http断点续传简单实现（java)

/* QEc4l[^{.B  
**SiteFileFetch.java Qe
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*/ ,d$D0w  
package NetFox; EfGy^`,'G  
import java.io.*; \U.js-  
import java.net.*; OzAxnd\.N  
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public class SiteFileFetch extends Thread { "43F.!P  
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SiteInfoBean siteInfoBean = null; //文件信息Bean FPukV^  
long[] nStartPos; //开始位置 kt7x}F(?<  
long[] nEndPos; //结束位置 EjP9/VG@=  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ZhY03>X  
long nFileLength; //文件长度 |H>;a@2d  
boolean bFirst = true; //是否第一次取文件 {fS~G2@1  
boolean bStop = false; //停止标志 |X;|=
.  
File tmpFile; //文件下载的临时信息 Y |9  
DataOutputStream output; //输出到文件的输出流 0?O$->t  
@IV,sze  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） dK>sHUu  
public SiteFileFetch(SiteInfoBean bean) throws IOException LyRW\\z2  
{ O9_SVX
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siteInfoBean = bean; ~9n30j%]s  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Ih)4.lLcKn  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); .:~E.b  
if(tmpFile.exists ()) 0HN%3AG]  
{ %{
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bFirst = false; 8T8
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read_nPos(); }mpFo2  
} BRXD
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else ) (0=w4  
{ moL3GV%]Gq  
nStartPos = new long[bean.getNSplitter()]; Ae
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nEndPos = new long[bean.getNSplitter()]; 5:(/k\9+yv  
} "<&) G{  
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} U<<XeSp  
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public void run() i(> WeC+  
{ -`UOqjb]3  
//获得文件长度 2WC$r8E  
//分割文件 17-B'Gl!<%  
//实例FileSplitterFetch ; *\xdg{d  
//启动FileSplitterFetch线程 2d&]V]:R*  
//等待子线程返回 ox5Wbo
L  
try{ gF
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if(bFirst) &z@}9U*6b  
{ iw%""q(`  
nFileLength = getFileSize(); U7HfDDh  
if(nFileLength == -1) +QP(ATdM  
{ Y=t?"E  
System.err.println("File Length is not known!"); IZs&7  
} 1)!2D?w  
else if(nFileLength == -2) ik1asj1  
{ k~)@D| ?  
System.err.println("File is not access!"); jXPbj.  
} h s_x @6  
else zI4d|
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{ 2S-f5&o  
for(int i=0;i<nStartPos.length;i++) #_WkV  
{ bj
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); -F_cBu81V  
} `\GRY @cg  
for(int i=0;i<nEndPos.length-1;i++) 3n~O&{  
{ qiH)J- ~GZ  
nEndPos = nStartPos[i+1]; m|3Q'  
} 88l1g,`**  
nEndPos[nEndPos.length-1] = nFileLength; u~PZK.Uf0  
} KW$.Yy  
} d:"7Tw2v+  
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//启动子线程 y?U@F/^}N  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; FC WF$'cO  
for(int i=0;i<nStartPos.length;i++) F}=_"IkZ  
{ udmLHc  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), L7R!,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 'KDt%?24  
nStartPos,nEndPos,i); >Y(JC#M;  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6|IJwP^Q_  
fileSplitterFetch.start(); }B_?7+  
} 70 Ph^e)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "Mz#1Laby`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); IwRP,MQ~  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", rgDl%X2B  
nEndPos = " + nFileLength); A1r%cs  
// fileSplitterFetch[nPos.length-1].start(); %J Jp/I  
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;A4j_8\[  
//等待子线程结束 N3N~z1x0h  
//int count = 0; gu:vf/  
//是否结束while循环 Mdq|:^px  
boolean breakWhile = false; Z_fwvcZ?05  
UA4c4~$S  
@ qi|}($  
while(!bStop) w 62m}5eA  
{ [XttT  
write_nPos(); 8!YQ9T[  
Utility.sleep(500); 'n=bQ"bQu  
breakWhile = true; -}PE(c1%?q  
JY@bD:  
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0  
for(int i=0;i<nStartPos.length;i++) \Zh&[D!2  
{ KDP"z  
if(!fileSplitterFetch.bDownOver) N;,zPWa  
{ WP?]"H  
breakWhile = false; "a9j2+9  
break; @,7r<6E  
} EV-sEl8ki  
} _>BYUPY  
if(breakWhile) HDTA`h?t;  
break; OQ4Pk/-'  
nCQ".G  
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//count++; #-PMREgO  
//if(count>4) u})*6l.  
// siteStop(); 7r^Cs#b+I  
} (>E/C^Tc%  
IaQm)"Z  
Na@;F{  
System.err.println("文件下载结束！"); \o=9WKc  
} *JfGGI_E  
catch(Exception e){e.printStackTrace ();} J9OL>!J  
} j Neb*dPoK  
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QmSMDWkh  
//获得文件长度 'n>44_7L  
public long getFileSize() l0;u$  
{ H-nhq-fut  
int nFileLength = -1; S(nQ?;9,  
try{ 63J3NwFt  
URL url = new URL(siteInfoBean.getSSiteURL()); t- TUP>_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); wVFa51a)yy  
httpConnection.setRequestProperty("User-Agent","NetFox"); IZm6.F  
`"PHhCG+z  
L)&^Pu  
int responseCode=httpConnection.getResponseCode(); B9[vv;lzu  
if(responseCode>=400) M$.bC0}T  
{ S>r}3,]S  
processErrorCode(responseCode); YtKT3u:x  
return -2; //-2 represent access is error ]f?r@U'AS|  
} ;Z`a[\i':  
:3XvHL0rx  
_'17C/  
String sHeader; ^*4#ZvpG2  
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for(int i=1;;i++) .ahY 1CO
 
