http断点续传简单实现（java)

/* :0j?oY~e  
**SiteFileFetch.java uk<4+x,2)  
*/ /ivJsPH  
package NetFox; Pmr5S4Ka  
import java.io.*; B:;pvW]  
import java.net.*; 8>2.UrC  
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public class SiteFileFetch extends Thread { _"Dv uR  
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SiteInfoBean siteInfoBean = null; //文件信息Bean o/$}  
long[] nStartPos; //开始位置 *
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long[] nEndPos; //结束位置 < Mn ;  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 SO|NaqWa  
long nFileLength; //文件长度 QuF:p  
boolean bFirst = true; //是否第一次取文件 !N\@'F!  
boolean bStop = false; //停止标志 '8RsN-w  
File tmpFile; //文件下载的临时信息 Bw)/DM]  
DataOutputStream output; //输出到文件的输出流 F#,90F'  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） UUYSFa%  
public SiteFileFetch(SiteInfoBean bean) throws IOException g|DF[  
{ =w_Ype`  
siteInfoBean = bean; RE7?KR>  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); t9kzw*U9  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ';w#w<yaI  
if(tmpFile.exists ()) b,l$1{  
{ 25nt14Y0u  
bFirst = false; (Ft+uuG  
read_nPos(); (^
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} ^EtMxF@D  
else k2omJ$?v  
{ ITE{@1  
nStartPos = new long[bean.getNSplitter()]; Xk~D$~4<  
nEndPos = new long[bean.getNSplitter()]; ~9,,~db  
} =V,mtT  
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} }WC[$Y_@  
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public void run() 5Md=-,'J!  
{ sQUM~HD\a  
//获得文件长度 ="1Ind@w!  
//分割文件 MnsJEvn/  
//实例FileSplitterFetch 0rQMLx  
//启动FileSplitterFetch线程 E<{R.r  
//等待子线程返回 ~WeM TXF>y  
try{ I*:%ni2  
if(bFirst) !1jBC.G1  
{ $u$!tj  
nFileLength = getFileSize(); )Ys x}vSZ  
if(nFileLength == -1) vjbASFF0=  
{ f O}pj:  
System.err.println("File Length is not known!"); Maha$n*  
} d\&U*=  
else if(nFileLength == -2) /kZebNf6H  
{ Dzpq_F!;V  
System.err.println("File is not access!"); @
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} SB;&GHq"n  
else G, }Yl  
{ !fV+z%:  
for(int i=0;i<nStartPos.length;i++) Avge eJi  
{ O W_{$9U  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); IA fcT!{  
} vONasD9At  
for(int i=0;i<nEndPos.length-1;i++) .wEd"A&j  
{ 9%o32eo,3  
nEndPos = nStartPos[i+1]; jnkR}wAA  
} L4@K~8j7  
nEndPos[nEndPos.length-1] = nFileLength; 6+#Ydii9E  
} =m]v8`g  
} f&NgS+<K$  
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//启动子线程 m<<+  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; a{L%7  
for(int i=0;i<nStartPos.length;i++) fbyd"(V8r  
{ 2 ~dE<}  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), a kkNI3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), n2"a{Ofhlf  
nStartPos,nEndPos,i); gldAP:  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Q4#.X=.d  
fileSplitterFetch.start(); on!,c>nNa  
} HDz5&7* .  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), f$o_e90mu  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); vz@A;t  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", f%A;`4`q  
nEndPos = " + nFileLength); #>a\>iKQ2q  
// fileSplitterFetch[nPos.length-1].start(); S^JbyD_yoh  
]vB$~3||  
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//等待子线程结束 vSGH[nyCY  
//int count = 0; ^)470K`%)  
//是否结束while循环 :p1u(hflS  
boolean breakWhile = false; 7zl5yKN  
] 7[ 3>IN  
v8wq,CYV  
while(!bStop) s-NX 
o  
{ mtpeRVcF  
write_nPos(); CYf$nYR  
Utility.sleep(500); Zcey|m*|  
breakWhile = true; 9sM!`Lz{  
(=FRmdeYl1  
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for(int i=0;i<nStartPos.length;i++) (fhb0i-  
{ 4V"E8rUL(  
if(!fileSplitterFetch.bDownOver) zF@/K`  
{ j
}#w)M  
breakWhile = false; [DYQ"A=)d  
break; Ky`qskvu  
} _kC-dEGf!y  
} SjK  
if(breakWhile) !K#qeY}  
break; 4XL^D~V  
oe ~'o'  
 }t!Gey  
//count++; HRpte=`q  
//if(count>4) b3P+H r  
// siteStop(); Yz9owe8}[  
} !@5 9)  
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System.err.println("文件下载结束！"); b;L\EB  
} ~kV/!=  
catch(Exception e){e.printStackTrace ();} H[T?\Lq  
} xPdG*OcX!  
