http断点续传简单实现（java)

/* D[#6jJAb  
**SiteFileFetch.java ?y"=jn  
*/ !Z(3dtUy  
package NetFox; ?P
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import java.io.*; 4@0y$Dv\  
import java.net.*; bMU0h,|]  
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*{TB<^ *  
public class SiteFileFetch extends Thread { 9\f%+?p  
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SiteInfoBean siteInfoBean = null; //文件信息Bean z"D'rHxy  
long[] nStartPos; //开始位置 Lgr(j60s  
long[] nEndPos; //结束位置 ;fiH=_{us  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 9IfeaoZZ4q  
long nFileLength; //文件长度 so=Ux2  
boolean bFirst = true; //是否第一次取文件 KcPI,.4{  
boolean bStop = false; //停止标志 ny++U;qi  
File tmpFile; //文件下载的临时信息 T'8d|$X  
DataOutputStream output; //输出到文件的输出流 85gdmla@9  
';,Rq9-'  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ,
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public SiteFileFetch(SiteInfoBean bean) throws IOException uz U2)n3y  
{ jc0Trs{Jf  
siteInfoBean = bean; cI#! Y  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); I)s~kA.e  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); KdN+$fe*g  
if(tmpFile.exists ()) v2K6y|6,  
{ k z{_H`5.  
bFirst = false; 0Tp,b (;n  
read_nPos(); C]dK/~Z#r  
} `%@|sK2  
else SobOUly5{  
{ ;;f&aujSHD  
nStartPos = new long[bean.getNSplitter()]; n.L/Xp@gc  
nEndPos = new long[bean.getNSplitter()]; @T 5dPmn  
} HdR%
n  
/
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} K (px-jY  
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public void run() I l2`c}9  
{ ~Y)h[  
//获得文件长度 RvXK?mL4F  
//分割文件 :n0czO6E  
//实例FileSplitterFetch
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//启动FileSplitterFetch线程 K3*8-Be  
//等待子线程返回 MdKkj[#  
try{ ~[[(_C3  
if(bFirst) mu$0x)  
{ =]F;{x  
nFileLength = getFileSize(); 1^v?Ly8  
if(nFileLength == -1) <<vT"2Q]  
{ K+P:g%M  
System.err.println("File Length is not known!"); %Eq4>o?D  
} myq:~^L ;  
else if(nFileLength == -2) _]aA58,j  
{ AhA4IOG`.  
System.err.println("File is not access!"); .).}ffhOL  
}
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else [Z-S0  
{ a@?2T,$  
for(int i=0;i<nStartPos.length;i++) +-$Hx5  
{ q{RH/. l  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); $C.;GUEQ  
} @hVF}ybp  
for(int i=0;i<nEndPos.length-1;i++) GeydVT-  
{ g#}a?kTM@  
nEndPos = nStartPos[i+1]; T*3>LY+bb  
} z Go*N,'  
nEndPos[nEndPos.length-1] = nFileLength; =}pPr]Cc  
} ;)7GdR^K  
} ]ucz8('  
X}5}M+'~  
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//启动子线程 P\k5%  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; P/?'ea  
for(int i=0;i<nStartPos.length;i++) c|hT\1XR,  
{ rY:A
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Et0[HotO  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 7SVqfWp  
nStartPos,nEndPos,i); q-<t'uhs[  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?7k%4~H t  
fileSplitterFetch.start(); =jEh#  
} yRdME>_L  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >Y>>lE! k  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); =[ZuE0c  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", iVdY\+N!<  
nEndPos = " + nFileLength); "54t7  
// fileSplitterFetch[nPos.length-1].start(); aM6qYO!jA  
~9Jlb-*I5  
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//等待子线程结束 }]BH
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//int count = 0; +r<d z  
//是否结束while循环 I}hY @  
boolean breakWhile = false; V;-$k@$b.  
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while(!bStop) *= ;M',nx  
{ 9*b(\Z)N  
write_nPos(); p*ic@n*G  
Utility.sleep(500); rAwuWM@BIg  
breakWhile = true; ==XO:P  
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for(int i=0;i<nStartPos.length;i++) Tj3xK%K_r3  
{ <RaUs2Q3.  
if(!fileSplitterFetch.bDownOver) 6aMG!_jC  
{ {1VMwANj  
breakWhile = false; :d{-"RAG"  
break; !M*$pQi}  
} pf@H;QS`  
} =bgu2#%Z  
if(breakWhile) c8<qn+=%?  
break; =_)yV0  
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//count++; 
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//if(count>4) z7$,m#tw  
// siteStop(); PYhRP00}M  
} 2M`:/shq  
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System.err.println("文件下载结束！"); W[4 V#&Z  
} "MX9h }
7  
catch(Exception e){e.printStackTrace ();} 9Z!|oDP-  
} [!'fE#"a  
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//获得文件长度 P;7 Y9}  
public long getFileSize() zxhE9 [`*e  
{ 5S/YVRXq  
int nFileLength = -1; ~A-Y%P  
try{ yR'%UpaE  
URL url = new URL(siteInfoBean.getSSiteURL()); s-lNpOi  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Xub<U>e;b  
httpConnection.setRequestProperty("User-Agent","NetFox"); (_.0g}2  
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int responseCode=httpConnection.getResponseCode(); mYRsM s  
if(responseCode>=400) vDit&Lh{T  
{ 7AouiL 2-W  
processErrorCode(responseCode); 
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return -2; //-2 represent access is error A.wuB  
} L,7+26XV"B  
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String sHeader; mLb>*xt$b@  
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for(int i=1;;i++) Y)*:'&~2e  
{ X Z4q{^o  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); -?}Z0e(w
 