{ >N2kWSa  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); QH4m7M@ni  
//Utility.log(in.readLine()); n#Dy YVb  
sHeader=httpConnection.getHeaderFieldKey(i); J[r_ag  
if(sHeader!=null) l)o!&]2  
{ GD)paTwO<  
if(sHeader.equals("Content-Length")) D "5|\  
{ H\n6t-l  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); DTuco9yr[  
break; H ?9Bo!  
} ("ix!\1K@  
} gK;dfrU.8Y  
else X Db%-  
break; kTfRm^  
} n0gjcDHQ  
} H^5,];  
catch(IOException e){e.printStackTrace ();} ULu@"  
catch(Exception e){e.printStackTrace ();} k{lo'  
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b;d7mh4  
Utility.log(nFileLength); 5%(whSKZF  
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[%R?^*]  
return nFileLength; 1%vE7a>{  
}
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//保存下载信息（文件指针位置） ~PQR_?1  
private void write_nPos() h lc!}{$%8  
{ c^'bf_~-W  
try{ ^H2TSaJ;  
output = new DataOutputStream(new FileOutputStream(tmpFile)); X]2Ib'(  
output.writeInt(nStartPos.length); ,1B4FAR&  
for(int i=0;i<nStartPos.length;i++) S LeA,T  
{ Q?LzL(OioN  
// output.writeLong(nPos); 7VZ^J`3  
output.writeLong(fileSplitterFetch.nStartPos); {+cx}`  
output.writeLong(fileSplitterFetch.nEndPos); U';)]vB$  
} ^Ss<<  
output.close(); PPrvVGP   
} f. >[ J  
catch(IOException e){e.printStackTrace ();} T"3LO[j+  
catch(Exception e){e.printStackTrace ();} bv(+$YR  
} E&z^E2  
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//读取保存的下载信息（文件指针位置） *oIIcE4g7  
private void read_nPos() W^Fkjqpv  
{ t4d/%b~{:U  
try{ YGM7?o  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); p=eSJ*  
int nCount = input.readInt(); roAHkI  
nStartPos = new long[nCount]; 2B6u) 95  
nEndPos = new long[nCount]; e@vZg8Ie  
for(int i=0;i<nStartPos.length;i++) g#l!b%$  
{ uEr.LCAS  
nStartPos = input.readLong(); R\n@q_!`X  
nEndPos = input.readLong(); #Pz'-lo  
} 
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input.close(); `|"o\Bg<  
} :jkPV%!~  
catch(IOException e){e.printStackTrace ();} fj(WHL  
catch(Exception e){e.printStackTrace ();} >k@{N
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} C"`\[F`.k  
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private void processErrorCode(int nErrorCode) G@~
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{ FMn|cO.vEP  
System.err.println("Error Code : " + nErrorCode); 0QquxYYw,  
} hUp3$4w  
rVsCJuxI  
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//停止文件下载 2uY:p=DxG9  
public void siteStop() KYKF$@ <G  
{ ]v@ng8  
bStop = true; qkc,93B3  
for(int i=0;i<nStartPos.length;i++) I Gb'ii=A  
fileSplitterFetch.splitterStop(); QjJlVlp  
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} K)`R?CZ:s  
} x~8R.Sg  
//负责部分文件的抓取 <?8cVLW}O  
**FileSplitterFetch.java V_v+ic^  
*/ >d
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package NetFox; {i3x\|  
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tVX|e2Y  
import java.io.*; n31nORx50  
import java.net.*; X%iqve"{nB  
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public class FileSplitterFetch extends Thread { Ebi~gGo  
{/?{UbU  
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String sURL; //File URL HP3%CB  
long nStartPos; //File Snippet Start Position <>-gQ9  
long nEndPos; //File Snippet End Position ]>sMu]biH  
int nThreadID; //Thread's ID .g}Y! l  
boolean bDownOver = false; //Downing is over kIt1kw  
boolean bStop = false; //Stop identical 6~s{HI!  
FileAccessI fileAccessI = null; //File Access interface c(?OE' "Z  
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l{ fL
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException EOqV5$+  
{ ji,`?  
this.sURL = sURL; M5`m5qc3  
this.nStartPos = nStart; /n,a0U/  
this.nEndPos = nEnd; *x2u  
nThreadID = id; 3+U2oI:I  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 }gX4dv B  
} 5/m*Lc+r  
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public void run() J[K>)@I/  
{ u6\W"LW  
while(nStartPos < nEndPos && !bStop) \vj xCkg{  
{ ;lTgihW-  
J(XK%e[8  
nu|odP  
try{ zCwb>v  
URL url = new URL(sURL); F>@z&a}(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _J3\e%ys  
httpConnection.setRequestProperty("User-Agent","NetFox"); W`wT0kP?*]  
String sProperty = "bytes="+nStartPos+"-"; `wLmGv+V  
httpConnection.setRequestProperty("RANGE",sProperty); u8y('\(  
Utility.log(sProperty); 2@ZuH^qhk  
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W$" >\A0%  
InputStream input = httpConnection.getInputStream(); )@.ODW;`  
//logResponseHead(httpConnection); @ eP[*Q  
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byte[] b = new byte[1024]; A#79$[>w  
int nRead; N *n?hN  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) aMJ9U)wnK  
{ bV@5B#] 2R  
nStartPos += fileAccessI.write(b,0,nRead); 2fUz}w (  
//if(nThreadID == 1) 3URrK[%x`  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6XeqK*r*  
} }T=\hM  
,}Ic($To  
(jE[W:  
Utility.log("Thread " + nThreadID + " is over!"); \ $9n `  
bDownOver = true; hJ V*  
//nPos = fileAccessI.write (b,0,nRead); kRzqgVr%  
} P'Jb')m  
catch(Exception e){e.printStackTrace ();} .7#04_aP  
} UZc{ Av  
} 0j'k%R[l  
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gD6BPW~0  
//打印回应的头信息 Rmh,P>  
public void logResponseHead(HttpURLConnection con) <,T#* fg  
{ @eDL j}  
for(int i=1;;i++) )#cGePA  
{ >LR+dShG  
String header=con.getHeaderFieldKey(i); BQ~&gy{  
if(header!=null) v{U1B
 
