http断点续传简单实现（java)

/* "S6d^  
**SiteFileFetch.java L]9*^al  
*/ '5{gWV`  
package NetFox; m@TU2  
import java.io.*; eLl;M4d  
import java.net.*; jg2>=}  
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public class SiteFileFetch extends Thread { k2O==IG]
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SiteInfoBean siteInfoBean = null; //文件信息Bean X4 xnr^  
long[] nStartPos; //开始位置 `@eQL[Z9x  
long[] nEndPos; //结束位置 [x9eamJ,H  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 539[,jH  
long nFileLength; //文件长度 ga!t:O@w  
boolean bFirst = true; //是否第一次取文件 C'hZNFsF;  
boolean bStop = false; //停止标志 G;`+MgJ)  
File tmpFile; //文件下载的临时信息 |nv8&L8  
DataOutputStream output; //输出到文件的输出流 5J1,Usm  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） <sn^>5Ds  
public SiteFileFetch(SiteInfoBean bean) throws IOException $,bLb5}Qu  
{ *y u|]T  
siteInfoBean = bean; hfVJg7-  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 9D-PmSnv  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); `43E-'g  
if(tmpFile.exists ()) \vpUl  
{ (LQ*U3J]_  
bFirst = false; [?_^Cy  
read_nPos(); &Q 3!ty  
} "y#$| TMB  
else l8jm7@.E  
{ JrS|Ib)6  
nStartPos = new long[bean.getNSplitter()]; 4fQ<A <2/  
nEndPos = new long[bean.getNSplitter()]; `Y8
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} q,kdr)-  
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} N9idk}T  
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public void run() Pe~[qETv  
{ X`#vH8  
//获得文件长度 REc69Y.k  
//分割文件 THkg,*;:  
//实例FileSplitterFetch }-!0d*I  
//启动FileSplitterFetch线程 -I'#G D>  
//等待子线程返回 wNq#vn  
try{ g2BE-0,R  
if(bFirst) RQ!kVM@  
{ =J<3B H^m  
nFileLength = getFileSize(); c7,p5[  
if(nFileLength == -1) Qne@Vf kA  
{ bRfac/:}  
System.err.println("File Length is not known!"); o4\\q66K  
} yIA-+# r[  
else if(nFileLength == -2) 6||zfH  
{ k_/*>lIZY  
System.err.println("File is not access!"); 'de&9\  
} K>N\U@@8i  
else 0EKi?vP@y7  
{ k`_sKr]9  
for(int i=0;i<nStartPos.length;i++) 2.qEy6  
{ -QN1=G4  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); kq8.SvIb  
} gwm!Pw j  
for(int i=0;i<nEndPos.length-1;i++) X0.kQ  
{ F}wy7s2i  
nEndPos = nStartPos[i+1]; Z8%?ej`8  
} pE,2pT2>  
nEndPos[nEndPos.length-1] = nFileLength; E{k$4  
} 9$$dSN\&  
} ]{s0/(EA  
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SYkwM6  
//启动子线程 s'b 4Me  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Y 3h`uLQ  
for(int i=0;i<nStartPos.length;i++) _(l?gj  
{ L7;8:^ v  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), m}hEi  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ^CO{86V  
nStartPos,nEndPos,i); c#(Hh{0
 
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); -Aaim`06bv  
fileSplitterFetch.start(); 0"}J!c<g  
} N?`V;`[  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -M5vh~Tp  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); dhv?36uE  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", HCfme<'  
nEndPos = " + nFileLength); %D1 |0v8}  
// fileSplitterFetch[nPos.length-1].start(); Swa0TiT(  
Ql"kJ_F!br  
)0+6^[Tqq  
//等待子线程结束 0Q?)?8_  
//int count = 0; FkE)~g  
//是否结束while循环 p>_Qns7W  
boolean breakWhile = false; & 6'Rc#\P  
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while(!bStop) z36wWdRa6  
{ GXC,p(vbE  
write_nPos(); YLJ^R$pi  
Utility.sleep(500); ckGmwYP9  
breakWhile = true; 6S`0<Z;;/  
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}D>#AFs6#  
for(int i=0;i<nStartPos.length;i++) o3]Lrzh  
{ f7YBhF  
if(!fileSplitterFetch.bDownOver) h4Wt oE>i  
{ d|?Xo\+  
breakWhile = false; UodBK7y  
break; !7Eodq-0  
} ;/:Sx/#s  
} 5`Q j<
  
if(breakWhile) t:MSV?  
