http断点续传简单实现（java)

/* ijT^gsLL  
**SiteFileFetch.java $xwF;:)  
*/ FL}8h/  
package NetFox; @bE?WXY  
import java.io.*; zj}efv<e  
import java.net.*; w}0P
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public class SiteFileFetch extends Thread { ^^mi@&ApLD  
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SiteInfoBean siteInfoBean = null; //文件信息Bean uDUSR+E>  
long[] nStartPos; //开始位置 B$n\m854  
long[] nEndPos; //结束位置 dWEx55>,1  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Ro69woU  
long nFileLength; //文件长度 -R]S)Odml  
boolean bFirst = true; //是否第一次取文件 "^%Il  
boolean bStop = false; //停止标志 p^3d1H3  
File tmpFile; //文件下载的临时信息 5^i ^?  
DataOutputStream output; //输出到文件的输出流 _;+&'=6.[  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 1,,:4*)  
public SiteFileFetch(SiteInfoBean bean) throws IOException ~M=`f{-$K  
{ q9>w3 <  
siteInfoBean = bean; {w(N9Va,(  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ^|2qD: ;  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); W*#/@/5  
if(tmpFile.exists ()) w\a#Bfcv  
{ {0~ p"%*  
bFirst = false; _,QUH"
  
read_nPos(); /fEXAk  
} j(hC't-  
else UKdzJEhG  
{ GWsFW[T?~  
nStartPos = new long[bean.getNSplitter()]; `,z{70  
nEndPos = new long[bean.getNSplitter()]; B:SRHd{*Wu  
} *&km5@*
 
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} K,Vl.-4?  
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public void run() )ALcmC?!#  
{ L!RLw4   
//获得文件长度 r0,}f\  
//分割文件 F$
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//实例FileSplitterFetch m"5gzH  
//启动FileSplitterFetch线程 +VDB\n  
//等待子线程返回 8d
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try{ |gNOv;l  
if(bFirst) `CBTZG09  
{ }T@AoIR0t  
nFileLength = getFileSize(); x :s-\>RcA  
if(nFileLength == -1) 3zkq'lZ  
{ d4U_Wu&  
System.err.println("File Length is not known!"); aE}u5L$#  
} \_oHuw  
else if(nFileLength == -2) =:lacK(0  
{ <cS1}"  
System.err.println("File is not access!"); oz QL2  
} )DW;Gc  
else S!uyplYKF  
{ ]`x~v4JU  
for(int i=0;i<nStartPos.length;i++) _XN sDW4|  
{ E;SFf  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); _[V 6s#Wk3  
}  zcc]5>  
for(int i=0;i<nEndPos.length-1;i++) [Fe5a  
{ U3>G9g>^B  
nEndPos = nStartPos[i+1]; >dO^pDSs  
} Ag
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nEndPos[nEndPos.length-1] = nFileLength; BQ(`MM@  
} (,
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} ?V+=uTCq  
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//启动子线程 cVU[>gkg_  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; M~v{\!S  
for(int i=0;i<nStartPos.length;i++) d] {^  
{ X#fI$9a  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Cs<d\"+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), $Khc?v  
nStartPos,nEndPos,i); 5u8 Y
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); hhpH)Bi=  
fileSplitterFetch.start(); FRr<K^M  
} +aMPwTF:3  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 3j6$!89'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); z;LntQZp-  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 4IVCTz[  
nEndPos = " + nFileLength); N9hBGa$  
// fileSplitterFetch[nPos.length-1].start(); SI\zW[IL  
9 HuE'(wQ  
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//等待子线程结束 9ItsK  
//int count = 0; ^#Shs^#  
//是否结束while循环 tkA '_dcIC  
boolean breakWhile = false; :jA~zHO  
a"}?{
  
