http断点续传简单实现（java)

/* /g/]Q^  
**SiteFileFetch.java J,iS<lV_  
*/ 6,wi81F,}  
package NetFox; 2IfcdYG  
import java.io.*; 0d>|2QV   
import java.net.*; {KQ-QKxxS  
>:o$h2  
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public class SiteFileFetch extends Thread { I/2{I  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 5 [GdFd>{  
long[] nStartPos; //开始位置 n["G ry  
long[] nEndPos; //结束位置 o >wty3l:  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 A9 *P7  
long nFileLength; //文件长度 :.
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boolean bFirst = true; //是否第一次取文件 2:5Go  
boolean bStop = false; //停止标志
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File tmpFile; //文件下载的临时信息 >X@4wP7l  
DataOutputStream output; //输出到文件的输出流 Nm{+!}cC  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 7)RDu,fx  
public SiteFileFetch(SiteInfoBean bean) throws IOException \wZ 4enm  
{ D02'P{  
siteInfoBean = bean; YCPU84f  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); hwx1fpo4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); SEKR`2Zz,  
if(tmpFile.exists ()) 2ezk<R5q+  
{ nYsB^Nr6
 
bFirst = false; /Fr*k5I  
read_nPos(); et`1#_o  
} v[Mh[CyB  
else i'cGB5-j  
{ Oj=g;iY  
nStartPos = new long[bean.getNSplitter()]; wZUZ"Y}9  
nEndPos = new long[bean.getNSplitter()]; $.Ia;YBf  
} G;ihm$Cad  
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} R$Rub/b6  
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public void run() "g
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{ y&n-8L_  
//获得文件长度 5)c B\N1u  
//分割文件 Lo<WK  
//实例FileSplitterFetch ?]%ZJd  
//启动FileSplitterFetch线程 >b7Yk)[%  
//等待子线程返回 xe4`D>LUo  
try{ m2a[E0  
if(bFirst) ZGw6Bd_I  
{ +B '<0  
nFileLength = getFileSize(); X:#}E7]j  
if(nFileLength == -1) {^@vCBE+  
{ 6:Hd`  
System.err.println("File Length is not known!"); %zKTrsMZ  
} `_iK`^(-  
else if(nFileLength == -2) " k0gZb  
{ Y=?Tm,z4  
System.err.println("File is not access!"); ]\1H=g%Ou  
} lNLa:j  
else Qef5eih  
{ M7fPaJKL  
for(int i=0;i<nStartPos.length;i++) 6vfut$)[{  
{ {1"kZL  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); u0Bz]Ux/Q  
} `t7z LC^c  
for(int i=0;i<nEndPos.length-1;i++) K_Pbzj4(P  
{ :u,Ji9 u  
nEndPos = nStartPos[i+1]; h1~/zM/`  
} &c^tJ-s  
nEndPos[nEndPos.length-1] = nFileLength; \zJb}NbnT  
} ms&6N']  
} .~a.mT  
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//启动子线程 3dx.%~c  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; WCYVonbg"  
for(int i=0;i<nStartPos.length;i++) *qA:%m3  
{ <lZVEg  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), w5+(A_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), :sS4T&@1=  
nStartPos,nEndPos,i); Z5V_?bm$  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); a"{b}UP  
fileSplitterFetch.start(); OI,F,4e  
} ok1w4#%,  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _G$21
=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); J1R5_b  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", WR9-HPF  
nEndPos = " + nFileLength); }vb.>hy  
// fileSplitterFetch[nPos.length-1].start(); z%;_h-  
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//等待子线程结束 GP(nb,  
//int count = 0; 65vsQ|Zw  
//是否结束while循环 7*kTu0m  
boolean breakWhile = false; Hf+oG  
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while(!bStop) Y%!k'\n[2  
{ {
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write_nPos(); L0R$T=~%)  
Utility.sleep(500); %KPQ|^WE  
breakWhile = true; F@KtRUxE  
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for(int i=0;i<nStartPos.length;i++) !ir%Pz^)  
{ Elt"tJ  
if(!fileSplitterFetch.bDownOver) \8)FVpS  
{ q26qY5D  
breakWhile = false; /&E]qc*-p  
break; k/M{2Po+
 
