http断点续传简单实现（java)

/* WN]k+0#  
**SiteFileFetch.java q 4Pv\YO  
*/ .]E(P   
package NetFox; .u mqyU~  
import java.io.*; (Z<@dkO?)  
import java.net.*; |&K;*g|a  
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public class SiteFileFetch extends Thread { 8Yc-3ozH  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 7 7bwYKIn  
long[] nStartPos; //开始位置 ((gI OTV  
long[] nEndPos; //结束位置 T.cTL.}  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 FWu:5fBZY  
long nFileLength; //文件长度 /)[-5n{  
boolean bFirst = true; //是否第一次取文件 Z"c-Ly{vEj  
boolean bStop = false; //停止标志 
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File tmpFile; //文件下载的临时信息 +E. D:  
DataOutputStream output; //输出到文件的输出流 bIm4s  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） kk5&lak2V  
public SiteFileFetch(SiteInfoBean bean) throws IOException '=nmdqP  
{ T[4xt,[a  
siteInfoBean = bean; @7}XBg[pI  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 0d2RB^"i  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); *  1}dk`-  
if(tmpFile.exists ()) >V8!OaY5n  
{ -aBhN~  
bFirst = false; mh4 VQ9  
read_nPos(); <yl@!-'J7  
} O
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else @(L}:]{@  
{ 25Ee+&&%  
nStartPos = new long[bean.getNSplitter()]; G-i2#S   
nEndPos = new long[bean.getNSplitter()]; ]]y>d!  
} 1tTP;C l#  
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} ,m*HRUY  
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public void run() I;}U/'RR>  
{ ^+-QY\N j  
//获得文件长度 X8v)yDt
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//分割文件 a5Vlfx  
//实例FileSplitterFetch [? "hmSJ  
//启动FileSplitterFetch线程 !Gnm<|.  
//等待子线程返回 $m ;p@#n  
try{ hpQ #`rhn  
if(bFirst) 1q;R+65  
{  6 wd  
nFileLength = getFileSize(); Z42q}Fhm*R  
if(nFileLength == -1) YKUAI+ks  
{ E uO:}[  
System.err.println("File Length is not known!"); CnuM=S:  
} M#Z^8(  
else if(nFileLength == -2) E 1`g8Hk'  
{ KT<i%)t2  
System.err.println("File is not access!"); EwcFxLa!F  
} lI46 f  
else FS8l}t  
{ <VU-ja*(J  
for(int i=0;i<nStartPos.length;i++) (]sm9PO  
{ 27R4B O  
nStartPos = (long)(i*(nFileLength/nStartPos.length));
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} POm;lM$  
for(int i=0;i<nEndPos.length-1;i++) /V0Put  
{ ]u<U[l-w  
nEndPos = nStartPos[i+1]; BO}IN#  
} EO(l?Fgw]$  
nEndPos[nEndPos.length-1] = nFileLength; ?VxQ&^|  
} GR(m+%Vw!  
} 2.JrLBhN  
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//启动子线程 Q(x=;wf5r  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ;~ Xjk  
for(int i=0;i<nStartPos.length;i++) mx1Bk9h%Xe  
{ [jNVk3  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), L$a{%]I  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), u`B/9-K)y  
nStartPos,nEndPos,i); E_30)"]  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); A##Q>|>)  
fileSplitterFetch.start(); j/O9LygB  
} ^{J^oZ'%~  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), tag)IWAiE  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 44n41.Q]  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", U1 3Lsky%  
nEndPos = " + nFileLength); !1S!)#  
// fileSplitterFetch[nPos.length-1].start(); Y#):1C1  
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//等待子线程结束 aiX4;'$x!  
//int count = 0; f dJg7r*  
//是否结束while循环 LDw.2E  
boolean breakWhile = false; -A}
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while(!bStop) \{rhHb\|h  
{ r#j3O}(n  
write_nPos(); .0>bnw  
Utility.sleep(500); W|;`R{<I%  
breakWhile = true;  ZJ)>gV  
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for(int i=0;i<nStartPos.length;i++) 8>|4iT  
{ 8DD1wK\U~  
if(!fileSplitterFetch.bDownOver) /QlzWson  
{ _Q\rZ l  
breakWhile = false; ZQR)k:k7  
break; A$~H`W<yxB  
} y]i}j,e0L  
} u<n['Ur}|  
if(breakWhile) /Re67cMQ*  
break; \4G9fR4  
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//count++; ~yngH0S$[b  
//if(count>4) bA6^RIf?  
