http断点续传简单实现（java)

/* /g$cQ=c  
**SiteFileFetch.java vEQw`OC  
*/ qJV2x.!  
package NetFox; 'YQ^K`lV  
import java.io.*; ;Z>u]uK4+  
import java.net.*; 1
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public class SiteFileFetch extends Thread { CB
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SiteInfoBean siteInfoBean = null; //文件信息Bean PF=BXY1<UL  
long[] nStartPos; //开始位置 qyi5j0
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long[] nEndPos; //结束位置 B=)&43)\  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 >f)/z$ qn  
long nFileLength; //文件长度 DD 8uG`<  
boolean bFirst = true; //是否第一次取文件 
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boolean bStop = false; //停止标志 9vIqGz-o  
File tmpFile; //文件下载的临时信息 lO^Ly27  
DataOutputStream output; //输出到文件的输出流 y[QQopy4:  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ((KNOa5  
public SiteFileFetch(SiteInfoBean bean) throws IOException <zd_-Ysn  
{ abog\0  
siteInfoBean = bean; XS:W{tL!  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); X}"Ic@8  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); D*7JE  
if(tmpFile.exists ()) /mS|Byx  
{ tYb
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bFirst = false; >4I,9TO  
read_nPos(); z}Y23W&sX  
} 3B*b d  
else vbFi#|EU  
{ A'A5.
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nStartPos = new long[bean.getNSplitter()]; [/Q .MmnL  
nEndPos = new long[bean.getNSplitter()]; cD^`dn%$  
} t2bv nh  
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} 0}LBnV  
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public void run() +M )ep\j  
{ LWH(bs9U  
//获得文件长度 Kjw==5)}  
//分割文件 Myj5qh  
//实例FileSplitterFetch 5(9SIj^O  
//启动FileSplitterFetch线程 8{0=tOXx{  
//等待子线程返回 FYwMmb ~3  
try{ Tt;h?  
if(bFirst) l]g /rs  
{ \\ZR~f!<  
nFileLength = getFileSize(); Rgstk/1  
if(nFileLength == -1) TRLz>mQ  
{ -4 *94<  
System.err.println("File Length is not known!"); fEv`iXZG  
} 31VDlcnE  
else if(nFileLength == -2) tW^oa  
{ J\06j%d,  
System.err.println("File is not access!"); ShP&ss  
} X283.?  
else &^q!,7.J  
{ c:*[HO\  
for(int i=0;i<nStartPos.length;i++)
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{ #|92+  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); k4n4BL  
} CBkI! In2  
for(int i=0;i<nEndPos.length-1;i++) p :v'"A}  
{ 4n9".UH
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nEndPos = nStartPos[i+1]; !O*'mX  
} iX&eQ{LB  
nEndPos[nEndPos.length-1] = nFileLength; g4eEkG`XTS  
} X  jPPgI  
} J\@ r~x5G  
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//启动子线程 xX !`0T7Y  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; z_i(o  
for(int i=0;i<nStartPos.length;i++) kv!QO^;^Y  
{ ul@swp
 
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 96(3il
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), g36:OK"  
nStartPos,nEndPos,i); cVV@MC  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %#_"Ie  
fileSplitterFetch.start(); Pv#Oea?  
} "=0(a)01p:  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?IN'Dc9&%-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 24g\xNnt  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", $a@T:zfe  
nEndPos = " + nFileLength); v3*y43  
// fileSplitterFetch[nPos.length-1].start(); Z
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9mmkFaBQ  
//等待子线程结束 KD<smwXjG  
//int count = 0; 4ZUTF3  
//是否结束while循环 2\4ammwT  
boolean breakWhile = false; 04j]W]8#  
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while(!bStop) hR4\:s+[  
{ gR\z#Sg  
write_nPos(); aAbK{=/y_!  
