http断点续传简单实现（java)

/* (.#nl}fA  
**SiteFileFetch.java ?'k_K:_  
*/ n-9xfn0U~#  
package NetFox; XM\\Imw  
import java.io.*; >w.;A%|N  
import java.net.*; (G|!
{  
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public class SiteFileFetch extends Thread { #zsaQg, B  
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SiteInfoBean siteInfoBean = null; //文件信息Bean &2W"4SE]6  
long[] nStartPos; //开始位置 V?EX`2S  
long[] nEndPos; //结束位置 mu\1hKq;B  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 f-M:ap(O  
long nFileLength; //文件长度 $OZ=
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boolean bFirst = true; //是否第一次取文件 U`6|K$@  
boolean bStop = false; //停止标志 O:0{vu9AQ  
File tmpFile; //文件下载的临时信息 bSe\d~{  
DataOutputStream output; //输出到文件的输出流 w+6P x#  
}
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） kP`#zwp'Ci  
public SiteFileFetch(SiteInfoBean bean) throws IOException Zu"qTJE/1  
{ .))g]CH  
siteInfoBean = bean; zQ+Mu^|u+  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); {Zc8,jm  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 6k hBT'n  
if(tmpFile.exists ()) 1hw.gn*JK>  
{ Vit-)o{zr  
bFirst = false; EV( F!&  
read_nPos(); n3p@duC4  
} )%^l+w+&  
else h\!8*e;RAW  
{ G' U_I  
nStartPos = new long[bean.getNSplitter()]; ]$2 yV&V&  
nEndPos = new long[bean.getNSplitter()]; e 6mZ;y5_  
} r|l?2 eO~  
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} %np(z&@wi  
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public void run() 6,5h4[eF*  
{ NFTv4$5d  
//获得文件长度 rXW.F'=K6  
//分割文件 4w+AOWjd  
//实例FileSplitterFetch S TWH2_`  
//启动FileSplitterFetch线程 kl]
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//等待子线程返回 ,ciX *F"  
try{ ?t%{2a<X  
if(bFirst) s~{rC{9X  
{ <eXGtD  
nFileLength = getFileSize(); bse`Xfg  
if(nFileLength == -1) [;wJM|Z J0  
{ kTH""h{  
System.err.println("File Length is not known!");
b>ZAkz)U+  
} V.{HMeE4  
else if(nFileLength == -2) w
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{ FO/cEu  
System.err.println("File is not access!"); z%E(o%l8  
} Tw';;euw  
else KKsVZ~<6u  
{ ^N^G?{EV/#  
for(int i=0;i<nStartPos.length;i++) sUlf4<_zW  
{ (m'-1wX.  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); #HV5M1mb  
} H5 z1_O_+  
for(int i=0;i<nEndPos.length-1;i++) r[(;J0=  
{ 6?u`u t  
nEndPos = nStartPos[i+1];  +rv##Z  
} }<~(9_+  
nEndPos[nEndPos.length-1] = nFileLength; <%YW/k"o  
} `<g]p-=":  
} PPl o0R  
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//启动子线程 oJD]h/fQs  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; /W.s1N  
for(int i=0;i<nStartPos.length;i++) 9}QIqH\p  
{ z6)N![X  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), UJ,vE}=_{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), oaQW~R`_  
nStartPos,nEndPos,i); (eF[nfM  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Q
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fileSplitterFetch.start(); 'ge$}L}4  
} 9C)VW  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), O1~7#nJ*4[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); |@_<^cV110  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ng/h6 S  
nEndPos = " + nFileLength); Q~(Qh_Ff  
// fileSplitterFetch[nPos.length-1].start(); WSMpX-^e@  
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//等待子线程结束 Pd+*syOM  
//int count = 0; ^oav-R&  
//是否结束while循环 z00X ?F  
boolean breakWhile = false; ~IYR&GEaUG  
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*` mxv0w~(  
while(!bStop) q6pHL  
{ 8KJ`+"<=@  
write_nPos(); ' ds2\gN  
Utility.sleep(500); .u\$wJ9Ai  
breakWhile = true; (.=ig X  
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for(int i=0;i<nStartPos.length;i++) Aa_@&e  
{ [;Ih I  
if(!fileSplitterFetch.bDownOver) T;3qE1c  
{ FS5iUH+5  
breakWhile = false; =~JVU  
break; iDcTO}  
} Zj -#"Gm  
} adu6`2*$  
if(breakWhile) gs!'