//Utility.log(in.readLine()); &cuDGo.  
sHeader=httpConnection.getHeaderFieldKey(i); @{LD_>R  
if(sHeader!=null) yq<mE(hS?  
{ J)n^b  
if(sHeader.equals("Content-Length")) n~Qo@%J
r  
{ UY~N4IR8  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ms/!8X$Mz  
break; al@H
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} 2Sb68hJIE  
} cD JeYduK  
else `c.P`@KA  
break; ;t\oM7J|  
} F`8B PW
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} ~`Rb"Zn  
catch(IOException e){e.printStackTrace ();} Bp9_\4  
catch(Exception e){e.printStackTrace ();} %k=c9ll@:  
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Utility.log(nFileLength); {\p&?  
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return nFileLength; Q4e+vBECkq  
} 2Y1y;hCK  
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//保存下载信息（文件指针位置） >j6"\1E+Dz  
private void write_nPos() 
0 P2lq  
{ P+<4w  
try{ pSKwXx  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ]@wKm1%v  
output.writeInt(nStartPos.length); c\DMeYrg  
for(int i=0;i<nStartPos.length;i++) }-N4D"d4o  
{ F|bg2)|du8  
// output.writeLong(nPos); .g?Ppma  
output.writeLong(fileSplitterFetch.nStartPos); ~v|NC([(  
output.writeLong(fileSplitterFetch.nEndPos); -I'Jm=q3]  
} )l6(ss!J  
output.close(); W'! I+nh  
} tYUg%2G  
catch(IOException e){e.printStackTrace ();} Q$58K9  
catch(Exception e){e.printStackTrace ();} K*9~g('  
} q~6a$
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}CGA)yK~3  
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//读取保存的下载信息（文件指针位置） 8{DW$ZtR  
private void read_nPos() f~P~%  
{ 34c+70x7  
try{ . ytxe!O  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); K)N'~jCG  
int nCount = input.readInt(); S=_*<[W%4  
nStartPos = new long[nCount]; -jWXE  
nEndPos = new long[nCount]; k, >*.Yoh  
for(int i=0;i<nStartPos.length;i++) (MzThGJK_  
{ =k\Qx),Ir  
nStartPos = input.readLong(); y"Ios:v@-  
nEndPos = input.readLong(); 5a%i%+;N  
} ]QSQr*  
input.close(); apwA  
} +N2R'Phv  
catch(IOException e){e.printStackTrace ();} g+%Pg@[  
catch(Exception e){e.printStackTrace ();} ,Fzuo:{uy  
} L2> )HG
 
