http断点续传简单实现（java)

/* NyI0[]z
 
**SiteFileFetch.java v'7,(.E  
*/  k'X v*U  
package NetFox; ziR}  
import java.io.*; |BnjT*_9  
import java.net.*; s_-G`xT>{  
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public class SiteFileFetch extends Thread { >tnQuFKg]  
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SiteInfoBean siteInfoBean = null; //文件信息Bean &Vfdq6Y]  
long[] nStartPos; //开始位置 Y 9]  
long[] nEndPos; //结束位置 ~U#afGH$  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 AzVON#rj  
long nFileLength; //文件长度 g4(B=G\j  
boolean bFirst = true; //是否第一次取文件 [s$vY~_  
boolean bStop = false; //停止标志 q'77BRD3  
File tmpFile; //文件下载的临时信息 O^48c$Apv  
DataOutputStream output; //输出到文件的输出流 x):cirwkl  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 7udMF3;>  
public SiteFileFetch(SiteInfoBean bean) throws IOException WY#A9i5Ge  
{ W/9dT^1y4'  
siteInfoBean = bean; 08{0i,Fs  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); N"/jn_>+j  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ~YKe:K+&z  
if(tmpFile.exists ()) bsy\L|wd  
{ Lt0JUUa0  
bFirst = false; pb1/HhRR^n  
read_nPos(); TaeN?jc5  
} "Q6oPDX(  
else "S.5
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{ | ?3\xw  
nStartPos = new long[bean.getNSplitter()]; Mfe/(tlI  
nEndPos = new long[bean.getNSplitter()]; ZIQy}b'  
} `q7O\  
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} Tz3 L#0:j  
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public void run() n#XiCo_\  
{ &{NN!X  
//获得文件长度 g-"@%ps  
//分割文件 `z%f@/:fG  
//实例FileSplitterFetch 4Tgy2[D?q  
//启动FileSplitterFetch线程 2{Nv&ZX?  
//等待子线程返回 Y%y=  
try{ z&[Rw<{Psb  
if(bFirst) dO}6zQ\  
{ /"?yB$s  
nFileLength = getFileSize(); GZ,`?  
if(nFileLength == -1) p/L|;c  
{ i1$ $86  
System.err.println("File Length is not known!"); G=Hvh=K(  
} OAO|HH  
else if(nFileLength == -2) @igr~hJ  
{ .Nz2K[  
System.err.println("File is not access!"); S0\QZ/je  
} U8qb2'a8  
else U;u
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{ F8mS5oB|^  
for(int i=0;i<nStartPos.length;i++) p;cNmMm  
{ :,%~R2  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); @dei}!e  
} xX$'u"dsA  
for(int i=0;i<nEndPos.length-1;i++) z ^t6VFM  
{ T#kPn#|  
nEndPos = nStartPos[i+1]; ,Bax0p  
} tIfA]pE  
nEndPos[nEndPos.length-1] = nFileLength; 3*x_S"h  
} AL@8v=  
} QG {KEj2V  
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//启动子线程 (~ro_WC/I  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ,Z*&QR  
for(int i=0;i<nStartPos.length;i++) UngDXD )  
{ N\{Xhr7d  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(),  @v&hr  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), )(yD"]co  
nStartPos,nEndPos,i); ci*rem  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); y(/"DUx  
fileSplitterFetch.start(); F!.Z@y P  
} Qc1NLU9:  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
t4(Z@X$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); +*&bgGhT  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", pFb}5Q  
nEndPos = " + nFileLength); j<|I@0  
// fileSplitterFetch[nPos.length-1].start(); VbX+`CwH  
*YH5kX  
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//等待子线程结束 LkYcAY$w  
//int count = 0; |j:"n3~6  
//是否结束while循环 }2c)UQD8  
boolean breakWhile = false; Aiyx!Q6vT  
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while(!bStop) [Z~h!}  
{ Q(v*I&k  
write_nPos(); K|[p4*6  
Utility.sleep(500); D>tex/Of3  
breakWhile = true; "LZQ1P*ef$  
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for(int i=0;i<nStartPos.length;i++) z OwKh>]  
{ UF37|+"E  
if(!fileSplitterFetch.bDownOver) i2.g}pM.A  
{ u~b;m  
breakWhile = false; khFr%u ?S  
break; IBfLb(I  
} y2Eq-Ie  
} 96G8B62  
if(breakWhile) n}0n!Pr^  
break; \tR](, /  
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//count++; HK}br!?  