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while(!bStop) r'j*f"uAm  
{ /D eU`rj  
write_nPos(); $?7}4u,  
Utility.sleep(500); \
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breakWhile = true; *v6'I-#  
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for(int i=0;i<nStartPos.length;i++) 6+>q1,<  
{ Gk<h_1WW
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if(!fileSplitterFetch.bDownOver) >zhbOkR9c  
{ ke/QFN-`  
breakWhile = false; 9G&l{7=  
break; <)&;9C  
} <~]s+"oVc  
} 3]T2Zp&;  
if(breakWhile) SOd(& >  
break; hD"Tjd` P  
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//count++; I-^Y$6-  
//if(count>4) ;s{rJG{inG  
// siteStop(); P66>w})@  
} +<I>]J2  
1^vN?#Kt  
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System.err.println("文件下载结束！"); 74>.E^/x  
}  'y1=Z  
catch(Exception e){e.printStackTrace ();} \S _ycn  
} (@]{=q<  
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//获得文件长度 lbMb  
public long getFileSize() ">|fB&~A  
{ ?me0J3u_  
int nFileLength = -1; Bc$t`PI  
try{ +Bgy@.a?  
URL url = new URL(siteInfoBean.getSSiteURL()); w18kTa!4@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); zbrDDkZ1  
httpConnection.setRequestProperty("User-Agent","NetFox"); 0} uH  
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 ,_HVPE  
int responseCode=httpConnection.getResponseCode(); -B'<*Y  
if(responseCode>=400) sdrALl;w|  
{ &W*9'vSm.  
processErrorCode(responseCode); 7a
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return -2; //-2 represent access is error yqZKn=1:  
} RCKb5p9  
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String sHeader; D >$9(  
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for(int i=1;;i++) w!7Hl9BW  
{ Z
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); !A qSG-  
//Utility.log(in.readLine()); R]H/Jv\'  
sHeader=httpConnection.getHeaderFieldKey(i); }9=VhC%J  
if(sHeader!=null) z^b
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{ *Mk5*_  
if(sHeader.equals("Content-Length")) NvY%sx,  
{ mGb,oj7l  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); (V5_q,2  
break; D}OvD |<-  
} 63 F@Ft  
} rxJmK$qd  
else l!
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break; I'm.+(1m,  
} WZ> }  
} {94qsVxQZ  
catch(IOException e){e.printStackTrace ();} O8qA2@,  
catch(Exception e){e.printStackTrace ();} eh`n?C  
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Utility.log(nFileLength); c"~+Y2]tL  
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return nFileLength; ?hHVawt  
} {oOzXc
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//保存下载信息（文件指针位置） lcO;3CrJ!  
private void write_nPos() k  <SFl  
{ 8cI<~|4_  
try{ A%(t'z  
output = new DataOutputStream(new FileOutputStream(tmpFile)); &?59{B.mD  
output.writeInt(nStartPos.length); :(ni/,~Q  
for(int i=0;i<nStartPos.length;i++) TL'^@Y7X5  
{ g$+ $@~  
// output.writeLong(nPos); |1!RvW:[!  
output.writeLong(fileSplitterFetch.nStartPos); [TRHcz n  
output.writeLong(fileSplitterFetch.nEndPos); |L wn<y  
} ?> )(;Ir9  
output.close(); u)J&3Ah%  
} GI']&{  
catch(IOException e){e.printStackTrace ();} v"-@'qN'  
catch(Exception e){e.printStackTrace ();} d|I?%LX0p  
} kzozjh%`9h  
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|T3F:],`  
//读取保存的下载信息（文件指针位置） m%7T ~  
private void read_nPos() I8M^]+c  
{ *7cc4 wGQ  
try{ K FMx(fD  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); w\SfzJN  
int nCount = input.readInt(); x`9IQQ  
nStartPos = new long[nCount]; 0q}k"(9  
nEndPos = new long[nCount]; GE?M. '!{{  
for(int i=0;i<nStartPos.length;i++) 6)5Akyz4V  
{ A}"aH  
nStartPos = input.readLong(); fRlO.!0(  
nEndPos = input.readLong(); jxeZ,w o  
} *e/8
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input.close(); |&wwH&<[z  
} {_[\k^98>  
catch(IOException e){e.printStackTrace ();} 'Sk-L 5  
catch(Exception e){e.printStackTrace ();} z"D'rHxy  
} Lgr(j60s  
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private void processErrorCode(int nErrorCode) so=Ux2  
{ KcPI,.4{  
System.err.println("Error Code : " + nErrorCode); ny++U;qi  
} a]NH >d  
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2d:IYCl4q  
//停止文件下载 V d`}F0WD  
public void siteStop() Z2@_F7cXt  
{ D05JQ*  
bStop = true; ;cpQ[+$nKp  
for(int i=0;i<nStartPos.length;i++) _98 %?0  
fileSplitterFetch.splitterStop(); +T!7jC(O Q  
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} aI^Z0[P+  
} R-[t4BHn  
//负责部分文件的抓取 L@VIC|~E  
**FileSplitterFetch.java X7."hGu@  
*/ @vHj>N  
package NetFox; Fm-D>PR
 
