http断点续传简单实现（java)

/* uyt]\zVT  
**SiteFileFetch.java UenB4  
*/ p`@7hf|hm  
package NetFox;  iw!kV  
import java.io.*; m{(G%n>E&  
import java.net.*; ;naD`([  
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public class SiteFileFetch extends Thread {  ~yQby&s  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ZXP9{Hh  
long[] nStartPos; //开始位置 3g!tk9InG  
long[] nEndPos; //结束位置 UADD 7d  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 oe<9CK:?>  
long nFileLength; //文件长度 "*E#4e[  
boolean bFirst = true; //是否第一次取文件 & 5!.!Z3  
boolean bStop = false; //停止标志 0{0|M8  
File tmpFile; //文件下载的临时信息  jpcbW  
DataOutputStream output; //输出到文件的输出流 YK[PC]w  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ai7*</ls  
public SiteFileFetch(SiteInfoBean bean) throws IOException Ob:}@jj  
{ N/ 7Q(^  
siteInfoBean = bean; (1`z16  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 2!Ip!IQ:  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ZJCD)?]=3  
if(tmpFile.exists ()) ZP>KHiA  
{ >7yOu!l  
bFirst = false; >syQDB  
read_nPos(); HmWU;9Vn+  
} 86bl'FdKS  
else s8,N9o[.~P  
{ [42vO  
nStartPos = new long[bean.getNSplitter()]; xz1jRI$  
nEndPos = new long[bean.getNSplitter()]; ][ri A  
} %UEV['=  
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} pBW|d\8  
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public void run() {ZiZ$itf  
{ S GAu.8Js  
//获得文件长度 )<
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//分割文件 6\MH2&L<  
//实例FileSplitterFetch a!Z.Z
A  
//启动FileSplitterFetch线程 [yzDa:%  
//等待子线程返回 T~shJ0%  
try{ ~&>|u5C*@  
if(bFirst) Vo@[  
{ *\9JIi 2  
nFileLength = getFileSize(); H5@N<v5u  
if(nFileLength == -1) (DzV3/+p^  
{ iOCx7j{BS  
System.err.println("File Length is not known!"); 5

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} 7_,)"J2^  
else if(nFileLength == -2) "c[ D0{\{  
{ 9$-V/7@)  
System.err.println("File is not access!"); >EQd;Af  
} @lo6?9oNo  
else 4a'GWzUtS  
{ h?f)Bt}ry  
for(int i=0;i<nStartPos.length;i++) vWbf5?  
{ ^a=,,6T  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); %O$4da"y  
} u`Ew^-">  
for(int i=0;i<nEndPos.length-1;i++)  2=X\G~a  
{ bERYC|  
nEndPos = nStartPos[i+1]; $S~e"ca1  
} jD@KG  
nEndPos[nEndPos.length-1] = nFileLength; JTH8vk:@  
} y#[PQT  
} obUX7N  
cN/8b0C  
cTy;?
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//启动子线程 Im9^mVe  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; < * )u\A  
for(int i=0;i<nStartPos.length;i++) F8(6P1}E  
{ giU6f!%  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _x<CTFTL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), l56D?E8  
nStartPos,nEndPos,i); [12^NEt  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~~h@(2/Q>x  
fileSplitterFetch.start(); jl# )CEx  
} F-MN%WD~  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), q$[x*!~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Rk
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ^j1?LB  
nEndPos = " + nFileLength); 7<W7pXDp  
// fileSplitterFetch[nPos.length-1].start(); Etk`>,]Y>y  
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&%QtUPvr9  
//等待子线程结束 BdHLow  
//int count = 0; ulM6R/V:?  
//是否结束while循环 vi+k#KE  
boolean breakWhile = false; 92}UP=RW!  
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V,=V   
while(!bStop) F<wwuCbF  
{ &lg+uK  
write_nPos(); !C&
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Utility.sleep(500); 6PETIs  
breakWhile = true; /aa'ryl_%  
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for(int i=0;i<nStartPos.length;i++) k(>hboR5n  
{ Q_<CG[,6D1  
if(!fileSplitterFetch.bDownOver) X(m&  
{ !^ko"^p  
breakWhile = false; 4%#C _pE9  
break; :cv_G;?  
