http断点续传简单实现（java)

/* A7|CG[wZ  
**SiteFileFetch.java 7q%<JZPY  
*/ L<GF1I)  
package NetFox; e@Cv')]B  
import java.io.*; f&z@J,_=  
import java.net.*; \]@XY_21  
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public class SiteFileFetch extends Thread { WcG!6.U>  
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SiteInfoBean siteInfoBean = null; //文件信息Bean aJQx"6c?  
long[] nStartPos; //开始位置 p "J^  
long[] nEndPos; //结束位置 \R m2c8Z2  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ?Re6oLm<B  
long nFileLength; //文件长度 hI&ugdf  
boolean bFirst = true; //是否第一次取文件 1XwW4cZ>:  
boolean bStop = false; //停止标志 5BztOYn,  
File tmpFile; //文件下载的临时信息 $p(,Qz(.8  
DataOutputStream output; //输出到文件的输出流 l'pu?TP{a  
3!+N}[$iy  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） @[:JQ'R=  
public SiteFileFetch(SiteInfoBean bean) throws IOException V_>)m3zsL  
{ # 1S*}Q<k  
siteInfoBean = bean; aMUy^
>  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 0:,8Ce  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); I6k S1  
if(tmpFile.exists ()) M-K.[}}-d  
{ JTK0#+?  
bFirst = false; 9PU9BYBG  
read_nPos(); ]~')OSjw  
} Mp8FYPjZ  
else <Z$r\Huf  
{ -w0U}Te^  
nStartPos = new long[bean.getNSplitter()]; gypE~@  
nEndPos = new long[bean.getNSplitter()]; ;yc|=I^  
} oAMB}a;  
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} :;wb{q$O  
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public void run() R)%1GG4  
{ M"E ]r=1  
//获得文件长度 *zf@J'  
//分割文件 AADvk_R  
//实例FileSplitterFetch L$ nFRl&  
//启动FileSplitterFetch线程 S
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//等待子线程返回 97$1na3gq  
try{ # j
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if(bFirst) L5"|RI}  
{ mXX9Aa>  
nFileLength = getFileSize();  qep<7 QO  
if(nFileLength == -1) L4)@lmd3  
{ OMr&f8  
System.err.println("File Length is not known!");  Tl.%7)  
} OT&mNE4  
else if(nFileLength == -2) *@M7J  
{ GM5s~,  
System.err.println("File is not access!"); `&)khxT/  
} x8]9Xe:_>O  
else /K#t$
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{ _` %z  
for(int i=0;i<nStartPos.length;i++) {kLL&`ii  
{ l )hg!(  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 8:BPXdiK  
} :QSCky*i  
for(int i=0;i<nEndPos.length-1;i++) /r4QDwu  
{ (z[|\6O  
nEndPos = nStartPos[i+1]; +sTZ) 5vQ  
} #>SvYP  
nEndPos[nEndPos.length-1] = nFileLength; :Kc}R)6  
} .K`^n\T t  
} Vx]{<}(gr  
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//启动子线程 }y-b<J?H  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 39W"G7n?v  
for(int i=0;i<nStartPos.length;i++) iU5Aj:U3  
{ k$V.hG|6M  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), '`$US;5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ar0y8>]3  
nStartPos,nEndPos,i); #j_<iy  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); y;N[#hY#CD  
fileSplitterFetch.start(); bDLPA27  
} w[>/(R7im  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), E(i<3U"4h[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); >Q0HqOq  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ^]He]FW':G  
nEndPos = " + nFileLength); l vuoVINEp  
// fileSplitterFetch[nPos.length-1].start(); *"N756Cj  
1D /{Y  
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//等待子线程结束 8^3Z]=(Q  
//int count = 0; MQR@(>TZy  
//是否结束while循环 DrD68$,QN  
boolean breakWhile = false; mQQ5>0^m  
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while(!bStop) )v!>U<eprD  
{ `TBI{q[y  
write_nPos(); +DwyMzeE  
Utility.sleep(500); .P[ %t=W  
breakWhile = true; Xa._  
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for(int i=0;i<nStartPos.length;i++) /J8'mCuC.  
{ `[JX}<~i  
if(!fileSplitterFetch.bDownOver) %DAF26t  
{ u$c)B<.UR  
breakWhile = false; ?XVJ$nzW  
break; kve{CO*  
} 2}P<}-?6  
} $x&\9CRM  
if(breakWhile) wL]7d3t  
break; A*ImruV  
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//count++; Aj06"ep  
//if(count>4) 4'pg>;*.  
// siteStop(); %2=nS<kC  
} L3M
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System.err.println("文件下载结束！"); Y?Yix  
}
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catch(Exception e){e.printStackTrace ();} `vJ+sRf  
} %Uk]e5Hu  
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//获得文件长度 8Ua;< h%  
public long getFileSize() 'z\K0  
{ zV {[0s  
int nFileLength = -1; { U a19~'>  
try{ 9V&%_.Z
 
