http断点续传简单实现（java)

/* PVsKI<  
**SiteFileFetch.java TWzLJ63*  
*/ 1h&`mqY)L.  
package NetFox; IdQ./@?  
import java.io.*; %WgN+A0  
import java.net.*; b~J)LXj]w  
&}r"Z?f)  
fes s6=k  
public class SiteFileFetch extends Thread { b,Oh8O;>  
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SiteInfoBean siteInfoBean = null; //文件信息Bean j-":>}oW2.  
long[] nStartPos; //开始位置 ` y\)X C7  
long[] nEndPos; //结束位置 hW~.F  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Ttt'X<9  
long nFileLength; //文件长度 uMJ\  
boolean bFirst = true; //是否第一次取文件 /]_t->  
boolean bStop = false; //停止标志 Ot2o=^Ng  
File tmpFile; //文件下载的临时信息 } o%^ Mu B  
DataOutputStream output; //输出到文件的输出流 Y !?'[t  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） G3~`]qf  
public SiteFileFetch(SiteInfoBean bean) throws IOException [ QiG0D_'=  
{ H"#ITL  
siteInfoBean = bean; yOq@w!xz  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); wT4@X[5$  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); E5w;75,  
if(tmpFile.exists ()) 9af.t  
{ {'5"i?>s0>  
bFirst = false; O`B,mgT(  
read_nPos(); CIjc5^Y2  
} `ePC$Ovn  
else !y= R)k  
{ -QrC>3xZR  
nStartPos = new long[bean.getNSplitter()]; V)j[`,M:  
nEndPos = new long[bean.getNSplitter()]; ,%
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} A*EOn1hN  
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} DN*5q9.  
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public void run() AcC &Q:g  
{ aQCu3T  
//获得文件长度 ieFl4hh[G  
//分割文件 8]ZzO(=@{  
//实例FileSplitterFetch .T| }rB<c  
//启动FileSplitterFetch线程 0zaK&]oY0  
//等待子线程返回 =dmr
,WE  
try{ T5(S2^)o  
if(bFirst) *m~-8_ >;  
{ Vw;Z0_C  
nFileLength = getFileSize(); '<R>cN"  
if(nFileLength == -1) ~HZdIPcC  
{ aD^$v  
System.err.println("File Length is not known!"); Smr{+m a  
} 3v/B*M VI  
else if(nFileLength == -2) "& ,ov#  
{ IS2cU'  
System.err.println("File is not access!"); hH %>  
} p+VU:%.t  
else jJy:/!i  
{ EB~]6.1  
for(int i=0;i<nStartPos.length;i++) ?sf<cFF  
{ 1E+12{~m"i  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); g!'R}y  
} >|$]=e,Z  
for(int i=0;i<nEndPos.length-1;i++) $[ {5+*  
{ [#PE'i4  
nEndPos = nStartPos[i+1]; szI7I$Qb  
} lQn" 6o1  
nEndPos[nEndPos.length-1] = nFileLength; U2q6^z4l  
} Xz$4cI#n:  
} p3I"LY  
kT%wt1T4  
v}G^+-?  
//启动子线程 g'8Y5x[  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; w;z7vN~/O  
for(int i=0;i<nStartPos.length;i++) |#oS7oV(  
{ /*K2i5&X  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #B `?}a=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ;_o]$hV|  
nStartPos,nEndPos,i); ekM? '9ez  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); YuXJT*  
fileSplitterFetch.start(); T(b9b,ov)  
} x:Y9z_)O  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;G[V:.o-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); _yg_?GH  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ^L[:D
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nEndPos = " + nFileLength); 2jsbg{QS#_  
// fileSplitterFetch[nPos.length-1].start(); *FlPGBjJ  
"6B7EH  
fz&B$1;8  
//等待子线程结束 OQVrg2A%(  
//int count = 0; }9~^}99}  
//是否结束while循环 .iXN~*+g  
boolean breakWhile = false; z/@_?01T=  
}A#IBqf5  
7]ieBUfS  
while(!bStop) 0> f!S` *  
{ iOE. .xA:  
write_nPos(); K7 e~%mY  
Utility.sleep(500); /%wS5IZ^  
breakWhile = true; |Splbsk  
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for(int i=0;i<nStartPos.length;i++) 5)[~ T2j!  
{ HA6tGZP*L  
if(!fileSplitterFetch.bDownOver) i"8mrWb  
{ LP<A q  
breakWhile = false; _plK(g-1J%  
break; -dntV=  
} }z3j7I  
}
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if(breakWhile) +#O+%!  
break; >Vuvbo  
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K_7pr~D]@r  
//count++; %y1!'R:ZW  
//if(count>4) jc^QWK*q  
// siteStop(); t@q'm.:uw<  
} +H)'(<  
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7_0p& 3  
System.err.println("文件下载结束！"); |)-kUu  
} vOQ%f?%G\  
catch(Exception e){e.printStackTrace ();} @Nu2 :~JO  
} Z;BS@e  
|P|B"I<?  
