  
{ :sXn*k4v  
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} 4Rev7Mc  
h;2n2.Q  
//线程睡眠 A>W8^|l6+-  
public static void sleep(int nSecond) p1(<F_Kta  
{ rP7f~"L  
try{ @b"J FB|  
Thread.sleep(nSecond); %oqC5O6  
} u.L{3gkT  
catch(Exception e) w-9fskd6e  
{ qx<h rC0Z&  
e.printStackTrace (); eNw9"X}g  
} <hSrx7o  
} b6A]/290x  
*&lNzz5&  
//日志 %vFoTu)2  
public static void log(String sMsg) i$!-mYi+Q!  
{ kA%"-$3  
System.err.println(sMsg); CP!>V:w%9!  
} $d_%7xx  
{P@OV1  
U<H< !NV  
public static void log(int sMsg) yCT:U&8%F  
{ 6`Af2Y_  
System.err.println(sMsg); [<p7'n3x  
} DKxzk~sOM  
} XKt">W  
ts3BmfR?  
Km9Y_`?  
/* YFY$iN~B,  
**TestMethod.java (R)(%I1Oz  
*/ C|W\qXCqu  
package NetFox; ^%pM$3ov  
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ME%W,B.|"s  
public class TestMethod { `$odxo+  
G 0;5I_D/  
dy%#E2f  
public TestMethod() ypK1 sw  
{ ///xx/weblogic60b2_win.exe Apx
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try{ lYq4f|5H}m  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); s9'lw'  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Mk~]0d  
SiteFileFetch fileFetch = new SiteFileFetch(bean); "]M]pR/j  
fileFetch.start(); PA(XdT{  
} ZW0gd7Wh  
catch(Exception e){e.printStackTrace ();} 43 h0i-%1  
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,AO]4Ec  
} 42wa9UL<Ka  
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public static void main(String[] args) ~@wM[}ThP$  
{ ^ A`@g4!
 
new TestMethod(); O8drR4Pt  
} SuU_psF  
} zrg#BXj7  
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