http断点续传简单实现（java)

/* Z-t}6c'Kg  
**SiteFileFetch.java ,t%CK!8  
*/ }kCn@  
package NetFox; P,/13tZ#3  
import java.io.*; 9R@abm,I  
import java.net.*; ~+<xFi  
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public class SiteFileFetch extends Thread { 7^I$%o1g  

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SiteInfoBean siteInfoBean = null; //文件信息Bean r2SJp@f  
long[] nStartPos; //开始位置 'l' X^LMD  
long[] nEndPos; //结束位置 [T4 pgt'H  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 lj EB  
long nFileLength; //文件长度 (3ZvXpzvF  
boolean bFirst = true; //是否第一次取文件 =s0g2Zv"\  
boolean bStop = false; //停止标志 pfL2v,]g  
File tmpFile; //文件下载的临时信息 r}R^<y@I  
DataOutputStream output; //输出到文件的输出流 dqD;y#/  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 3V/_I<y  
public SiteFileFetch(SiteInfoBean bean) throws IOException xHv|ca.E  
{ 
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siteInfoBean = bean; q8?
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ,TF<y#wed  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); #u8*CA9  
if(tmpFile.exists ()) 0):uF_t<  
{ dv^e9b|  
bFirst = false; :/@k5#DY  
read_nPos(); BH&/2tO%  
} <Spr6U9p7  
else
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{ h-r6PY=i  
nStartPos = new long[bean.getNSplitter()]; Nt zq"ces)  
nEndPos = new long[bean.getNSplitter()]; '!
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} ^V<J69ny|9  
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} e(}oq"'z  
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public void run() d&aBs++T  
{ #D`S  
//获得文件长度 DC|xilP1O  
//分割文件 9m\)\/V  
//实例FileSplitterFetch S9G8aea/  
//启动FileSplitterFetch线程 0 &*P}U}Uc  
//等待子线程返回 m x3}m?W
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try{ [as-3&5S  
if(bFirst) oMh~5 W  
{ 0\5M^:8i3  
nFileLength = getFileSize(); g|ql 5jW  
if(nFileLength == -1) FNz84qVIx'  
{ YO@hE>  
System.err.println("File Length is not known!"); 7o;x
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} >"cr-LB  
else if(nFileLength == -2) <\, &:<  
{ UvPp~N7,  
System.err.println("File is not access!"); gf0PMc3l  
} /:#j?c  
else :v#k&Uh3y  
{ W *YW6  
for(int i=0;i<nStartPos.length;i++) j6n2dMRvSE  
{ #"Fg%36Zd  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 99F>n[5  
} 4@
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for(int i=0;i<nEndPos.length-1;i++) X$Q2m{dR  
{ B;eW/#`  
nEndPos = nStartPos[i+1]; x8 f6,  
} RRx`}E9,  
nEndPos[nEndPos.length-1] = nFileLength; #mgA/q?A  
} n&_YYEHx  
} 4JGE2ArR  
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//启动子线程 Ab*]dn`z  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ]@*tfz\YaH  
for(int i=0;i<nStartPos.length;i++) GS}0;x  
{ so}l#  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), LkaG8#m1R  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), R `;o!B}[  
nStartPos,nEndPos,i); H \r`
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); -&trk  
fileSplitterFetch.start(); azvDvEWCQZ  
} |xq}'.C  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), M|U';2hZN:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); %v]7BV^%6  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ER{yuw  
nEndPos = " + nFileLength); BwJNi6,  
// fileSplitterFetch[nPos.length-1].start(); >RM 0=bO  
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//等待子线程结束 ^[en3aQ  
//int count = 0; 6/|U  
//是否结束while循环 c2/FHI0J;  
boolean breakWhile = false; rW[SU
:  
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while(!bStop) GUKDhg,W  
{ @|^jq  
write_nPos(); Z%Vr+)!4  
Utility.sleep(500); ?hKm&B;d  
breakWhile = true; 6%>/og\%  
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for(int i=0;i<nStartPos.length;i++) ^Ss<X}es-  
{ !@( M_Z'  
if(!fileSplitterFetch.bDownOver) 77``8,  
{ 6!Qknk$  
breakWhile = false; YQ52~M0L  
break; o1U}/y+R\  
} w.tW=z5  
} "s% 686Vz  
if(breakWhile) BjYOfu'~z  
break; H;qJH1EdD  
)+?HI^-[S  
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//count++; {-Yee[d<
?  
//if(count>4) <p09oZ{6  
// siteStop(); [qiOd!  
} INOH{`}Ew  
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System.err.println("文件下载结束！"); t{~
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} Hv3W{
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catch(Exception e){e.printStackTrace ();} (e(Rr4  
} )R~a;?T_c0  
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//获得文件长度 O5O.><RP  
public long getFileSize()
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{ XYts8}y5  
int nFileLength = -1; "i&fp:E0  
try{ |IAW{_9)U  
URL url = new URL(siteInfoBean.getSSiteURL()); +Jdm#n?_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Gp,'kw"I  
httpConnection.setRequestProperty("User-Agent","NetFox"); :v_w!+,/  
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int responseCode=httpConnection.getResponseCode(); )XpVu  
if(responseCode>=400) /V#7=,,  
{ #J\s%60pt  
processErrorCode(responseCode); dKb ^x^  
return -2; //-2 represent access is error Gh'X.?3   
} |<1M&\oaQ'  
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String sHeader; n6/fan;  
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for(int i=1;;i++) ZEqE$:  
{ u7[pLtOwN  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); $]1qbE+  
//Utility.log(in.readLine()); A0OB$OK  
sHeader=httpConnection.getHeaderFieldKey(i); )L >Q;'  
if(sHeader!=null) 0TmZ*?3!4  
{ hD*(AJ  
if(sHeader.equals("Content-Length")) &5d\~{;  
{ /w0w*nH  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); \TZ|S,FS  
break; bH,M,xIL2  
} -8/JP  
} 3 &Sp@,  
else k1RV'  
break; |WBZN1W)  
} ZB$NVY  
} pu#[pa  
catch(IOException e){e.printStackTrace ();} p.5e: i^LJ  
catch(Exception e){e.printStackTrace ();} nn'Af,ko/  
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Utility.log(nFileLength); L/%Y#  
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return nFileLength; UG #X/%p  
} nSHNis  
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//保存下载信息（文件指针位置） m d_g}N(C  
private void write_nPos() me:iQ.g
 