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private void processErrorCode(int nErrorCode) MHQM'  
{ ZfVw33z  
System.err.println("Error Code : " + nErrorCode); OfPv'rW{x  
} e!N%  
Y,M2D  
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//停止文件下载 bPA1>p7  
public void siteStop() BT|n+Y[  
{ fRK=y+gl@  
bStop = true; ~u-_DOA  
for(int i=0;i<nStartPos.length;i++) 7;@o]9W  
fileSplitterFetch.splitterStop(); <tgfbY^nL  
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} Q`!<2i;  
} M,sZ8eeq  
//负责部分文件的抓取 \2[sUY<W  
**FileSplitterFetch.java CF]#0*MI  
*/ PwC^ ]e  
package NetFox; cpu|tK.t  
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import java.io.*; jhB+ ]  
import java.net.*; |\T!,~  
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public class FileSplitterFetch extends Thread { H,Yrk(O-  
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String sURL; //File URL %`0*KMO3  
long nStartPos; //File Snippet Start Position  U92?e}=]  
long nEndPos; //File Snippet End Position sNsHl  
int nThreadID; //Thread's ID $D;-;5[-/r  
boolean bDownOver = false; //Downing is over :wz]d ~)  
boolean bStop = false; //Stop identical QRHM#v S  
FileAccessI fileAccessI = null; //File Access interface cF}9ldc  
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* TByAa{  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException kb[+II  
{ ,+!|~1  
this.sURL = sURL; 5"z~
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this.nStartPos = nStart; j$Vtd&  
this.nEndPos = nEnd; >K*TgG6!X  
nThreadID = id; GB{Q)L  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 , %A2wV  
} G5*_  
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public void run() ,U=7#Cf!  
{ u"-."_  
while(nStartPos < nEndPos && !bStop) ,B$e'KQ  
{ 7
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try{ &Vbcwv@  
URL url = new URL(sURL); \ mg  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~' q&rvk`  
httpConnection.setRequestProperty("User-Agent","NetFox"); kY#sQz}8  
String sProperty = "bytes="+nStartPos+"-"; <ELqj2`
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httpConnection.setRequestProperty("RANGE",sProperty); O6]X\Cwj%  
Utility.log(sProperty); lB(P+yY,/'  
~`<_xIvrq  
23'Ac,{  
InputStream input = httpConnection.getInputStream(); }u.1$Y  
//logResponseHead(httpConnection);
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byte[] b = new byte[1024]; [-2Tj)P C  
int nRead; $o^N_`l  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) k@Bn}r
 
{ #R#|hw  
nStartPos += fileAccessI.write(b,0,nRead); ]]/p.#oD,  
//if(nThreadID == 1) N[wyi&m4  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); oD_#oX5\  
} M[6WcH0/T  
]?V2L`/  
9`G}GU]@}  
Utility.log("Thread " + nThreadID + " is over!"); !uN_<!  
bDownOver = true; FmhN*ZXr#  
//nPos = fileAccessI.write (b,0,nRead); *wV`7\@  
} L87=*_!B;  
catch(Exception e){e.printStackTrace ();} %i@Jw  
} ~i=5NUE  
} CM 8Ub%  
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)P9&I.a8  
//打印回应的头信息 ~}ba2dU8  
public void logResponseHead(HttpURLConnection con) p"QV| `  
{ '/@i} digf  
for(int i=1;;i++) `W{y  
{ M~-jPY,+  
String header=con.getHeaderFieldKey(i); 54%h)dLDy  
if(header!=null) /igbn  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); A#CGD0T  
Utility.log(header+" : "+con.getHeaderField(header)); xcC^9BAj  
else ju(QSZ|;  
break; `:5W1D(  
}
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} U_AmRiy  
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public void splitterStop() z5 :53,`D'  
{ xB,(!0{`  
bStop = true; $<d3g:  
} WGI4DzKa  
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} h;t5v6["  
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/* |=#uzp7*  
**FileAccess.java 2IFEl-IB[  
*//文件访问(定位，写) =
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package NetFox; b_-?ZmV^r  
import java.io.*; p"o_0{8  
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public class FileAccessI implements Serializable{ AHdh
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 RyZy2^0<  
RandomAccessFile oSavedFile; EALgBv>#ZL  
long nPos; P~u~`eH*  
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public FileAccessI() throws IOException ~k/GmH  
{ 6F08$,%Y  
this("",0);  bj U]]  
} j(];b+>  
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public FileAccessI(String sName,long nPos) throws IOException gIcm`5+T  
{ gBJM|"_A
?  
oSavedFile = new RandomAccessFile(sName,"rw"); K)TMr"j\  
this.nPos = nPos; NEcE-7aT  
oSavedFile.seek(nPos); j4!oBSp  
} k{.`=j  
>kG: MJj  
v>p}f"$`  
public synchronized int write(byte[] b,int nStart,int nLen) Ap9 %5:]  
{ mE3M$2}  
int n = -1; m>LC2S; f  
try{
t^(wbC  
oSavedFile.write(b,nStart,nLen); ^.(i!BG'  
n = nLen; ^y3snuLtE  
} +4m~D`fqt[  
catch(IOException e) uz[5h0c  
{ mNnt9F3Eq  
e.printStackTrace (); h . R bdG  
} =aJb}X  
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return n; 9xIz[`)i.  
} ("ulL5  
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} SZm&2~|J  
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/* EHcgWlTu  
**SiteInfoBean.java 6YpP/ K  
*/ 7W `gN[*  
package NetFox; EmubpUS;  
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public class SiteInfoBean { yfCdK-9+B  
<jHo2U8/"s  
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private String sSiteURL; //Site's URL XonI   
private String sFilePath; //Saved File's Path V~_aM@q1  
private String sFileName; //Saved File's Name Tq`rc"&7u  
private int nSplitter; //Count of Splited Downloading File !%Qm{R  
&kNJs{  
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public SiteInfoBean() eBxOa  
{//nSplitter的缺省值为5 18kzR6(W  
//default value of nSplitter is 5 o2r)K AA  
this("","","",5); 8@- UvT&o  
} 'n0u6hCSb  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 2'5%EQW;0y  
{ 8sGaq [  
sSiteURL= sURL; *:hHlH* t1  
sFilePath = sPath; 5p`.RWls  
sFileName = sName; k\`~v$R3  
this.nSplitter = nSpiltter; zTQTmO  
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} 8^ezqd`  
\oc*  
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public String getSSiteURL() QeZK&^W  
{ v35=4>Y  
return sSiteURL; Ht!]%  
} S1oP_A[|  
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public void setSSiteURL(String value) uf<nVdC.  
{ N)b.$aC  
sSiteURL = value; 2#?qey  
} /1R` E9  
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public String getSFilePath() TSHQ>kP  
{ m C&*K  
return sFilePath; \C.s%m  
}
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public void setSFilePath(String value) qL?`l;+  
{ \OX;ZVb?5  
sFilePath = value; fNTe_akp  
} eJ O+MurO  
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public String getSFileName() K:\db'``  
{ k1)=xv#S  
return sFileName; cczV}m2)  
} z c7P2@  
iR(jCD?) Y  
,/bv3pE  
public void setSFileName(String value) F2#s^4Ii  
{ 01/yog
 