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.w:DFk^E]b  
//获得文件长度 PgAf\.48a  
public long getFileSize() XjBW9a  
{ ,S\CC{!  
int nFileLength = -1; )|ccX  
try{ MnmVl"(/  
URL url = new URL(siteInfoBean.getSSiteURL()); hy9\57_#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1l9G[o *  
httpConnection.setRequestProperty("User-Agent","NetFox"); *nd!)t  
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int responseCode=httpConnection.getResponseCode(); l#&8x  
if(responseCode>=400) t <~h'U  
{ >:SHV W  
processErrorCode(responseCode); PhLn8jNti  
return -2; //-2 represent access is error ]iVcog"T  
} pt?bWyKG  
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HH`'*$]7  
String sHeader; -+-?w|}qV  
/>C^WQI^  
53_Hl]#qZ  
for(int i=1;;i++) "%)qRe  
{ \Zk;ikEY  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); cUk7i`M;6  
//Utility.log(in.readLine()); `Uq#W+r,  
sHeader=httpConnection.getHeaderFieldKey(i); D#aDv0b  
if(sHeader!=null) b\f O8{k  
{ #x@$lc=k3  
if(sHeader.equals("Content-Length")) oueC  
{ 7Y lchmd  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 4>YR{  
break; cs48*+m  
} <(#(hDwy  
} 0J*??g-n  
else *YI98  
break; ?
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} . P viA  
} I]|Pq  
catch(IOException e){e.printStackTrace ();} oE@a'*.\  
catch(Exception e){e.printStackTrace ();} &md`$a/  
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Utility.log(nFileLength); 6dQ-HI*Y#  
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3=#<X-);  
return nFileLength; E#RDqL*J  
} e}voV0y\v:  
 y`iBFC;_  
q~Hn-5H4Q  
//保存下载信息（文件指针位置） gE'sOT9v  
private void write_nPos() _{ue8kGt  
{ ,O5NLg-  
try{ ~i= _J3'  
output = new DataOutputStream(new FileOutputStream(tmpFile)); I@\lN&HC  
output.writeInt(nStartPos.length); B^=-Z8  
for(int i=0;i<nStartPos.length;i++) pp?D7S  
{ .N;=\C
*  
// output.writeLong(nPos); ;._ l0Jw  
output.writeLong(fileSplitterFetch.nStartPos); DDQx g  
output.writeLong(fileSplitterFetch.nEndPos); E,Z$pKL?  
} XTs8s12  
output.close(); q_lKKzA  
} Q>qUk@  
catch(IOException e){e.printStackTrace ();} ux-/>enc  
catch(Exception e){e.printStackTrace ();} evJ4C#Pr  
} k?yoQL*  
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//读取保存的下载信息（文件指针位置） Cl.x'v  
private void read_nPos() [|wZ77\  
{ sfH_5 #w  
try{ NSMyliM1Y  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); BU)U/A8iS  
int nCount = input.readInt(); wVXS%4|v  
nStartPos = new long[nCount]; &<g|gsG`  
nEndPos = new long[nCount]; >gQ>1Bwvi  
for(int i=0;i<nStartPos.length;i++) uh_RGM&  
{ *tFHM &a  
nStartPos = input.readLong(); "s-"<&>a(  
nEndPos = input.readLong(); a~`eQ_ND  
} .8g)av+  
input.close(); Eh`7X=Z7E  
} !.$I["/=  
catch(IOException e){e.printStackTrace ();} 9)yJ: N#F  
catch(Exception e){e.printStackTrace ();} .~db4d]  
} KM0ru  
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private void processErrorCode(int nErrorCode) }v;V=%N+v  
{ '6`3(TK.a  
System.err.println("Error Code : " + nErrorCode); yf)%%&  
} UXz<)RvB  
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;a!S!%.h  
//停止文件下载 S>+|OCl";  
public void siteStop() hNiE\x  
{ ^#-l q)  
bStop = true; @s>Czm5  
for(int i=0;i<nStartPos.length;i++) D8Ic?:iX[  
fileSplitterFetch.splitterStop(); dbLZc$vPj  
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YDsb3X<0'  
} ;V_e>TyG  
} LP^$AAy  
//负责部分文件的抓取 H'5)UX@LP  
**FileSplitterFetch.java f5"k55}  
*/ )}R0Y=e  
package NetFox; ~NgA  
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import java.io.*; Y Uc+0  
import java.net.*; pad*oPH,  
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public class FileSplitterFetch extends Thread { bP#:Oi0v`  
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String sURL; //File URL 7"D",1h  
long nStartPos; //File Snippet Start Position ]%SH>  
long nEndPos; //File Snippet End Position (Rh,,  
int nThreadID; //Thread's ID _ye |Y  
boolean bDownOver = false; //Downing is over /N+dQe  
boolean bStop = false; //Stop identical q$UJ$7=f8  
FileAccessI fileAccessI = null; //File Access interface 6v!`1} ~  
5I;&mW`1,`  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException (/YHk`v2  
{ <nf@U>wlw  
this.sURL = sURL; ]
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this.nStartPos = nStart; F<1fX7c  
this.nEndPos = nEnd; p>N(Typ0b  
