http断点续传简单实现（java)

/* ",vK~m2W_  
**SiteFileFetch.java
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*/ Cd=$XJ-b  
package NetFox; 7}~w9jK"F  
import java.io.*; [ 't.x=  
import java.net.*; yhbU;qEG9  
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public class SiteFileFetch extends Thread { N[\J#x!U  
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SiteInfoBean siteInfoBean = null; //文件信息Bean :Z2997@Y  
long[] nStartPos; //开始位置 lN:;~;z_  
long[] nEndPos; //结束位置 3
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 ;n*|AL7(  
long nFileLength; //文件长度 sF[gjeIb  
boolean bFirst = true; //是否第一次取文件 G'}N?8s1  
boolean bStop = false; //停止标志 D84&=EpVZ  
File tmpFile; //文件下载的临时信息 Q4LPi;{\  
DataOutputStream output; //输出到文件的输出流 YG8C<g6E7  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） [:gg3Qzx  
public SiteFileFetch(SiteInfoBean bean) throws IOException {5X,xdzR  
{ _4L6  
siteInfoBean = bean; 5fiWo^s}  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath()));
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); [ei~Xkzkj  
if(tmpFile.exists ()) uI?Z_  
{ sU*?H`U3d  
bFirst = false;
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read_nPos(); 4TPdq&';C:  
} Op]*wwI*h  
else m>P\}A^N  
{ 9{Etv w  
nStartPos = new long[bean.getNSplitter()]; RC1bTM  
nEndPos = new long[bean.getNSplitter()];
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} ] L#c <0  
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} D^m2iW;  
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public void run() sK+uwt  
{ XLaD#J  
//获得文件长度 ~BuBma_  
//分割文件 2Ah
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//实例FileSplitterFetch &
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//启动FileSplitterFetch线程 wn.6l `  
//等待子线程返回 u*=^>LD  
try{ kw2yb   
if(bFirst) M$@~|pQ<  
{ 5m0lk|`  
nFileLength = getFileSize(); 1~~GF_l?  
if(nFileLength == -1) =_C&lc"  
{ 5j]!r  
System.err.println("File Length is not known!"); pQ0*)}l,  
} U*Y]cohh  
else if(nFileLength == -2) 2/V%jS[4#y  
{ *aM7d>nG5  
System.err.println("File is not access!"); Zv9JkY=+@  
} 0%L:jq{5  
else @M<qz\ [  
{ =6:9y}~  
for(int i=0;i<nStartPos.length;i++) y6d!?M(0U  
{ YzG?K0O%  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); \WC,iA%Y  
} +CdUr~6  
for(int i=0;i<nEndPos.length-1;i++) e_|<tYx><  
{ (T pnJq  
nEndPos = nStartPos[i+1]; fu~iF  
} :fL7"\ pf~  
nEndPos[nEndPos.length-1] = nFileLength; K.wRz/M&g  
} zGg)R  
} >5kz#|@P  
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//启动子线程 G,?a8(  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; A_U=`M=-  
for(int i=0;i<nStartPos.length;i++) XtZd% #2},  
{ ibQ xL3  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +kYp!00  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ]k]bLyz\J  
nStartPos,nEndPos,i); B1~`*~@  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); K*DH_\SPK  
fileSplitterFetch.start(); \ Xh C  
} Ekq(  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "k@[7 7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Pi?G:IF  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", U7n#TPet  
nEndPos = " + nFileLength); +3zQ"lLD^  
// fileSplitterFetch[nPos.length-1].start(); [DeDU:  
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//等待子线程结束 B%Qo6*b  
//int count = 0; EU:N9oT  
//是否结束while循环 ub>:dNBN  
boolean breakWhile = false; >/4[OPB0R  
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while(!bStop) 0F- +)S?M[  
{ Uq'W<.v5  
write_nPos(); S{e3aqT#N  
Utility.sleep(500); 9<3}zwJ  
breakWhile = true; wt
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for(int i=0;i<nStartPos.length;i++) Gchs$^1`t  
{ ;Krs*3 s  
if(!fileSplitterFetch.bDownOver) :PN%'~}n  
{ Q~wS2f`)  
breakWhile = false; QbHX
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break; 9QHj$)?k,  
} yZp/P%y  
} MLTS<pW/  
if(breakWhile) GQYn |vm  
break; |+HJ>xA4I  
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//count++; EMr|#}]#s  
//if(count>4) 1@'I eywg  
// siteStop(); <Bn0wr8)\  
} /t]1_  
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System.err.println("文件下载结束！"); 7n8
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} 4,:I{P_>6B  
catch(Exception e){e.printStackTrace ();} Y&,}q_Z:  
} 1CZO+MB&"$  
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//获得文件长度 +\ "NPK@3  
public long getFileSize() Ue;Z)}  
{ (r?hD*2r  
int nFileLength = -1; G+2fmVB*X  
try{ > fV"bj.  