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break; oUn+t
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//count++; +%j27~R>D  
//if(count>4) Ej)7
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// siteStop(); L{VnsY V  
} 4L:O0Ggz}  
~S<aIk0l  
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System.err.println("文件下载结束！"); z2{y<a9;?  
} mKu,7nMvF  
catch(Exception e){e.printStackTrace ();} -BP10-V  
} Ms+ekY)  
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//获得文件长度 7k,BE2]"  
public long getFileSize() q)9n%- YgP  
{ 2FaCrc/  
int nFileLength = -1; bD=H$)  
try{ *lA+-gkK*  
URL url = new URL(siteInfoBean.getSSiteURL()); LU;zpXg\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @]IRB1X  
httpConnection.setRequestProperty("User-Agent","NetFox"); =v^#MU{k?  
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int responseCode=httpConnection.getResponseCode(); VoYL}67c  
if(responseCode>=400) b-/QZvg  
{ @;Jv/N6@  
processErrorCode(responseCode); WZ>nA[/  
return -2; //-2 represent access is error FR
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} u=Ik&^v Wq  
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)#z{P[
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String sHeader; 7b08Lo7b  
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for(int i=1;;i++) *Sdx:G~gp  
{ 9,~7,Py}  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); }wRm ~  
//Utility.log(in.readLine()); @gbW:  
sHeader=httpConnection.getHeaderFieldKey(i); IV!`~\@  
if(sHeader!=null) a9;KS>~bq  
{ O$r/{{I.  
if(sHeader.equals("Content-Length")) p~3
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{ ^%zhj3#  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); q++\<
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break; 'WhJ}Uo
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} $365VTh"  
} al}J^MJ  
else :8eI_X  
break; ?R)dxuj  
} #S9J9k  
} {|>Wwa2e  
catch(IOException e){e.printStackTrace ();} XQn1B3k+  
catch(Exception e){e.printStackTrace ();} N,K/Ya)1  
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Utility.log(nFileLength); mrRid}2  
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return nFileLength; <-?C\c~G@  
} .Ja].hP  
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//保存下载信息（文件指针位置） Q;VuoHj!  
private void write_nPos() o/7u7BQl2  
{ +'c+X^_  
try{ >Y8\f:KQ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); uarfH]T{  
output.writeInt(nStartPos.length); 'm~=sC_uL  
for(int i=0;i<nStartPos.length;i++) 9h6Oq(0b8  
{ .,z6a  
// output.writeLong(nPos); Wgh@XB  
output.writeLong(fileSplitterFetch.nStartPos); WtZI1`\qe  
output.writeLong(fileSplitterFetch.nEndPos); 1N(1h D  
} 8u~  
output.close(); :p}8#rb  
} /a^ R$RHl'  
catch(IOException e){e.printStackTrace ();} nyi!D  
catch(Exception e){e.printStackTrace ();} qJ`:$U  
} f%.Ngf9  
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//读取保存的下载信息（文件指针位置） ^K"BQ~-w  
private void read_nPos() $O*@Jg=  
{ cg3}33Z;6  
try{ $2h%IK>#G  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 9}9VZ r?  
int nCount = input.readInt(); J6s]vV q"  
nStartPos = new long[nCount]; -ymDRoi  
nEndPos = new long[nCount]; -MS#YcsV  
for(int i=0;i<nStartPos.length;i++) ]87BP%G  
{ :sg}e  
nStartPos = input.readLong(); Dj96t5R  
nEndPos = input.readLong(); )%Fwfb  
} lvWwr!w  
input.close(); ?< b{  
} J?3/L&seA  
catch(IOException e){e.printStackTrace ();} .+u b\  
catch(Exception e){e.printStackTrace ();} 7?R600OA  
} dWQs
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private void processErrorCode(int nErrorCode) L_Gw:"-+Q  
{ z4SJxL  
System.err.println("Error Code : " + nErrorCode); *p $0(bz  
}
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//停止文件下载 K{ar)_V/  
public void siteStop() .c-a$39  
{ &$/ #"lW,V  
bStop = true; d)vP9vXy  
for(int i=0;i<nStartPos.length;i++) oV:oc,  
fileSplitterFetch.splitterStop(); D;C';O  
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} eo9/  
} ~I5hV}ZT  
//负责部分文件的抓取 >E<ib[vK[  
**FileSplitterFetch.java sRD fA4/TF  
*/ RJ3oI+gI  
package NetFox; pc*)^S  
/jGBQ-X  
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import java.io.*; )k,n}  
import java.net.*; p@G7}'|eyA  
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public class FileSplitterFetch extends Thread { OtqFI!ns  
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String sURL; //File URL +>q#eUS)  
long nStartPos; //File Snippet Start Position :_R:>n9 p  
long nEndPos; //File Snippet End Position Os"('@jd>  
int nThreadID; //Thread's ID 2DCQ5XewYe  
boolean bDownOver = false; //Downing is over PoF3fy%.  