URL url = new URL(siteInfoBean.getSSiteURL()); \[&~.B  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .IYE+XzV  
httpConnection.setRequestProperty("User-Agent","NetFox"); 2 @g'3M  
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int responseCode=httpConnection.getResponseCode(); Fl GKy9k  
if(responseCode>=400) fG O.wb  
{ \HFh?3-g  
processErrorCode(responseCode); 28M!G~|  
return -2; //-2 represent access is error  hM2^[8  
} 95giqQ(N  
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String sHeader; x
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for(int i=1;;i++) +`Bm  
{ [Dp6q~RM  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); @)iv'  
//Utility.log(in.readLine()); Ftj3`Mu  
sHeader=httpConnection.getHeaderFieldKey(i); +ib72j%A  
if(sHeader!=null) & v=2u,]T  
{ pLL ^R  
if(sHeader.equals("Content-Length")) kEWC  
{ pdsjX)O+f  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); NMY~f (x  
break;
+\9Y;Ny  
} 5nzkZw  
} f+Nq?GvwBQ  
else yB(^t`)}N  
break; o9~Z! &p  
} sj003jeko  
} ptGM'  
catch(IOException e){e.printStackTrace ();} ^r73(8{)  
catch(Exception e){e.printStackTrace ();} P5Ms X~mT  
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Utility.log(nFileLength); OUn,
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return nFileLength; :<Y,^V(  
} Z<z(;)?c  
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//保存下载信息（文件指针位置） K=VYRY  
private void write_nPos() 5[[4A]#T  
{ mZJ"e,AY  
try{ Ra[{K@  
output = new DataOutputStream(new FileOutputStream(tmpFile)); HS]|s':  
output.writeInt(nStartPos.length); tlu-zUsi  
for(int i=0;i<nStartPos.length;i++) )#Ea~>
v  
{ FSd842O  
// output.writeLong(nPos); $/nU0W  
output.writeLong(fileSplitterFetch.nStartPos); 4&~1|B{Z  
output.writeLong(fileSplitterFetch.nEndPos); >V@-tT"^:  
} Uaj8}7v  
output.close(); >}GtmnF  
} z'3  
catch(IOException e){e.printStackTrace ();} bNp RGhlV  
catch(Exception e){e.printStackTrace ();} 6",1JH,;p  
} 3J~Q pw0<  
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//读取保存的下载信息（文件指针位置） f{AbCi  
private void read_nPos() xRq|W4ay  
{ Y~hBVz2g  
try{ ?SRG;G
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); D`,W1Z#  
int nCount = input.readInt(); ?kX$Y{M}  
nStartPos = new long[nCount]; |"?0H#  
nEndPos = new long[nCount]; R8Nr3M9 )  
for(int i=0;i<nStartPos.length;i++) L+7L0LbNU  
{ +DaPXZ5.  
nStartPos = input.readLong(); %f
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nEndPos = input.readLong(); '@i/?rNi%N  
} 2G<\Wz  
input.close(); LJ`*&J  
} 5ycccMx0V  
catch(IOException e){e.printStackTrace ();} XzgJ@  
catch(Exception e){e.printStackTrace ();} 9^QiFgJy  
} }&Ngh4/  
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private void processErrorCode(int nErrorCode) BSYJ2  
{ "VR>nyG%  
System.err.println("Error Code : " + nErrorCode); kL\
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} zs:OHEZw  
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.;)7)%  
//停止文件下载 pSvRyb.K  
public void siteStop() 0eUK'  
{ S\b[Bq  
bStop = true; X*hY?'Rp  
for(int i=0;i<nStartPos.length;i++) '!^5GSP3&  
fileSplitterFetch.splitterStop(); pyYm<dn  
/ E}L%OvE  
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} w=H  
} P|HxD0c^u  
//负责部分文件的抓取 _ dEc? R}  
**FileSplitterFetch.java }5 ^2g!M  
*/ _b|mSo,{Y  
package NetFox; 4v9jGwnzt  
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import java.io.*; no_;^Ou?  
import java.net.*; p)v|t/7  
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/}A"F[5  
public class FileSplitterFetch extends Thread { (37dD!  
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String sURL; //File URL C'$w*^me  
long nStartPos; //File Snippet Start Position M|8vP53=q  
long nEndPos; //File Snippet End Position !*Ex}K99  
int nThreadID; //Thread's ID VF[$hs
  