//if(count>4) 2S%[YR>>  
// siteStop(); 
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} :c75*h`  
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System.err.println("文件下载结束！"); YA+jLy6ZL  
} YkWv*l  
catch(Exception e){e.printStackTrace ();} arVu`pD*n  
} ]'IZbx:  
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//获得文件长度 SXqWq  
public long getFileSize() FR*CiaD1  
{ BQWhTS7  
int nFileLength = -1; yV"k:_O{  
try{ r_
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URL url = new URL(siteInfoBean.getSSiteURL()); J!{"^^*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); GgT 5'e;N  
httpConnection.setRequestProperty("User-Agent","NetFox"); +lYo5\1=  
'%Fg+cZN\  
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int responseCode=httpConnection.getResponseCode(); K Eda6zZH  
if(responseCode>=400) OdKfU^  
{ &,DZ0x
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processErrorCode(responseCode); jpwR\"UJ  
return -2; //-2 represent access is error zv%]j0 ?  
} ]S  
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String sHeader; "FD`1  
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for(int i=1;;i++) 1>yh`Bp\=  
{ hZZ  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 5S9i>B  
//Utility.log(in.readLine()); kh4., \'  
sHeader=httpConnection.getHeaderFieldKey(i); e:9s%|]T  
if(sHeader!=null) fk*I
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{ KIRCye  
if(sHeader.equals("Content-Length")) {{:QtkN  
{ 9-/u _$  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); eW<|I  
break; SAVA6 64  
} ^5'pJ/BV  
} EjA3hHJ  
else F>F2Yql&W  
break; nsA}A~(E  
} jT'09r3P  
} 60\`TsFobT  
catch(IOException e){e.printStackTrace ();} 4 EE7gkM5  
catch(Exception e){e.printStackTrace ();} Tv[|^G9x  
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Utility.log(nFileLength); 8(zE^W,[8"  
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}AW"2<@  
return nFileLength;  Y+d+  
}
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//保存下载信息（文件指针位置） eG_@WLxwD  
private void write_nPos() =?3b3PZn  
{ PQd*)6K:A  
try{ wPE\?en  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ROhhd.  
output.writeInt(nStartPos.length); H8x66}  
for(int i=0;i<nStartPos.length;i++) +^<s'  
{ H:#sf][&,L  
// output.writeLong(nPos); !kxJ&VmeF  
output.writeLong(fileSplitterFetch.nStartPos); P @Jo[J<  
output.writeLong(fileSplitterFetch.nEndPos); \Ota~A  
} sRI0;  
output.close(); ^7Rc\  
} >d3`\(v-  
catch(IOException e){e.printStackTrace ();} WR"?j9y_q  
catch(Exception e){e.printStackTrace ();} B"Ma<"HU  
} nl-y0xD9c  
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//读取保存的下载信息（文件指针位置） .fgVzDR|+  
private void read_nPos() [C#H _y(  
{ r!<)CT}D  
try{ diWi0@  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); OZR{+YrB^  
int nCount = input.readInt(); vbh 5  
nStartPos = new long[nCount]; L9$`zc  
nEndPos = new long[nCount]; ew.jsa`TrW  
for(int i=0;i<nStartPos.length;i++) `N}aV
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{ PX- PVW  
nStartPos = input.readLong(); 8w$q
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nEndPos = input.readLong(); V7"^.W*  
} F{G.dXZZ<  
input.close(); /UqIkc  
}
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catch(IOException e){e.printStackTrace ();} %Ze]6TP/><  
catch(Exception e){e.printStackTrace ();} w{WEYS
 
} LO;?#e7  
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private void processErrorCode(int nErrorCode) $(]E$ek  
{ P,rD{ 0~  
System.err.println("Error Code : " + nErrorCode); bo-L|R&O  
} n_{az{~  
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+QEP:#qZw  
//停止文件下载 ]]NTvr  
public void siteStop() R $@$  
{ "-Yj~  
bStop = true; yNhRh>l  
for(int i=0;i<nStartPos.length;i++) e-Zul.m  
fileSplitterFetch.splitterStop(); mb>8=hMg  
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} Z,oC
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} hkB|rhJgm  
//负责部分文件的抓取 ]1 jhy2j  
**FileSplitterFetch.java !'#GdRstv  
*/ $H`{wJ?2(  
package NetFox; qg2Vmj<H  
[pC2#_}  
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import java.io.*; aL&nD1f=!-  
import java.net.*; ,1B`Ve  
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public class FileSplitterFetch extends Thread { DLN zH  
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String sURL; //File URL CiV^bYi  
long nStartPos; //File Snippet Start Position ^ib =fLu  
