http断点续传简单实现（java)

/* TwT@_
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**SiteFileFetch.java rIhe}1  
*/ H6vO}pq)r  
package NetFox; 6+iZJgwAy  
import java.io.*; gz~)v\5D/  
import java.net.*; &~ .n}h&  
 &$x1^  
&x#3N=c#  
public class SiteFileFetch extends Thread { iiWm>yy  
}u `~lw(Z  
;+Mee^E>!  
SiteInfoBean siteInfoBean = null; //文件信息Bean ^h5h kIx0  
long[] nStartPos; //开始位置 'ZXd|WI  
long[] nEndPos; //结束位置 )_H>d<di
 
FileSplitterFetch[] fileSplitterFetch; //子线程对象 xV+cX*4h  
long nFileLength; //文件长度 qQ/<\6Sl  
boolean bFirst = true; //是否第一次取文件 *@-a{T}  
boolean bStop = false; //停止标志 T:G8xI1 P  
File tmpFile; //文件下载的临时信息 3yXSv1  
DataOutputStream output; //输出到文件的输出流 sq;nUA=  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） .1@8rVp7  
public SiteFileFetch(SiteInfoBean bean) throws IOException TEEt]R-y  
{ ndE"v"_H  
siteInfoBean = bean; LV6BSQyQ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); \5q0nB@i5y  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Lt?k$U{qe)  
if(tmpFile.exists ()) $psPNJG  
{ [a2Q ^ab  
bFirst = false; +)06*"I  
read_nPos(); }[O/u <Z  
} -NL=^O$G  
else y/\0qQ/  
{ ^dP]3D1 @  
nStartPos = new long[bean.getNSplitter()]; 4^uwZ:  
nEndPos = new long[bean.getNSplitter()]; )"sJaH
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} G>?'b  
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} kWm[Lt  
|-zefzD|  
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public void run() rIRkXO)  
{ '6zk>rN  
//获得文件长度 ^a#  
//分割文件 C%T$l8$  
//实例FileSplitterFetch \*i[m&3;q  
//启动FileSplitterFetch线程 ZhnRsn9  
//等待子线程返回 ;>jLRx<KC  
try{ F*{1, gb  
if(bFirst) mO0a: i!  
{ %;-r->  
nFileLength = getFileSize(); L`@)*x)~R  
if(nFileLength == -1) 71wtO  
{ yGZsPQIaV  
System.err.println("File Length is not known!"); /~6)Vt  
} dkI(&/  
else if(nFileLength == -2) ELa:yIl0  
{ JM>4m)h#  
System.err.println("File is not access!"); >DkRl  
} U!D\Vd  
else .J fV4!=o  
{ (|t)MnPfY  
for(int i=0;i<nStartPos.length;i++) f J$>VN  
{ =+>^:3cCQ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 3Jj 3!aDB  
} ^oH!FN`;{  
for(int i=0;i<nEndPos.length-1;i++) Fb^f`UI  
{ yh{Wuz=T  
nEndPos = nStartPos[i+1]; 3+tr_psH  
} m`B.3  
nEndPos[nEndPos.length-1] = nFileLength; Ew$-,KC[  
} bG&vCH;}%  
} c8}jO=/5+  
E As1 =  
A>Y!d9]ti  
//启动子线程 ,Jqk0cW2  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; E*]%@6tH  
for(int i=0;i<nStartPos.length;i++) 2& ZoG%)  
{ 6,j&u7  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Hr/3nq}.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), AiOz1Er  
nStartPos,nEndPos,i); ~9h/{$  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ZB5u\NpcW  
fileSplitterFetch.start(); v3Xt<I=4y  
} C#@>osC  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), P%_PG%O2p  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); yaWHGre  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", e,I{+^P  
nEndPos = " + nFileLength); >X0c:pPu  
// fileSplitterFetch[nPos.length-1].start(); T*v@hbJ  
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u
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//等待子线程结束 p({)ZU3  
//int count = 0; y - Ge"mY  
//是否结束while循环 _;8+L\  
boolean breakWhile = false; O$$$1VHYo  
NUb:5tL  
$,DX^I%!  
while(!bStop) 0{zA6Xu  
{ +E8}5pDt  
write_nPos(); e_z"<yq  
Utility.sleep(500); ^e4y:#Nu  
breakWhile = true; IP-}J$$1  
jSMs<ox  
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for(int i=0;i<nStartPos.length;i++) ;&?l1Vu  
{ ^iz2=}Q8  
if(!fileSplitterFetch.bDownOver) rn"}@5  
{ /'WVRa  
breakWhile = false; $kCXp.#k@~  
break; x39n7+j4  
} ;VIW/  
} I$vM )+v=  
if(breakWhile) FEqR7  
break; p&<X&D   
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9G)q U  
//count++; `|
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//if(count>4) E])X$:P?  