;b~ S/  
//获得文件长度 PwY/VGT  
public long getFileSize() tFN >]`Z  
{ i\R0+O{  
int nFileLength = -1; OM*_%UF  
try{ ua\t5M5  
URL url = new URL(siteInfoBean.getSSiteURL()); kaG/8G(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); BZR{}Aj4pa  
httpConnection.setRequestProperty("User-Agent","NetFox"); 0[;2dc  
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int responseCode=httpConnection.getResponseCode(); 
]hl*6  
if(responseCode>=400) 12$0-@U  
{ >)><u4}  
processErrorCode(responseCode); _)A|JC!jId  
return -2; //-2 represent access is error 8tY>%A~^z  
} U&?hG>  
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|,8z"g  
String sHeader; |s8N  
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for(int i=1;;i++) d2\!tJm  
{ Ni$'# W?t  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Epzg|
L1)  
//Utility.log(in.readLine()); =c8}^3L~7  
sHeader=httpConnection.getHeaderFieldKey(i); N&9o
1_}  
if(sHeader!=null) z;OYPGvkw  
{ Rr) 5[  
if(sHeader.equals("Content-Length")) o)`PSw=  
{ } ueFy<F  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); aDlp>p^E>  
break; Fs+tcr/\[  
} O zAIz+`  
} 4kOO3[r  
else #-{<d%qk  
break; xtV+Le%  
} e`*}?N4d  
} ]#/nn),Z  
catch(IOException e){e.printStackTrace ();} t
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catch(Exception e){e.printStackTrace ();} )"?4d[ 5  
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Utility.log(nFileLength); Hv,|XE@Y  
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return nFileLength; ,Oo`*'a[o7  
} NvK9L.K  
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eJDZ|$  
//保存下载信息（文件指针位置） z^Hc'oVXj:  
private void write_nPos() 0<M-asI?  
{ W.wPy@yi  
try{ $8EEtr,!  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 1gI7$y+?  
output.writeInt(nStartPos.length); -I< >Ab  
for(int i=0;i<nStartPos.length;i++) Vk5Z[w a  
{ .i0K-B  
// output.writeLong(nPos); kpOdyn(  
output.writeLong(fileSplitterFetch.nStartPos); 5LeZ?'"c  
output.writeLong(fileSplitterFetch.nEndPos); *k?:k78L  
} lu utyK!  
output.close(); ''17(%  
} woI5aee|  
catch(IOException e){e.printStackTrace ();} =H95?\}T[  
catch(Exception e){e.printStackTrace ();} WtSs:D  
} K#"=*p,  
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//读取保存的下载信息（文件指针位置） #^FM~5KK  
private void read_nPos() +qi& ?}  
{ \Ne`9k  
try{ VQ
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); !2!~_*sGe  
int nCount = input.readInt(); 7>hcvML  
nStartPos = new long[nCount]; unDW2#GX  
nEndPos = new long[nCount]; 3:nhZN/95T  
for(int i=0;i<nStartPos.length;i++) 0KA*6]h t  
{ SmXJQ@jN  
nStartPos = input.readLong(); 7?lz$.*Avp  
nEndPos = input.readLong(); Bk8}K=%w  
} <JPN< Kv  
input.close(); cXweg;  
} ,05PYBc3  
catch(IOException e){e.printStackTrace ();} y
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catch(Exception e){e.printStackTrace ();} *)^6'4=  
} `Fqth^RK?p  
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private void processErrorCode(int nErrorCode) [@$ SLl^Y  
{ 
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System.err.println("Error Code : " + nErrorCode); ?G{0{c2  
} >t+ ENYb  
!
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//停止文件下载 y4\X~5kU  
public void siteStop() iSfRJ:_&6  
{ S!K<kn`E3  
bStop = true; ?<Qbp;WBo  
for(int i=0;i<nStartPos.length;i++) m:BzIcW<\  
fileSplitterFetch.splitterStop(); ]2zM~  
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} rzY)vC+ZT  
} aIgexi,  
//负责部分文件的抓取 =%_=!%  
**FileSplitterFetch.java @52#ZWy  
*/ w4 yrAj 2  
package NetFox; S2X@t>u-  
1$cl "d`~  
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import java.io.*; VuLb9Kn  
import java.net.*; \zd[A~!  