{ tJAnuhX  
try{ L?Cjo4xS  
output = new DataOutputStream(new FileOutputStream(tmpFile)); WI{;#A  
output.writeInt(nStartPos.length); :xtT)w  
for(int i=0;i<nStartPos.length;i++) 9OfU7_m  
{ )T/J  
// output.writeLong(nPos); 2eHx"Ha  
output.writeLong(fileSplitterFetch.nStartPos); D?mDG|Z  
output.writeLong(fileSplitterFetch.nEndPos); _Z$?^gn  
} m@[3~ 6A  
output.close(); /S[?{QA  
} - zQ<ZE  
catch(IOException e){e.printStackTrace ();} A$:|Qd7F1  
catch(Exception e){e.printStackTrace ();} bOb Nc  
} !?b/-~o7S  
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//读取保存的下载信息（文件指针位置） 5D L,U(Y  
private void read_nPos() 8gAu7\p}  
{ {:$NfW  
try{ XfDX:b1p  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); M9DgO4xl  
int nCount = input.readInt(); ?M~  k$  
nStartPos = new long[nCount];
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nEndPos = new long[nCount]; D7gHE  
for(int i=0;i<nStartPos.length;i++) ]VDn'@uM  
{ tpZ->)1  
nStartPos = input.readLong(); Wj tft%  
nEndPos = input.readLong(); 4kh8W~i;/  
} =+\$e1Mb*  
input.close(); O+b6lg)q  
} AOAO8%|I  
catch(IOException e){e.printStackTrace ();} j_V/GnEQ  
catch(Exception e){e.printStackTrace ();} /?U!y?t&@  
} b`zET^F  
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private void processErrorCode(int nErrorCode) =JxFp, Xr  
{ O"iak  
System.err.println("Error Code : " + nErrorCode); >jKjh!`)!e  
} 1mix+.d  
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//停止文件下载 G1[(F`t>  
public void siteStop() B!uxs  
{ He<;4?:  
bStop = true; &`@lB (m  
for(int i=0;i<nStartPos.length;i++) U=DEV7E  
fileSplitterFetch.splitterStop(); Zw24f1iY  
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} T%~SM5  
} A2BRbwr>  
//负责部分文件的抓取 t}~UYG(h~  
**FileSplitterFetch.java #Cx%OIi[f  
*/ Ld~q1*7J  
package NetFox; ?BsH{QRYQ  
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import java.io.*; b5S7{"<V  
import java.net.*; mLaCkn
  