long nEndPos; //File Snippet End Position mqtYny'  
int nThreadID; //Thread's ID &3OV|ly]  
boolean bDownOver = false; //Downing is over R;zf x/  
boolean bStop = false; //Stop identical uO)vGzt3^x  
FileAccessI fileAccessI = null; //File Access interface =6 3tp 9  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException DKF` xuJP  
{ v_Hy:O}R  
this.sURL = sURL; M0T z('~s  
this.nStartPos = nStart; h'+F'1=  
this.nEndPos = nEnd; 6rWb2b  
nThreadID = id; &xpvHKJl  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 c^<~Y$i  
} \&l@rMD3s  
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public void run() m8V
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{ Q_Wg4n5  
while(nStartPos < nEndPos && !bStop) s!S_Bt):3  
{ g4y&6!g  
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];'7~",Y  
try{ z8XWp[K  
URL url = new URL(sURL); f40OVT
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); phQ{<wzwp  
httpConnection.setRequestProperty("User-Agent","NetFox"); s\< @v7A  
String sProperty = "bytes="+nStartPos+"-"; FKPR;H8>  
httpConnection.setRequestProperty("RANGE",sProperty); 6Jq3l_  
Utility.log(sProperty); I
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InputStream input = httpConnection.getInputStream(); A+
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//logResponseHead(httpConnection); B>4/[ YHr;  
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byte[] b = new byte[1024]; gWL`J=DiU  
int nRead; vOLa.%X]h  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 5,4m_fBoW  
{ {9@u:(<X9  
nStartPos += fileAccessI.write(b,0,nRead); U^eos;:s8  
//if(nThreadID == 1) +* j8[sz  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,"F
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} =kf"%vFV  
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Utility.log("Thread " + nThreadID + " is over!"); DN iH" 0%  
bDownOver = true; -L<FVB  
//nPos = fileAccessI.write (b,0,nRead); -$X4RS  
} h#c7v!g  
catch(Exception e){e.printStackTrace ();} zkiwFEHA=  
} !
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} K9]zUe&#w  
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&8Z.m,s]  
//打印回应的头信息 E*IP#:R  
public void logResponseHead(HttpURLConnection con) =ZO lE|4  
{ ]1pB7XL  
for(int i=1;;i++) 1w,34*-}  
{ AF8:
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String header=con.getHeaderFieldKey(i); eco&!R[G  
if(header!=null) [[pt~=0  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); K- $,:28  
Utility.log(header+" : "+con.getHeaderField(header)); &YcOmI/MM  
else 'kco. 1{  
break; "$aoIXv  
} B,&QI&k`~  
} y=.bn!u}z  
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public void splitterStop() `23][V  
{ 9UVT]acq  
bStop = true; }-J0cV  
} NuOxEyC  
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} 2wDDVUwyB  
+ ~5P7dh6  
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/* ,tcUJ}l  
**FileAccess.java 89;@#9  
*//文件访问(定位，写) 6Ol9P56j  
package NetFox; H9PnJr8 \  
import java.io.*; 1q@R04i  
4P"bOt5izR  
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public class FileAccessI implements Serializable{ u1Slu%^e  
R&BWCC{  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 d=n{Wn{C  
RandomAccessFile oSavedFile; b$%Kv
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long nPos; E4>}O;m0  
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public FileAccessI() throws IOException ><Zu+HX  
{ q5L^>"  
this("",0); ."=%]l0  
} |q8N$m  
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public FileAccessI(String sName,long nPos) throws IOException }]PHE(}7  
{ \D(3~y>  
oSavedFile = new RandomAccessFile(sName,"rw"); ajtH1Z#  
this.nPos = nPos;
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oSavedFile.seek(nPos); q\x.e.@  
} Rw%?@X3m]  
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public synchronized int write(byte[] b,int nStart,int nLen) 3l45(%g+  
{ (XW'1@b  
int n = -1; E5@=LS  
try{ xOAq!,|V  
oSavedFile.write(b,nStart,nLen); mO]>]   
n = nLen; ZJQFn  
} 1}c'UEr%)  
catch(IOException e) QnD8L.Dg  
{ _@!vF,Wcf  
e.printStackTrace (); &Cv  
} Um6}h@>  
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return n; [A/2 Ms  
} RJzIzv99m  
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} r A(A$VR  
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"n`z`{<n  
/* <<CWN(hQWO  
**SiteInfoBean.java `G/g/>y  
*/ }`Ya;  
package NetFox; rU&Y/  