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@ZEBtM%.O  
public class FileSplitterFetch extends Thread { py6<QoGV  
b'4a;k!rS  
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String sURL; //File URL Mo/R+\u+Y  
long nStartPos; //File Snippet Start Position PRfq_:xy  
long nEndPos; //File Snippet End Position .Ys e/oEo  
int nThreadID; //Thread's ID &%J{uRp  
boolean bDownOver = false; //Downing is over , ['}9:f9  
boolean bStop = false; //Stop identical 4U2{1aN`  
FileAccessI fileAccessI = null; //File Access interface lpT&v;$`  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException B*/!s7c.  
{ DG&'x;K"$  
this.sURL = sURL; 8Qi)E1n  
this.nStartPos = nStart;  }$oS/bo  
this.nEndPos = nEnd; c[2t,+O  
nThreadID = id; 3f=ZNJ>  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 sY<UJlDKT  
} r8"2C#  
=gF035  
|JkfAnrN$I  
public void run() 9hr7+fW]t  
{ *eg0^ByeD  
while(nStartPos < nEndPos && !bStop) "DN,1Q lCp  
{ _2KIe(,;  
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try{ c5p,~z_Dtu  
URL url = new URL(sURL); (]w6q&,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); eA N{BPN[  
httpConnection.setRequestProperty("User-Agent","NetFox"); &mX_\w/%  
String sProperty = "bytes="+nStartPos+"-"; $yU 5WEX  
httpConnection.setRequestProperty("RANGE",sProperty); Zk`y"[J  
Utility.log(sProperty); =A!oLe$%  
/? %V% n  
9L$OSy|  
InputStream input = httpConnection.getInputStream(); tR51Pw  
//logResponseHead(httpConnection); 
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byte[] b = new byte[1024]; bo<P%$(D  
int nRead; HMVP71  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) yjT>bu]  
{ DN:| s+Lz  
nStartPos += fileAccessI.write(b,0,nRead); {Q>OZm\+  
//if(nThreadID == 1) A=kOSq 4Q  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Cab-:2L]  
} 1$RJzHS  
4?Y7.:x  
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Utility.log("Thread " + nThreadID + " is over!"); f2~Aug  
bDownOver = true; <T>s;b  
//nPos = fileAccessI.write (b,0,nRead); MK3h~`is  
} rC@VMe|0  
catch(Exception e){e.printStackTrace ();} 7V%P  
} -sJ1q^;f@  
} !aSj1 2J  
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//打印回应的头信息 pPa]@ z~O  
public void logResponseHead(HttpURLConnection con) .B~}hjOZK  
{ B*_K}5UO  
for(int i=1;;i++) gaN/ kp  
{ RP$u/x"b  
String header=con.getHeaderFieldKey(i); '( I0VJJ   
if(header!=null) ZK;/~9KU  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 4T3Z9KD!8  
Utility.log(header+" : "+con.getHeaderField(header)); % PzkVs  
else Z*M
{  
break; Jqb~RP~  
} NsI.mTc2  
} D\M"bf>q1  

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public void splitterStop() c:7V..  
{ Dtd~}-_Q  
bStop = true; 6):1U  
} N!ihj:,  
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} \ Bj{.
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/* T1q27I  
**FileAccess.java i&m_G5u88  
*//文件访问(定位，写) L ~'98C  
package NetFox; c5%}* "z  
import java.io.*; =/K)hI!u  
H.Z
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XB7*S*"!  
public class FileAccessI implements Serializable{ W`PJflr|  
YyYZD{^  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ^"O>EY':  
RandomAccessFile oSavedFile; p _[,P7  
long nPos; O:#YLmbCN  
|K_%]1*riC  
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public FileAccessI() throws IOException uGz)Vz&3  
{ 4GP?t4][  
this("",0); |dQz(z&6{5  
} !`%j#bv  
ATqblU>D  
O|sk"YXF  
public FileAccessI(String sName,long nPos) throws IOException O
)`L( x  
{ :+6W%B  
oSavedFile = new RandomAccessFile(sName,"rw"); q83^?0WD  
this.nPos = nPos; `E1G9BbU  
oSavedFile.seek(nPos); C jf<,x$  
} 6HZtdRQF  
vY
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~qQZhu"  
public synchronized int write(byte[] b,int nStart,int nLen) {[#)Q.2  
{ F(n<:TvlK  
int n = -1; ;U>nj],uv  
try{ IQU1 JVkZ  
oSavedFile.write(b,nStart,nLen); @]q^OMLY  
n = nLen; Bc.de&Bxz_  
} K?J_cnJ`  
catch(IOException e) ,z.l#hj,{  
{ 2Snb+,o2  
e.printStackTrace (); KO=$Hr?f;  
} G+N1#0,q  
1iY4|j;ahV  
~\(c;J*Ir  
return n; [ne51F5_  
} }0pp"
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/%g9g_rt#  