//responseHeaders.put(header,httpConnection.getHeaderField(header)); w{ x=e  
Utility.log(header+" : "+con.getHeaderField(header)); QV%eTA  
else zhwajc  
break; j7Lw(AJ  
} lGX_5R  
} Zxv{qbF
 
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public void splitterStop() :3*0o3C/  
{ Bk1gE((  
bStop = true; ';x5 $5k'  
} ]p~,C*UH0  
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} \RTXfe-`  
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/* d4-cZw}+  
**FileAccess.java .aR$ou,7  
*//文件访问(定位，写) /E
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package NetFox; "{(4  
import java.io.*; JE+{Vx}  
gMZ?MG  
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public class FileAccessI implements Serializable{ /F @a@m|  
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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 1hgmlY`  
RandomAccessFile oSavedFile; W?auY_+P  
long nPos; -zLxT  
(z<&PP  
#bLeK$  
public FileAccessI() throws IOException [kq+a]q  
{ uH!;4@uI  
this("",0); "7a;Apq*  
} rB%acTCz=[  
!ly]{DTmm  
LaiUf_W#X  
public FileAccessI(String sName,long nPos) throws IOException }vdhk0  
{ =u`^QE  
oSavedFile = new RandomAccessFile(sName,"rw"); 7":0CU%%  
this.nPos = nPos; 7J2i /m  
oSavedFile.seek(nPos); c=HL 6v<
 
