http断点续传简单实现（java)

/* cO2 .gQo'  
**SiteFileFetch.java hu-fwBK  
*/ N}wi<P:*)  
package NetFox; *-bR~  
import java.io.*; 06I'#:]  
import java.net.*; :N#gNtC)b  
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public class SiteFileFetch extends Thread { c"%XE#D  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 65RWaz;|  
long[] nStartPos; //开始位置 OvU]|4h  
long[] nEndPos; //结束位置 oUEpzv,J  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 "])X0z yM  
long nFileLength; //文件长度 Z>Nr"7k  
boolean bFirst = true; //是否第一次取文件 $%VFk53I  
boolean bStop = false; //停止标志 JoA^9AYhR  
File tmpFile; //文件下载的临时信息 pi? q<p%  
DataOutputStream output; //输出到文件的输出流 8^;[c  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） mFOuE5  
public SiteFileFetch(SiteInfoBean bean) throws IOException <tAn2e!  
{ 7Xv.C&jzd  
siteInfoBean = bean; AFL*a*  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); !z
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); /ocd
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if(tmpFile.exists ()) +Ij>\;vM"  
{ XU.ZYYZ=  
bFirst = false; 38Lc|w  
read_nPos(); o"t+G/M  
} -MoI{3a  
else j& f-yc'i-  
{  m2%uGqz  
nStartPos = new long[bean.getNSplitter()]; "8VCX
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nEndPos = new long[bean.getNSplitter()]; x=yBB;&  
} PdJtJqA8h\  
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} wQ[~7 ,o  
b mZRCvW>A  
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public void run() {Q^P<  
{ ]*U\ gm%  
//获得文件长度 -G]\"ZGi  
//分割文件 lu_ y9o^  
//实例FileSplitterFetch MuYr?1<q  
//启动FileSplitterFetch线程 #"%oz^~\  
//等待子线程返回 |)i-c`x  
try{ Y1
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if(bFirst) [zIX&fPk$  
{ \?h +  
nFileLength = getFileSize(); qX`?4"4  
if(nFileLength == -1) x;lIw)Ti  
{ }u5;YNmXxF  
System.err.println("File Length is not known!"); {FraM,w:  
} u&".kk  
else if(nFileLength == -2) |vA3+kG  
{ ~\}%6W[2  
System.err.println("File is not access!"); S0 M-$  
} ^]^Y~$u  
else nX<!n\J T  
{ n NZq`M  
for(int i=0;i<nStartPos.length;i++) Lie\3W  
{ <WtX> \]l(  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); cnC&=6=a<  
} S #%'Vrp  
for(int i=0;i<nEndPos.length-1;i++) cC1nC76[  
{ 8$-Wz:X&  
nEndPos = nStartPos[i+1]; MOP %vS  
} P~iu|j  
nEndPos[nEndPos.length-1] = nFileLength; PX52a[wNDH  
} F4>}mIA  
} ItHKpTer  
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%FLz}QW*  
//启动子线程 vLJ<_&6  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; O[3J Px  
for(int i=0;i<nStartPos.length;i++) &6FRw0GX  
{ a*6x^R;)  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +Vt@~Z4K  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), bSU9sg\  
nStartPos,nEndPos,i); 2X;,s`)  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); BgJ;\NV  
fileSplitterFetch.start(); gCz^JM  
} 0FsGqFt  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %#2[3N{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); T/MbEqAf  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", KQaw*T[Q3w  
nEndPos = " + nFileLength); qbu Lcy3  
// fileSplitterFetch[nPos.length-1].start(); #*j  
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1$?O5.X:  
//等待子线程结束 5W>i'6*  
//int count = 0; tn+i5Eso  
//是否结束while循环 A5z`_b4f  
boolean breakWhile = false; 1Jc-hrN-  
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while(!bStop) 
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{ tx}{E<\>$  
write_nPos(); }:5r#Cd  
Utility.sleep(500); =B4mi.;@i  
breakWhile = true; Xl;u  
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for(int i=0;i<nStartPos.length;i++) @fRB0m"3  
{ BM&95p  
if(!fileSplitterFetch.bDownOver) ~0>g 4 D.  
{ ?Q="w5OOD  
breakWhile = false; 8<Asg2]6  
break; m[!t7e  
} Ex^7`-2,B  
} ;:vbOG#aSN  
if(breakWhile) ^O6PZm5J}  
break; Yb]eWLv  
PbJn8o  
bqFGDmu6'  
//count++; 66fv
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//if(count>4) s[nXr  
// siteStop(); BC%t[H} >R  
} vi["G7  
:R{Xd{?  