} C^]y iR-U  
} Yrb[:;Y  
if(breakWhile) a=LjFpv/]  
break; rYI9?q  
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//count++; cX$ Pq  
//if(count>4) \TM%,RC3K  
// siteStop(); \hSOJ,{)U  
} ~
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]$)J/L(p/]  
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System.err.println("文件下载结束！"); o g.LD7&/  
} bqmOfGM  
catch(Exception e){e.printStackTrace ();} {9wBb`.n^  
} Z/=x(I0  
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//获得文件长度 (dO, +~  
public long getFileSize() ,@2d<d]  
{ >SA?lG8f%  
int nFileLength = -1; 0w?\KHT  
try{ 't3/< h<  
URL url = new URL(siteInfoBean.getSSiteURL()); -P+( =U  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !2oe;q2X[G  
httpConnection.setRequestProperty("User-Agent","NetFox"); }0Isi G  
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int responseCode=httpConnection.getResponseCode(); '\ec ,&4Z  
if(responseCode>=400) "y@B|  
{ (r_xs  
processErrorCode(responseCode); ,]e!OZ[$m  
return -2; //-2 represent access is error /M>8
ad  
} 3^kZydZCN  
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String sHeader; xmz83Ll9  
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for(int i=1;;i++) Lc;4 Hg  
{ Cs$wgm*  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); =VkbymIZ4y  
//Utility.log(in.readLine()); pNFL;k+p}  
sHeader=httpConnection.getHeaderFieldKey(i); h@$M.h@mcG  
if(sHeader!=null) @;m7u
  
{ 4}sfJ0HhX  
if(sHeader.equals("Content-Length")) wkm;yCF+  
{ SEm3T4dfzf  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); pQc5'*FKd  
break;  WTi8  
} OF^v;4u  
} 9I*zgM!F  
else 3QSP](W-(  
break; yRaB\'  
} T1ZAw'6(K  
} b!VaEK  
catch(IOException e){e.printStackTrace ();} j["b*X`8G  
catch(Exception e){e.printStackTrace ();} MH|!tkW>:  
ES72yh]  
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Utility.log(nFileLength); i,>yIPBU!  
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return nFileLength; h%MjVuLn  
} " SkTVqm  
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//保存下载信息（文件指针位置） YUdCrb9F  
private void write_nPos() d0YN:lJc  
{  ~0 <?^  
try{ `(A>7;]:  
output = new DataOutputStream(new FileOutputStream(tmpFile)); } y@pAeS,  
output.writeInt(nStartPos.length); 8"R;axeD  
for(int i=0;i<nStartPos.length;i++) \nM$qr'`B  
{  6jFc'  
// output.writeLong(nPos); C*kGB(H7  
output.writeLong(fileSplitterFetch.nStartPos); p b:mw$XQ7  
output.writeLong(fileSplitterFetch.nEndPos); YX38*Ml+V  
} dXgj  
output.close(); zk8s?$  
} 1euL+zeh  
catch(IOException e){e.printStackTrace ();} RYzDF+/  
catch(Exception e){e.printStackTrace ();} D4%5T>^LW[  
} h?[3{Z^  
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//读取保存的下载信息（文件指针位置） n@[&SgZq  
private void read_nPos() <o
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{ iK{ a9pt  
try{ in_~,fd  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); rnWU[U8
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int nCount = input.readInt(); "H
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nStartPos = new long[nCount]; [*ylC,w  
nEndPos = new long[nCount]; jO\29(_  
for(int i=0;i<nStartPos.length;i++) =pQA!u]QE  
{ *x3";
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nStartPos = input.readLong(); 42mi 7%f  
nEndPos = input.readLong(); 4G;FpWQm  
} [|PVq#(  
input.close(); x]|8  
} B,?Fjot#m  
catch(IOException e){e.printStackTrace ();} uKF?UXc  
catch(Exception e){e.printStackTrace ();} HlEp Dph%  
} Eyu]0+  
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private void processErrorCode(int nErrorCode) BH _y0[y  
{ pE(\q+1<  
System.err.println("Error Code : " + nErrorCode); ^b=]=w  
} 9B&QY 2v  
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:|/bEP]p/  
//停止文件下载 Rh#0EbE2  
public void siteStop() AA&398F  
{ 7Yp;B:5@  
bStop = true; ro{q':Z3  
for(int i=0;i<nStartPos.length;i++) ]nE_(*w  
fileSplitterFetch.splitterStop(); m~Q]#r  
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} O<nJbsl_w  
} c]:sk[u  
//负责部分文件的抓取 F4+mkB:w*7  
**FileSplitterFetch.java ,|SO'dG  
*/ |}
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package NetFox; .`4N#EjP  
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import java.io.*; QF:">G  
import java.net.*; H'68K8i0  
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@@$=MSN  
public class FileSplitterFetch extends Thread { Rt!G:hy7  
-N`j` zb|  
/VB n  
String sURL; //File URL yU"lW{H@  
long nStartPos; //File Snippet Start Position weCRhA  
long nEndPos; //File Snippet End Position (,$ H!qKy  
int nThreadID; //Thread's ID DueQ1+ P  
boolean bDownOver = false; //Downing is over 2Wz/s 0`  
boolean bStop = false; //Stop identical x]umh{H~  
FileAccessI fileAccessI = null; //File Access interface O8+e: K[D  
h*2Q0GRX  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException g0t$1cUR  
{ X;ef&n`U0  
this.sURL = sURL; gzqx{ ]  
this.nStartPos = nStart; )%p.v P'p  
this.nEndPos = nEnd; UEmNT9V  
nThreadID = id; S%n5,vwE  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 (pXZ$R:  
} 3f9J!B`n  
-Si'[5@  
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public void run() H|>dF)%pj  
{ q)R&npP7  
while(nStartPos < nEndPos && !bStop) F XJI,(:-  
{ Ys,}L.  