nThreadID = id; *R,5h2;  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 `hm-.@f,9  
} ?<,l3pwqa  
}K>d+6qk5  
3*bU6$|5FP  
public void run() By,eETU]  
{ uZYF(Yu  
while(nStartPos < nEndPos && !bStop) }tuC}  
{ Q*cf
(  
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try{ T{^rt3a  
URL url = new URL(sURL); uMv,zO5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); bWS&Yk(  
httpConnection.setRequestProperty("User-Agent","NetFox"); J{<X7uB  
String sProperty = "bytes="+nStartPos+"-"; lFj]4  
httpConnection.setRequestProperty("RANGE",sProperty); ~P qM]^  
Utility.log(sProperty); E=Bf1/c\  
1H`,WQ1mG  
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InputStream input = httpConnection.getInputStream(); 'oVx#w^mf  
//logResponseHead(httpConnection); n&/ `  
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byte[] b = new byte[1024]; >|=ts  
int nRead; H41?/U,{  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ty!`T+3  
{ *>}@7}f  
nStartPos += fileAccessI.write(b,0,nRead); E&w7GZNt  
//if(nThreadID == 1) nFCC St$  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); BOX2O.Pm  
} 6|=
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Utility.log("Thread " + nThreadID + " is over!");
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bDownOver = true; RP|`HkP-2  
//nPos = fileAccessI.write (b,0,nRead); DCa^ u'f  
} yPp9\[+^j  
catch(Exception e){e.printStackTrace ();} cVpp-Z|s8  
} IPpN@  
} y.k~Y0  
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//打印回应的头信息 >Tx?%nQ  
public void logResponseHead(HttpURLConnection con) TX/Xt7#R:  
{ |e&\<LwsP  
for(int i=1;;i++) 3}1u
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{ (9d&  
String header=con.getHeaderFieldKey(i);  %;'s4ly  
if(header!=null) .{^5X)  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ^\% (,KNo  
Utility.log(header+" : "+con.getHeaderField(header)); 8,%^ M9zBP  
else 2,F.$X  
break; ;(%QD 3>  
} @HCVmg:  
} ~~P5k:  

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public void splitterStop() 5DZ#9m/  
{ gD?l-RT>  
bStop = true; uW{l(}0N  
} .<FH>NW)  
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} 00y!K m_D  
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/* xo&_bMO  
**FileAccess.java ^ @5QP$.  
*//文件访问(定位，写) V!=,0zy~Z  
package NetFox; 3d]S!=4H"  
import java.io.*; J8(lIk:e  
&z3o7rif$  
L*+@>3mu)  
public class FileAccessI implements Serializable{ ITBE|b  
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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 /6*42[r  
RandomAccessFile oSavedFile; +'a
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long nPos; !pW0qX\1n  
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public FileAccessI() throws IOException t:Q*gWRh  
{ Lq^)R  
this("",0); {
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} y%T_pTcU  
kevrsV]/$  
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public FileAccessI(String sName,long nPos) throws IOException Gd=RyoJl  
{ KpGhQdR#  
oSavedFile = new RandomAccessFile(sName,"rw"); niyV8
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this.nPos = nPos; aFYIM`?(  
oSavedFile.seek(nPos); r19 pZAc  
} +\9NDfYIA  
H <l7ZS:  
a=2%4Wmz  
public synchronized int write(byte[] b,int nStart,int nLen) CdQ!GS<'y  
{ t{96p77)=  
int n = -1; +<C!U'  
try{ K%oG,-wdg  
oSavedFile.write(b,nStart,nLen); D,feF9  
n = nLen; ?tbrbkx  
} bn5 Su
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catch(IOException e) 25?6gu*Z  
{ ICQKP1WFp  
e.printStackTrace (); .q>iXE_c  
} C'x&Py/#  
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return n; L,!?Nt\  
} GTd,n=  
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} {<KVx9  
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f  
[W&T(%(W-  
/* S9.o/mr  
**SiteInfoBean.java 77Dn97l)&  
*/ 7@Qcc t4A  
package NetFox; ZECfR>`x  
e^voW"?%  
hVY$;s  
public class SiteInfoBean { z03K=aZ  
9'B `]/L  
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private String sSiteURL; //Site's URL |6-nbj  
private String sFilePath; //Saved File's Path 2>%=U~5  
private String sFileName; //Saved File's Name xqh  
private int nSplitter; //Count of Splited Downloading File <hyKu  
GbI/4<)l}  
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public SiteInfoBean() {l@{FUv  
{//nSplitter的缺省值为5 ^cWnF0)j.  