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System.err.println("文件下载结束！"); q El:2<  
} eEb(TG~,Y  
catch(Exception e){e.printStackTrace ();} A&~G  
} 1,T8@8#  
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//获得文件长度 `]#DdJ_|  
public long getFileSize() Dh BUMDoB  
{ .8uJ%'$)  
int nFileLength = -1; ce.'STm=  
try{ (\e,,C%;  
URL url = new URL(siteInfoBean.getSSiteURL()); W=&\d`><k  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0rxlN [Yp  
httpConnection.setRequestProperty("User-Agent","NetFox"); pjvChl5  
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int responseCode=httpConnection.getResponseCode(); &Zs h-|N  
if(responseCode>=400) {vx{H
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{ aDm$^yP  
processErrorCode(responseCode); ,jQkR^]j-  
return -2; //-2 represent access is error uwsGtgd&  
} Z`o}xV  
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String sHeader; |+mhYq|`  
5O#CdN-S  
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for(int i=1;;i++) *JZU 0Xb  
{ 1>c`c]s3  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ,oT?-PC$z  
//Utility.log(in.readLine()); LUna stA^  
sHeader=httpConnection.getHeaderFieldKey(i); Vx;f/CH3!  
if(sHeader!=null) MIub^ $<C  
{ .!\y<9  
if(sHeader.equals("Content-Length")) 1RY}mq  
{ ?9mFI(r~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); kn
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break; m4<8v  
} usZmf=p-r  
} ,v4Z[ (  
else X4!` V?  
break; MlkTrKdGi  
} AA;\7;k{  
} eG72=l)Mz  
catch(IOException e){e.printStackTrace ();} puG$\D-[  
catch(Exception e){e.printStackTrace ();} ^6Q(he  
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Utility.log(nFileLength); #[vmS  
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return nFileLength; DM/J,q  
} Qf6]qJa|  
,}2M'DSWa  
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//保存下载信息（文件指针位置） /(8Usu?g.  
private void write_nPos() tQ< ou,  
{ 
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try{ IVzJ|  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ,@tYD(Z  
output.writeInt(nStartPos.length); 9w[7X"#n  
for(int i=0;i<nStartPos.length;i++) A7>0Pn%D3  
{ [h""
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// output.writeLong(nPos); vRp =L54z  
output.writeLong(fileSplitterFetch.nStartPos); A-aukJg9  
output.writeLong(fileSplitterFetch.nEndPos); /k|y\'<  
} IFlDw}M!9  
output.close(); 3
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} %L.,:mtq)  
catch(IOException e){e.printStackTrace ();} )?^0<l#s  
catch(Exception e){e.printStackTrace ();} }\|$8~  
} cF_ Y}C  
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//读取保存的下载信息（文件指针位置） B_i@D?bTD  
private void read_nPos() !R-M:|  
{ fLA!oeq{&}  
try{ #WwQ^6ESc  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); d&&^_0O  
int nCount = input.readInt(); 4ZrX=e,  
nStartPos = new long[nCount]; ,Bk mf|  
nEndPos = new long[nCount]; N&K:Jp  
for(int i=0;i<nStartPos.length;i++) tH,}_Bp  
{ v T2YX5k&,  
nStartPos = input.readLong(); }i!hzkK#  
nEndPos = input.readLong(); F&<si:}KB  
} /B.\6  
input.close(); wqx@/--E(  
} 8G; t[9  
catch(IOException e){e.printStackTrace ();} c}kZx1  
catch(Exception e){e.printStackTrace ();} A1Ia9@=Mf  
} /)ps_gM  
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private void processErrorCode(int nErrorCode) Ac0C
,*|^  
{ !FX0Nx=oi  
System.err.println("Error Code : " + nErrorCode); 1q]V/V}  
} jw?/@(AC6  
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//停止文件下载 Vcz ExP  
public void siteStop() w{f!t8C*s  
{ <k-&Lh:o3  
bStop = true; =o^oMn  
for(int i=0;i<nStartPos.length;i++) XrS.[  
fileSplitterFetch.splitterStop(); -^]8wQU  
xQ\/6|  
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} D+lzISp~e  
} +ObP[F  
//负责部分文件的抓取 >&6pBtC_  
**FileSplitterFetch.java X1?7}VO  
*/ =k
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package NetFox; U+>!DtOYK  
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import java.io.*; j9)P3=s  
import java.net.*; NNLZ38BV7  
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public class FileSplitterFetch extends Thread { secD `]  
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|=
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String sURL; //File URL ^2%_AP0=  
long nStartPos; //File Snippet Start Position :IlRn`9X`  
long nEndPos; //File Snippet End Position [* ,k  
int nThreadID; //Thread's ID ,*$L_itL  
boolean bDownOver = false; //Downing is over A;7p  
boolean bStop = false; //Stop identical 7nM]E_  