// siteStop(); 7\p<k/TS  
} 'l`T(_zL\%  
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q)E J?-  
System.err.println("文件下载结束！"); y*fU_Il|!  
} `Z!NOC  
catch(Exception e){e.printStackTrace ();} "i3Q)$"S  
} FdVWj 5 $a  
+5C*i@v  
r-SQk>Y}  
//获得文件长度 '@Q aeFm  
public long getFileSize() oP( Hkp,'  
{ XkJzt  
int nFileLength = -1; qGgqAF#B  
try{ l: X]$2;  
URL url = new URL(siteInfoBean.getSSiteURL()); oN/T>&d  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8E9W\@\  
httpConnection.setRequestProperty("User-Agent","NetFox"); 2(Ez H  
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int responseCode=httpConnection.getResponseCode(); Tl ?]K  
if(responseCode>=400) U3zwC5}BN  
{ 3cztMi  
processErrorCode(responseCode); ?]bZ
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return -2; //-2 represent access is error %}%vey  
} d,0Yi u.p  
r\sQ8/  
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String sHeader; eE'2B."F  
=5yI>A0  
kb>/R/,9  
for(int i=1;;i++) gbJz5EEq  
{ ]\Tcy[5  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); |(=`l  
//Utility.log(in.readLine()); &v
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sHeader=httpConnection.getHeaderFieldKey(i); &bO0
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if(sHeader!=null) xo46L\  
{ nS}XY  
if(sHeader.equals("Content-Length")) HBc^[fJ^-  
{ 8}0O @ wq  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); jLEwFPz  
break; Zg@NMT  
} utz!ElzA  
} TLk=HGw  
else u\-f\Z7  
break; Jc:gNQCsP  
} -r!N; s$t  
} 2nFSu9}
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catch(IOException e){e.printStackTrace ();} XdDy0e4{%<  
catch(Exception e){e.printStackTrace ();} .CL\``
  
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Utility.log(nFileLength); -$]Tn#`Fb  
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return nFileLength; ttwfWfX  
} N}*|*!6hI  
n0T'"i[  
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//保存下载信息（文件指针位置） #.(6.Li  
private void write_nPos() 7O)U(<70  
{ h>6'M  
try{ d2x|PpmH  
output = new DataOutputStream(new FileOutputStream(tmpFile)); &.Jp,Xt)  
output.writeInt(nStartPos.length); dfDz/sD*  
for(int i=0;i<nStartPos.length;i++) x_JCH7-  
{ EEaf/D/jt  
// output.writeLong(nPos); f3+@u2Pv  
output.writeLong(fileSplitterFetch.nStartPos); f@R j;R~Jp  
output.writeLong(fileSplitterFetch.nEndPos); C#<:x!  
} 'wd-!aZAd  
output.close(); SY` U]-h  
} IQS:tL/  
catch(IOException e){e.printStackTrace ();} T>&d/$;]  
catch(Exception e){e.printStackTrace ();} wnL\.%Y^  
} 0wLu*K5$4E  
d (Fb_  

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//读取保存的下载信息（文件指针位置） Yd4J:  
private void read_nPos() aMSX"N"ot  
{ -
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try{ `o6Hm  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ag-\(i;K]  
int nCount = input.readInt(); m"~^-mJ-  
nStartPos = new long[nCount]; 2z7+@!w/  
nEndPos = new long[nCount];
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for(int i=0;i<nStartPos.length;i++) jB*%nB*x  
{ b<de)MG  
nStartPos = input.readLong(); x?:[:Hf   
nEndPos = input.readLong(); t%e}'?#^  
} ec:?Q0  
input.close(); vr|9NP]v  
} "r!O9X6  
catch(IOException e){e.printStackTrace ();} ngprTMO$&  
catch(Exception e){e.printStackTrace ();} (bxSN@hp2  
} |hjm^{!TpW  
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private void processErrorCode(int nErrorCode) ,F7W_f# @3  
{ -aDGXQM{~  
System.err.println("Error Code : " + nErrorCode); #Mt'y8|}$  
} Ll%CeP  
<FIc!  
