http断点续传简单实现（java)

/* 'F^1)Ga$  
**SiteFileFetch.java ;0o% hx  
*/ 1Q7]1fRu  
package NetFox; 0*,]`A=  
import java.io.*; AEd9H
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import java.net.*; 9z+ZFIf7d  
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public class SiteFileFetch extends Thread { A3.*d:A  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 1cS*T>`  
long[] nStartPos; //开始位置 };g<|v*o  
long[] nEndPos; //结束位置 G5NAwpZf  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Ry40:;MYN  
long nFileLength; //文件长度 jt0f*eYE8  
boolean bFirst = true; //是否第一次取文件 Pp.]/;  
boolean bStop = false; //停止标志 "}2I0tM  
File tmpFile; //文件下载的临时信息 Q>I7.c-M|  
DataOutputStream output; //输出到文件的输出流 SM4'3d&mf  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） K.Y.K$NjP{  
public SiteFileFetch(SiteInfoBean bean) throws IOException ]4B&8n!  
{ ),lE8A{ H  
siteInfoBean = bean; A&{eC C  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); x$z>.4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); EKUiX#p:M  
if(tmpFile.exists ()) 9?uU%9r5P  
{ 6$t+Q~2G!  
bFirst = false; GHQm$|3I  
read_nPos(); |<JBoE]3B  
} H#3Ma1z  
else d wku6lCk  
{  Q!(qb  
nStartPos = new long[bean.getNSplitter()]; lL,0IfC,  
nEndPos = new long[bean.getNSplitter()]; 4'y@ne}g!  
} |?v+8QL,;t  
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} h>A~yDT[  
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public void run() >$7{H]  
{ ,WE2MAjhT  
//获得文件长度 1]&{6y  
//分割文件 4Mox
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//实例FileSplitterFetch mOJ-M@ME  
//启动FileSplitterFetch线程 bUe6f,8,  
//等待子线程返回 ,U>G$G^  
try{ \=H+m%  
if(bFirst) 7 iQa)8,  
{ U:gvK8n  
nFileLength = getFileSize(); aZmac'cz{  
if(nFileLength == -1) VDlP,Mm*  
{ F1/BtGvQE  
System.err.println("File Length is not known!"); QwLSL<.  
} |P-kyY34  
else if(nFileLength == -2) M %!O)r#Pn  
{ @=K*gbq
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System.err.println("File is not access!"); q:mqA$n  
} *JO%.QNg  
else f.:0T&%G  
{ |eksvO'~  
for(int i=0;i<nStartPos.length;i++) +*G<xW :M  
{ $\L=RU!c}  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); j07b!j:"\}  
} } a!HbH  
for(int i=0;i<nEndPos.length-1;i++) cHJ4[x=  
{ Y8/&1s_  
nEndPos = nStartPos[i+1]; u6 4{w,  
} p+CK+m   
nEndPos[nEndPos.length-1] = nFileLength; !gi3J @  
} d!y_N&z|(  
} {(Ba  
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i<!1s%i}  
//启动子线程 T/tCX[}  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; R#Z m[S  
for(int i=0;i<nStartPos.length;i++) 6%&DJBU!  
{ awSi0*d~  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), vb$i00?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), {w]L'0ES[  
nStartPos,nEndPos,i); J"fv5{  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); A",R2d  
fileSplitterFetch.start(); B %  
} AIw~@*T  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |5*:ThC[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); <W/YC2b  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", #(-?i\i  
nEndPos = " + nFileLength); oTveY  
// fileSplitterFetch[nPos.length-1].start(); ;oOv~YB7H  
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/a\]Dwj5  
//等待子线程结束 k;HI-v  
//int count = 0; Is!+`[ma  
//是否结束while循环 7TA&u'  
boolean breakWhile = false; [pSQ8zdF"  
w +HKvOs5c  
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while(!bStop) yS4nB04`=  
{ `m\ ?gsw7  
write_nPos(); R.rE+gxO1  
Utility.sleep(500);  @4>?Y=#  
breakWhile = true; Q7_#k66gb7  
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for(int i=0;i<nStartPos.length;i++) fwSI"cfM  
{ RA}Y$}^#'  
if(!fileSplitterFetch.bDownOver) `rpmh7*WV  
{ alyA#zao|  
breakWhile = false; &&Otj-n5  
break; ki8Jl}dr  
} /p)y!5e  
} Hqb-)8 ~  
if(breakWhile) B]PG  
break; 3*e )D/lm  
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//count++; |^O3~!JP(>  
//if(count>4) e*39/B0S  
// siteStop();
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} LGWQBEXw  
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System.err.println("文件下载结束！"); 7 ;x to =  
} UC!"1)~mt`  
catch(Exception e){e.printStackTrace ();} DK<}q1
xi  
} L]=LY  
B";Dj~y  
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//获得文件长度 @Dd3mWKq  
public long getFileSize() _J0(GuG=~  
{ fKa]
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int nFileLength = -1; MYUL y2)  
try{ z"Wyf6H0T  
URL url = new URL(siteInfoBean.getSSiteURL()); xS_
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); xfA@GYCfT  
httpConnection.setRequestProperty("User-Agent","NetFox"); WU6F-{M"?  