Utility.sleep(500); &g.do?  
breakWhile = true; }OsAO  
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for(int i=0;i<nStartPos.length;i++) |&oTxx$S  
{ !=3Ce3-  
if(!fileSplitterFetch.bDownOver) w *pTK +  
{ sBq-"YcjR  
breakWhile = false; v 1.8]||^  
break; /g`!Zn8a  
} &FpoMW  
} f0|wN\  
if(breakWhile) ?~:4O}5Ax  
break; uGc0Lv4i/  
1PN!1=F}  
ke)}JU^"  
//count++; @zCp/fo3  
//if(count>4) d:vuRK4+  
// siteStop(); S
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} #FhgKwx  
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System.err.println("文件下载结束！"); v[2N-  
} '8"nXuL-  
catch(Exception e){e.printStackTrace ();} j[RY  
} z 0}JiWR  
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//获得文件长度 =j"bLX6;  
public long getFileSize() _2a)b(<tF  
{ \zT{zO&!  
int nFileLength = -1; KaIkO8Dq0  
try{ ~(;HkT  
URL url = new URL(siteInfoBean.getSSiteURL()); |V&E q>G  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ] :SbvsPm  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]:r(U5 #  
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int responseCode=httpConnection.getResponseCode(); S]Qf p,  
if(responseCode>=400) UrmnHc>}c  
{ ZVyJ%"(E  
processErrorCode(responseCode); s/0bXM$^  
return -2; //-2 represent access is error xFzaVjjP  
} q&kG>  
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String sHeader; =x@v{cP  
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for(int i=1;;i++) [$D%]]/,  
{ IcA]B?+  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ]Om;b
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//Utility.log(in.readLine()); DP.Y<V)B  
sHeader=httpConnection.getHeaderFieldKey(i); ^ AJ_  
if(sHeader!=null) +7mUX  
{ R^w}o,/  
if(sHeader.equals("Content-Length")) GN0duV  
{ `y'aH 'EEd  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 1f<RyAE?5  
break; AhR0zg  
} 691G15  
} Uh*@BmDA  
else YhS{$Z  
break; M</Wd{.g"  
} PzLJ/QER  
} s*f1x N<  
catch(IOException e){e.printStackTrace ();} b9y)wBC%`  
catch(Exception e){e.printStackTrace ();} aF!WIvir  
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Utility.log(nFileLength); g*F~8+]Y  
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return nFileLength; [-Cu4mff  
} nW11wtiO.  
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//保存下载信息（文件指针位置） w]F!2b!  
private void write_nPos() 8]HY. $E  
{ ?]5Ix1  
try{ -8/JP  
output = new DataOutputStream(new FileOutputStream(tmpFile)); QypZH"Np  
output.writeInt(nStartPos.length); $,@JYLC2  
for(int i=0;i<nStartPos.length;i++) SetX#e?q~  
{ 7C?E z%a@  
// output.writeLong(nPos); /~tP7<7A  
output.writeLong(fileSplitterFetch.nStartPos); a>w~FUm*  
output.writeLong(fileSplitterFetch.nEndPos); }Bi@?Sb  
} W/=7jM   
output.close(); .'&V#D0  
} m d_g}N(C  
catch(IOException e){e.printStackTrace ();} 'mJ1
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catch(Exception e){e.printStackTrace ();} z-I|h~ii  
} :xtT)w  
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//读取保存的下载信息（文件指针位置） cl_TF[n?  
private void read_nPos() D?mDG|Z  
{ p_r4^p\  
try{ S2Vxe@b)  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 14-]esSa  
int nCount = input.readInt(); ;t!9]1  
nStartPos = new long[nCount]; Cdmy.gx^  
nEndPos = new long[nCount]; 5D L,U(Y  
for(int i=0;i<nStartPos.length;i++) #"<?_fao~  
{ c;^A)_/  
nStartPos = input.readLong(); hX3@f;[B2  
nEndPos = input.readLong(); 0#^Bf[Dn  
} `,P >mp)uU  
input.close(); # M>wH`Q#  
} Mt=R*M}D0  
catch(IOException e){e.printStackTrace ();} 86qcf"?E  
catch(Exception e){e.printStackTrace ();} &oEyixe  
} &Sa~/!