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try{ a.)Gd]}g  
URL url = new URL(sURL); lO},fM2j  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Omo1p(y  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8mTjf Br  
String sProperty = "bytes="+nStartPos+"-"; `?VtB!p@x=  
httpConnection.setRequestProperty("RANGE",sProperty); :Bc)1^I  
Utility.log(sProperty); U085qKyCw  
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InputStream input = httpConnection.getInputStream(); \IY)2C<e  
//logResponseHead(httpConnection); T'.U?G  
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byte[] b = new byte[1024]; YGrmco?G  
int nRead; + 5E6|  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ?,e7v.b
 
{ c"R`7P  
nStartPos += fileAccessI.write(b,0,nRead); eaP,M
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//if(nThreadID == 1) Bv,u kQ\CH  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _ +Ww1f  
} ,[enGw  
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Utility.log("Thread " + nThreadID + " is over!"); WP&P#ju&  
bDownOver = true; \y?Vou/  
//nPos = fileAccessI.write (b,0,nRead); /NFv?~</k  
} |T7 < !  
catch(Exception e){e.printStackTrace ();} ?2hoY  
} J$6tCFD  
} td-2
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$h1`-=\7  
LY}%|w  
//打印回应的头信息 vgRjd1k.\y  
public void logResponseHead(HttpURLConnection con) &L}e&5  
{ 0-#SvTf>;:  
for(int i=1;;i++) @? 4-  
{ 0eq="|n^|  
String header=con.getHeaderFieldKey(i); O~yPe.  
if(header!=null) +=#sam*i  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); KJc fbZ~  
Utility.log(header+" : "+con.getHeaderField(header)); 9?<WRM3a>  
else =N,9#o6^  
break; mKY}+21!Q  
} vfAR^*7e  
} Arh0m. w  
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public void splitterStop() 1(0LX^%  
{ TJ9JIxnS  
bStop = true; I3uS?c  
} dr3
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5{cbcuG  
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} 4Z>KrFO  
--E_s/  
1~\YJEsb}d  
/* Up?w>ly  
**FileAccess.java d5&avL\  
*//文件访问(定位，写) UZsL0  
package NetFox; [pi!+k  
import java.io.*; X3zkUMk  
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8'J"+TsOW  
public class FileAccessI implements Serializable{ ;w";s$  
[#S[=%  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 fT1/@  
RandomAccessFile oSavedFile; <A?- *
 
long nPos; ]5W|^%  
+[C(hhk("  
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public FileAccessI() throws IOException s0,c4y  
{ t|q@~B :  
this("",0); K?0f)@\nx  
} "<6X=|C  
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public FileAccessI(String sName,long nPos) throws IOException e]-bB#-A  
{ GZ.X
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oSavedFile = new RandomAccessFile(sName,"rw"); ${\iHg[vZ  
this.nPos = nPos; ZN75ONL  
oSavedFile.seek(nPos); 0LX;Vvo  
} ^hPREbD+f  
"&(
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public synchronized int write(byte[] b,int nStart,int nLen) BUR96YN.  