sFileName = value; _BP!{~&;  
} m"y_@Jk  
1 /dy@'  
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public int getNSplitter() oe*Y(T\G  
{ 27q=~R}  
return nSplitter; "Gh5 ^$w?j  
} a
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public void setNSplitter(int nCount) m/(f?M l  
{ >wOqV!0<  
nSplitter = nCount; e qzmEg  
} OX!<{9o  
} \Q m1+tg  
/>,KWHR|:  
12JmSvD  
/* x%d\}%]  
**Utility.java oPCtLz}z  
*/ :497]c3#5C  
package NetFox; a(BEm_l3  
y>YQx\mK
 
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public class Utility { 8M&q  
OPtFz6  
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public Utility() wq@{85  
{ _)U[c;^6  
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^;@Q3~DpP%  
} f;7I{Z\<  
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//线程睡眠 .lt|$["  
public static void sleep(int nSecond) -mur`tC  
{  ^D.u   
try{ ft"t  
Thread.sleep(nSecond); Z\9DtvV
 
} gfY1:0  
catch(Exception e) BhcTPQsW  
{ MJDW-KL-  
e.printStackTrace (); 44p?x8(z*  
} 8,^2'dK34  
} MaS"V`NI  
$pLJtQ  
//日志 z:7
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public static void log(String sMsg) e!hy,O{Pw  
{ o$%I{}9x  
System.err.println(sMsg); P/e6b .M  
} gXP)Y
N  
aR0'$*3E  
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public static void log(int sMsg) Y;dQLZCC  
{ eF%>5  
System.err.println(sMsg); cFF'ygJ/  
} BV@xE  
} ={
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[]I_r=  
{^jk_G\ys  
/* lI*uF~ 'D  
**TestMethod.java W8>
<  
*/ CL)*cu6zG  
package NetFox; N" =$S|Gs  
9-( \\$%  
BdQ/kXZu+  
public class TestMethod { }
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~(~ y=M  
public TestMethod() WPpS?  
{ ///xx/weblogic60b2_win.exe _ \LPP_  
try{ t 8,VRFV  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 4/J"}S  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 5dXDL~/2p  
SiteFileFetch fileFetch = new SiteFileFetch(bean); j :$Ruy  
fileFetch.start(); 4!k0  
} li7"{+ct  
catch(Exception e){e.printStackTrace ();} L7rH=gZ&!]  
l =Is-N`  
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} D%%@+3a  
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public static void main(String[] args) 4;D>s8dgG  
{ fUV;3du  
new TestMethod(); :% m56  
} }xG~a=,  
}
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