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} "<+~uz  
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g,]o+nT  
/* ViiJDYT>E<  
**SiteInfoBean.java ('J@GTe@xj  
*/ aC`>~uX##V  
package NetFox; k*?T^<c3  
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@Pk<3.S0  
public class SiteInfoBean { n[0u&m8  
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private String sSiteURL; //Site's URL ymxA<bICS8  
private String sFilePath; //Saved File's Path BW)-F (v   
private String sFileName; //Saved File's Name 1s(T#jh  
private int nSplitter; //Count of Splited Downloading File ?'0!>EjY"  
eMnK@J  
mP\V.^  
public SiteInfoBean() .F8[;+  
{//nSplitter的缺省值为5 O Ol:  
//default value of nSplitter is 5 Lo'pNJH;$  
this("","","",5); Oe1WnS 7(]  
} wp&G]/4m  
[-*&ZYp  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) T='uqKW\  
{ 4*qBu}(  
sSiteURL= sURL; )>{.t=#  
sFilePath = sPath; te(H6c#0  
sFileName = sName; uCr& `  
this.nSplitter = nSpiltter; BJwuN  
F8Ety^9>9  
"6\5eFN;  
} z.8nYL5^}  
l+@;f(8}  
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public String getSSiteURL() ]uox ^HC  
{ pZ'q_Oux  
return sSiteURL; \"(?k>]E  
} ,i6E L  
pi"M*$  
AMjr[!44 @  
public void setSSiteURL(String value) Q~nVbj?c2v  
{ zEFS\nP}E  
sSiteURL = value; ,Tr&`2w  
} $h pUI  
%CHw+wT&  
+]cf/_8+s  
public String getSFilePath() } doAeTZ  
{ 3
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return sFilePath; 2>9\o]ac4  
} F}So=Jz9h  
]6B9\C.2-_  
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|S  
public void setSFilePath(String value) neM.M)0  
{ c`;oV-f  
sFilePath = value; ]0*aE  
} iSO xQ  
 q6F1Rt  
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public String getSFileName() r1< '
l  
{ yF(9=z"?  
return sFileName; A#cFO)"  
} i'li;xUhZ  
k)-+ZmMOh  
0RA#Y(IR  
public void setSFileName(String value) B{&W|z{$  
{ L@GICW~  
sFileName = value; LHA^uuBN}  
} ij0I!ilG4  
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public int getNSplitter() #aL.E(%  
{ pRV.\*:c  
return nSplitter; z)hK2JD  
} 8%CznAO"?W  
68,j~e3-i  
,WWd%DF)  
public void setNSplitter(int nCount) .)[E`a  
{ 1rZ E2  
nSplitter = nCount; KsOSPQDGE  
} Zzjx;SF  
} Dst;sLr[,  
8_!qoW@B  
Y^Buz<OiG  
/* &*OwoTgk+  
**Utility.java :ir#7/  
*/ %U{sn\V  
package NetFox; P_3IFHe  
N9M}H#  
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public class Utility { DGGySO6=$e  
5go)D+6s  
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public Utility() s U`#hL6;  
{ .5; JnJI  
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[8za=B/  
} (E0WZ$f}  
)q_,V"  
//线程睡眠 dY}5Kmt  
public static void sleep(int nSecond) HE+'fQ!R  
{ U>*@VOgB  
try{ >bV3~m$a+  
Thread.sleep(nSecond); ?<t?G  
} dY
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catch(Exception e)  it H  
{ (Z>?\iNJ  
e.printStackTrace (); mh"PAp  
} LA
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} u_WUJ_  
E|;>!MMA;  
//日志 Fxa{ 9
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public static void log(String sMsg) ,|RKM  
{ i}8OaX3x  
System.err.println(sMsg); poafGoH-Y  
} E'{:HX  
@lDnD%vZ`  
n>u_>2Ikkj  
public static void log(int sMsg) <!
m.+  
{ <7`k[~)VB  
System.err.println(sMsg); O<p=&=TD7  
} bJMsB|r  
} EgG3XhfS  
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/* &V+_b$  
**TestMethod.java $&.(7F^D  
*/ 3_wR2AU~  
package NetFox; EFDmNud`Q  
UUz{Qm%  
;V~x[J|x  
public class TestMethod { olQP>sa  
1@I#Fv  
#Db^*  
public TestMethod() VM5'd  
{ ///xx/weblogic60b2_win.exe ugN%8N  
try{ 02EX_tt),  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Yz2N(g[  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ,1 H|{<  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 1ik.|T<f0  
fileFetch.start(); &I ~'2mpk  
} {=?[:5  
catch(Exception e){e.printStackTrace ();} 38&K"  
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x$jLB&+ICz  
} pWE(?d_M{G  
uG'S&8i_  
h(@.bt#
 
public static void main(String[] args) =4+2y '  
{ y`m0/SOT  
new TestMethod(); ASEKP(]v  
} 3>3t(M|  
} rhOxyY0  
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