boolean bStop = false; //Stop identical <R$ 2x_  
FileAccessI fileAccessI = null; //File Access interface N;|^C{uz  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException b4_0XmL  
{ |[>@Kk4  
this.sURL = sURL; <PpvVDy3  
this.nStartPos = nStart; :ZrJL&  
this.nEndPos = nEnd; T-%=t
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nThreadID = id; Eu?z!  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 X@`a_XAfd  
} R7bG!1SHl  
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public void run() lv 8EfN  
{ _HUbE /  
while(nStartPos < nEndPos && !bStop) C[^V\?3ly:  
{ /IpCo  
2 kDsIEA  
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try{ 7s(tAb
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URL url = new URL(sURL); 92DM1~ *  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ss)x fG  
httpConnection.setRequestProperty("User-Agent","NetFox"); f4f2xe7\Q  
String sProperty = "bytes="+nStartPos+"-"; S!b18|o"  
httpConnection.setRequestProperty("RANGE",sProperty); s/D)X=P1  
Utility.log(sProperty); .hat!Tt9  
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InputStream input = httpConnection.getInputStream(); ~gfR1SE  
//logResponseHead(httpConnection); >c,s}HJ  
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byte[] b = new byte[1024]; <>3)S`C`p  
int nRead; IO+]^nY`  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) qNEp3WY:  
{ "bo0O7InOV  
nStartPos += fileAccessI.write(b,0,nRead); TQ4@|S:OF  
//if(nThreadID == 1) {6'Xz  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); L|'^P3#7`  
} >pU9}2fpT  
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Utility.log("Thread " + nThreadID + " is over!"); [C "\]LiX  
bDownOver = true; 3$\k=q3`#  
//nPos = fileAccessI.write (b,0,nRead); W'[V
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} 'h*jL@%TT  
catch(Exception e){e.printStackTrace ();} p>B2bv+L  
} 8 t5kou]h  
} 11=$]K>  
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 j#](Q
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//打印回应的头信息 i5 rkP`)j  
public void logResponseHead(HttpURLConnection con) gfQ?k  
{ W$c@C02<  
for(int i=1;;i++) n<ZPWlJ  
{ ,> zEG  
String header=con.getHeaderFieldKey(i); ||Zup\QB  
if(header!=null) 9@ tp#  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); V%s g+D2  
Utility.log(header+" : "+con.getHeaderField(header)); 8+F5n!
 
else Kw -SOFE  
break; 4yl{:!la  
} isZ5s\  
} "D(Lp*3hj&  
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public void splitterStop() _Iy\,<  
{ 8%[pno |0I  
bStop = true; @Wu-&Lb  
} L:G#>  
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} qA)OkR'm  
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/* *G19fJ[5  
**FileAccess.java =S&`~+  
*//文件访问(定位，写) C?<pD+]b_  
package NetFox; Q.mJ7T~T  
import java.io.*; fO*jCl  
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public class FileAccessI implements Serializable{ X]0>0=^  
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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 OK[J h  
RandomAccessFile oSavedFile; {K,In)4  
long nPos; 4-(kk0]`z  
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public FileAccessI() throws IOException 5~*)3z^V  
{ pCIzpEsRs  
this("",0); %$!3Pbui  
} ag=d6q  
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public FileAccessI(String sName,long nPos) throws IOException 9j,g&G.K  
{ n>M`wF>  
oSavedFile = new RandomAccessFile(sName,"rw"); .w2ID  
this.nPos = nPos; .Mt3ec<  
oSavedFile.seek(nPos); G.W !   
} 4.RQ3SoDa  
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public synchronized int write(byte[] b,int nStart,int nLen) Tg\bpLk0=  
{ YDt+1Kw}D  
int n = -1; y>^a~}Z
q  
try{ G95,J/w  
oSavedFile.write(b,nStart,nLen); {Mx(|)WkL  
n = nLen; 8K 3dwoT  
} M^FY6TT4O  
catch(IOException e) c`;\sW-_W  
{ zzqJeIS  
e.printStackTrace (); Uzu6>yT  
} [M?2axOC  
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return n; ccD+AGM.  