} R"{P#U,HNO  
} !iL6/  
if(breakWhile) YB_fy8Tfx  
break; h%5keiA  
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//count++; \"X_zM  
//if(count>4) 09=w  
// siteStop(); Ih[k{p  
} ltv~Kh  
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System.err.println("文件下载结束！"); s)+] pxV0-  
} e35")z~  
catch(Exception e){e.printStackTrace ();} Q$5%9  
} 4WPco"xH!  
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//获得文件长度 wjTW{Bg~G  
public long getFileSize() ^[6#Kw&E  
{ (ylZ[M&B:  
int nFileLength = -1; %"ehZd0r  
try{ {5 3#Xd  
URL url = new URL(siteInfoBean.getSSiteURL()); vcZ"4%w  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @W=:r/  
httpConnection.setRequestProperty("User-Agent","NetFox"); I5]58Ohx  
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int responseCode=httpConnection.getResponseCode(); ;<=z^1X9  
if(responseCode>=400) BnG{)\s  
{ d>0 j!+s  
processErrorCode(responseCode); HP=5a.  
return -2; //-2 represent access is error 4O4}C#6(4  
} )"g @"LJ=  
8
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String sHeader; t1p[!53(  
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for(int i=1;;i++) 6ZQ$5PY  
{ D77$aCt  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); P)[QC  
//Utility.log(in.readLine()); ^vZu[m  
sHeader=httpConnection.getHeaderFieldKey(i); (hIe!"s*  
if(sHeader!=null) >}r 1A  
{ lr[&*v?h  
if(sHeader.equals("Content-Length")) S-79
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{ (\4YBaGd  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); /S9n!H:MT  
break; &-KQ m20n  
} `a8&7J(  
} 91ec^g  
else y(j vl|z[  
break; ,w,)n^  
} +$R%Vbd  
} 6-\C?w A  
catch(IOException e){e.printStackTrace ();} N::.o+1  
catch(Exception e){e.printStackTrace ();} UdFYG^i  
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Utility.log(nFileLength); [bEm D  
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return nFileLength; MNX-D0`g  
} 6W'2w?qj?4  
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//保存下载信息（文件指针位置）  W|6.gN]  
private void write_nPos() lAAPV  
{ bQwiJ`B&  
try{ \V*E:_w*  
output = new DataOutputStream(new FileOutputStream(tmpFile)); wEEFpn_   
output.writeInt(nStartPos.length); >+S* Wtm5  
for(int i=0;i<nStartPos.length;i++) % %QAC4  
{ Ws[d.El  
// output.writeLong(nPos); _m1WY7
  