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public class FileSplitterFetch extends Thread { '$6PTa  
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String sURL; //File URL `I#`:hj  
long nStartPos; //File Snippet Start Position lRH0)5`  
long nEndPos; //File Snippet End Position Bq{]Eh0%  
int nThreadID; //Thread's ID [4\aYB9N  
boolean bDownOver = false; //Downing is over u>}zm_  
boolean bStop = false; //Stop identical t)'dF*L  
FileAccessI fileAccessI = null; //File Access interface .pW o>`"  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 4m\([EO  
{ DJ|BM+  
this.sURL = sURL; *m&%vj.Kc  
this.nStartPos = nStart; > Y]_K  
this.nEndPos = nEnd; \HD-vINV;  
nThreadID = id; N%*9&FjrL  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 r&Qt_  
} b!,j
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public void run() bBG/gQ  
{ N6q5`Ry  
while(nStartPos < nEndPos && !bStop) {#9,j]<  
{ qy&\Xgn;GA  
J'Gm7h{   
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try{ Oq}ip  
URL url = new URL(sURL); Ck@M<(x  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^9=4iXd  
httpConnection.setRequestProperty("User-Agent","NetFox"); \OA L Or  
String sProperty = "bytes="+nStartPos+"-"; 1lsLG+Rpxi  
httpConnection.setRequestProperty("RANGE",sProperty); dE GX3 -  
Utility.log(sProperty); 3fl7~Lw,  
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InputStream input = httpConnection.getInputStream(); IX.sy  
//logResponseHead(httpConnection); {lMqcK  
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byte[] b = new byte[1024]; k% NrL@z  
int nRead; L20rv:W$h  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >3!DOv   
{ LyV#j>gD  
nStartPos += fileAccessI.write(b,0,nRead); *F|+2?a:$  
//if(nThreadID == 1) &rP~`4Mkp  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @Kp1k> ov  
} =Sa~\k+  
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Utility.log("Thread " + nThreadID + " is over!"); zWtj|%ts  
bDownOver = true; 9cz)f\  
//nPos = fileAccessI.write (b,0,nRead); zuMO1s  
} 7jT#BWt  
catch(Exception e){e.printStackTrace ();} E[ 0Sst x  
} _jo$)x+'x  
} oSmjs  
<"A#Eok|4  
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//打印回应的头信息 #w;;D7{@m  
public void logResponseHead(HttpURLConnection con) ?Nu#]u-  
{ NZfd_? 3  
for(int i=1;;i++) 'QR4~`6I  
{ ET3,9+Gj  
String header=con.getHeaderFieldKey(i); =EWD |<  
if(header!=null) 0R*}QXph  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); NN11}E6  
Utility.log(header+" : "+con.getHeaderField(header)); GZS{
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else RyE_|]I62u  
break; ,8~dz  
} ]`K[W&  
} <ZV7|'^  
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public void splitterStop() GBW 7Y  
{ 9>I
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bStop = true; 'f8 p7_F  
} kR_E6Fl  
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} >pnz_MQ  
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/* }^Z<
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**FileAccess.java t:disL&!E  
*//文件访问(定位，写) 6kC)\uy  
package NetFox; gsi<S6DQ8  
import java.io.*; A>5S]  
;2BPPZ  
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public class FileAccessI implements Serializable{ sY_fq
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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 pIL`WE1'  
RandomAccessFile oSavedFile; *6'_5~G  
long nPos; hl}dgp((  
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public FileAccessI() throws IOException Sw[=S '(l  
{ P^ by'b+zI  
this("",0); HaS[.&\S0  
} *x5o=)Y  
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N!Rt;Xm2@  
public FileAccessI(String sName,long nPos) throws IOException wAPO{3  
{  X+\0%|  
oSavedFile = new RandomAccessFile(sName,"rw"); 7@3M]5:3g  
this.nPos = nPos; !SN6 ?Xy  
oSavedFile.seek(nPos); m[{nm95QZ  
} %N!h38N2  
JW2W>6Dgv[  
.ZM]%[4  
public synchronized int write(byte[] b,int nStart,int nLen) U24V55ZnI  
{ f7K8m|  
int n = -1; omr:C8T>  
try{ -B",&yTV  
oSavedFile.write(b,nStart,nLen); XPrY`,kN  
n = nLen; MuN[U17FB  
} H#_}^cGPR=  
catch(IOException e) S|tA[klh  
{ /]P%b K6B  
e.printStackTrace (); sY&rbJ(P  
} Idt@Hk5<&  
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return n; zp}yiE!bl  
} qEPf-O:lm  
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} !Mm+bWn=mB  
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/* !N@Yh"c  
**SiteInfoBean.java w}fqs/)w  
*/ "~B~{ _<j  
package NetFox; ^Jc$BMaVg  
&?&'"c{;m  
MAl{66  
public class SiteInfoBean { 3ZLr"O1l)  
 zgZi  
PpI+@:p[  
private String sSiteURL; //Site's URL K#%O3RRs  
private String sFilePath; //Saved File's Path qFB9,cUqh  
private String sFileName; //Saved File's Name b6 J2*;XG  
private int nSplitter; //Count of Splited Downloading File Tey,N^=ek  
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public SiteInfoBean() +F#=`+V  
{//nSplitter的缺省值为5 BHIZHp  
//default value of nSplitter is 5 sqgD?:@J  
this("","","",5); ]=O{7#  
} UXXqE4x  

