http断点续传简单实现（java)

/* 9v2(cpZ  
**SiteFileFetch.java .
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*/ !agtgS$qII  
package NetFox;
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import java.io.*; gUq)M  
import java.net.*; >5|;8v-r  
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public class SiteFileFetch extends Thread { rH<iUiA?O  
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SiteInfoBean siteInfoBean = null; //文件信息Bean !Ci\Zg  
long[] nStartPos; //开始位置 [!v| M  
long[] nEndPos; //结束位置 cLD
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 i%R2#F7I  
long nFileLength; //文件长度 :8<\]}J  
boolean bFirst = true; //是否第一次取文件 U.@j!UrZ  
boolean bStop = false; //停止标志 yfD)|lK  
File tmpFile; //文件下载的临时信息 G2x5%`   
DataOutputStream output; //输出到文件的输出流  xedbr  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） bof{R{3q  
public SiteFileFetch(SiteInfoBean bean) throws IOException cP~?Iz8nD  
{ 1jhGshhp  
siteInfoBean = bean; 1K;i/  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); |F'k5Lh  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 1wqsGad+;  
if(tmpFile.exists ()) |5}~n"R5  
{ r|WoM39bp  
bFirst = false; 0*.> >rI  
read_nPos(); N!e?K=}tL  
} Dl#%tYL+3h  
else Odo"S;)  
{ -;?5<>zZ  
nStartPos = new long[bean.getNSplitter()]; w]{NaNIeq1  
nEndPos = new long[bean.getNSplitter()]; FB0y  
} I2!0,1Q  
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} ?CQ\94kO  
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public void run() fQ
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{ 3}H"(5dL}z  
//获得文件长度 FJN,er~T[  
//分割文件 !
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//实例FileSplitterFetch kd9GHN;7  
//启动FileSplitterFetch线程 G
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//等待子线程返回 RPvOup  
try{ !@_( W  
if(bFirst) jG3}V3|.  
{ at/v.U|F  
nFileLength = getFileSize(); "=unDpq]  
if(nFileLength == -1) lxRzyx  
{ FRicHs n  
System.err.println("File Length is not known!"); ;n*N9-|.  
} O/IW.t  
else if(nFileLength == -2) H>-?/H  
{ {V!Jj6n  
System.err.println("File is not access!"); ({cgak  
} "mAVkq~  
else m
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{ ,uD>.->  
for(int i=0;i<nStartPos.length;i++) 2&W(@wT$  
{ c?0uv2*Yh  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 3986;>v  
} yiUJ!m  
for(int i=0;i<nEndPos.length-1;i++) 2O|o%`?  
{ FxKb  
nEndPos = nStartPos[i+1]; G6zFCgFJ^y  
} gz[Ng> D+  
nEndPos[nEndPos.length-1] = nFileLength; [|2uu."$  
} @NXGVmY1}  
} BEM+FG  
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//启动子线程 XHO}(!l\  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; _9Kdcoh  
for(int i=0;i<nStartPos.length;i++) hnM|=[wM  
{ ]t|KFk!)  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), oy'Q#!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), -/aDq?<<  
nStartPos,nEndPos,i); /h0<0b?i  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kRgyvA,*;  
fileSplitterFetch.start(); %HuQc^  
} _[V.%k  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Uq/(xh,t5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 4];Qpln  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", x#e(&OjN7  
nEndPos = " + nFileLength); Y9m'RFZr  
// fileSplitterFetch[nPos.length-1].start(); J-fU,*Bk  
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//等待子线程结束 '?Q [.{<  
//int count = 0; &_&])V)<\S  
//是否结束while循环 Ifu$p]~z$  
boolean breakWhile = false; Jug1Va<^c  
~Gc+naE>  
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while(!bStop) "2CiW6X[M  
{  !+IxPn  
write_nPos(); U<eVLfSij  
Utility.sleep(500); Y[;Pl$  
breakWhile = true; +I2
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for(int i=0;i<nStartPos.length;i++) Z>a_vC  
{ b]mRn{r?  
if(!fileSplitterFetch.bDownOver) DB_ x  
{ kT UQ8U  
breakWhile = false; 9U58#  
break; C^r3r6  
} +U^dllL7  
} "G|Gyc  
if(breakWhile) 2?ZHWS>U  
break; oC U8;z  
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"twV3R  
//count++; @?K(+BGi  
//if(count>4) Bl'  
// siteStop(); v>g1\yIw  
} Y_%\kM?7  
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System.err.println("文件下载结束！"); s.KJYP  
} ]&VD$Z984r  
catch(Exception e){e.printStackTrace ();} [_qBp:_j?s  
} Z|d_G}  
]-)qL[Q  
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//获得文件长度 R]/F{Xs  
public long getFileSize() ^k^%w/fo  
{ .4F(Y_c  
int nFileLength = -1; d"5:/Mo  
try{ nI.#A  
URL url = new URL(siteInfoBean.getSSiteURL()); rN{&$+"2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #>~$`Sg  
httpConnection.setRequestProperty("User-Agent","NetFox"); h&yaug,.  