} f_Q_qckB%x  
y
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public synchronized int write(byte[] b,int nStart,int nLen) E>?T<!r~j  
{ N;\by<snN  
int n = -1; #r)c@?T@j  
try{ R|AGN*.  
oSavedFile.write(b,nStart,nLen); 4E& 3{hnp  
n = nLen; PDssEb7  
} H\<C@OkJS}  
catch(IOException e) nZM|8  
{ yf7p0;$?  
e.printStackTrace (); nPUq+cXy]C  
} {*%'vVv+  
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SuW_[6]  
return n; vrIM!~*W  
} Hv1d4U"qM  
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} T=2 91)@  
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2$? )
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/* =lG5Kc{B  
**SiteInfoBean.java 8f|  
*/ 8ESBui3;  
package NetFox; pOip$Z  
[0}^w[  
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public class SiteInfoBean { >c
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private String sSiteURL; //Site's URL _D(F[p|  
private String sFilePath; //Saved File's Path i
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private String sFileName; //Saved File's Name "ND 7,rQ  
private int nSplitter; //Count of Splited Downloading File p_QL{gn  
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@&2bLJJ+  
public SiteInfoBean() dYJW`Q;j.|  
{//nSplitter的缺省值为5 eW+z@\d9Gz  
//default value of nSplitter is 5 ZuF-$]oL&  
this("","","",5); YXa^jFp  
} gKS0!U  
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h
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) =2{^qvP  
{ D{/GjFO  
sSiteURL= sURL; nQvv'%v0  
sFilePath = sPath; u*&wMR>Crf  
sFileName = sName; 7{XI^I:n  
this.nSplitter = nSpiltter; z@biX  
nlK"2/W  
-`
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} )fR'1_  
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public String getSSiteURL() 1NT@}j~/  
{ z/N~HSh!d  
return sSiteURL; 5o2;26c  
} /'p(X~X:l  
'LR5s[$j  
}dE0WJcO  
public void setSSiteURL(String value) m^Btr  
{ UMw1&"0:  
sSiteURL = value; ? S>"yAoe  
} %Sfew/"R0  
-mG3#88*  
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public String getSFilePath() qV.*sdS>  
{ +X0?bVT  
return sFilePath; Jpws1~  
} sL XQ)Ce  
4jj@"*^a  
k|nv[xY0  
public void setSFilePath(String value) grnlJ=  
{ do%6P^qA  
sFilePath = value; 'cT R<LVo  
} $v+Q~\'  
L*1C2EL/q  
`(EY/EsY  
public String getSFileName() =\?KC)F*e  
{ BD9W-mF  
return sFileName; {(AYs*5  
} PygaW&9Z|d  
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5R/!e`(m  
public void setSFileName(String value) k 0z2)
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{ ">lu8F  
sFileName = value; ;2-,Xzz8  
} Q'&oSPXSDd  
p0UR5A>p  
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public int getNSplitter() CbA!  
{ |28z4
.  
return nSplitter; Uo<d]4p $  
} gEMxK2MNXj  
u)MdFz  

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public void setNSplitter(int nCount) \SS1-UbL  
{ <|~X,g;f  
nSplitter = nCount; <l(LQmM;  
} )}1J.>5  
} r%JJ5Al.S  
8/x@
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/* 34Q l7LQp[  
**Utility.java KQj5o>} 6  
*/ *pCT34'--  
package NetFox; |[;9$V
n  
+HQX]t:Y  
lO9ML-8C1  
public class Utility { B)O{+avu  
(hS j4Cp  
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public Utility() (\>3FwFHW|  
{ (V)nHF*<>  
/\hybx'  
r*fZS$e  
} kqYWa`eE  
BYFvf(>  
//线程睡眠 eYMp@Cx  
public static void sleep(int nSecond) 0 Ji>drn  
{ !v;N@C3C  
try{ O{uc
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Thread.sleep(nSecond); !jGe_xB}~  
} 6LrG+p`  
catch(Exception e) 1WRQjT=o  
{ a.
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e.printStackTrace (); UR44 iA]  
} Ds? @LE|  
} {M96jjiInf  
/qa{*"2Qo  
//日志 YD_hg#=n  
public static void log(String sMsg) lO! Yl:;m%  
{ ]*|+06  
System.err.println(sMsg); (B{`In8G>y  
} s4/4o_[W  
:a @_GIC  
> L_kSC?  
public static void log(int sMsg) ;fw}<M!6  
{ lk]q\yO_%  
System.err.println(sMsg); eW,{E)x:  
} HjAhz  
} O%L]*vIr  
VAX@'iZr  
w{l}(:xPp  
/* |*ss`W7F,2  
**TestMethod.java vg[A/$gLM  
*/ Zvz Zs  
package NetFox; Jw3VWc ]]  
UKV0xl  
YE
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public class TestMethod { Z:9xf:g*  
],#Xa.r  
Y S/x;  
public TestMethod() ^)oBa=jL4  
{ ///xx/weblogic60b2_win.exe viB'ul7o  
try{ A?i ~*#wE  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); .}!"J`{W  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Z"j #kaXA  
SiteFileFetch fileFetch = new SiteFileFetch(bean); p5`iq~e9
 
fileFetch.start(); LK\L}<;1V  
} yuIy?K  
catch(Exception e){e.printStackTrace ();} ,Ta k',  
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ybNo`:8A;  
} >G7dw1;  
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q@k/"ee*?  
public static void main(String[] args) KUJCkwQ  
{ mq 0d ea  
new TestMethod(); K!W7a~ @  
} q:h7Jik  
} )!z4LE  
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