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import java.io.*; MqKf'6z  
import java.net.*; D2N<a=#  
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public class FileSplitterFetch extends Thread { <4Ev3z*;Z  
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String sURL; //File URL =hAH6C  
long nStartPos; //File Snippet Start Position fY|P+{BO2  
long nEndPos; //File Snippet End Position )y#~eYn  
int nThreadID; //Thread's ID mu$0x)  
boolean bDownOver = false; //Downing is over =]F;{x  
boolean bStop = false; //Stop identical D:Rr|m0Tk  
FileAccessI fileAccessI = null; //File Access interface Z)
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1ZZ}ojq  
{ }}s.0Q  
this.sURL = sURL; oEJYAKN  
this.nStartPos = nStart; &\p=s.y?j  
this.nEndPos = nEnd; D #Ku5~j  
nThreadID = id; Ew,1*WK!  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 6C@W6DR3N  
} $-*E   
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public void run() 4+1aW BJ2  
{ X6Wj,a  
while(nStartPos < nEndPos && !bStop) 0r/
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{ kklM"Av  
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try{ P-Upv6J3  
URL url = new URL(sURL); b~Q8&z2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); qZ
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httpConnection.setRequestProperty("User-Agent","NetFox"); 2N/4.  
String sProperty = "bytes="+nStartPos+"-"; Z]^Ooy[pb  
httpConnection.setRequestProperty("RANGE",sProperty); <$+Cd=71\  
Utility.log(sProperty); ,GVD.whUl  
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InputStream input = httpConnection.getInputStream(); -F338J+J24  
//logResponseHead(httpConnection); OL0W'C9oA  
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byte[] b = new byte[1024]; #)7THx/=  
int nRead; z4B-fS]  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) vj#Y /B  
{ 0Z,a3)jcc  
nStartPos += fileAccessI.write(b,0,nRead); 7Z7e}| \W  
//if(nThreadID == 1) vw5f|Q92  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); l =`?Im  
} tgpg  
&ZR}Z7E*=  
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Utility.log("Thread " + nThreadID + " is over!"); uW{;
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bDownOver = true; 9\J6G8b>|I  
//nPos = fileAccessI.write (b,0,nRead); @o/126(k  
} L0QF(:F5  
catch(Exception e){e.printStackTrace ();}
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} 7FBaN7l  
} rAwuWM@BIg  
:GBM`f@  
m]"13E0*x  
//打印回应的头信息 }j\_XaB  
public void logResponseHead(HttpURLConnection con) y} W-OLE  
{ j
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for(int i=1;;i++) sc)}r_|g  
{ E(p*B8d  
String header=con.getHeaderFieldKey(i); qh)10*FB  
if(header!=null) sk>E(Myo  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); +[_mSt  
Utility.log(header+" : "+con.getHeaderField(header)); PgMU|O7To  
else &CcUr#|  
break; s%OPoRE  
} D.;iz>_}Y  
} RASPOc/]   
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public void splitterStop() c7R<5f  
{ H5J1j*P<d  
bStop = true; HA#9y;\  
} kS)azV  
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^\  
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} |9*8u>|RC  
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/* b>]MZhLJe  
**FileAccess.java K@R * V  
*//文件访问(定位，写) G.l ~!;  
package NetFox; *%p`Jk-U  
import java.io.*;
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public class FileAccessI implements Serializable{ P+2@,?9#  
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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 57~/QEdy  
RandomAccessFile oSavedFile; 'OjsV

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long nPos; )wdTs>W7  
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public FileAccessI() throws IOException 5N /NUs   
{ )z Hib;O  
this("",0); K Ml>~r  
} 29tih{xx  
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public FileAccessI(String sName,long nPos) throws IOException &cuDGo.  
{ ww#]i&6  
oSavedFile = new RandomAccessFile(sName,"rw"); H$44,8,m  
this.nPos = nPos; SpJIEw  
oSavedFile.seek(nPos); gT0N\oU"  
} EZb_8<DH  
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{,Z-GJ  
public synchronized int write(byte[] b,int nStart,int nLen) @{LD_>R  
{ NR9=V  
int n = -1; l)K8.(2  
try{ E
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oSavedFile.write(b,nStart,nLen); @F/yc
  