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int responseCode=httpConnection.getResponseCode(); %9BC%w]y  
if(responseCode>=400) \I,<G7!0  
{ Qkqn~>  
processErrorCode(responseCode); V* fDvr0  
return -2; //-2 represent access is error Dw[w%
uz  
} h+.^8fPR  
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String sHeader; LiQs;$V  
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for(int i=1;;i++) 3=dGz^Zdv:  
{ RPaB4>  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); m^T$H_*;  
//Utility.log(in.readLine()); o|alL-  
sHeader=httpConnection.getHeaderFieldKey(i); Cj5M  
if(sHeader!=null) jKI+-s  
{ QE)g==d  
if(sHeader.equals("Content-Length")) .1|'9@]lj4  
{ LAf!y"A#  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); [Bpgb57En  
break; r-Z'  
} )_.@M '?  
} h{<^?=  
else S~/iHXm  
break; 1Q
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} %F&j B
 
} g:;v]   
catch(IOException e){e.printStackTrace ();} ,{8~TVO  
catch(Exception e){e.printStackTrace ();} 9KXp0Q?-$  
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Utility.log(nFileLength); oi"Bf7{  
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return nFileLength; Y60ld7H  
} 30<dEoF  
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//保存下载信息（文件指针位置） 3O#7OL68v  
private void write_nPos() 4sZ^:h,1  
{ >454Yir0Mk  
try{  &.(ZO]  
output = new DataOutputStream(new FileOutputStream(tmpFile)); %Si3t2W/  
output.writeInt(nStartPos.length); ~01rc  
for(int i=0;i<nStartPos.length;i++) KM0#M'dXy  
{ HNU[W8mg8  
// output.writeLong(nPos); c}v:X Slh7  
output.writeLong(fileSplitterFetch.nStartPos); S8"X7\d{  
output.writeLong(fileSplitterFetch.nEndPos); >%[(C*Cks  
} ?m?e2{]u,  
output.close(); %WCpn<)  
} |UR.7rOV  
catch(IOException e){e.printStackTrace ();} o"n^zG  
catch(Exception e){e.printStackTrace ();} 8`u#tl(  
} 0^["&K/  
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//读取保存的下载信息（文件指针位置） YT:<AJm  
private void read_nPos() qU2>V  
{ m"x~Fjvd  
try{ %],.?TS2V  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); z9dVT'  
int nCount = input.readInt(); E>'pMw  
nStartPos = new long[nCount]; "n
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nEndPos = new long[nCount]; %&gx@ \v  
for(int i=0;i<nStartPos.length;i++) wEDU*}~  
{ -h.YQC`  
nStartPos = input.readLong(); ARU
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nEndPos = input.readLong(); e2B~j3-?z  
} C|!E'8Rw  
input.close(); >Q+EqT  
} 89 fT?tT  
catch(IOException e){e.printStackTrace ();} ]L&_R^  
catch(Exception e){e.printStackTrace ();} bQ .y,+  
} lsio\ $  
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private void processErrorCode(int nErrorCode) 7d4RtdI  
{ orHVL2 KK  
System.err.println("Error Code : " + nErrorCode); w$B7..r  
} ;[9cj&7C<  
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1km=9[;w'  
//停止文件下载 ;H\,w/E9  
public void siteStop() #d|.BxH  
{ 0IA '8_K  
bStop = true; v<2+y
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for(int i=0;i<nStartPos.length;i++) o9eK7*D  
fileSplitterFetch.splitterStop(); K}Z'!+<U  
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} r`7`f xe  
} m]DjIs*@%h  
//负责部分文件的抓取 Rwy:.)7B$q  
**FileSplitterFetch.java fp>o ^+VB  
*/ {H>iL  
package NetFox; =lDmP|^  
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import java.io.*; | c8u  
import java.net.*; CyXcA;H,.  