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public class SiteInfoBean { bTm
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private String sSiteURL; //Site's URL *bf 5A9  
private String sFilePath; //Saved File's Path
 <{Y3}Q  
private String sFileName; //Saved File's Name NRJp8G Z%U  
private int nSplitter; //Count of Splited Downloading File DE?k|Get2  
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public SiteInfoBean() _^#eO`4"  
{//nSplitter的缺省值为5  IPK1g3Z  
//default value of nSplitter is 5 xh$yXP0/  
this("","","",5); wCg7JW#  
} $%MgIy  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) n}IGxum8`  
{ xZ P SUEG  
sSiteURL= sURL; q
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sFilePath = sPath; &BrFcXF  
sFileName = sName; Lr"cO|F  
this.nSplitter = nSpiltter; Ht(TYq  
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7
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} n19A>
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public String getSSiteURL() ocW~I3  
{ 6,q_M(;c  
return sSiteURL; 7;AK=;  
} I V#
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&  
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public void setSSiteURL(String value) M.t,o\xl  
{ vw;aL
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sSiteURL = value; V<S6a
  
} G&^8)S@1  
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public String getSFilePath() .ZF%$H  
{ \{:A&X~\!  
return sFilePath; jDb\4QyC  
} 7WS$fUBi  
v
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public void setSFilePath(String value) trwQ@7  
{ EA>.SSs!  
sFilePath = value; #0b:5.vy  
} X/2GTU7?  
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public String getSFileName() ydYsm
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{ [(x*!
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return sFileName; 4h|*r !  
} g]: [^p  
XH~(=^/_  
 4bA^Gq  
public void setSFileName(String value) 7:?\1a  
{ FqA4 OU  
sFileName = value; Vsl,u  
} uc@4fn  
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public int getNSplitter() sk39[9  
{ A/2$~4,  
return nSplitter; -#9e
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} =YgH-{  
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public void setNSplitter(int nCount) 4;Ucas6  
{ >4luZnWMI  
nSplitter = nCount; B;(U?gC  
} uxD3+Q  
} gjG SI'M0B  
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/* _J6 Xq\  
**Utility.java y@~ VE5N  
*/ MZQDFuvDxZ  
package NetFox; W.[!Q`  
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^@*`vz^_  
public class Utility { mTtaqo_Bh  
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public Utility() Dch\k<Te  
{ o0`']-)*2  
6?[P^{GpH  
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} rIFW1`N}i  
o!+%|V8Y  
//线程睡眠 b-VtQ%Q  
public static void sleep(int nSecond) 7nnF!9JOv  
{ *:xOenI  
try{ 8]`#ax 5  
Thread.sleep(nSecond); .c}+kHv  
} h
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catch(Exception e) */IiL%g4u  
{ /_m)D;!y  
e.printStackTrace (); &^#iS<s1  
} Fdhgm{Y2s  
} R`<2DC>h9  
*1["x;A  
//日志 kVWcf-
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public static void log(String sMsg) 2
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{ J/e]
  
System.err.println(sMsg); Wx]Xa]-  
} ]Pe>T&  
:po6%}hn  
3A`]Rk   
public static void log(int sMsg) j8Z;}Ps  
{ K\9CW%W  
System.err.println(sMsg); E} XmZxHV  
} 0ex.~S_Oj4  
} [k%hl`}  
3E;@
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KHZ[drb6$  
/* d]s^?=gM  
**TestMethod.java asYk#;z\"  
*/ ~;CNWJtcf(  
package NetFox; lj}3TbM  
b/a\{  
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public class TestMethod { F|> 3gW  
nktGO  
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public TestMethod() FulFEnSV  
{ ///xx/weblogic60b2_win.exe ].xSX0YQ%  
try{ %:`v
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); C5V}L
  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); R]%"YQ V  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 'u v=D  
fileFetch.start(); d*s*AV  
} EP@u4F  
catch(Exception e){e.printStackTrace ();} oH6zlmqG"  
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} _[&V9Jt  
N,qo/At}R[  
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public static void main(String[] args) m0;j1-t  
{ Lp:VU-S  
new TestMethod(); xS_;p9{E  
} ' F.^ 8/>  
} lfDd%.:q4S  
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