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private void processErrorCode(int nErrorCode) =ajLa/m'  
{ UKj`_a6  
System.err.println("Error Code : " + nErrorCode); }1@E"6kF  
} s[T{c.F  
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//停止文件下载 lQ$+JX;n(y  
public void siteStop() GFt1  
{ GXYj+ qJ  
bStop = true; O2lIlCL  
for(int i=0;i<nStartPos.length;i++) #j.FJFGX  
fileSplitterFetch.splitterStop(); Eu4 &-i  
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} WUY,. 8  
} ]5)"gL%H`  
//负责部分文件的抓取 sv`"\3N[  
**FileSplitterFetch.java s`1^*Dl%+  
*/ o3\
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package NetFox; x?=B\8m  
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import java.io.*; jzMg'z/@J  
import java.net.*; 0Az/fzJlz  
@ t|3gF$X  
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public class FileSplitterFetch extends Thread { x{?sn  
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String sURL; //File URL 2qXo{C3  
long nStartPos; //File Snippet Start Position B.RRdK+:  
long nEndPos; //File Snippet End Position 9t0Cj/w}  
int nThreadID; //Thread's ID dE GX3 -  
boolean bDownOver = false; //Downing is over bs P6\'\4  
boolean bStop = false; //Stop identical ,(;5%+#n  
FileAccessI fileAccessI = null; //File Access interface <5k&)EoT  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException %Co b(C&}  
{ L^)qe^%3  
this.sURL = sURL; 3A d*
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this.nStartPos = nStart; 71*>L}H  
this.nEndPos = nEnd; g}YToOs  
nThreadID = id; B>@D,)/bT5  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 *w|iu^G  
} 7PA=)a\  
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public void run() 2^J/6R$  
{ NN11}E6  
while(nStartPos < nEndPos && !bStop) $YPQC  
{ }H; ]k-)  
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try{ H6{Rd+\Z  
URL url = new URL(sURL); $82zyq  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?`"<DH~:0B  
httpConnection.setRequestProperty("User-Agent","NetFox"); <ip)r;  
String sProperty = "bytes="+nStartPos+"-"; :/~_sJt C  
httpConnection.setRequestProperty("RANGE",sProperty); Rd0?zEKV  
Utility.log(sProperty); 6kC)\uy  
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InputStream input = httpConnection.getInputStream(); kHZKj!!R  
//logResponseHead(httpConnection); 9a-]T=5Ee  
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byte[] b = new byte[1024]; f}A^]6MO:  
int nRead; bnIf}ut-G  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >"i~ x  
{ D8W(CE^}  
nStartPos += fileAccessI.write(b,0,nRead);  eMztjN  
//if(nThreadID == 1) xR _DY'z  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %N!h38N2  
} b\H/-7<  
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Utility.log("Thread " + nThreadID + " is over!"); k#BU7Exij  
bDownOver = true; v#w4{.8)  
//nPos = fileAccessI.write (b,0,nRead); +h9`I/R  
} oK%K+h  
catch(Exception e){e.printStackTrace ();} s8C:QC  
} N IO;  
} bXk:~LE  
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//打印回应的头信息 A7mMgb_  
public void logResponseHead(HttpURLConnection con) _$~ex ~v  
{ }6F_2S3c  
for(int i=1;;i++) w}fqs/)w  
{ `Nc`xO?  
String header=con.getHeaderFieldKey(i); `W6:=H  
if(header!=null) AN50P!FZW  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Z{Lmd`<w`j  
Utility.log(header+" : "+con.getHeaderField(header)); 8.6no  
else Tey,N^=ek  
break; [J(@$Qix  
} 3^uL`ETm@  
} ]=O{7#  
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public void splitterStop() \k2C 5f  
{ .N'%hh  
bStop = true; iPR!JX _  
} :..E:HdYO  
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} !;BZ#tF&  
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/* -;W\f<q]  
**FileAccess.java 98"z0nI%  
*//文件访问(定位，写) +?J_6Mo@X  
package NetFox; =N[V{2}q  
import java.io.*; 9OO0Ht4j  
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public class FileAccessI implements Serializable{ ;'Z,[a  
d6Q :{!Sd"  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 .$}Z:,aB  
RandomAccessFile oSavedFile; * 7zN  
long nPos; [xp~@5r'  
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public FileAccessI() throws IOException gn4g 43  
{ _z_3%N  
this("",0); "
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} 4IGQ,RTB  
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public FileAccessI(String sName,long nPos) throws IOException 4,R\3`b  
{ s K$Sar  
oSavedFile = new RandomAccessFile(sName,"rw"); $HR(|{piZ  
this.nPos = nPos; Nsy9 h}+A  
oSavedFile.seek(nPos); ^0,&R\e+  
} )oz-<zW  
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public synchronized int write(byte[] b,int nStart,int nLen) 2=UTH%1D  
{ KzFs#rhpn  
int n = -1; 1dgN10  
try{ w!GU~0~3[  
oSavedFile.write(b,nStart,nLen); 7=M'n;!Mh  
n = nLen; S92!jp/  
} m= beB\=  
catch(IOException e) )uv$tnP*  
{ KI?1(L  
e.printStackTrace (); E)Zd{9A5)  
} " :nVigw&  
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return n; `'k's]Y  
} ~ @"Qm;} "  
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} 7_d#XKz@  
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/* H
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**SiteInfoBean.java ~>-;(YU"t  
*/ BrH`:Dw  
package NetFox; *]UEF_  
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+`vZg^_c`  
public class SiteInfoBean { kGTc~p(  
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private String sSiteURL; //Site's URL ?Dp^dR  
private String sFilePath; //Saved File's Path ^DCv-R+p  
private String sFileName; //Saved File's Name k^%ec3l  
private int nSplitter; //Count of Splited Downloading File ny?m&;^r:  
o%JIJ7M  
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public SiteInfoBean() >mDubP  
{//nSplitter的缺省值为5 \iE9&3Ie  
//default value of nSplitter is 5 7;-i_&vws  
this("","","",5); &-)Y[#\J  
} Z1lF[d,f;  
%L|bF"K5;  

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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) I\6<)2j/L  
{ 5Cyjq0+  
sSiteURL= sURL; M4PUJZ]  
sFilePath = sPath; r{jD,x2  
sFileName = sName; "@?kxRn!  