n = nLen; mK_2VZj&  
} :ND e<6?u  
catch(IOException e) dK d"2+fH  
{ kPvR ,  
e.printStackTrace (); J<h!H  
} /c|X:F!;X#  
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D  
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return n; 3Q:HzqG  
} O;8
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} 0/TP`3$X#"  
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/* }[mLtv%&  
**SiteInfoBean.java b2Oj 1dP1  
*/ Zp qb0ro  
package NetFox; S17 c#6vT  
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public class SiteInfoBean { MiN|u  
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private String sSiteURL; //Site's URL <Gw>}/-^  
private String sFilePath; //Saved File's Path reI4!,x  
private String sFileName; //Saved File's Name .9VhDrCK  
private int nSplitter; //Count of Splited Downloading File k^Qd%;bdF  
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public SiteInfoBean() >hv8zHOO:  
{//nSplitter的缺省值为5 ?)V|L~/  
//default value of nSplitter is 5 M'5PPBSR  
this("","","",5); 6.6;oa4j  
} CAbR+y  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) (U([T-H  
{ Lc
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sSiteURL= sURL; o>75s#= b=  
sFilePath = sPath; M.u1SB0  
sFileName = sName; b-
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this.nSplitter = nSpiltter; ~jD~_JGp  
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} vf0 fa46  
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+. tcEbFL  
public String getSSiteURL() oZ\zi> Y,  
{ ]Wg&r Y0  
return sSiteURL; z*e`2n#\  
} ,{Ga7rH*   
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public void setSSiteURL(String value) 0WQd#l  
{ 7 0Wy]8<P  
sSiteURL = value; ?%ei+  
} Y.KJP ?  
h pKrP  
<V1y^EW0  
public String getSFilePath() yF@72tK  
{ %(A@=0r#  
return sFilePath; Ti>2N  
} -GODM128 ^  
~9Cw5rwH<;  
99*QfC  
public void setSFilePath(String value) >=K~*$&>  
{ (Qd@Q,@(s  
sFilePath = value; 4Ul*`/d  
} ~tZy-1  
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n'9&q]GN|  
public String getSFileName() M,sZ8eeq  
{ \2[sUY<W  
return sFileName; Vo(>K34  
} (nAg ~i  
>A>_UT_"  
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public void setSFileName(String value) lS |:4U.  
{ Z+agS8e(  
sFileName = value; icN#8\E  
} R47tg&k6[  
y\XWg`X y  
48LzI@H&  
public int getNSplitter() u85?f  
{ f"Kl?IN8  
return nSplitter; mk[<=k~  
} ~F13}is  
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public void setNSplitter(int nCount) 8I<LZ{a10  
{ % |G"ZPO?  
nSplitter = nCount; LX</xI08W  
} JlE b  
} Xu& v3Y~k  
qJK-HF:#  
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/* j$Vtd&  
**Utility.java >K*TgG6!X  
*/ rnQ9uNAu  
package NetFox; , %A2wV  
)F m'i&F_  
} QpyU%  
public class Utility { 3Gt@Fo=  
#C+7~ns'  
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public Utility() V PI_pK  
{ 3Y=uBl  
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} YJ{_%z|U  
q],/%W  
//线程睡眠 # 66vkf*  
public static void sleep(int nSecond) 4IXa[xAm  
{ NT<}-^
  
try{ i+~H~k}"X  
Thread.sleep(nSecond); [='<K  
} F32U;fp3  
catch(Exception e) }u.1$Y  
{
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e.printStackTrace (); %:Y'+!bX  
} W<M\b#  
} qhOV>j,d  
v7mg8'  
//日志 uZ+vYF^  
public static void log(String sMsg) BV eIj }  
{ gPF5|% 3)  
System.err.println(sMsg); hEAP,)>F  
} YLid2aF  
-9yWf8;  
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public static void log(int sMsg) Vc&xXtm[v  
{ D`NQEt"(  
System.err.println(sMsg); c1h?aP  
} p1fy)K2{,j  
} a3^({;k!0  
.1h1J   
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/* g&O!w!T  
**TestMethod.java +A<7:`sO  
*/ p"QV| `  
package NetFox; 2qPQ3-'  
p/Ri|FD6  
M][Zu[\*  
public class TestMethod { GL3olKnL  
..yLtqos  
5 0<  
public TestMethod() !KLY*bt6  
{ ///xx/weblogic60b2_win.exe H~~>ut6`  
try{ B^BbA-I  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); AUPTtc`#Y  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 5<Y-?23  
SiteFileFetch fileFetch = new SiteFileFetch(bean); E7j9A`  
fileFetch.start(); !\|L(Paf  
} ;\gHFG}  
catch(Exception e){e.printStackTrace ();} MJG)fFl]O  
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} ]`\~(*;[W9  
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;"+]bne~  
public static void main(String[] args) @mu=7_$U  
{ V,>uM >$  
new TestMethod(); ,{g B$8z^  
} ;(;{~1~  
} pF'M
  
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