break; v5>A1\  
[?%q,>F  
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//count++; zD)/QFILy  
//if(count>4) Hvb8+"?~  
// siteStop(); KpA1Ac)T  
} ?4A/?Z]ub  
&AN1xcx\  
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System.err.println("文件下载结束！"); cbN;Kv?ak}  
} m g,1
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catch(Exception e){e.printStackTrace ();} ^/_Yk.w  
} /~MH]Gh  
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//获得文件长度 Q$uv \h;  
public long getFileSize() Kci. ,I  
{ G54J'*Z  
int nFileLength = -1; gg>QXui  
try{ (+c1.h  
URL url = new URL(siteInfoBean.getSSiteURL()); ],_+J*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )/?H]o$NU  
httpConnection.setRequestProperty("User-Agent","NetFox"); Aa=:AkrH  
AdVc1v&>  
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int responseCode=httpConnection.getResponseCode(); u\V^g  
if(responseCode>=400) 3pg=9*{  
{ *,mI=1  
processErrorCode(responseCode); AHRJ7l;
a  
return -2; //-2 represent access is error ak7kb75o  
} XeX"IhgS>E  
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String sHeader; !!A
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for(int i=1;;i++) 2 /FQ;<L  
{ (J[Xryub  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); lDTHK2f  
//Utility.log(in.readLine()); -QroT`gy  
sHeader=httpConnection.getHeaderFieldKey(i); 3V<@Vkf5  
if(sHeader!=null) .4p3~r?=S  
{ AH|gI2  
if(sHeader.equals("Content-Length")) @^A
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{ #obRr#8  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); z%OKv[/N  
break; @^xtxtjzux  
} 4);_f  
} %8,$ILN  
else g:>'+(H;  
break; T9C_=0(hn  
} `PC9t)%.pV  
} F}5d>nw  
catch(IOException e){e.printStackTrace ();} 6Q^~O*cw  
catch(Exception e){e.printStackTrace ();} V&w2pp0  
7~ PL8  
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Utility.log(nFileLength); &}r"Z?f)  
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return nFileLength;  .qgUD  
} Zz0e4C  
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//保存下载信息（文件指针位置） O\6U2b~  
private void write_nPos() _dJ(h6%3  
{ 5J10S  
try{ 6RnzT d  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 64<;6*
 
output.writeInt(nStartPos.length); 8NWo)y49H  
for(int i=0;i<nStartPos.length;i++) pFvu,Q"  
{ X H-_tvB  
// output.writeLong(nPos); [ QiG0D_'=  
output.writeLong(fileSplitterFetch.nStartPos);
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output.writeLong(fileSplitterFetch.nEndPos); 3 r&  
} l~6K}g?  
output.close(); %GHGd'KO&  
} 7uF|Z(  
catch(IOException e){e.printStackTrace ();} 7;s#QqG`I  
catch(Exception e){e.printStackTrace ();} Y()"2CCV  
} 7l D-|yx  
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8R,<S-+v  
//读取保存的下载信息（文件指针位置） 0B}4$STOo[  
private void read_nPos() H$KO[mW}  
{ K:wI'N"N  
try{ %2?+:R5.  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); xT%`"eM}  
int nCount = input.readInt(); n t}7|h|  
nStartPos = new long[nCount]; !sb r!Qt  
nEndPos = new long[nCount]; UFG_ZoD+  
for(int i=0;i<nStartPos.length;i++) uu9M}]mDl  
{ Ao\xse{E  
nStartPos = input.readLong(); "8xAe0-4  
nEndPos = input.readLong(); kAki9a(=!  
} D|N4X`T`  
input.close(); G0E5Y;YIN$  
} Bqq=2lj  
catch(IOException e){e.printStackTrace ();} S/nPK,^d2  
catch(Exception e){e.printStackTrace ();} Zh=arlk  
} 2 T!Tiu  
9}(w*>_L  
558P"w0"X  
private void processErrorCode(int nErrorCode) \$ytmtf5  
{ <$A,Ex94  
System.err.println("Error Code : " + nErrorCode); YmziHns`b  
} b:m+I  
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//停止文件下载 cHs3:F~~  
public void siteStop() 8xAV[i  
{ Mo,&h?VOM?  
bStop = true; U1[)eD`  
for(int i=0;i<nStartPos.length;i++) M:S-%aQ_<y  
fileSplitterFetch.splitterStop(); \N,ox(f?gW  
9)Fx;GxL  
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} N
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} &X=7b@r  
//负责部分文件的抓取 CXa[%{[n  
**FileSplitterFetch.java eb62(:=N6  
*/ ?=VvFfv%  
package NetFox; ~}Xus?e  
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import java.io.*; B5b:znW2@  
import java.net.*; %6UF%dbYH`  
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/  
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public class FileSplitterFetch extends Thread { Hiyg1  
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{]0e=#hw  
String sURL; //File URL #z\ub5um  
long nStartPos; //File Snippet Start Position D|]BFu)F  
long nEndPos; //File Snippet End Position H_+n_r*  
int nThreadID; //Thread's ID dftBD  
boolean bDownOver = false; //Downing is over s]arNaaA  
boolean bStop = false; //Stop identical bSB%hFp=Cp  
FileAccessI fileAccessI = null; //File Access interface SmRlZ!%e  
XYEwn_Y  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException fab'\|Y   
{ ,X4e?$7g  
this.sURL = sURL; d2rs+-  
this.nStartPos = nStart; asT-=p_ 0.  