a'7RzN ,]  
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int responseCode=httpConnection.getResponseCode(); D}?JX5.  
if(responseCode>=400) cFoeyI#v  
{ ?aU-Y_pMe  
processErrorCode(responseCode); 2MDY nMy  
return -2; //-2 represent access is error J!iKW  
} jC'Diu4|Q  
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String sHeader; $wqi^q*)  
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for(int i=1;;i++) Sp@{5  
{ ~.Cu,>fV  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ?YnB:z*eV  
//Utility.log(in.readLine()); gm}zF%B"  
sHeader=httpConnection.getHeaderFieldKey(i); ,>3|\4/Q  
if(sHeader!=null) ksQw
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{ s5oU  
if(sHeader.equals("Content-Length")) ?I 7hbqQd  
{ n)rSgzI  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); [?F]S:/i  
break;  -to3I  
} ^j7]> I  
} "=*  
else U_5

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break; E1>zKENN;  
} j6BFh=?D  
} =T|m#*{.L  
catch(IOException e){e.printStackTrace ();} vtXZ`[D,l)  
catch(Exception e){e.printStackTrace ();} YJBf~0r  
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incUa;  
Utility.log(nFileLength); ASaNac-3  
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return nFileLength; E^t}p[s  
} 2$?j'i!  
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//保存下载信息（文件指针位置） pv
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private void write_nPos() Dqm;twd>  
{ 7 JVonruaR  
try{ X=pPkgW  
output = new DataOutputStream(new FileOutputStream(tmpFile)); E7|P\^}m(f  
output.writeInt(nStartPos.length); RU,!F99'1  
for(int i=0;i<nStartPos.length;i++) )5ISkbsxD  
{ usI$  
// output.writeLong(nPos); ~)iQbLI  
output.writeLong(fileSplitterFetch.nStartPos); KgEfhO$W  
output.writeLong(fileSplitterFetch.nEndPos); 4UnN~  
}  ehQ~+x  
output.close(); @'FOM  
} /7Ft1f  
catch(IOException e){e.printStackTrace ();} IJofbuzw:  
catch(Exception e){e.printStackTrace ();} Nrk/_0^  
} Eb9{  
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//读取保存的下载信息（文件指针位置） b "5WsJ:'#  
private void read_nPos() `Qo}4nuRs  
{ 4AuJ1Z  
try{ <k-hRs2d  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); $|}PL[aA#  
int nCount = input.readInt(); }B2qtb3  
nStartPos = new long[nCount]; |BA<> WE  
nEndPos = new long[nCount]; >y iE}  
for(int i=0;i<nStartPos.length;i++) kB;!EuL  
{ of?0 y-LT%  
nStartPos = input.readLong(); FY<77i  
nEndPos = input.readLong(); xi"Ug41)  
} =idZvD  
input.close(); "6o5x&H  
} C/A~r  
catch(IOException e){e.printStackTrace ();} #nJ&`woZt  
catch(Exception e){e.printStackTrace ();} Ixv/xI  
} -gb'DN1BG  
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private void processErrorCode(int nErrorCode) '1Q [&  
{ =bB7$#al  
System.err.println("Error Code : " + nErrorCode); 73kL>u  
} v(z2,?/4  
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//停止文件下载 )>rHM6-W  
public void siteStop() #"aL M6Cfs  
{ }A'Ro/n  
bStop = true; BH`GUIk  
for(int i=0;i<nStartPos.length;i++) V2_I=]p_  
fileSplitterFetch.splitterStop(); VNWa3`w  
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} PU^@BZ_m  
} P(Ve' wOaf  
//负责部分文件的抓取 XpibI3:<  
**FileSplitterFetch.java xzTF| Z\  
*/ qn|~z@"  
package NetFox; nV&v@g4Tt  
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import java.io.*; 2K$#U|Qi  
import java.net.*; dNgjM Q  
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public class FileSplitterFetch extends Thread { Yq0=4#_  
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9
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String sURL; //File URL @mId{w z  
long nStartPos; //File Snippet Start Position MyJG2C#R  
long nEndPos; //File Snippet End Position 6pY<,7t0  
int nThreadID; //Thread's ID Y'v;!11#  
boolean bDownOver = false; //Downing is over y]TNjLpo$  
boolean bStop = false; //Stop identical 7H5t!yk|9  
FileAccessI fileAccessI = null; //File Access interface F otHITw[  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ;gNoiAxW  
{ 52d8EGC  
this.sURL = sURL; ZMI vzQYI  
