http断点续传简单实现（java)

/* 4UND;I&  
**SiteFileFetch.java :ciD!Ly  
*/ -Ir>pY\!  
package NetFox; uo;m  
import java.io.*; ,W;|K 5  
import java.net.*; uo(LZUjPbN  
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public class SiteFileFetch extends Thread { QZ[S, c^  
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SiteInfoBean siteInfoBean = null; //文件信息Bean tKds|0,j|  
long[] nStartPos; //开始位置 CWJ
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long[] nEndPos; //结束位置 X&Sah}0V&  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 4vNH"72P  
long nFileLength; //文件长度 wFjQ1
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boolean bFirst = true; //是否第一次取文件 gSf>+|  
boolean bStop = false; //停止标志 4J?\JcGs  
File tmpFile; //文件下载的临时信息 /2MZ
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DataOutputStream output; //输出到文件的输出流 .v-2A);I  
?y__ V
rw  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） BK wo2=m~  
public SiteFileFetch(SiteInfoBean bean) throws IOException s'OK])>`  
{ L(9AcP  
siteInfoBean = bean; (*,R21<%  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); e_g&L)  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); TI\EkKu"  
if(tmpFile.exists ()) \rE] V,,2  
{ 9<kMxtk$  
bFirst = false; ?mN!9/DIc  
read_nPos(); yo%Nz"  
} :^`Wrc
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else
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{ d[nz0LI|mk  
nStartPos = new long[bean.getNSplitter()]; U* uMMb}$  
nEndPos = new long[bean.getNSplitter()]; 1&vR7z]*  
} `wr*@/P  
#%L_wJB-  
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} w,_LC)9  
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public void run() >/NegJh'F}  
{ }^P"R[+4u  
//获得文件长度 2|U6dLZ!  
//分割文件 3+q-yP#X  
//实例FileSplitterFetch yU"#2 *C  
//启动FileSplitterFetch线程 P% 8U  
//等待子线程返回 P>$+XrTE  
try{ Om_ "X6  
if(bFirst) |;^$IZSsz  
{ lR
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nFileLength = getFileSize(); [nlq(DGJhp  
if(nFileLength == -1) `:jF%3ks+0  
{ e)}=T0 s  
System.err.println("File Length is not known!"); zU!d(ge.E  
} 7!)VOD8Z  
else if(nFileLength == -2) k~
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{ e2g`T{6M  
System.err.println("File is not access!"); hS>=pO+y  
} Qstd;qE~  
else ?6L8#"=  
{ E>O@Bv  
for(int i=0;i<nStartPos.length;i++) !|z!e>0  
{ `LKf$cx(A  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ;%cW[*Dw  
} 25r3[gX9`  
for(int i=0;i<nEndPos.length-1;i++) '@IReMl  
{ 2=%]Ax"R  
nEndPos = nStartPos[i+1]; c?aOX/C'  
} 3JqGLR`z3  
nEndPos[nEndPos.length-1] = nFileLength; &PFq(4  
} zAev@+.ld  
} 91DevizXx  
z46Sh&+  
tV4wkS=R|  
//启动子线程 =h+-1zp{M^  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; =kzHZc  
for(int i=0;i<nStartPos.length;i++) U-U(_W5&  
{ kf#S"[/E  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), NzN"_ojM  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Zv?"1Y< L  
nStartPos,nEndPos,i); y{~tMpo<  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); I|;C}lfp  
fileSplitterFetch.start(); W7{^/s5r  
} B|{E[]
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), VW;E14  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); M a3}w-=;  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", H6Gs&yk3  
nEndPos = " + nFileLength); h##U=`x3  
// fileSplitterFetch[nPos.length-1].start(); n</Rd=  
=}Q|#C  
=Lnip<t>ja  
//等待子线程结束 sM%l:Fv  
//int count = 0; 8-cuaa  
//是否结束while循环 qv|}>wU  
boolean breakWhile = false; KP$AT}D  
 -rT#Wi  
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while(!bStop) 8:0,jnS  
{ Der'45]*^  
write_nPos(); mX?t|:[b  
Utility.sleep(500); XN{zl*`  
breakWhile = true; B(O6qWsL  
x5rLGt  
4Y4zBD=<  