FileAccessI fileAccessI = null; //File Access interface :@x24wN/  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 0h/gqlTK1  
{ T;K@3]FbX  
this.sURL = sURL; LsH&`G^<  
this.nStartPos = nStart; A]L;LkEM  
this.nEndPos = nEnd; 7ZarXv z  
nThreadID = id; 4scY8(1  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 H^z6.!$m  
} mz$)80ly  
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public void run() t0h@i`  
{ nI7G"f[%r;  
while(nStartPos < nEndPos && !bStop) Sm-gi|A  
{ #=C!Xx&  
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try{ z+,l"#Vv  
URL url = new URL(sURL); 2Z K:S+c  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |YCGWJaci  
httpConnection.setRequestProperty("User-Agent","NetFox"); >]K:lJ]l  
String sProperty = "bytes="+nStartPos+"-"; Z^ynw8k"  
httpConnection.setRequestProperty("RANGE",sProperty); )d5Hv2/0  
Utility.log(sProperty); Lf0Y|^!S_u  
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InputStream input = httpConnection.getInputStream(); 2f
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//logResponseHead(httpConnection); "[M,PI!B  
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byte[] b = new byte[1024]; LA &W@  
int nRead; \) DJo  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) )7!q>^S{B  
{ Jm8{@D%  
nStartPos += fileAccessI.write(b,0,nRead); Ey<vvZ  
//if(nThreadID == 1) ~Sy/q]4ys*  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5-'jYp/  
} uqe{F+;8&  
7i^7sT8t  
 h0}r#L  
Utility.log("Thread " + nThreadID + " is over!"); %+Hhe]J ld  
bDownOver = true; c6/+Ye =h  
//nPos = fileAccessI.write (b,0,nRead); Wy1#K)LRb  
} &Ui*w%  
catch(Exception e){e.printStackTrace ();} IxN0m7  
} _2uRY  
} !bs{/?  
>%Rb}Ki4  
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//打印回应的头信息 >K:| +XbH  
public void logResponseHead(HttpURLConnection con) ffyDi1Q  
{ OBrb
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for(int i=1;;i++) KFQ4vavNh  
{ ^w]N#%k\H  
String header=con.getHeaderFieldKey(i); yKupPp);  
if(header!=null) pFE&`T@ <  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); r\nKJdh;ka  
Utility.log(header+" : "+con.getHeaderField(header)); dJyf.VJ  
else X*f#S:kiNU  
break; C>l{_J)n  
} ' cM2]<  
} Nl"Xl?y}  
;MRK*sfw{  
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public void splitterStop() .quui\I3  
{ U`YPzZp_  
bStop = true; 99W-sV  
} pc9m,?n  
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}/)vOUcEd  
} 2stBW5v3  
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/* abog\0  
**FileAccess.java %#5\^4$z|N  
*//文件访问(定位，写) Dsq_}6l{  
package NetFox; `N<6)MX3>g  
import java.io.*; J-iFAKN  
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public class FileAccessI implements Serializable{ nE"##2X  
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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 YY{0WWua  
RandomAccessFile oSavedFile; >i&"{GZ  
long nPos; [/Q .MmnL  
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public FileAccessI() throws IOException t2bv nh  
{ d_t
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this("",0); n*(9:y=l1  
} GjVq"S  
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public FileAccessI(String sName,long nPos) throws IOException ;4(ULJ*  
{ [D;wB|+,  
oSavedFile = new RandomAccessFile(sName,"rw"); ~7CQw^"R@  
this.nPos = nPos; hY*ylzr83  
oSavedFile.seek(nPos); qKt*<KGeY  
} *??!~RE  
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public synchronized int write(byte[] b,int nStart,int nLen) x}^:Bs+j  
{ IBP3  
int n = -1; y4N8B:j%  
try{ ]|H`?L  
oSavedFile.write(b,nStart,nLen); K)ZW1d;  
n = nLen; o7:~C]  
} J\06j%d,  
catch(IOException e) ShP&ss  
{ X283.?  
e.printStackTrace (); &^q!,7.J  
} c:*[HO\  
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return n; aNt+;M7g`  
} 4*`AYx(  
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} d+caGpaR  
9\dpJ\  
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/* n'
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**SiteInfoBean.java j\I{
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*/ mB\)Q J.%  
package NetFox; xYmh{Vc8  
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public class SiteInfoBean { RZY[DoF8u  
@Sr{6g
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private String sSiteURL; //Site's URL biLN
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private String sFilePath; //Saved File's Path +6zW(Ql/  
private String sFileName; //Saved File's Name k?bIu  
private int nSplitter; //Count of Splited Downloading File y 4 wV]1  
"V=IG{.  