this.nStartPos = nStart; N"rZK/@}  
this.nEndPos = nEnd; dt|f4XWF  
nThreadID = id; ~6-6aYhe  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 h`b[c.%  
} *]RCfHo\=  
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public void run() N
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{ Ig M_l=  
while(nStartPos < nEndPos && !bStop) F(#~.i  
{ AV*eGzz`  
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try{ ;l>C[6]  
URL url = new URL(sURL); W^AY:#eX~Q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \w+a Q?e_  
httpConnection.setRequestProperty("User-Agent","NetFox"); z^=e3~-J  
String sProperty = "bytes="+nStartPos+"-"; 
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httpConnection.setRequestProperty("RANGE",sProperty); ' 5%`[&  
Utility.log(sProperty); &i%1\o  
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InputStream input = httpConnection.getInputStream(); @CU~3Md*  
//logResponseHead(httpConnection); y:3d`E4Xw  
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byte[] b = new byte[1024]; -S,xR5  
int nRead; !@vM@Z"  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) K:g:GEDgf  
{ 0x/3Xz  
nStartPos += fileAccessI.write(b,0,nRead); zr5(nAl  
//if(nThreadID == 1) DTR/.Nr'K  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); s.7s:Q`  
} lYMNx|PF  
}./_fFN@  
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Utility.log("Thread " + nThreadID + " is over!"); 2?bE2^6  
bDownOver = true; +|=5zWI/  
//nPos = fileAccessI.write (b,0,nRead);  {!9i8T  
} 8${Yu  
catch(Exception e){e.printStackTrace ();} eX@7f!uz  
} J\V.J/  
} 3Ta<7tEM  
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//打印回应的头信息 &`J?`l X  
public void logResponseHead(HttpURLConnection con) p>@S61 & [  
{ c&JYbq  
for(int i=1;;i++) U DC>iHt  
{ mC}!;`$8p  
String header=con.getHeaderFieldKey(i); >7^
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if(header!=null) Lv{xwHnE  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); )"o+wSI1  
Utility.log(header+" : "+con.getHeaderField(header)); ^3:DeZf!u  
else |rbl sL2?Z  
break; 'F[ C 4  
} }&mFpc  
} ef;Ta|#  
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public void splitterStop() r\-25F<e5  
{ ,LHQ@/}A C  
bStop = true; mzX <!  
} l6S6Y  
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} 1xkU;no  
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9C{\=?e;  
/* J '^xDIZX  
**FileAccess.java *KXg;777  
*//文件访问(定位，写) E(&GZ QE  
package NetFox; *I(g~p  
import java.io.*; (cj3[qq  
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public class FileAccessI implements Serializable{ G{cTQH|  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ab=s+[r1  
RandomAccessFile oSavedFile; !j3V'XU#Zn  
long nPos; yT>t[t60/S  
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public FileAccessI() throws IOException Pj!{j)-tS  
{ .2b) rKo~  
this("",0); GD$jP?  
} 28j=q-9Z  
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public FileAccessI(String sName,long nPos) throws IOException m7XJe[O  
{ Iy}r'#N  
oSavedFile = new RandomAccessFile(sName,"rw"); $DfaW3bJ  
this.nPos = nPos; J\%<.S>  
oSavedFile.seek(nPos); V+df
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} Ur626}  
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public synchronized int write(byte[] b,int nStart,int nLen) :);]E-ch  
{ )6
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int n = -1; !_`T8pJ`  
try{ toipEp<ci  
oSavedFile.write(b,nStart,nLen); !j(KbAhWZ  
n = nLen; MGO.dRy_  
} k:4?3zJI  
catch(IOException e) bmAgB}Ior  
{ sK:,c5^  
e.printStackTrace (); /p [l(H  
} 8j,
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return n; G5Ci"0  
} k"SmbFn%N0  
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} y
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U
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/* 2`* %NJ  
**SiteInfoBean.java x~GV#c  
*/ r2T?LO0N{  
package NetFox; LoG@(g&)  
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public class SiteInfoBean { Uc0AsUu}?  