for(int i=0;i<nStartPos.length;i++) @RL'pKab9  
{ u:B=lZ[  
if(!fileSplitterFetch.bDownOver) &5[+p{2  
{ K}GRU)  
breakWhile = false; Prc1U)nfo  
break; /x_AWnU  
} @2hOy@V  
} }9!}T~NMs  
if(breakWhile) uc|ej9N  
break; q!~DCv df  
[$:L|V!{  
8U7dd[  
//count++; Lr=
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//if(count>4) )HvBceN  
// siteStop(); h
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} 6Tc!=lk  
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System.err.println("文件下载结束！"); eZ0-O /_i  
} EB6X Yr
 
catch(Exception e){e.printStackTrace ();} oq|`;k   
} _A0X[}^K  
nE2?3S>  
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//获得文件长度 |ZXz&Xor  
public long getFileSize() "=JE12=u  
{ /FC(d
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int nFileLength = -1; 8HHR  
try{ 7KJ0>0~Et  
URL url = new URL(siteInfoBean.getSSiteURL()); ={;+0Wj
b8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); m}S}fH(  
httpConnection.setRequestProperty("User-Agent","NetFox"); W5~!)Ec  
:_=YH+bZ  
X|QokAR{$>  
int responseCode=httpConnection.getResponseCode(); .])X.7@x  
if(responseCode>=400) :VLYF$|  
{ Q/*|ADoq  
processErrorCode(responseCode); R|``A5zQ  
return -2; //-2 represent access is error <
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} 0;`+e22  
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wbh=v;  
String sHeader; zE?dQD^OD  
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for(int i=1;;i++) obPG]*3  
{ }7P[%(T5  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); p{``a=  
//Utility.log(in.readLine()); %Z,n3iND  
sHeader=httpConnection.getHeaderFieldKey(i); bD|VT  
if(sHeader!=null) Pf?15POg&B  
{ 4?[1JN>  
if(sHeader.equals("Content-Length")) joZd  
{ 4Tx.|  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); o)DO[  
break; ,e'"SVQc  
} Np+pJc1  
} uY/CiTWr  
else {zLgLBM  
break; ^!n|j]aw  
} _={mKKoHs  
} 3TS:H1n  
catch(IOException e){e.printStackTrace ();} D,(:))DmR  
catch(Exception e){e.printStackTrace ();} ,ei=w,
O  
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Utility.log(nFileLength); jpTk@  
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return nFileLength; ?C   
} ?I"?J/zm  
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//保存下载信息（文件指针位置） m| 7v76(  
private void write_nPos() oJ/=&c  
{ sBqOcy  
try{ VwK7\jV  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Ai5+ ;8z+  
output.writeInt(nStartPos.length); 9
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for(int i=0;i<nStartPos.length;i++) h'_$I4e)  
{ aVr=7PeF  
// output.writeLong(nPos); BqA_CW  
output.writeLong(fileSplitterFetch.nStartPos); |oe  
output.writeLong(fileSplitterFetch.nEndPos); <E^;RG  
} wx!2/I>  
output.close(); 9-24c  
} 3a=\$x@  
catch(IOException e){e.printStackTrace ();} 5j9%W18  
catch(Exception e){e.printStackTrace ();} o=xMaA  
} 0<fQjXn  
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YIb7y1\UM  
//读取保存的下载信息（文件指针位置） 'm-5  
private void read_nPos() c"t&,OU:  
{ ^gR~~t;@  
try{ ;lhW6;oI'  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); P6=5:-Hh  
int nCount = input.readInt(); ^),t=!;p  
nStartPos = new long[nCount]; YRd`G3J  
nEndPos = new long[nCount]; ez5>V7Y  
for(int i=0;i<nStartPos.length;i++) yMD0Tj5ZQ  
{ /V#?d  
nStartPos = input.readLong(); +V[;DOlll  
nEndPos = input.readLong(); 'Z#>K*  
} -C!m#"P
DW  
input.close(); tT]mMlKJ  
} 5Nbq9YY  
catch(IOException e){e.printStackTrace ();} =ReSlt  
catch(Exception e){e.printStackTrace ();} Neii$  
} _g,_G  
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private void processErrorCode(int nErrorCode) sr(nd35  
{ [UB*39D7  
System.err.println("Error Code : " + nErrorCode); yw89*:A6  
} bMv[.Z@v(  
\%V !& !'  