// siteStop(); x`p908S^  
} -'
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System.err.println("文件下载结束！"); d]_].D$  
} b!QRD'31'j  
catch(Exception e){e.printStackTrace ();} 7 mA3&<&q  
} ~s?y[yy6i  
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//获得文件长度 KKg\n^  
public long getFileSize() .ezko\nU  
{ b V_<5PHP  
int nFileLength = -1; *!NW!,R  
try{ 9$(N q  
URL url = new URL(siteInfoBean.getSSiteURL()); otdv;xI9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0ly6  |:  
httpConnection.setRequestProperty("User-Agent","NetFox"); gpbdK?  
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int responseCode=httpConnection.getResponseCode(); &"1_n]JO  
if(responseCode>=400) O#^qd0e'P!  
{ sV%=z}n=  
processErrorCode(responseCode); 5M>SrZH  
return -2; //-2 represent access is error oY\;KPz  
} -
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String sHeader; a[=B?Bd  
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for(int i=1;;i++) 6!U~dt#a  
{ VzM (u_)  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); L'a s^Od  
//Utility.log(in.readLine()); *rm
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sHeader=httpConnection.getHeaderFieldKey(i); |jWA >S  
if(sHeader!=null) /HSg
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{ DfOigLG*  
if(sHeader.equals("Content-Length")) xy)W_~Mk  
{ :W'.SRD  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); JV;VR9-l  
break; obX2/  
} g1UQ6Oa  
} 0KZsWlD:L  
else s BuXwa  
break; z.t,qi$;{U  
}
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} X-"0Zc  
catch(IOException e){e.printStackTrace ();} A~a7/N6s;  
catch(Exception e){e.printStackTrace ();} VM3)L>x]/  
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Utility.log(nFileLength); _=qk.|p/  
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return nFileLength; |z)7XK  
} O4W2X@
 
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//保存下载信息（文件指针位置） @<1T&X{Z!  
private void write_nPos() ?`SBGN;  
{ 5)4?i p  
try{ 5e'**tbKH  
output = new DataOutputStream(new FileOutputStream(tmpFile)); i,y{*xBT  
output.writeInt(nStartPos.length); :y!{=[>M(  
for(int i=0;i<nStartPos.length;i++) *ul-D42!U  
{ UXS+GAWU  
// output.writeLong(nPos); f*[Uq0?  
output.writeLong(fileSplitterFetch.nStartPos); cPl$N5/5  
output.writeLong(fileSplitterFetch.nEndPos); cc3+Wx_  
} _ =(v? 2:?  
output.close(); f./j%R@  
} m?)F@4]  
catch(IOException e){e.printStackTrace ();} ub{Yg5{3S\  
catch(Exception e){e.printStackTrace ();} _lOyT$DN  
} fqm6Pd{:(  
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//读取保存的下载信息（文件指针位置） WODgG@w  
private void read_nPos() ~HX'8\5  
{ aFy'6c}  
try{ ;uU 8$  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 4=;`\-7!  
int nCount = input.readInt(); s.!gsCQme  
nStartPos = new long[nCount]; VC NQ}h[D  
nEndPos = new long[nCount]; 3_Re>i  
for(int i=0;i<nStartPos.length;i++) 'p,54<e  
{ `9VRT`e  
nStartPos = input.readLong(); wIQt f|ZI>  
nEndPos = input.readLong(); )9rJ]D^B  
} DM !B@  
input.close(); Y#Pg*C8>8  
} mLeK7?GL  
catch(IOException e){e.printStackTrace ();} VSm{]Z!x  
catch(Exception e){e.printStackTrace ();} GplEad $  
} 14Jkr)N  
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private void processErrorCode(int nErrorCode) Z uO 7N  
{ KQrG|<J  
System.err.println("Error Code : " + nErrorCode);  !*-|s}e  
} Jpo(O>\P  
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//停止文件下载 0a's[>-'A  
public void siteStop() Dn.%+im-u  
{ ca$K
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bStop = true; A!`Q[%$  
for(int i=0;i<nStartPos.length;i++) EYKV}`  
fileSplitterFetch.splitterStop(); RMxFo\TK;  
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} O>2i)M-h9x  
} ,fD#)_\g2  
//负责部分文件的抓取 <#:ey^q<  
**FileSplitterFetch.java ;ywUl`d  
*/ -xU4s  
package NetFox; ,tHV H7[  
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import java.io.*; UJQGwTA W  
import java.net.*; vHx[:vuq:  
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public class FileSplitterFetch extends Thread { q{+Pf/M5  
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String sURL; //File URL
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long nStartPos; //File Snippet Start Position 7 +kU8}  
long nEndPos; //File Snippet End Position @7,k0H9Moa  
int nThreadID; //Thread's ID rW0-XLbL5H  
boolean bDownOver = false; //Downing is over `KmM*_a  
boolean bStop = false; //Stop identical 8A2_4q@34  
FileAccessI fileAccessI = null; //File Access interface r/mKuGa]  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException OOj}CZ6  
{ 2umgF  
this.sURL = sURL; 96S#Q*6+R  
this.nStartPos = nStart; S/7?6y~  
this.nEndPos = nEnd; QNgfvy  
nThreadID = id; 4Yya+[RY  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 }:hN}*H  
} /}$D&KwYg  
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public void run() J`d;I#R%c  
{ 5Z*6,P0  
while(nStartPos < nEndPos && !bStop) % (x9~"  
{ YS+|n%?  