output.writeLong(fileSplitterFetch.nStartPos); X'5+)dj  
output.writeLong(fileSplitterFetch.nEndPos); u2 U4MV1C  
} 7T?7KS  
output.close(); P#2;1ki>  
} EU()Nnm2  
catch(IOException e){e.printStackTrace ();} ?D]T|=EZY  
catch(Exception e){e.printStackTrace ();} Of{'A  
} cWa>rUsF  
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//读取保存的下载信息（文件指针位置） ]K%D$x{+\  
private void read_nPos() Ay\!ohIS3  
{ _1?Fyu&<5  
try{ mGUl/.;yp-  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); #J4,mFMr  
int nCount = input.readInt(); =_d-MJy~6  
nStartPos = new long[nCount]; C5oIl_t  
nEndPos = new long[nCount]; :w4I+*]  
for(int i=0;i<nStartPos.length;i++) =Y5*J#  
{ .w)T2(  
nStartPos = input.readLong(); 1;9 %L@  
nEndPos = input.readLong(); CYC6:g|)  
} Oxf,2r  
input.close(); qzu%Pp6If  
} }u'O<d~z?  
catch(IOException e){e.printStackTrace ();} l7GLN1#m  
catch(Exception e){e.printStackTrace ();} ^i~'aq  
} (9D,Ukw  
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private void processErrorCode(int nErrorCode) _xXDvBU  
{ jz$83TB-  
System.err.println("Error Code : " + nErrorCode); |p+ xM  
} c
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"zN]gz=OV>  
//停止文件下载 )IZ~!N|-w  
public void siteStop() [es-&X07<  
{ yO09NQ 5u  
bStop = true;
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for(int i=0;i<nStartPos.length;i++) 5P < F  
fileSplitterFetch.splitterStop(); !yX4#J(  
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} ppM^&6x^  
} '^.}5be&  
//负责部分文件的抓取 ic|>JX$G  
**FileSplitterFetch.java }g[(h=Qi  
*/ #oD*H:%*  
package NetFox; ^k}jPc6  
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import java.io.*; {!vz 6QDS  
import java.net.*; w`OHNwXh#I  
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public class FileSplitterFetch extends Thread { kP}91kja  
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String sURL; //File URL awa$o  
long nStartPos; //File Snippet Start Position >P\/\xL=  
long nEndPos; //File Snippet End Position kzLtI w&.  
int nThreadID; //Thread's ID %z:;t  
boolean bDownOver = false; //Downing is over [Lo}_v&  
boolean bStop = false; //Stop identical rhe;j//`  
FileAccessI fileAccessI = null; //File Access interface c\pPwG  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException i&?do{YQ)  
{ &4O0}ax*Zm  
this.sURL = sURL;
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this.nStartPos = nStart; :V#W y  
this.nEndPos = nEnd; *n%J#[e(  
nThreadID = id; P9D'L{yS/x  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ?#917M  
} ;1 02ddRV  
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public void run() SggS8$
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{ fX2PteA0qX  
while(nStartPos < nEndPos && !bStop) S?_ ;$Cn  
{ OVm $  
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try{ pB;p\9A*q  
URL url = new URL(sURL); L?n*b  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <ctn_"p Z  
httpConnection.setRequestProperty("User-Agent","NetFox");
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String sProperty = "bytes="+nStartPos+"-"; If_S_A c  
httpConnection.setRequestProperty("RANGE",sProperty); nP>*0Fq  
Utility.log(sProperty); >K9uwUi|b]  
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bu#}`/\_  
InputStream input = httpConnection.getInputStream(); 7=ZB?@bU~  
//logResponseHead(httpConnection); @u2nG:FG  
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byte[] b = new byte[1024]; ivbuS-f=r  
int nRead; O`hOVH
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) jo4*,B1x  
{ _KkLH\1g$  
nStartPos += fileAccessI.write(b,0,nRead); 2|)3Ly9  
//if(nThreadID == 1) ~a5p_xP  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =,~h]_\_  
} :,=no>mMx  
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Utility.log("Thread " + nThreadID + " is over!"); )vK %LmP  
bDownOver = true; 8]N+V:  
//nPos = fileAccessI.write (b,0,nRead); B{SzC=4f}  
} RYaf{i`  
catch(Exception e){e.printStackTrace ();} 8JUUK(&Z  
} V(Ps6jR"BS  
} rQbL
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4l$(#NB<  
//打印回应的头信息 HhaUC?JtSK  
public void logResponseHead(HttpURLConnection con) |Y!#`  
{ _e=R[  
for(int i=1;;i++) tw]RH(g+#  
{ Q-
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String header=con.getHeaderFieldKey(i); ^Q]*CU+C  
if(header!=null) s45Y8!c  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Yo c N
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Utility.log(header+" : "+con.getHeaderField(header)); #s1O(rLRl  
else vvLm9T
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break; Poacd;*  
} rs3Uk.Z^'  
} M? oK@i  

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public void splitterStop() W$0<a@
 
{ fi%u]  
bStop = true; 6v0^'}  
} OZ1+`4 v  
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} ZgLO[Bj  
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/*
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**FileAccess.java 0}c*u) ,  
*//文件访问(定位，写) l/_3H\iM  
package NetFox; Xz0jjO,  
import java.io.*; 0CxQ@~ttl  
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#:Di1I9<O7  
public class FileAccessI implements Serializable{ dfe 9)m>  
hq/\'Z&!+P  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 pK#Ze/!  
RandomAccessFile oSavedFile; d+%1q
 