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//停止文件下载 \0&$n  
public void siteStop() %5@> nC?`[  
{ :1@jl2,  
bStop = true; ];N/KHeZ  
for(int i=0;i<nStartPos.length;i++) PpF`0w=1%l  
fileSplitterFetch.splitterStop(); |)*!&\Ch  
hFhC&2HN  
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} hPCSAo!|  
} #MiO4zXgd  
//负责部分文件的抓取 8+32hg@^F  
**FileSplitterFetch.java we@*;k@_  
*/ y6MkaHW[m  
package NetFox; B+pLW/4l  
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import java.io.*; Y@T$O<*  
import java.net.*; fGe"1MfU  
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public class FileSplitterFetch extends Thread { 1'dZ?`O  
;sz_W%-;@  
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String sURL; //File URL (|3?wX'2U  
long nStartPos; //File Snippet Start Position B8!$?1*^a  
long nEndPos; //File Snippet End Position R"\(a  
int nThreadID; //Thread's ID dX[Xe  
boolean bDownOver = false; //Downing is over wjT#D|soI  
boolean bStop = false; //Stop identical r/HG{XH`  
FileAccessI fileAccessI = null; //File Access interface ?`6Mfpvj96  
&>K|F >7q  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Ke~!1S8=  
{ ZZfi,0R  
this.sURL = sURL; N.SV*G @  
this.nStartPos = nStart; #c'}_s2F[  
this.nEndPos = nEnd; n0%S: (  
nThreadID = id; 3x z z* <  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 #Pg?T%('`  
} |It{L0=U  
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public void run() t^%)d7$  
{ s:z  
while(nStartPos < nEndPos && !bStop) _)4zm  
{ BIg2`95F|  
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try{ s5MG#M 9  
URL url = new URL(sURL); 'RNj5r  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &lxM
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httpConnection.setRequestProperty("User-Agent","NetFox"); LJt5?zQKrW  
String sProperty = "bytes="+nStartPos+"-"; ,">CPl]  
httpConnection.setRequestProperty("RANGE",sProperty); }wEt=zOJ  
Utility.log(sProperty); ?iHcY,  
r'XWt]B+[  
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InputStream input = httpConnection.getInputStream(); zn|O)"C  
//logResponseHead(httpConnection); vB5mOXGNq  
[?g}<fa  

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byte[] b = new byte[1024]; yWr&G@>G  
int nRead; r"\<+$ 7  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) GW%!?mJ  
{ -Q ];o~  
nStartPos += fileAccessI.write(b,0,nRead); Vn_>c#B  
//if(nThreadID == 1) WM=)K1p0u  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); $%ww$3  
} %Rk0sfLvn  
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Utility.log("Thread " + nThreadID + " is over!"); *ODc[k'(  
bDownOver = true; <UGM/+aO  
//nPos = fileAccessI.write (b,0,nRead); ygUX]*m!  
} m+ #G*  
catch(Exception e){e.printStackTrace ();} f;&XTF5D^  
} W4h]4X  
} e%0IEX  
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//打印回应的头信息 p-7?S^!l  
public void logResponseHead(HttpURLConnection con) Us>
 
{ +|4olK$[  
for(int i=1;;i++) 4
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{ zXwdU58  
String header=con.getHeaderFieldKey(i); B\;fC's+  
if(header!=null) ax2#XSCO  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ?~]mOv>  
Utility.log(header+" : "+con.getHeaderField(header)); 
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else v)*eLX$  
break; Y$qjQ1jF+  
} !8RJHMX&  
} =~dsIG  
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public void splitterStop() vQDR;T"]  
{ @Qqf4h  
bStop = true; CwO$EL:[`  
} )>;387'Y  
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} Nvd(Tad  
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/* s>TC~d82  
**FileAccess.java x LK,Je  
*//文件访问(定位，写) !__^M3S,k  
package NetFox; e.!~7c_z?  
import java.io.*; W,nn,%  
1X?q4D"  
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public class FileAccessI implements Serializable{ 8yuTT^  
,%y!F3m  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 mt-t8~A  
RandomAccessFile oSavedFile; =Q!V6+}nY^  
long nPos; ~k ]$J|}za  
8,B#W#*{  
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public FileAccessI() throws IOException ?.nD!S@  
{ 6(q8y(.`  
this("",0); Jb8%A@Z+  
} Q:Y`^jP   
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op_ 1J;RF  
public FileAccessI(String sName,long nPos) throws IOException 3tmS/tQp  
{ GbC JGqOR  
oSavedFile = new RandomAccessFile(sName,"rw"); }5QUIK~NA  
this.nPos = nPos; U(<~("ocN  
oSavedFile.seek(nPos); xp"F)6  
} n."XiXsN  
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public synchronized int write(byte[] b,int nStart,int nLen) \T;(k?28HN  
{ :&s8G*  
int n = -1; C3C&hq\%  
try{ `O?j -zR  
oSavedFile.write(b,nStart,nLen); W{kTM4  
n = nLen; [Lf8*U"  
} 1EliR uJ  
catch(IOException e) y*I,i*iv  
{ : p7PiqQ  
e.printStackTrace ();
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} ' KNg;  
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return n; Oc/ i'  
} F[0w*i&u5  
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} 08nA}+k  
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/* XeAH.i<  
**SiteInfoBean.java rX|{
nb  
*/ Ys@\~?ym+  
package NetFox; e~$aJO@B.R  
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public class SiteInfoBean { v&"sTcS|  
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HU-#xK  
private String sSiteURL; //Site's URL :2;c@ uj  
private String sFilePath; //Saved File's Path -L2%,.E>4  
private String sFileName; //Saved File's Name zY&/lWW._  
private int nSplitter; //Count of Splited Downloading File I -V=Z:  
F'njtrO3  
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public SiteInfoBean() ^<Sy{KY  
{//nSplitter的缺省值为5 t\-;n:p-  
//default value of nSplitter is 5 sTECNY=l  
this("","","",5); EB5^eNdL  
} (gUxS.zU  
oX6()FR  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ezr'"1Ba}  
{ >NBwtF>  
sSiteURL= sURL; >uYGY{+j[  
sFilePath = sPath; }A7]bd  
sFileName = sName; Gq.fQ_oOb  
this.nSplitter = nSpiltter; V}q=!zz  
;QQ/bM&I  
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} ?L>}( {9  
>]?!9@#IH  
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public String getSSiteURL() lJU]sZ9~b  
{ cb_nlG!  