this.nEndPos = nEnd; oQ!M+sRmF  
nThreadID = id; :E:e ^$p  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 mk-{@$QJb  
} XzUGlrp:Y#  
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public void run() 7]ieBUfS  
{ 2hh8G5IaQ  
while(nStartPos < nEndPos && !bStop) iOE. .xA:  
{ K7 e~%mY  
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try{ %op
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URL url = new URL(sURL); xoaO=7\io  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +$2{u_m,  
httpConnection.setRequestProperty("User-Agent","NetFox"); S;|:ci<[=  
String sProperty = "bytes="+nStartPos+"-"; k6G
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httpConnection.setRequestProperty("RANGE",sProperty); +>$]leqa  
Utility.log(sProperty); !l:GrT8J  
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InputStream input = httpConnection.getInputStream(); Shn,JmR  
//logResponseHead(httpConnection); s|[>@~gXk  
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byte[] b = new byte[1024]; ajYe?z  
int nRead; 9T,/R1N8  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) .tBlGMcN  
{ 0-. d{P  
nStartPos += fileAccessI.write(b,0,nRead); r*X,]\V0x  
//if(nThreadID == 1) `Q]N]mK  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &Y@i:O  
} }X(&QZ7i`  
+mQ5\14#  
=L6#=7hcl  
Utility.log("Thread " + nThreadID + " is over!"); Gp"GTPT{  
bDownOver = true; ?J}Q&p.  
//nPos = fileAccessI.write (b,0,nRead); $( hT{C,K  
} $] 6u#5  
catch(Exception e){e.printStackTrace ();}  @MW@mP)#  
} +-9vrEB  
} g=*jKSZ  
5&]5*;BvJ  
tne_]+  
//打印回应的头信息 sZ;|NAx)  
public void logResponseHead(HttpURLConnection con) D6 B-#u!M  
{ @^{Hq6_`  
for(int i=1;;i++) 2 $>DX\h  
{ Z\&f"z?L  
String header=con.getHeaderFieldKey(i); sD|l}f  
if(header!=null) QY\k3hiqn  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); dcz?5O_{,  
Utility.log(header+" : "+con.getHeaderField(header)); nl@an!z  
else |Uh8b %  
break; #&3,T1i`  
} 7Ai?}%b-  
} O-iE0t  
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/y$Omc^  
public void splitterStop() KA3
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{ d} >Po%r:  
bStop = true; bIQ,=EA1  
} x4_
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}@DCcf$<  
} )S
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/* N0`
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**FileAccess.java [Nyt0l "z  
*//文件访问(定位，写) $d?+\r:I{,  
package NetFox; 6].[z+  
import java.io.*; MP]<m7669*  
=BJLj0=N  
b@CB +8$  
public class FileAccessI implements Serializable{ n1[c\1  
t],a1I.gk  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 <_?zln:4.  
RandomAccessFile oSavedFile; j,IRUx13f  
long nPos; !MbzFs~  
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public FileAccessI() throws IOException ,Oo`*'a[o7  
{ NvK9L.K  
this("",0); uvys>]+  
} iP:i6U]  
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public FileAccessI(String sName,long nPos) throws IOException ZOK!SBn^?  