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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) mg/C Ux  
{ \k2C 5f  
sSiteURL= sURL; Nn~tb2\vk  
sFilePath = sPath; `HMligT  
sFileName = sName; &6=TtTp"9  
this.nSplitter = nSpiltter; Q%_!xQP`  

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:..E:HdYO  
} ljaAB+  
/@xr[=L  
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public String getSSiteURL() !xJLeQFJI]  
{ !;BZ#tF&  
return sSiteURL; |:J*>"sq  
} <lsi.x\y<  
rF <iWM=  
6z%&A]6k:  
public void setSSiteURL(String value) N?Z+zN&P  
{ U~JG1#z6  
sSiteURL = value; %FXIlH
5
 
} 2`q^Q  
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*)}Ap4[  
public String getSFilePath() =N[V{2}q  
{ (9'G  
return sFilePath; k}+MvGq  
} HZ[68T[8b  
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public void setSFilePath(String value) Rz])wBv e  
{ @eAGN|C5  
sFilePath = value; Q}k_#w  
} 7k[`]:*o  
=]2RC1#}e  
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public String getSFileName() J"a2 @S&  
{ :c+a-Py $E  
return sFileName; &D&5UdN x  
} PG-cu$\??  
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public void setSFileName(String value)  \!' {-J  
{ ~
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sFileName = value; iYmzk?U  
} V}Y~
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public int getNSplitter() "
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{ <W^XSk  
return nSplitter; =_H*fhXS  
} ux/[d6To  
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;{F;e)${M  
public void setNSplitter(int nCount) 4,R\3`b  
{ 4p/V6kr&r  
nSplitter = nCount; $HR(|{piZ  
} "8C(_z+]K`  
} OA8b_k~  
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%l]rQjV-  
/* G+\~rl  
**Utility.java !]jNVg  
*/ * zJiii  
package NetFox; M%Kx{*aw&  
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public class Utility { S|u1QGB  
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V
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public Utility() xVwi }jtG|  
{ cvLcre% >A  
4)>\rqF+v  
*M**h-p2'  
} \VhpB   
ah&plaVzC  
//线程睡眠 "351s3ff  
public static void sleep(int nSecond) ]aMa*fF  
{ ~]t2?SqNm  
try{ BzG!Rg|J  
Thread.sleep(nSecond); `- uZv  
} (^@;`8Dy8  
catch(Exception e) uBL~AC3>O  
{ xr7<(:d  
e.printStackTrace ();
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} y0mg}N1  
} *MyS7<  
vng8{Mx90*  
//日志 >=q!!'$:  
public static void log(String sMsg) 6[Pr<4J  
{ %_X[{(  
System.err.println(sMsg); =w>>7u$4  
} @0@'6J04  
iRr&'k  
J Wyoh|  
public static void log(int sMsg) ] !*  
{ Zv7$epDUz  
System.err.println(sMsg); TYLl_nGr  
} T;pn -  
} snk{u/0Xm  
KX`nHu;  
7!Q
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/* ~>-;(YU"t  
**TestMethod.java #p9z#kin  
*/ MH~qfH>K  
package NetFox; `?S?)0B  
5t1DB'K9$_  
B[m{2XzGH  
public class TestMethod { )^'B:ic  
moM&2rgdrQ  
_/w-gL{  
public TestMethod() b+#~N>|  
{ ///xx/weblogic60b2_win.exe @^4M~F%  
try{ }T*xT>p^3  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); W;@ae,^  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); R8W44I*R:  
SiteFileFetch fileFetch = new SiteFileFetch(bean); l$_+WC*wp  
fileFetch.start(); l?<z1Acd&  
} w!9WCl]9M  
catch(Exception e){e.printStackTrace ();} PHL@1K{)  
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>yHnz?bf@  
} !?-5hh1\  
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DO,&Foh\  
public static void main(String[] args) S/:QVs  
{ s/&]gj"  
new TestMethod(); &^D@(m7>{K  
} ~E|V{z%  
} G78j$ ^/0  
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