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public class FileSplitterFetch extends Thread { r%B5@+{so  
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String sURL; //File URL fO(.I  
long nStartPos; //File Snippet Start Position pxY5S}@  
long nEndPos; //File Snippet End Position T:}Ed_m}q  
int nThreadID; //Thread's ID 1MV^~I8Dd  
boolean bDownOver = false; //Downing is over G3OQbqn  
boolean bStop = false; //Stop identical 9X*q^u  
FileAccessI fileAccessI = null; //File Access interface ix$+NM<n  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 0`qq"j[6a  
{ P4N{lQ.>  
this.sURL = sURL; !.w S+  
this.nStartPos = nStart; 6U""TR!   
this.nEndPos = nEnd; qBwqxxTc  
nThreadID = id; \+>b W(  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 4l3N#U0Q  
} twN(]w}Ps|  
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public void run() TLV)mCZ  
{ <]!IC]+  
while(nStartPos < nEndPos && !bStop) 8vP d~te  
{ U>I#f  
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try{ #pVk%5N  
URL url = new URL(sURL); mC93 &0  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $jntT(V  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,Y5+UzE@  
String sProperty = "bytes="+nStartPos+"-"; TZ*ib~  
httpConnection.setRequestProperty("RANGE",sProperty); }=L >u>cP  
Utility.log(sProperty); uC}YKT>V7  
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InputStream input = httpConnection.getInputStream(); `kz_q/K  
//logResponseHead(httpConnection); !nYAyjf  
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byte[] b = new byte[1024]; yT,UM^'  
int nRead; nv8,O=#s  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) +,KuYa{lu  
{ +X- k)9  
nStartPos += fileAccessI.write(b,0,nRead); \m\.+q]  
//if(nThreadID == 1) 1ii.nt1u  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); L NE]#8ue  
} {&4qknPd%  
6Q>w\@lF  
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Utility.log("Thread " + nThreadID + " is over!"); ?O3G  
bDownOver = true; ~/Ry=8  
//nPos = fileAccessI.write (b,0,nRead); [NFAdE  
} ~/.&Z`ls  
catch(Exception e){e.printStackTrace ();} 0FW=8hFp,  
} " DFg"  
} N0Y!  
[n^___7  
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//打印回应的头信息 &=UzF  
public void logResponseHead(HttpURLConnection con) 2n7[Op  
{
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for(int i=1;;i++) }i[jJb`bY  
{ %Wu8RG}  
String header=con.getHeaderFieldKey(i); MdKZH\z/  
if(header!=null) :L?zk"0C  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); q<UqGj7#   
Utility.log(header+" : "+con.getHeaderField(header)); S xgYq  
else ^:q(ksssY  
break; [Q*kom :  
} IrVeP&KM+  
} !bY{T#i)k  
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0>  
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public void splitterStop() t3WlVUtq3  
{ L\B+j+~  
bStop = true; LRI_s>7  
} uu/MXID  
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} OGVhb>LO1  
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/* -OHG1"/  
**FileAccess.java /U`"|3  
*//文件访问(定位，写) ?|L)!LYx  
package NetFox; .xD-eWw3R  
import java.io.*; R'3i
{ 1  
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public class FileAccessI implements Serializable{ WV6vM()#!C  
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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 V?gQ`( ,  
RandomAccessFile oSavedFile; [ wROIvV  
long nPos; $M8'm1R9  
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public FileAccessI() throws IOException Ug"B/UUFd  
{ l5MxJ>?4%B  
this("",0); PFc02 w  
} q@\D5F% >  
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x O)nS _I  
public FileAccessI(String sName,long nPos) throws IOException 7}#vANm  
{ 78Gvc~j  
oSavedFile = new RandomAccessFile(sName,"rw"); olJ9Kfc0  
this.nPos = nPos; $W2g2[+  
oSavedFile.seek(nPos); JrQN-e!  
} s)N1@RBR  
e^FS/=  
w_-{$8|  
public synchronized int write(byte[] b,int nStart,int nLen) AV'>  
{ jy*wj7fj1  
int n = -1; Gg&jb=  
try{ QV
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oSavedFile.write(b,nStart,nLen); CeZ5Ti?F  
n = nLen; QA%GK4F70  
} J+;.t&5R  
catch(IOException e) fT@#S}t  
{ k`&mHSk-  
e.printStackTrace (); (;n|>l?*  
} o0/03O  
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return n; !At_^hSqz  
} o#T,vu0s  
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*=I#VN*_<.  