URL url = new URL(siteInfoBean.getSSiteURL()); 7O|`\&RYR  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); F%lC%~-qh  
httpConnection.setRequestProperty("User-Agent","NetFox"); f &NX
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int responseCode=httpConnection.getResponseCode(); q!U$\Q&  
if(responseCode>=400) K>~YO~~  
{ kUGFg{"  
processErrorCode(responseCode); GL9'dL|  
return -2; //-2 represent access is error d#d&CJAfr  
} Z6Mjc/  
( 6zu*H)  
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String sHeader; havmhS)O  
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for(int i=1;;i++) eF7I5k4  
{
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); wS,fj gX  
//Utility.log(in.readLine()); 7
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sHeader=httpConnection.getHeaderFieldKey(i); ~$^>Vo  
if(sHeader!=null) c}S<<LR  
{ +C7W2!I[G2  
if(sHeader.equals("Content-Length")) jbZTlG  
{ I~~":~&  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); dJrUcZBr  
break; CflyK@  
} 6Ktq7'Z@  
} bnvY2-O6  
else 1D[>oK\  
break; 8"d??3ZXJ  
} kQ&Q_FSO  
} 54WX#/<Yik  
catch(IOException e){e.printStackTrace ();} ,S(Z\[x0  
catch(Exception e){e.printStackTrace ();} Hq>hnCT  
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Utility.log(nFileLength); v \;/P  
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return nFileLength; Bnwq!i!M  
} |Axbx?  
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//保存下载信息（文件指针位置） RiQg]3oY  
private void write_nPos() /|&4&$  
{ >tMI%r  
try{ 4|Y1W}!0/  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 1Lje.%(E.  
output.writeInt(nStartPos.length); t(6i4c>  
for(int i=0;i<nStartPos.length;i++) wRK27=\z  
{ |${ImP  
// output.writeLong(nPos); :6(@P1vA 6  
output.writeLong(fileSplitterFetch.nStartPos); Cq<Lj  
output.writeLong(fileSplitterFetch.nEndPos); &'Nzw2  
} T]/>c  
output.close(); Ax=)J{4v  
} }z9v*C  
catch(IOException e){e.printStackTrace ();} F+BCzsm7$  
catch(Exception e){e.printStackTrace ();} @}PX:*c  
} :YkAp9civ  
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//读取保存的下载信息（文件指针位置） G[u6X_Q  
private void read_nPos() yEh{9S%6p  
{ ndN*X'  
try{ >hG*=4oh  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); hiV!/}'7  
int nCount = input.readInt(); GCr]x '  
nStartPos = new long[nCount]; n?D/bXp  
nEndPos = new long[nCount]; X$Q.A^9  
for(int i=0;i<nStartPos.length;i++) %`]!atH  
{ Y+g(aak+.  
nStartPos = input.readLong(); WLVkrTvX  
nEndPos = input.readLong(); >P}XCAU  
} <RC%<  
input.close(); rhaq!s38:  
} hc0$mit  
catch(IOException e){e.printStackTrace ();} #E\6:UnT  
catch(Exception e){e.printStackTrace ();} %8Y+Df;ax  
} 5{DwD{Q  
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private void processErrorCode(int nErrorCode) - 3PLP$P  
{ d9jD?HgM(  
System.err.println("Error Code : " + nErrorCode); sy4Nm0m  
} ld({1jpX,  
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//停止文件下载 l(F\5Ys  
public void siteStop() O<@L~S]  
{
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bStop = true; c3#eL  
for(int i=0;i<nStartPos.length;i++) grkA2%N  
fileSplitterFetch.splitterStop(); 6;!)^b  
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} .rwW5"RPq  
} Nq9M$Nt]  
//负责部分文件的抓取 6r@>n_6LY  
**FileSplitterFetch.java EASmB  
*/ ; 5[W*,7s  
package NetFox; ^liW*F"UY  
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import java.io.*; (ToD u@p  
import java.net.*; ]WcN6|b+  
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public class FileSplitterFetch extends Thread { )^6Os2  
{;u+?uY  
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String sURL; //File URL fsnZHL}=n  
long nStartPos; //File Snippet Start Position HmU6:8V *Z  
long nEndPos; //File Snippet End Position #D{Eq8dp  
int nThreadID; //Thread's ID +`V<& Y-5l  
boolean bDownOver = false; //Downing is over '+g[n  
boolean bStop = false; //Stop identical v*As:;D_  
FileAccessI fileAccessI = null; //File Access interface suLC7x`Z  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException BOy&3.h5?  