{ 5_yQI D%Sq  
oSavedFile = new RandomAccessFile(sName,"rw"); 3m1g"  
this.nPos = nPos; JWVV?~1  
oSavedFile.seek(nPos); JK,MK|  
} #w$Y
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{Jr1K,  
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public synchronized int write(byte[] b,int nStart,int nLen) q'3{M]Tk  
{ F72#vS j  
int n = -1; d^=BXCoC  
try{ >w,L=z=  
oSavedFile.write(b,nStart,nLen); >XN[KPTa  
n = nLen; 7iB!Uuc  
} I&PJ[U#~a  
catch(IOException e) )f8>kz(  
{ h]7_ N,  
e.printStackTrace (); c:Ua\$)u3,  
} -t-f&`S||  
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return n; 5Cf!NNV  
} Y,]Lk<Hm3  
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} .)E#*kLWR  
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/* Bfb~<rs[  
**SiteInfoBean.java jkeerU6  
*/ X$};K\I  
package NetFox; pn"!wqg  
j cd<'\;  
j?T'N:Qd  
public class SiteInfoBean { 7UT
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`IHP_IfR  
Ou[K7-m%&  
private String sSiteURL; //Site's URL p.8bX  
private String sFilePath; //Saved File's Path 79DNNj~  
private String sFileName; //Saved File's Name ixTjXl2g  
private int nSplitter; //Count of Splited Downloading File jCd]ENl+_  
]3r}>/2(  
.ARYCTyG  
public SiteInfoBean() bWyimr&B  
{//nSplitter的缺省值为5 4[ uqsJB  
//default value of nSplitter is 5 G?4@[m  
this("","","",5); O]:9va  
} tFU4%c7V  
k@xinK%O{  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) :s)cTq|3  
{ If'q8G3]-  
sSiteURL= sURL; }:$cK(|  
sFilePath = sPath; ?;~!C2Zs  
sFileName = sName; UiU/p
 
this.nSplitter = nSpiltter; C T~6T&'  
(g6e5Sgi>  
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} 5:PS74/  
?XKX&ws  
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public String getSSiteURL() qI'pjTMDY  
{ (Ypy}  
return sSiteURL; jUT`V ZK4&  
} *%uzLW0  
U~ X  
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public void setSSiteURL(String value) C-pR$WM:HN  
{ \g0vzo"u  
sSiteURL = value; M)13'B
.  
} #H$lBCWI  
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XtCIUC{r,  
public String getSFilePath() .AN1Yt  
{ Y9BQLu4F  
return sFilePath; 8W3zrnc  
} 5OM#_.p  
le*+(aw  
:N8n6)#1=  
public void setSFilePath(String value) d` GN!^  
{ %/dOV[/  
sFilePath = value; Wh
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} X5owAc6  
$Sc_E:`]  
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public String getSFileName() ]p|?S[!=  
{  |q3X#s72  
return sFileName; [kg^S`gc#  
} 2poo@]M/  
}u#3hYa  
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public void setSFileName(String value) L|1,/h 8p  
{ loA/d  
sFileName = value; <NZPLo F  
} #7;
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public int getNSplitter() $yU 5WEX  
{ Zk`y"[J  
return nSplitter; =A!oLe$%  
} /? %V% n  
Z/,R{Jgt"  
#91^1jyMf  
public void setNSplitter(int nCount) yPE3Awh5  
{ U\%r33L )  
nSplitter = nCount; RUY7Y?  
} b}TvQ+W]2  
} !-MY<'  
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YCRE-5!  
/* y`9#zYgqA  
**Utility.java zS:2?VXxq  
*/ $WIE`P%  
package NetFox; &~2m@X(o  
3JC uM_y  
1 b7jNkQ  
public class Utility { b |:Y3_>  
"{8j!+]4i  
JuZkE9C,${  
public Utility() Mbc&))A  
{ qu^g~"s  
#^$_/Q#C  
]RAh['u|  
} lEl.'X$  
|uf
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//线程睡眠 brp3xgQ`]  
public static void sleep(int nSecond)
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J  
{ )bM,>x  
try{ KBM*7raA  
Thread.sleep(nSecond); N3$1f$`  
} wa<k%_# M  
catch(Exception e) 3qTr|8`s  
{ t U}6^yc  
e.printStackTrace (); )W=O~g  
} _-BP?'lN  
} lU 62$2  
uxyj6(  
//日志 7c"Csq/]I  
public static void log(String sMsg) R'sNMWM  
{ .@):
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System.err.println(sMsg); Z,"4f*2  
} .Wt3|?\=nd  
U
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z&QfZs  
public static void log(int sMsg) o/3.U=px~  
{ \ Bj{.
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System.err.println(sMsg); &]YyV.
 
} Ck#e54gJX  
} T1q27I  
i&m_G5u88  
2.WI".&y=  
/* %16Lo<DPm  
**TestMethod.java WOZuFS13  
*/ %|e)s_%XE  
package NetFox; -E1-(TS  
.K84"Gdx  
lrZ]c:%k  
public class TestMethod { G_?U?:!AC  
S?CT6moXA  
)!v"(i.5Xo  
public TestMethod() \dJhDR  
{ ///xx/weblogic60b2_win.exe T; tY7;<  
try{ -$"$r ~ad  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); =Rx4ZqTI|  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); W8Ssv  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ^vMlRt;  
fileFetch.start(); M6
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} uGz)Vz&3  
catch(Exception e){e.printStackTrace ();} 4GP?t4][  
|dQz(z&6{5  
!-tw  
} _{c_z*rM8  
?fH1?Z\'K  
%SB4_ r*<  
public static void main(String[] args) /pjl6dJ t  
{ "LTw;& y  
new TestMethod(); A:ts_*  
} =s!0EwDH3  
} ,
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