} ~/NA?E
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/* 5|Y4GQVz  
**SiteInfoBean.java b+C>p2%  
*/ }Orc;_)r  
package NetFox; k&**f_b  
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public class SiteInfoBean { _#
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private String sSiteURL; //Site's URL &o8\ $A  
private String sFilePath; //Saved File's Path & =frt3  
private String sFileName; //Saved File's Name }ri"u;.R  
private int nSplitter; //Count of Splited Downloading File \Lc pl-;?  
5~sJ$5<,  
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public SiteInfoBean() eg}|%GG  
{//nSplitter的缺省值为5 1xx-}AIH#  
//default value of nSplitter is 5 T.{I~_  
this("","","",5); tVe*J@i\$  
} ,:#prT[P"  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)
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{ ?>,aq>2O$  
sSiteURL= sURL; fb#Ob0H  
sFilePath = sPath; {
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sFileName = sName; ,og@}gOMB  
this.nSplitter = nSpiltter; |S4yol  
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} 5!5P\o  
>2wjV"W?  
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public String getSSiteURL() |mKd5[$  
{ 9]S}m[8k  
return sSiteURL; ;~@2YPj  
} X-ml0 =M[  
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public void setSSiteURL(String value) H,uOshR  
{ O@ "6)/  
sSiteURL = value; jeJGxfii  
} O<+C$J|  
c XY!b=9  
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public String getSFilePath() v5*SoUOF  
{ 1.';:/~(  
return sFilePath; ckTnb  
} u?aq' "t  
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public void setSFilePath(String value) Ck[Z(=b$$:  
{ }q~A( u  
sFilePath = value; Z|j8:Ohz  
} \V&ly/\ )  
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public String getSFileName() ir\   
{ %;zA_Wg  
return sFileName; .t["kaA  
} Gd'^vqo<  
E2\)>YF{P  
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public void setSFileName(String value) !,1~:*:  
{ iBc( @EJ  
sFileName = value; q_W NN/w  
} 8..itty  
=g&0CFF<  
i=SX_#b^  
public int getNSplitter() -nU_eDy  
{ 1r
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return nSplitter; H%/$Rqg  
} ^%_LA't'R  
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public void setNSplitter(int nCount) G&;W  
{ eR3!P8t  
nSplitter = nCount; paF2{C)4  
} vF*H5\ m<a  
} {)Gh~~57_W  
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tB
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/* SR\#>Qwx_  
**Utility.java Y[pGaiN:  
*/ #ocT4  
package NetFox; pM4 j=F  
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public class Utility { LxG :?=O.  
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public Utility() KJ~f~2;  
{ 8Y4YE(x5  
@@! R Iq!  
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} bbnAF*7s8  
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//线程睡眠 yyZjMnuD  
public static void sleep(int nSecond) 6vmkDL8{A8  
{ 8T1`TGSFC  
try{ L1aN"KGMF  
Thread.sleep(nSecond); 6v.*%E*P  
} {9)LHX7dN  
catch(Exception e) B\4SB  
{ @jjp\~  
e.printStackTrace (); |&C.P?q  
} [y'jz~9c  
} 9}":}!  
^&.F!  
//日志 4}l,|7_&I  
public static void log(String sMsg) C~:aol i;  
{ {)`5*sd  
System.err.println(sMsg); &
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} =n$,Vv4A  
lM?P8#3  
Vg2s~ce{  
public static void log(int sMsg) f)*}L?  
{ /TpM#hkq/2  
System.err.println(sMsg); _~6AUwM  
} in%+)`'nH7  
} @P)GDB7A  
(z"Cwa@e  
>yT:eG  
/* =WN6Fj`  
**TestMethod.java JP[BSmhAV  
*/ CjIkRa@!x  
package NetFox; Prr<:q  
a-O9[?G/x  
\ar.(J  
public class TestMethod { koaH31Q  
0xH$!?{b  
+DVU"d  
public TestMethod()  #p\sw  
{ ///xx/weblogic60b2_win.exe Z\NC+{7k]  
try{ VP|9Cm=Fg  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); PN<Y&/fB  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); o%CBSm]  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 4(o0I~hpB?  
fileFetch.start(); Vrz<DB^-e  
} #
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catch(Exception e){e.printStackTrace ();} d<!bE(  
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+-xA/nU.c  
} _Z2VS"yH  
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public static void main(String[] args) `Ol*"F.+I  
{ IDcu#Nz
`  
new TestMethod(); (swP#t5S  
} dpTap<Noby  
} T|oz_c\e  
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