{ `j+aAxJ=\  
int n = -1; Wt=QCutt  
try{ `
8^4,  
oSavedFile.write(b,nStart,nLen); tow0/Jt  
n = nLen; .OI&Zm-  
} l1*qDzb  
catch(IOException e) #~]S  
{ SSH))zJ  
e.printStackTrace (); H4DM
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} Q
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return n; .$nQD.X  
} zzlV((8~  
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} +[386  
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/* tKtKW5n~  
**SiteInfoBean.java F*""n  
*/ wyF'B  
package NetFox; +u+|9@  
 l* C>  
^
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public class SiteInfoBean { XV)<Oavs  
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private String sSiteURL; //Site's URL epw*Px  
private String sFilePath; //Saved File's Path 8nCw1  
private String sFileName; //Saved File's Name J^t-pU  
private int nSplitter; //Count of Splited Downloading File UQZ<sp4v;  
CJ+/j=i;~c  
iZsZSW \  
public SiteInfoBean() ^e*Tg&  
{//nSplitter的缺省值为5 L9(mY `d>"  
//default value of nSplitter is 5 cE(P^;7D  
this("","","",5); 9i+OYWUO  
} FKhmg&+>  
LIzdP,^pc  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 6&jW.G8/  
{ 8:*   
sSiteURL= sURL; (9gL  
sFilePath = sPath; P`ZzrN  
sFileName = sName; }J=>nL'B  
this.nSplitter = nSpiltter; @\{L%y%a0  
ybsQ[9_36  
C(N' +VV_  
} / =]h@m-`  
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public String getSSiteURL() `" B
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{ H&$L1CrdL  
return sSiteURL; qUNK Dt  
} %H)^k${  
`6bIxb{  
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public void setSSiteURL(String value) _p;>]0cc.  
{ L!:8yJK  
sSiteURL = value; {J#SpG 7  
} 0j{Rsy  
clhmpu  
JATW'HWC|I  
public String getSFilePath() dJvT2s.t[  
{ m |Isi  
return sFilePath; An0DqjR  
} +Cf"rN  
B{}<DP.  
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public void setSFilePath(String value) [)efh9P*  
{ S($8_u$U  
sFilePath = value; q!L@9&KAQ  
} &m{SWV+  
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244[a] %&;  
public String getSFileName() 4gR;,%E\TO  
{ \mK;BWg)  
return sFileName; aMU0BS"  
} Gm`#0)VC  
zWs("L(#s  
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public void setSFileName(String value) <b JF&,  
{ :mYVHLmea  
sFileName = value; B3AWJ1o  
} /RG
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/)+V(Jlu  
public int getNSplitter() T`ofj7$:  
{ G 6r2 "  
return nSplitter; Jy^.L$bt  
} .ei5+?V<i  
a:v5(@8  
LE@<)}Au^  
public void setNSplitter(int nCount) QUQw/  
{ Am'%tw ~  
nSplitter = nCount; M6nQ17\{  
} `[)!4Jb  
} _^%DfMP3i\  
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T]_]{%z  
/* "26=@Q^Y  
**Utility.java R$|"eb5  
*/ ,1K`w:uhS  
package NetFox; _O,k0O   
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public class Utility { f(Su  
e 48N[p  
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public Utility() s~p(59  
{ ;_~9".'<d  
>0X_UDAWz  
[r#m +R"N  
} `=Z3X(Kc  
BjSd\Ul  
//线程睡眠 {D$5M/$  
public static void sleep(int nSecond) /:Q  
{ <jAn~=Uq[,  
try{ 4 (c{%%  
Thread.sleep(nSecond); m[}@\y  
} -F$v`|(O+  
catch(Exception e) B?nw([4m  
{ Fp&tJ]=B.  
e.printStackTrace (); UdOO+Z_K%  
} >vPv4e7&3  
} _ ?o>i/  
g)mjw  
//日志 :<P3fW  
public static void log(String sMsg) 2MU$OI0|  
{ \1ncr4  
System.err.println(sMsg); `B$rr4_  
} `s8o2"12  
}vXiqT  
;F;Vm$  
public static void log(int sMsg) =]fOQN`  
{ $TX]*hNn  
System.err.println(sMsg); .du2;`[$r  
} n&%0G2m:  
} 9;7|MPbR  
(V x2*Aw]  
OLZs}N+;]  
/* h(K}N5`  
**TestMethod.java ucYweXsO3  
*/ B#;6z%WK  
package NetFox; dQs>=(|t  
a=4
 `C*)  
nw-%!}Ot"  
public class TestMethod { tMiy`CPh  
 3GL,=q  
3y%,f|ju  
public TestMethod() LC,6hpmh  
{ ///xx/weblogic60b2_win.exe Bra}HjHO  
try{ -#Ys67,4N  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); JJHO E{%  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 9Ca }+  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Sq SiuO.D  
fileFetch.start(); ` 7P%muY.  
}  X`20=x  
catch(Exception e){e.printStackTrace ();} >{)\GK0i7  
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8ZF!}kb0F  
} }nRTw2-z  
}X/>WiGh:  
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public static void main(String[] args) b]4\$rW7  
{ \iRmGvT  
new TestMethod(); G1a56TIN~  
} <{T5}"e  
} pkf$%{"e  
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