{ ;qWSfCt/^  
this.sURL = sURL; tgl 4pAc  
this.nStartPos = nStart; k w   
this.nEndPos = nEnd; x7i<dg&  
nThreadID = id; BE~-0g$W  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _]D 6m2R  
} R(P(G;#j  
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public void run() Sx0{]1J  
{ yn<J>e  
while(nStartPos < nEndPos && !bStop) j]R[;8g  
{ Q^05n$ tI  
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try{ $o
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URL url = new URL(sURL); w2('75$J  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); UH\{:@GjNO  
httpConnection.setRequestProperty("User-Agent","NetFox"); VUHf-bKl  
String sProperty = "bytes="+nStartPos+"-"; B J IN  
httpConnection.setRequestProperty("RANGE",sProperty); 7#
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Utility.log(sProperty); EymSrZw  
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InputStream input = httpConnection.getInputStream(); vW?/:  
//logResponseHead(httpConnection); Y}Y~?kE>M|  
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byte[] b = new byte[1024]; 9v3n4=gc  
int nRead; 7kT X  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) tuuwoiQ*`  
{ Gui[/iY,F  
nStartPos += fileAccessI.write(b,0,nRead); `f~$h?}3-@  
//if(nThreadID == 1) Lz:FR*  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); YH^@8   
} EQ
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dI
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Utility.log("Thread " + nThreadID + " is over!"); pm:-E(3#  
bDownOver = true; Bm%|W
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//nPos = fileAccessI.write (b,0,nRead); lq,]E/<&  
} kDM?`(r  
catch(Exception e){e.printStackTrace ();} U&a(WQV9&  
} ~.0'v [N  
} '^[+]
  
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//打印回应的头信息 +KNd%AJ  
public void logResponseHead(HttpURLConnection con) EdSUBoWF}  
{ qZ@d:u  
for(int i=1;;i++) mieyL9*n7  
{ "^wIoJ6H'  
String header=con.getHeaderFieldKey(i); I,)\506  
if(header!=null) oK4xRv8Hd  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ^}wF^ _  
Utility.log(header+" : "+con.getHeaderField(header)); $4)L~g|  
else r=AA /n<  
break; hk S:_e=  
} UTN[!0[  
} .P?n<n#  
g)|vS>^~  
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public void splitterStop() 9e vQQN6D|  
{ )N1iGJO)  
bStop = true; v'^}zO  
} Sl<1Rme=w  
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}#g+~9UK  
} X-TGrdoX  
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/* D.x8=|;  
**FileAccess.java gNA!)}m\  
*//文件访问(定位，写) unbIfl=  
package NetFox; p0]\QM l1  
import java.io.*; :)tsz;  
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public class FileAccessI implements Serializable{ ^=1u2YdVw  
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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 LEOa=(mN\  
RandomAccessFile oSavedFile; l+hOD{F4pS  
long nPos; Em5,Zr_  
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public FileAccessI() throws IOException kp}[nehF  
{ khD)x0'b  
this("",0); g#7Q-n3^  
} }&2,!;"">3  
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public FileAccessI(String sName,long nPos) throws IOException uwZ,l-6T  
{ <o*b6m%  
oSavedFile = new RandomAccessFile(sName,"rw"); 6-J}ZfGj  
this.nPos = nPos; y'>JT/Q5  
oSavedFile.seek(nPos); 6%>'n?  
} 6?C';1  
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public synchronized int write(byte[] b,int nStart,int nLen) V|}9bNF  
{ iSW<7pNq0  
int n = -1; ^yq}>_  
try{ vNl)ltzJF  
oSavedFile.write(b,nStart,nLen);
dga4|7-MY  
n = nLen; o76!