return sSiteURL; WNiM&iU  
} ?qczMck_  
j4eq.{$  
lD?]D&  
public void setSSiteURL(String value) UphZRgT!N  
{ ":01M},RA  
sSiteURL = value; Yr 1k\q  
} 3xpygx9
 
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E <h9o>h  
public String getSFilePath() O[HBw~  
{ lBOxB/`  
return sFilePath; ?xzDz  
} s"0Hz"[^=  
r?=3TA
A  
nbU?:=P  
public void setSFilePath(String value) >2LlBLQ  
{ Trml?zexD  
sFilePath = value; wRQMuFGY  
} VJ|80?4h  
3qwSm<  
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public String getSFileName() L7$1rO<  
{ 2<^eVpNJR  
return sFileName; cK1RmL"3  
} O*hQP
*Rs  
J"yq)0  
<l^#FH  
public void setSFileName(String value) ZNY),3?  
{ J8PZVeWx  
sFileName = value; u$y5?n|  
} lgh+\pj  
3b1%^@,ACy  
ci{WyIh  
public int getNSplitter() xU$15|ny  
{ ug9]^p/)^  
return nSplitter; JS0957K  
} k3r<']S^  
(:ij'Zbz  
}1
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public void setNSplitter(int nCount) ~DUOL~E  
{ `Bv, :i  
nSplitter = nCount; ')~[J$qz  
} ^TCfj^FP  
} ]YwvwmZ  
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iLJBiZ+  
/* Ox"SQ`nSj'  
**Utility.java %1%@L7wP>  
*/ r*W&SU9Z  
package NetFox; &W-1W99auE  
S *K0OUq  
j'nrdr6n  
public class Utility { j+NpQ}t:  
!9.`zW"40  
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public Utility() ]d50J@W c  
{ ?E.MP7Y#V  
A>QAR)YP  
-bQi4  
} 6ragRS/'x  
G0pqiU6  
//线程睡眠 A=pyaU`aE  
public static void sleep(int nSecond) TvwkeOS#}7  
{ 6B`,^8Lp  
try{ ;&]oV`Ib  
Thread.sleep(nSecond); z%Ivc*x5  
} UViWejA/*u  
catch(Exception e) )VFS&|#\  
{ u_X(c'aE;  
e.printStackTrace (); (c1Kg
  
} I8{ohFFo  
} |NXe{q7{  
a3[lZPQe  
//日志 $h8,QPy  
public static void log(String sMsg) 8WMGuv  
{ ue"e><c6:  
System.err.println(sMsg); vB1nj<]&z  
} gatxvR7H  
h9WyQl7  
L$ ZZ]?7j  
public static void log(int sMsg) %2EHYBQjN  
{ LFPYnK  
System.err.println(sMsg); i$S*5+  
} Kma-W{vGD  
} ;@G5s+<l  
h&m4"HBL_  
uPBtR  
/* #tlhH\Pr[  
**TestMethod.java { ^ @c96&  
*/ ^F`\B'8MF  
package NetFox; lxXIu8  
@[w.!GW%  
glgXSOj  
public class TestMethod { yu@u0vlc  
4#2iq@s  
Ej/P:nB  
public TestMethod() 7DCu#Y[  
{ ///xx/weblogic60b2_win.exe iVqXf;eB!5  
try{ 4dI=  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); C9"yu&l  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); |A19IXZ\  
SiteFileFetch fileFetch = new SiteFileFetch(bean); a qIpO  
fileFetch.start(); LQ.0"6oj  
} b?%Pa\,!  
catch(Exception e){e.printStackTrace ();} X(fT[A_2C  
_"'0^F$I  
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} Cy'! >  
G.sf>
.[  
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public static void main(String[] args) -q}I; cH  
{ :dj=kuUTbu  
new TestMethod(); gtw?u b  
} gaxxB]8  
} sD,FJ:dy  
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