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private String sSiteURL; //Site's URL [&*$!M  
private String sFilePath; //Saved File's Path {K'SOhH4?  
private String sFileName; //Saved File's Name 8mA6l0  
private int nSplitter; //Count of Splited Downloading File F$ .j|C1a  
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public SiteInfoBean() B>?Y("E  
{//nSplitter的缺省值为5 &Jj> jCg  
//default value of nSplitter is 5 nRQIrUNq  
this("","","",5);
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} 7o z(hO~  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) [6S"iNiyKT  
{ =] 5;=>(  
sSiteURL= sURL; <nsl`C~6g0  
sFilePath = sPath; (?\ZN+V)  
sFileName = sName; !BEOeq@2.  
this.nSplitter = nSpiltter; U>;itHW/  
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} 1MJ]Gh]5  
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public String getSSiteURL() dr6 dK
  
{ i`]M2Q   
return sSiteURL; ,:\2Lf  
} l3MbCBX2  
8 (^2  
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public void setSSiteURL(String value) s*CKFEb#  
{ GP1>h.J  
sSiteURL = value; a`pY&xq::  
} eZ
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public String getSFilePath()  ^RWt  
{ P'9aZd  
return sFilePath; om_&|9B)  
} h.=B!wKK  
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public void setSFilePath(String value) Rg[e~##  
{ >!)VkDAG  
sFilePath = value; , D1[}Lr=K  
} JNp`@`0V  
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.;KupQ;*  
public String getSFileName() u}%&LI`.  
{ |I\A0aa  
return sFileName; ,Vs:Lle  
} ,IJNuu\  
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public void setSFileName(String value) ^LU[{HZV  
{ k13/
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sFileName = value; pn $50c  
} J#x91Jh  
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public int getNSplitter() mTP.W#N
 
{ [d&Faa[`  
return nSplitter; Fc
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} 78QFaN$  
?3Jh{F_+  
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public void setNSplitter(int nCount) $GO'L2oLwn  
{ ^p7(  
nSplitter = nCount; =hs@W)-O  
} xY'g7<})$  
} ,xh9,EpBk  
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)(L&+
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/* <@vE3v;  
**Utility.java 8S02 3  
*/ `2fuV]FW  
package NetFox; E7h}0DX  
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public class Utility { o7T|w~F~R  
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public Utility() Y>#c2@^i<  
{ B7PmG f)b  
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} ]s -6GT  
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//线程睡眠 ww,c)$  
public static void sleep(int nSecond) 4By-+C*  
{ _[phs06A  
try{ {;}8Z$  
Thread.sleep(nSecond); sR9F:  
} Ii,:+
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catch(Exception e)

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{ $KKaA{0-  
e.printStackTrace (); W^N"y&  
} VxFy[rP  
} ``<1Lo@  
^"l$p,P+  
//日志 Qm.kXlsDI  
public static void log(String sMsg) ~ 9;GD4  
{ _-&.=3\1  
System.err.println(sMsg); IID(mmy6 L  
} l =yHx\  
9A_7:V]_  
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public static void log(int sMsg) vvM)Rb,  
{ hjG1fgEj  
System.err.println(sMsg); =R'v]SXj  
} =e;wEf%`  
} fEjW7 c  
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/* dvD<>{U,8  
**TestMethod.java LbR-uc?x  
*/ WNb$2q=  
package NetFox; ]2(c$R
 
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public class TestMethod { 8[C6LG  
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public TestMethod() S
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{ ///xx/weblogic60b2_win.exe &FrB6y  
try{ 9^ r  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); u,m-6@il  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Z~(XyaN  
SiteFileFetch fileFetch = new SiteFileFetch(bean); RNdnlD#P  
fileFetch.start(); cWc)sb  
} L)}V[j#  
catch(Exception e){e.printStackTrace ();} gxOmbQt@;  
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} vy@Lu cB  
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public static void main(String[] args) XX-T"
,  
{ uB1!*S1f  
new TestMethod(); MI(i%$R-A  
} 4c=kT@=jX  
} (@E#O$'  
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