} g)D_!iz  
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} qNp1<QO0  
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/* {@Mr7*u  
**SiteInfoBean.java o2 14V\  
*/ wX$:NOO  
package NetFox; /ZLY@&M  
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public class SiteInfoBean { ()
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private String sSiteURL; //Site's URL ,"(L2+Yp  
private String sFilePath; //Saved File's Path ]Bw0Qq F#  
private String sFileName; //Saved File's Name sDY~jP[Oa  
private int nSplitter; //Count of Splited Downloading File .L'w/"O  
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public SiteInfoBean() EY}:aur  
{//nSplitter的缺省值为5 em$pU*`P  
//default value of nSplitter is 5 y_]+;%w:  
this("","","",5); @ZKf3,J0  
} W U(_N*a  
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u^  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ~/ %Xm<  
{ l'@-?p(Vuw  
sSiteURL= sURL; cTqkM@S  
sFilePath = sPath; cNs'GfD}  
sFileName = sName; !3v&+Jrf6  
this.nSplitter = nSpiltter; (~T*yH ~  
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} I<SgKva;c  
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public String getSSiteURL() gT+/nSrLV  
{ C*9X;+S0J  
return sSiteURL; 1I+9?fa  
} 2|1fb-AR  
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public void setSSiteURL(String value) 'j
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{ EeIDlm0o  
sSiteURL = value; }\pI`;*O|  
} PT"}2sR)  
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public String getSFilePath() `]Bb0h1![  
{ #;!&8iH  
return sFilePath; 'sNZFB#  
} W&z jb>0b0  
1uF$$E6[  
]rcF/uQJ<n  
public void setSFilePath(String value) '\Xkvi  
{  EM,C  
sFilePath = value; MB plhVK8  
} Tt;F-  
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public String getSFileName() x2"iZzQlD  
{ LQ0/oYmNc  
return sFileName; yNu_>!Cp5  
} {.Tx70kn  
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public void setSFileName(String value) [P$Xr6#  
{ Bx\&7|,x  
sFileName = value; V0ze7tSG[f  
} 8^mE<  
|rmelQ-  
4=PjS<Lu8  
public int getNSplitter() CB@7XUR  
{ :qYp%Ub  
return nSplitter; ~zp8%lEe  
} <,d550GSm  
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public void setNSplitter(int nCount) j;x()iZ<  
{ ez4!5&TzRm  
nSplitter = nCount; L"_XWno  
} J0G@]H  
} ">uN={Iy  
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/* gY}In+S  
**Utility.java (Wzp sDte  
*/ ju~$FNt8R  
package NetFox; Gvb2>ZN  
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public class Utility { X-pbSq~5  
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public Utility() UBvp32p  
{ J~~\0 u  
b UG,~\Z  
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} m_NX[>&Y3  
`
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//线程睡眠 F^ q{[Z  
public static void sleep(int nSecond) 4vhf!!1  
{
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try{ -Cf)`/  
Thread.sleep(nSecond); }$6L]   
} oOFTQB_6  
catch(Exception e) nep#L>LP$x  
{ ttP7-
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e.printStackTrace (); gt kV=V  
} |}"YUk^  
} %"RJi?  
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//日志 yR[6s#F/h  
public static void log(String sMsg) Met?G0[  
{ {gMe<y  
System.err.println(sMsg); k %I83,+  
} 8
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public static void log(int sMsg) y:G%p3h)[  
{ m
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System.err.println(sMsg); E0HqXd?  
} CTMC78=9}  
} Nc[@QC{  
=NB[jQ :(  
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/* '/Aq2  
**TestMethod.java oEIpv;:_  
*/
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package NetFox;  Y@,iDQ  
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public class TestMethod { IZVP-  
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>%/x~UFc5  
public TestMethod() yT^x0?
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{ ///xx/weblogic60b2_win.exe {16a P  
try{ "Eh=@?]S_  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ax@H^Gj@2  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); S-t#d7'B  
SiteFileFetch fileFetch = new SiteFileFetch(bean); *-VRkS-G  
fileFetch.start(); eORXyh\K  
} {C |R@S  
catch(Exception e){e.printStackTrace ();} v,4{:y]p  
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>Kgw2,y+  
} q,v<:sS9T  
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{}$9 70y  
public static void main(String[] args) -CPtYG[s  
{ 7x)Pt@c  
new TestMethod(); jAJ='|[X\  
} cILS  
} LV}R 9f  
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