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try{ 2"!s8x1$  
URL url = new URL(sURL); K)F6TvWv  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]?a i  
httpConnection.setRequestProperty("User-Agent","NetFox"); S;I}:F#5  
String sProperty = "bytes="+nStartPos+"-"; e4(E!;Z!QF  
httpConnection.setRequestProperty("RANGE",sProperty); i5jsM\1j  
Utility.log(sProperty); 2N[/Cc2Tg/  
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InputStream input = httpConnection.getInputStream(); ($r-&]y  
//logResponseHead(httpConnection); $irF  
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byte[] b = new byte[1024]; |WDMyKf6J  
int nRead; D $3Mg  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 6$A>%Jtwe  
{ EK$3T5e  
nStartPos += fileAccessI.write(b,0,nRead); nv/'C=+L  
//if(nThreadID == 1) $ucA.9pJ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); M A  
} E]dmXH8A  
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Utility.log("Thread " + nThreadID + " is over!"); h0)Dj(C  
bDownOver = true; <
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//nPos = fileAccessI.write (b,0,nRead);
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} =`Lci1#pu}  
catch(Exception e){e.printStackTrace ();} H[D<G9:  
} F;sZc,Y,^  
} 1j?+rs+o-  
_|I`A6`=  
/l1OC(hm  
//打印回应的头信息 VHqHG`}:  
public void logResponseHead(HttpURLConnection con) /Xk-xg+U  
{ 25{-GaB
 
for(int i=1;;i++)  aK33bn'j  
{ a(oa?OdJ  
String header=con.getHeaderFieldKey(i); &r)[6a$fW  
if(header!=null) 1V:I}~\  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); iq
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Utility.log(header+" : "+con.getHeaderField(header)); omzG/)M:O  
else Z|$M 9E  
break; x ?24oO  
} 1U6z2i+y  
} _kXq0~  
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public void splitterStop() liU8OXBl  
{ &OsO _F  
bStop = true; <sli!r
v  
} y,s`[=CT  
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} ?!HU$>  
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/* W.CbNou  
**FileAccess.java dJ>~  
*//文件访问(定位，写) 7!U^?0?/  
package NetFox; `i<omZ[aT  
import java.io.*; @|([b r|O  
:T )R;E@  
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public class FileAccessI implements Serializable{ ez<V  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节   D9h  
RandomAccessFile oSavedFile; Q@KCODi  
long nPos; we8aqEomr  
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public FileAccessI() throws IOException i
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{ V:h7}T95  
this("",0); O',
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} f0&%  
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public FileAccessI(String sName,long nPos) throws IOException ,49Z/P  
{ 4-m6e$p;  
oSavedFile = new RandomAccessFile(sName,"rw"); OE*Y%*b  
this.nPos = nPos; 7@ \:l~{  
oSavedFile.seek(nPos); lHAWZyO  
} iD*L<9  
VwOcWKD  
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public synchronized int write(byte[] b,int nStart,int nLen) \@[,UZ  
{ BU#3fPl  
int n = -1; e|N~tUVrrN  
try{ >L')0<!&  
oSavedFile.write(b,nStart,nLen); +pRNrg?k  
n = nLen; A `{hKS  
} -X
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catch(IOException e) pX+4B=*  
{ S$ffTdRz  
e.printStackTrace (); :V1j*)  
} tI)|y?q  
_n1[(I  
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return n; Al=ByX@  
} B"8jEYT5  
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} w2db=9  
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||?@pn\  
/* 1ktxG1"1  
**SiteInfoBean.java .5uqc.i"f  
*/ F$bV}>-1k  
package NetFox; T*nP-b  
stUUez>  

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public class SiteInfoBean { 4jt(tZS  
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private String sSiteURL; //Site's URL )2_[Ww|.  