//default value of nSplitter is 5 $&c*'3  
this("","","",5); _[BP0\dPW  
} hZb_P\1X  
/n&&Um\  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) jP.
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{ 8s@3hXD&
 
sSiteURL= sURL; >t+P(*u  
sFilePath = sPath; jH:[2N?  
sFileName = sName; f o3}W^0  
this.nSplitter = nSpiltter; ;uGv:$([g  
:3 mh@[V  
flx(HJK  
} @6.vKCSE  
]SEZaT  
sI2^Qp@O1  
public String getSSiteURL() Ewz!O`  
{ %hP^%'G  
return sSiteURL; HzsdHH(J  
} .%-8 t{dt  
c+ie8Q!  
o8MZiU1Xf  
public void setSSiteURL(String value) 8Zdn,}Z  
{ 53h0UL  
sSiteURL = value; #'}*dy/  
} :`sUt1Fw.  
h68 xet;  
HzJz+ x:  
public String getSFilePath() ]?4hyN  
{ (9)Q ' 'S  
return sFilePath; Q!3_$<5<E>  
} uY*L,j^)  
3so%gvY.'  
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public void setSFilePath(String value) *4 n)  
{ zbiLP83  
sFilePath = value; 0g;|y4SN=  
} Z_NCD`i;  
=_^X3z0  
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public String getSFileName() *^`Vz?g<  
{ pj(,Zd[47  
return sFileName; LP=)~K
<  
} t{>q|0  
;.C\Ss<>*  
]M3yLYK/P  
public void setSFileName(String value) zuCSj~  
{ ,!9zrYi}  
sFileName = value; O6Y0XL  
} I-)4
YQI  
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public int getNSplitter() xSu >  
{ B5QFK  
return nSplitter; 5V-I1B&  
} wIgS3K  
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Ys7]B9/1O  
public void setNSplitter(int nCount) 'GScszz  
{ q(w(Sd)#L  
nSplitter = nCount; X>^fEQq"  
} "N#Y gSr  
} ^zr`;cJ+c  
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Y:`&=wjP~  
/* wC*X4 '  
**Utility.java i/.6>4tE:  
*/ lquLT6]  
package NetFox; m {}Lm)M  
9BB=YnKE  
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public class Utility { P<-@h1p,  
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public Utility() $~kA B8z  
{ W*G<X.Hf  
{`_i`  
g)B]FH1  
} |y*c9  
Rb;'O89Hj@  
//线程睡眠 F"kAkX>3}  
public static void sleep(int nSecond) rM SZ"  
{ 3g B7g'U  
try{ `0svy}
  
Thread.sleep(nSecond); /kG_*>.Z  
} /_.|E]  
catch(Exception e) ->jDb/a{C  
{ )5H?Vh>36  
e.printStackTrace (); Fzcwy V   
} }0 ?3:A  
} iDD$pd,e\  
x~sBzTa  
//日志 CGFDqCNr-  
public static void log(String sMsg) #K&Gp-  
{ +,l-Nz  
System.err.println(sMsg); 'fW-Y!k%  
} L50n8s  
mZB
o~(}  
ig"L\ C"
T  
public static void log(int sMsg) tX[WH\(xI  
{ bd`P0f?  
System.err.println(sMsg); 9JwPSAo;  
} T4F/w|Q  
} R-14=|7a-  
_dU\JD  
Xc.`-J~Il  
/* {G-kNU  
**TestMethod.java 1mJHued=6  
*/ sRf
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package NetFox; zeRyL3fnmb  
m+9#5a-  
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public class TestMethod { (%9$!v{3  
0{mex4  
Zd&S@Z  
public TestMethod() P {'b:C  
{ ///xx/weblogic60b2_win.exe 2zpr~cB=  
try{ DwF hK*  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); #E]59_  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); <N@Gu
!N8  
SiteFileFetch fileFetch = new SiteFileFetch(bean); f mGc^d|=  
fileFetch.start(); QL*IiFR  
} vSh`&w^*  
catch(Exception e){e.printStackTrace ();} ?ubro0F:  
5-M-X#(  
AwN!;t_0+N  
} ^@]3R QB  
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public static void main(String[] args) nFn5v'g  
{ N g,j#  
new TestMethod(); }7X%'Bg=M  
} 5dg(e3T  
} >d6|^h'0  
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