_ cK"y2  
//停止文件下载 _\YBB=Os  
public void siteStop() a$p?r3y  
{ #Jv|zf5Z  
bStop = true; Z~o6%_xe  
for(int i=0;i<nStartPos.length;i++) Y]aVa2!Wb  
fileSplitterFetch.splitterStop(); ?(el6J}  
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} @UCGsw  
}
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//负责部分文件的抓取 \kU0D  
**FileSplitterFetch.java 9kmkF,  
*/ 96UL](l(`  
package NetFox; kw&,<V77~  
ld8E!t[  
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import java.io.*; 7U>Xi'?  
import java.net.*; ?IR]y-r  
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public class FileSplitterFetch extends Thread { 1*\JqCR  
jj2 [Zh/h  
q(sEN!^L`  
String sURL; //File URL P(BjXMd  
long nStartPos; //File Snippet Start Position Umx~!YL!  
long nEndPos; //File Snippet End Position Atc<xp  
int nThreadID; //Thread's ID egMl(~D  
boolean bDownOver = false; //Downing is over "]\sw"zO?  
boolean bStop = false; //Stop identical !sWKi)1  
FileAccessI fileAccessI = null; //File Access interface n1+1/  
84v7g`lrR  
p4QQ5O$;  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException P;_}n
bB  
{ eT33&:n4  
this.sURL = sURL; '4-J0S<<_  
this.nStartPos = nStart; b&[bfM<  
this.nEndPos = nEnd; S B2R  
nThreadID = id; DX>Yf}  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 "Sm'TZx  
} iIT7pq1  
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public void run() i\~@2  
{ |q0F*\z3  
while(nStartPos < nEndPos && !bStop) M)sM G C  
{ D%[yAr;r  
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?
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try{ og0su  
URL url = new URL(sURL); O5X@'.#rU  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); RuyqB>[o  
httpConnection.setRequestProperty("User-Agent","NetFox"); xF4S  
String sProperty = "bytes="+nStartPos+"-"; d$DNiJ ,  
httpConnection.setRequestProperty("RANGE",sProperty); C_CUk d[  
Utility.log(sProperty); l9Xz,H  
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InputStream input = httpConnection.getInputStream(); ckDWY<@v  
//logResponseHead(httpConnection); fkKk/M>1  
i|N%dl+T=  
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byte[] b = new byte[1024]; |
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int nRead; [f
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) DIAHIV<  
{ LVHIQ9  
nStartPos += fileAccessI.write(b,0,nRead); ''p7!V?  
//if(nThreadID == 1) YCBp]xuE  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \S5YS2,P  
} ]2zzY::Sd=  
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Utility.log("Thread " + nThreadID + " is over!"); B}?$kp  
bDownOver = true; r<)>k.] !  
//nPos = fileAccessI.write (b,0,nRead); FdwlRuG  
} G q&[T:  
catch(Exception e){e.printStackTrace ();} P3e}G-Oz  
} {OIktG2gZ  
} +HAd=DU  
:,8eM{.Q  
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//打印回应的头信息 w?JRY  
public void logResponseHead(HttpURLConnection con) mMt~4(5  
{ "aT"o  
for(int i=1;;i++) 7my7|s[  
{ [}*xxy   
String header=con.getHeaderFieldKey(i); cXDG(.!n7B  
if(header!=null) fkHCfcU  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); }57d3s  
Utility.log(header+" : "+con.getHeaderField(header)); jhx
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else Jf</83R
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break; UL3++bt  
} iJaA&z5sr  
} KlbUs\E  
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public void splitterStop() {Gi:W/jJ  
{ du5|/  
bStop = true; JI7.:k;  
} "k>;K,:  
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} yv+DM`0  
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R=m9[TgBm  
/* U#gv ~)\k  
**FileAccess.java ;n2b$MB?nM  
*//文件访问(定位，写) @\)a&p
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package NetFox; dk@j!-q^  
import java.io.*; uc?`,;8{`  
LVAnZ'h/|  
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public class FileAccessI implements Serializable{  Z5[f  
^BN?iXQhN  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 nep-?7x  
RandomAccessFile oSavedFile; ;Y@"!\t}  
long nPos; \EC7*a0  
> Du>vlTY  
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public FileAccessI() throws IOException `7o(CcF6H  
{ 67b[T~92o  
this("",0); ;Y"*Z2U  
} ZnXq+^Z4  
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F  
[*2|#KSCX  
public FileAccessI(String sName,long nPos) throws IOException jb {5   
{ .=% ,DT"  
oSavedFile = new RandomAccessFile(sName,"rw"); (U@uJ  
this.nPos = nPos; rxM)SC;P  
oSavedFile.seek(nPos); +ug[TV  
} ;=oGg%@aP  
t^(#~hx  
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public synchronized int write(byte[] b,int nStart,int nLen) r\f|r$i  
{ ypA)G/;  
int n = -1; .0H!B#9  
try{ a"|\n_  
oSavedFile.write(b,nStart,nLen); qW(_0<E  
n = nLen; ab-MEN`5  
} }N}\<RG  
catch(IOException e) QnPgp(d<  
{ cQ<* (KU  
e.printStackTrace (); u,Rhm-`  
} 3NA G}S  
v*.#LJEm  
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return n; 4t;m^I
v  
} ;th]/ G  
$h|rd+},  
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} <1EmQ)B  
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/* $}/Q%
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**SiteInfoBean.java uY5Gn.Y  
*/ 9X2lH~C  
package NetFox; 1>1ii  
7L=V{,,v  
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public class SiteInfoBean { D;l)&"|r?  