I ~U1vtgp  
public SiteInfoBean() )7aUDsu>4  
{//nSplitter的缺省值为5 *\-$.w)k  
//default value of nSplitter is 5 CI#6r8u  
this("","","",5); JJQS7,vG  
} QLPb5{>KDS  
iH`Q4  
*dAQ{E(rO  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) *XU2%"Sc  
{
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sSiteURL= sURL; X_3*DqY  
sFilePath = sPath; -n:
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sFileName = sName; AT:L&~O.  
this.nSplitter = nSpiltter; i?3~Gog  
" jBc5*  
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} )X2/_3  
jW8,}Xs  
?lPn{oB9"  
public String getSSiteURL() `MLOf  
{ ]Pp}=hcD  
return sSiteURL; p{vGc-zP.  
} _Xqa_6+/  
'5)PYjMnH  
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public void setSSiteURL(String value) B
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{ f0|wN\  
sSiteURL = value; ?~:4O}5Ax  
} mG*ER^Y@D  
ez-jVi-Fi  
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public String getSFilePath() m ?e::W  
{ C>:,\=y%  
return sFilePath; tH)fu%:p  
} <G_71J`MLC  
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public void setSFilePath(String value) @*<`*W  
{ 'PqKb%B|  
sFilePath = value; ~Fe$/*v  
} <-h[
I&."  
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FX  %(<M  
public String getSFileName() h}U>K4BJ  
{ T!jMh-8  
return sFileName; 3 ,f3^A  
} 'lMDlTU O  
K
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public void setSFileName(String value) 6QYHPz  
{ ri1;i= W  
sFileName = value; :\]qB&  
} tuslkOE#  
rU |%  
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public int getNSplitter() YD,<]q%  
{ B;^1W{%J  
return nSplitter; |%g)H,6c  
} moD)^':.  
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public void setNSplitter(int nCount) *AG01# ZF  
{ J(Fk@{!F.*  
nSplitter = nCount; FvXpqlp  
} n#S?fsQN  
} :I2spBx  
)E*-  
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/* FM
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**Utility.java 1l s8h  
*/ ~hb;kc3  
package NetFox; 8 +mW  
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public class Utility { v@,`(\Ca'  

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public Utility() ~^J9v+  
{ @ek8t2??x  
+O4//FC-"  
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} w$0*5n>)  
re fAgS!=q  
//线程睡眠 juA}7   
public static void sleep(int nSecond) ]$!7;P  
{ w:9M6+mM^  
try{ l
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Thread.sleep(nSecond); u/apnAW@M  
} ZmvtUma  
catch(Exception e) &],O\TAul  
{ J
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e.printStackTrace (); Q">wl  
} 7|k2~\@q  
} e\._M$l  
K_fJ{Vc>O  
//日志 Flaqgi/j  
public static void log(String sMsg) \rY\wa  
{ 2S//5@~_m  
System.err.println(sMsg); sWKv>bx  
} kbSl.V%)  
n]8*yoge  

{S`Rr/E|%  
public static void log(int sMsg) N}Or+:"O:q  
{ NNBT.k3)  
System.err.println(sMsg); nK`H;k  
} U45-R-  
} P! P` MX  
DAy|'%rF1-  
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/* gZ us}U  
**TestMethod.java ir5e
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*/ ]/|D
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package NetFox; b?/Su<q  
\[ W`hhJ  
1 J[z ![Tf  
public class TestMethod { @9lGU#  
*, R ~[g  
]YY4{E(9d  
public TestMethod() r-Oz
k$  
{ ///xx/weblogic60b2_win.exe w+{{4<+cd  
try{ bYYjP.rcF  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 1[-RIN;U8  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Lr Kx  
SiteFileFetch fileFetch = new SiteFileFetch(bean); RN$q,f[#  
fileFetch.start(); Hp@cBj_@P2  
} *fSX3Dk  
catch(Exception e){e.printStackTrace ();} `(]mU
W  
ceLr;}?Ws  
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} ppu<k N  
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t&-c?&FO\;  
public static void main(String[] args) fO837  
{ z=4E#y`?U  
new TestMethod();

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} W$` WkR  
} +!t *LSF  
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