long nPos; hNXPm~O
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public FileAccessI() throws IOException /J8AnA1  
{ 86~HkHliv  
this("",0); /!UuGm  
} phUno2fH  
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}.7!@!q.  
public FileAccessI(String sName,long nPos) throws IOException 0%}$@H5i  
{ ,*r"cmz  
oSavedFile = new RandomAccessFile(sName,"rw"); tq?lF$mM:  
this.nPos = nPos; BSG_),AH  
oSavedFile.seek(nPos); L*9^-,  
} n6[bF"v  
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public synchronized int write(byte[] b,int nStart,int nLen) tn;e PcU  
{ 8UoMOeI3  
int n = -1; cn=~}T@~Z  
try{ l2=.;7IV  
oSavedFile.write(b,nStart,nLen); 3~BL!e,  
n = nLen; }#q9>
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} -[v:1\Vv  
catch(IOException e) O1coay  
{  "=H7p3  
e.printStackTrace (); #;a 1=8H  
} UKQ,]VC  
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return n; M'W@K  
} ,>2ijk#  
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} |v}"UW(y  
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/* 9">}@1k  
**SiteInfoBean.java RM-|?%  
*/ NyJU?^f&v  
package NetFox; Q}W6?XDu  
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public class SiteInfoBean { =XJ SE+ 7  
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private String sSiteURL; //Site's URL 75@){ :  
private String sFilePath; //Saved File's Path !~m)_Q5?~  
private String sFileName; //Saved File's Name tk<dp7y7  
private int nSplitter; //Count of Splited Downloading File ]OM|O
o  
06pLa3oi  
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public SiteInfoBean() c&3 ]%urL  
{//nSplitter的缺省值为5 ,2[laJ  
//default value of nSplitter is 5 u1ggLH!U  
this("","","",5); RERum  
} zVZZdG~8  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) n%3rv?m7  
{ /P5w}n  
sSiteURL= sURL; a =*(>=  
sFilePath = sPath; NUEy0pLw  
sFileName = sName; OTL=(k  
this.nSplitter = nSpiltter; {~k/xM.-  
m7^aa@^m  
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} $=4T# W=m  
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PNd]Xmv)  
public String getSSiteURL() CwTx7 ^qa  
{ <O?iJ=$  
return sSiteURL; ZBcZG  
} 26yv w  
@ _U]U  
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public void setSSiteURL(String value) Iujly f  
{ ?a7PxD.  
sSiteURL = value; n wToZxHZ~  
} *&+e2itm
p  
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public String getSFilePath() |zKe*H/  
{ 4Ucg<Z&%  
return sFilePath;
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} '49&qO5B  
7qA0bUee5  
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public void setSFilePath(String value) 1<fS&)^W  
{ y!6B Gz  
sFilePath = value; ANc)igo  
} kTAb <  
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public String getSFileName() JWr:/?  
{ bA@!0,m  
return sFileName; tU>wRw=
d  
} CuR\JKdRo  
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public void setSFileName(String value) ;RflzY|D  
{ :`2<SF^0O  
sFileName = value; A)kx,,[  
} ]U!vZY@\  
1Zx|
SBF  
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public int getNSplitter() \-0@9E<D  
{ `L`qR,R  
return nSplitter; Ah;2\0|t  
} ^G[xQcM73  
-X'HZ\)  
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public void setNSplitter(int nCount) `ky< *  
{ %2f``48#  
nSplitter = nCount; R5g-b2Lm  
} K19/M1~  
} h8Q+fHDYv  
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/* 8;ke,x  
**Utility.java S(
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*/ iE=Yh  
package NetFox; =<e|<EwSZ  
(wEaa'XL  
%%`Nq&'  
public class Utility { #:s*)(Qn  
[4"1TyW  
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public Utility() AqB5B5}  
{ SG_
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} = I,O+^  
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//线程睡眠 B]L5K~d  
public static void sleep(int nSecond) U&y
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{
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try{ 1uZ[Ewl]  
Thread.sleep(nSecond); (MY#;v\AYE  
} n1m[7s.[&  
catch(Exception e) FB9PIsFS  
{ /vll*}}  
e.printStackTrace (); 1 0lvhzU  
} L6./b;  
} |iKk'Rta4  
(9% ki$=}+  
//日志 bXF>{%(}E  
public static void log(String sMsg) Oi AZA<  
{ -$**/~0zU  
System.err.println(sMsg); @X4Ur+d  
} a yn6k=F  
\ T/i]z  
nDuf<mw  
public static void log(int sMsg) ^E\{&kaUp  
{ <nlZ?~
%}  
System.err.println(sMsg); _BO:~x  
} LSQWveZz  
} 59!yz'feF  
t~ruP',~\  
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/* zI$^yk-vn  
**TestMethod.java &E0L7?l  
*/ T]Z|Wq`bot  
package NetFox; s:3 altv  
#"-?+F=rk  
5Ds/^fA  
public class TestMethod { 0D/u`-  
(|)`~z  
("Z;)s4q  
public TestMethod() s0uI;WMg  
{ ///xx/weblogic60b2_win.exe SF$7WG3Q  
try{ >$SP2(Y~  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); IROX]f}r(  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 4)0 %^\p  
SiteFileFetch fileFetch = new SiteFileFetch(bean); QEKSbxL\W  
fileFetch.start(); d~F`q7F'?]  
} ^`~M f  
catch(Exception e){e.printStackTrace ();} _;(`u!@/{  
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} A'r 3%mC  
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public static void main(String[] args) M4 SJnE  
{ Cw42bO  
new TestMethod(); 7K.&zn  
} J!5BH2bg  
} U/F<r3.`#  
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