private String sFilePath; //Saved File's Path c]zFZJ6M  
private String sFileName; //Saved File's Name 3{fg3?  
private int nSplitter; //Count of Splited Downloading File W.NZ%~|+e/  
<{GVA0nr  
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public SiteInfoBean() A; wT`c  
{//nSplitter的缺省值为5 UWidT+'Sa  
//default value of nSplitter is 5 J ZkQ/vp(  
this("","","",5); LT"H-fTgs  
} K_@?Q@#YhR  
/ywP 0  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) vd)zvI  
{ Q;J( 5;  
sSiteURL= sURL; ?xrOhA9  
sFilePath = sPath; 7B)1U_L0H  
sFileName = sName; d$jwh(Ivs  
this.nSplitter = nSpiltter; }opw_h+/F  
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^H&U_  
} > K?OsvX  
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public String getSSiteURL() n}j6gN!O  
{ 9! /kyyU  
return sSiteURL; a{
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} I}m20|vv  
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public void setSSiteURL(String value) bMxK@$G~  
{ |-G2pu;  
sSiteURL = value; 4eY?#8  
} !nCq8~#  
@0 /qP<E  
5|nc^ 12  
public String getSFilePath() X.#)CB0c1Q  
{ RFyMRE!?  
return sFilePath; y
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} z V\+za,  
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public void setSFilePath(String value) o$buoGSPc  
{ q+y\pdhdO  
sFilePath = value; &'x~<rx  
} Rh?bBAn8  
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public String getSFileName()
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{ u;gO+)wqv  
return sFileName; )muNfs m  
} "GZieI D  
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public void setSFileName(String value) *Ud(HMTe  
{ \7uM5 k}l  
sFileName = value; lU%}_!tp3/  
} L]|mWyzT  
:t]HY2  
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public int getNSplitter() {@^;Nw%J  
{ *B"Y]6$  
return nSplitter; Z(T{K\)uN  
} RHg-Cg`  
. \"k49M`  
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public void setNSplitter(int nCount) R<L
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{ `daqzn  
nSplitter = nCount; wOl?(w=|  
} WXl+w7jr  
} )&Oc7\J,  
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u]};QR  
/* =O![>Fu5  
**Utility.java t82'K@sq  
*/  OegeZV  
package NetFox; ~0a5  
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public class Utility {  b.&WW  
^AS\a4`/  
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public Utility() &)%+DUV|  
{ H<Oo./8+  

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} CwA_jOp  
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//线程睡眠 X#lNS+&='  
public static void sleep(int nSecond) 'J|)4OG:  
{ .B# .   
try{ (Q^sK\  
Thread.sleep(nSecond); DK)W ,z|  
} K^shTh8k  
catch(Exception e) 4hL%J=0:  
{ hm`=wceK  
e.printStackTrace (); `}
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} :"\,iH  
} \^c4v\s<o#  
wZ
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//日志 :$MOdLr  
public static void log(String sMsg) I6W`y
h`I)  
{ zTF{ g+  
System.err.println(sMsg); O?JJE8~']  
} NXU:b"G S  
3/kT'r  
}}JMwT  
public static void log(int sMsg) =?<WCR C*  
{ `Vb  
System.err.println(sMsg); 3@>F-N  
} `6D?te  
} vk& gR  
{LO Pm1K8Y  
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/* %lF*g  
**TestMethod.java E-bswUVaEE  
*/ QJGGce  
package NetFox; "is(  
)/H;5 cn  
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public class TestMethod { 5p;AON  
\<4N'|:  
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public TestMethod() Z!1D4`w  
{ ///xx/weblogic60b2_win.exe 9%/hoA)  
try{ KA5)]UF`l  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); z%;plMj  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); iC gZ3M]  
SiteFileFetch fileFetch = new SiteFileFetch(bean); :Ha/^cC/3  
fileFetch.start(); &L;ocd$  
} BUO5g8m{  
catch(Exception e){e.printStackTrace ();} "O&93#8  
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^SdF\uk{?6  
} T*z]<0E]  
Xwm3# o.&)  

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public static void main(String[] args) Z'z)Oo  
{ hi
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new TestMethod(); ToXWFX  
} `fu_){  
} @I_cwUO  
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