boolean bDownOver = false; //Downing is over m#6RJbEz  
boolean bStop = false; //Stop identical %d?.v_Hu0  
FileAccessI fileAccessI = null; //File Access interface 8'XAZSd(  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException h [*/Tnr  
{ W D8  
this.sURL = sURL; A1>fNilC9  
this.nStartPos = nStart; pGZiADT  
this.nEndPos = nEnd; (~S=DFsP  
nThreadID = id; eka<mq|W  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 {BV0Y.O  
} }fC=  
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public void run() {:=sCY!  
{ P=3mLz-  
while(nStartPos < nEndPos && !bStop) V[DiN~H  
{ 7:/gO~gI  

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try{ KXrZ:4bg
 
URL url = new URL(sURL); U80h0t%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;f?suawMv  
httpConnection.setRequestProperty("User-Agent","NetFox"); KBC?SxJSJc  
String sProperty = "bytes="+nStartPos+"-"; r=}v` R&  
httpConnection.setRequestProperty("RANGE",sProperty); q4MR9ig1E_  
Utility.log(sProperty); ohU}ST:9  
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InputStream input = httpConnection.getInputStream(); i0}f@pCB?X  
//logResponseHead(httpConnection); l+nT$IPF  
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byte[] b = new byte[1024]; `!(IQ&  
int nRead; gpw,bV  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) )JrG`CvdU  
{ LWdA3%  
nStartPos += fileAccessI.write(b,0,nRead); /
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//if(nThreadID == 1) )FpizoVq0  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); xovsh\s  
} O!G!Gq&  
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Utility.log("Thread " + nThreadID + " is over!"); OwCbv j0#  
bDownOver = true; 9Iu"DOxX%  
//nPos = fileAccessI.write (b,0,nRead); +)hxYLk&I  
} R53^3"q~  
catch(Exception e){e.printStackTrace ();} F|jl=i  
} ,njlKkFw^Z  
} )+Y"4?z~  
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//打印回应的头信息 Vk> &
 
public void logResponseHead(HttpURLConnection con)
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{ L} "bp  
for(int i=1;;i++) n)0M1o#  
{ |}?H$d  
String header=con.getHeaderFieldKey(i); D0Mxl?S?  
if(header!=null) }Y^o("c(  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Aydpr_lp  
Utility.log(header+" : "+con.getHeaderField(header)); WG&! VK  
else to'CuPkT  
break; W#+f2 RR  
} k;B[wEW@  
} n2can  
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public void splitterStop() NB4Q,iq$  
{ * RyU*au  
bStop = true; L+S)hgUH  
} t`="2$NO  
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} ^J&D)&"j  
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/* h\p!J-V  
**FileAccess.java c`/VYgcTqB  
*//文件访问(定位，写) ttdY]+Fj  
package NetFox; 2i0;b|-=  
import java.io.*; HUMy\u84H  
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public class FileAccessI implements Serializable{ c~4Cpy^  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 B~E">}=!  
RandomAccessFile oSavedFile; .^M#BAt2  
long nPos; ,p3]`MG  
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public FileAccessI() throws IOException bf@g*~h@  
{ =%<, ^2o  
this("",0); 2F>Y{3&  
} (c)=Do=  
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public FileAccessI(String sName,long nPos) throws IOException cE:s\hG  
{ z bYv}q  
oSavedFile = new RandomAccessFile(sName,"rw"); >I0;MNX  
this.nPos = nPos; ZM})l9_o"  
oSavedFile.seek(nPos); ^utOVi  
} -yB}(69  
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public synchronized int write(byte[] b,int nStart,int nLen) faDS!E' +  
{ ,{!,%]bC  
int n = -1; (_|*&au J  
try{ Cyd/HTNh<  
oSavedFile.write(b,nStart,nLen);
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n = nLen; :Rb\Ca  
} |,p"<a!+{w  
catch(IOException e) u{_,S3Aa  
{ ?tY+P`S  
e.printStackTrace (); 7tXy3-~biz  
} {QM rgyQE  
uDie
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05  
ed`
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return n; I)V=$r{  
} !Pw*p*z  
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} JyZuj>` 6  
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/* TG}owG]]  
**SiteInfoBean.java !nSa4U,$w<  
*/ c 9f"5~  
package NetFox; ^T!Zz"/:  
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public class SiteInfoBean { gMI%!Y  
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private String sSiteURL; //Site's URL H[u9C:}9b  
private String sFilePath; //Saved File's Path yuZLsH  
private String sFileName; //Saved File's Name )]j3-#  
private int nSplitter; //Count of Splited Downloading File VkFh(Br<{  
9$\s v5  
6?F88;L  
public SiteInfoBean() DLrV{8%W  
{//nSplitter的缺省值为5 QcL@3QC  
//default value of nSplitter is 5 o6MFMA+vi  
this("","","",5); rP4T;Clout  
} ;|WUbc6&g  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) d <}'eBT'  
{ rJ Jx8)M  
sSiteURL= sURL; oRCc8&  
sFilePath = sPath; xn3 _ED  
sFileName = sName; @e)}#kN.  
this.nSplitter = nSpiltter; $(9QnH1KY  
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} XLn9NBT4K  
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public String getSSiteURL() @GN2v,WA?  
{ I1fpX |  
return sSiteURL; 1Z}5ykM3  
} "Au4&Fu  
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!kE5]<H\  
public void setSSiteURL(String value) eB5>uKa  
{ 6j(/uF4!#  
sSiteURL = value; '3b\d:hN  
} g,+e3f  
2$Mnwxfk  
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public String getSFilePath() N[/<xW~x?4  
{ Ks%0!X?3q  
return sFilePath; 1tNL)x"w  
} jo:Z  
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public void setSFilePath(String value) LlX)xJ  
{ RM|J |R  
sFilePath = value; +Y7M7  
} LL(x