7  
} kN8B,  
catch(IOException e) ?TK`sGy  
{ X!'C'3X  
e.printStackTrace (); {&B_b|g*fW  
} )|k#cT{=M  
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return n; w%\{4T~  
} DG0I-"s  
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} Y Q.Xl_  
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/* |0}7/^  
**SiteInfoBean.java WVOj;c  
*/ %iEdUV\$  
package NetFox; NqNU:_}  
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public class SiteInfoBean { k`|E&+
og  
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#  
private String sSiteURL; //Site's URL : xg
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private String sFilePath; //Saved File's Path DLqH*U  
private String sFileName; //Saved File's Name Vw
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private int nSplitter; //Count of Splited Downloading File bDJ!Fc/  
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public SiteInfoBean() 5y\35kT'  
{//nSplitter的缺省值为5 7Hgn/b[?b  
//default value of nSplitter is 5 rwP)TJh"  
this("","","",5); % -AcA  
} wQjYH!u,YZ  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) I2*(v%.-  
{ {f)aFGp  
sSiteURL= sURL; Kl%[fjI)  
sFilePath = sPath; dg|x(p#  
sFileName = sName; SOM? 0.  
this.nSplitter = nSpiltter; T#E$sZ  
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} i$@xb_  
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public String getSSiteURL() E QU@';~8  
{ fDplYn#  
return sSiteURL; *ls6k`ymL  
} x>TIx[x  
}5(_gYr  
I *sT*;U  
public void setSSiteURL(String value) 8Q<Nl=g>'  
{ R%\3
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sSiteURL = value; -Fn/=  
} '/9j"mIA9$  
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public String getSFilePath() gT$WG$^i  
{ FK~wr;[  
return sFilePath; b|DU  
} Sk!' 2y*@&  
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public void setSFilePath(String value) 24? _k]Y  
{ FZ+2{wIV^  
sFilePath = value; W,Q>3y
*
 
}  aY(s &  
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public String getSFileName() iv6G9e{cx  
{ gWa0x-  
return sFileName; jy5[K.  
} %H"  
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public void setSFileName(String value) h'=)dFw7  
{ { >izfG,\  
sFileName = value; \i//Aq  
} y'odn;  
mhhc}dS(H  
8~-TN1H  
public int getNSplitter() 3))R91I  
{ )^s>21  
return nSplitter; ;7?oJH;  
} H,w8+vZ4\  
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public void setNSplitter(int nCount) $fD%18  
{ hp2E! Cma  
nSplitter = nCount; ^" g?m  
} mIYKzu_k=  
} OhCdBO  
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+[uh);vD`G  
/* 1 Vt,5o5  
**Utility.java >h#juO
"  
*/ mkyYs[  
package NetFox; EHn!ZrQgh  
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public class Utility { >TCit1yD  
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public Utility() E.NfVeq  
{ l{C]0^6>i  
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} C za}cF  
y|MhV/P04  
//线程睡眠 VpHwc!APq  
public static void sleep(int nSecond) DGCvH)Q  
{ ((`{-y\K  
try{ e#h&Xa  
Thread.sleep(nSecond); P(7el  
} Qfy_@w]  
catch(Exception e) z,m3U(  
{ _oBx:G6E  
e.printStackTrace (); ]] 0M  
} 86-Rm  
} ?r&~(<^z  
r5hkxk'  
//日志 M\CzV$\y  
public static void log(String sMsg) FO_}9<s  
{ z5iC
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System.err.println(sMsg); lN5PKsGl  
} leNX5 sX  
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}[PwA[k'  
public static void log(int sMsg) [3-u7Fx!  
{ .Er+*j;&w  
System.err.println(sMsg); ETL7|C"  
} (9aOET>GG  
} 3Q62H+MC  
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/* <HRPloVKo  
**TestMethod.java ,{q#U3  
*/ 0.R3(O  
package NetFox; &XC
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U ^O4HJ  
public class TestMethod { 2Q@na@s  
wn_ >Vi1  
fuA] y4A  
public TestMethod() 9x4z m  
{ ///xx/weblogic60b2_win.exe ivl %%nY'  
try{ $04lL/;  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); }\8-&VoY#X  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 6o6yx:  
SiteFileFetch fileFetch = new SiteFileFetch(bean); fI0"#iv}  
fileFetch.start(); (NR( )2  
} `&fW<5-  
catch(Exception e){e.printStackTrace ();} =d5;F`m  
B:v_5e\f@  
!F}GSDDV*  
} ?F[_5ls|]  
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public static void main(String[] args) X!z-J>  
{ ~1*37w~  
new TestMethod(); |*zgX]-+;  
} #M w70@6  
} r]\[G6mE%  
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