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private String sSiteURL; //Site's URL .$,.w__m~  
private String sFilePath; //Saved File's Path <Gr775"  
private String sFileName; //Saved File's Name V,@Y,  
private int nSplitter; //Count of Splited Downloading File i%R2#F7I  
vs)1Rm  
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public SiteInfoBean() @$(/6]4p  
{//nSplitter的缺省值为5 A-dL_3  
//default value of nSplitter is 5 jSj (ZU6  
this("","","",5); Jc#()4  
} 1K;i/  
VK)K#!O8  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) [@qUQ,Ie  
{ v$`AN4)}  
sSiteURL= sURL; Odo"S;)  
sFilePath = sPath; ]o(&J7Z6-  
sFileName = sName; -pRyN]YD  
this.nSplitter = nSpiltter;  t: =  
~!,Q<?  
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} h69: Tj!  
4^KoHeM6  
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public String getSSiteURL() V^t5 Y+7  
{ !S/hH%C  
return sSiteURL; ezt_ct/Z  
} !8|]R  
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{
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public void setSSiteURL(String value) o%Lk6QA$  
{ m4@y58n=  
sSiteURL = value; xy%lp{  
} 0 mWfR8h0  
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>a]4}  
public String getSFilePath() eo4<RDe<  
{
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return sFilePath; 62}bs/%  
} v UAYYe  
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*|x2"?d-F:  
public void setSFilePath(String value) xa#:oKF3  
{ Q^v8n1  
sFilePath = value; RGGP6SDc  
} s &v<5W2P  
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public String getSFileName() #](k,% 2  
{ n>\BPiz  
return sFileName; b9(d@2MtK  
} HLAYmXX"w  
(J): >\a]  
@ -JD`2z  
public void setSFileName(String value) Y}"|J ~  
{ ?Z]}G  
sFileName = value; bK%go  
} ?|+bM`  
"t8mQ;n  
qkv.,z"  
public int getNSplitter() -(>x@];r0  
{ ?M7nbfy[A@  
return nSplitter; 0i$jtCCL(  
} `NV =2T  
/U)w:B+p/g  
G`w,$:,  
public void setNSplitter(int nCount) *ZGQ`#1.X6  
{ ?4q6>ipx  
nSplitter = nCount; ZzI^*Nyg  
} Bl'  
} 2Z,;#t  
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J mFzSR?}  
/* wH!]B-hn  
**Utility.java gSu+]N  
*/ D}!U?]la&  
package NetFox; . xX xjl  
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public class Utility { -H.;73Kb[  
g@nk0lQewj  
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public Utility() jzEimKDE's  
{ -.g5|B  
9A3Q&@,  
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} fQuphMOl6  
sj. eJX"z  
//线程睡眠 r9s1\7]x  
public static void sleep(int nSecond) z]P|%  
{ %)l2dK&9"j  
try{ o|alL-  
Thread.sleep(nSecond); -mX _I{BJ  
} )OH!<jW  
catch(Exception e) {(7.X4\x  
{ R) @k|  
e.printStackTrace (); o,Ha-z]f  
} ZQl[h7c/N  
} x6,S#p  

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//日志 $am7 xd  
public static void log(String sMsg) P$]Vb'Fz  
{ 348Bu7':  
System.err.println(sMsg); .D4D!!  
} yo (&~r  
3O#7OL68v  
&% M^:WT  
public static void log(int sMsg) M_79\Gz"  
{ [.<vISRir  
System.err.println(sMsg); zG& N5t96X  
} A%+~   
} SfL,_X]*  
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R>gj"nB  
/* #C>pA<YJzK  
**TestMethod.java z=ppNP0  
*/ sUbZVPDr  
package NetFox; YT:<AJm  
wau81rSd  
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public class TestMethod { )-jvp8%BK  
4,<~t>M1  
oTx#e[8f{  
public TestMethod() Vs07d,@w>  
{ ///xx/weblogic60b2_win.exe gXw\_ue<  
try{ Vx0V6{JX  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); a~XNRAh  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); mup3ua]!  
SiteFileFetch fileFetch = new SiteFileFetch(bean); #Wc)wL-Tg  
fileFetch.start(); **s:H'Mw_  
} z6{0\#'K  
catch(Exception e){e.printStackTrace ();} %0u7pk  
{L4^IKI  
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} d1E~H]X4  
/+IR^WG#C}  
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public static void main(String[] args) K@>v|JD  
{ 'QW 0K]il  
new TestMethod(); R jAeN#,?  
} 5 !NPqka}.  
} ZcdS?Z2k  
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