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public String getSFileName() |owr?tC  
{ _@ao$)q{J  
return sFileName; 6iU&9Z<%  
} c|?(
>  
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public void setSFileName(String value) ~~/
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{ @Go_5X(  
sFileName = value; WN'AQ~qA  
} xOTvrX  
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public int getNSplitter() :'p)xw4K|  
{ 7%^G]AFi  
return nSplitter; w5m/[Z  
} =<n ]T;  
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public void setNSplitter(int nCount) roS" q~GS,  
{ GY$Rkg6d  
nSplitter = nCount; IBT>&(cnV  
} J>_mDcPo  
} W2
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#kW=|8X  
/* `jE[Xt"@  
**Utility.java ~wa4kS<>  
*/ UdO8KD#r3  
package NetFox;  y<Koc>8  
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public class Utility { 07.p {X R  
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public Utility() 6Ryc&z5  
{ 84(Jo_9  
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} 9~UR(Ts}l  
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//线程睡眠 L~&S<5?  
public static void sleep(int nSecond) v^&HZk=(  
{ q'jOI_b  
try{ n5QO'Jr%[  
Thread.sleep(nSecond); \m7\}Nbz0/  
} uc,>VzdB  
catch(Exception e) .B`$hxl*0c  
{ ^2'Y=g>  
e.printStackTrace (); /O[6PG  
} \92M\S  
} gclj:7U  
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//日志 T, #-: }  
public static void log(String sMsg) 12^uu)6Xm,  
{ I{$suPk  
System.err.println(sMsg); ?62zv[#  
} ^JY {<  
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|lLe^FM  
public static void log(int sMsg) EP38Ho=[  
{ @*hv|zjs  
System.err.println(sMsg); va@;V+cD  
} g+o$&'
\  
} P"7` :a  
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#.Dl1L/  
/* V_ 6K?~j  
**TestMethod.java 4<s;xSCL  
*/ <);j5)/  
package NetFox; <~|n}&  
wQ(DX!   
~T}D#}  
public class TestMethod { G:e=9qTf  
E:rJi]  
_CNXyFw.7  
public TestMethod() "pt[Nm76)8  
{ ///xx/weblogic60b2_win.exe b#7nt ?`7p  
try{ MO~T_6  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 5JOfJ$(n  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); .x$V~t  
SiteFileFetch fileFetch = new SiteFileFetch(bean); y6am(ugE  
fileFetch.start(); ydD:6bBX  
} &#fPJc  
catch(Exception e){e.printStackTrace ();} -AnJLFY  
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e[k\VYj[  
} @{V`g8P>  
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public static void main(String[] args) #p"F$@N  
{ W[QgddR  
new TestMethod(); ^/2O_C  
} ++2a xRl  
} xD7Y"%Pbx  
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