this.nSplitter = nSpiltter; kxf=%<l  
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} q _|5,_a  
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public String getSSiteURL() s3
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{ iC2n
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return sSiteURL; Ui;s.f  
} X[Gk!dr#  
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public void setSSiteURL(String value) ov>L-  
{ ~,-O  
sSiteURL = value; )#B
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} <s3(
  
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public String getSFilePath() %-|q3 ^s  
{ -RDs{c`y%N  
return sFilePath; dph6aN(49  
} ;CBdp-BUj  
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public void setSFilePath(String value) 5)<jP
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{ gP%!  
sFilePath = value; 6\@, Lb  
} N)Kr4GC  
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public String getSFileName() R/|{?:r?:x  
{ :!hH`l}p  
return sFileName; ^uzVz1%mM  
} @'4D9A  
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public void setSFileName(String value) +,>bpp1  
{ axOy~%%c  
sFileName = value; *^_!W'T{j  
} W7"s
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public int getNSplitter() o#6}?g.  
{ 
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return nSplitter; |pY0IqO  
} [L^#<@S  
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public void setNSplitter(int nCount) [Nc
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{ !6C d.fpWL  
nSplitter = nCount; k>`X! "  
} $)V4Eu;  
} JM%#L*;  
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$n"Llw&)  
/* cpVi9]  
**Utility.java oMbCljUC  
*/ 2Oa-c|F  
package NetFox; wQc w#  
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public class Utility { %Z4=3?5B"9  
#v-!GK_<  
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public Utility() !:5n  
{ aJ5R
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} U<b!$"P9  
;+U9;  
//线程睡眠
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public static void sleep(int nSecond) K~]jXo^M  
{ 85mQH
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try{ y(
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Thread.sleep(nSecond); :-)[B^0  
} $u :=lA:N  
catch(Exception e) +,lD_{}_  
{ A?/?9Gr  
e.printStackTrace (); $m>e!P>%u  
} _,^sI%  
} ,l6W|p?ZO^  
&ly[mBP~  
//日志 !NCT) #G`  
public static void log(String sMsg) !Xm:$KH  
{ _OY;SJ(  
System.err.println(sMsg); m_B5M0},  
} 9M<? *8)  
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~&x%;cnv_  
public static void log(int sMsg) m"*:XfOL  
{ vl<J-+|0C  
System.err.println(sMsg); }5k"aCno  
} m{*l6`dF  
} II91Ia  
1f=L8Dr  
.\VjS^o&Z&  
/* =BtE
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**TestMethod.java ')BQ 0sg  
*/ 4Qv|Z+$i  
package NetFox; 0e7!_/9  
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public class TestMethod { &l Q j?]  
[Ue>KG62=  
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public TestMethod() >b?,zWiw  
{ ///xx/weblogic60b2_win.exe :.dQY=6I  
try{ rnr7t \a~]  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); =8iM,Vl3  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ymKdRF  
SiteFileFetch fileFetch = new SiteFileFetch(bean); \c]/4C +/  
fileFetch.start(); )L{\k$r!EM  
} ql#K72s  
catch(Exception e){e.printStackTrace ();} "CaVT7L  
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} )6(mf2&  
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public static void main(String[] args) Pwq} ;+  
{ \R<yja  
new TestMethod(); /90@ 85%r  
} sLTf).xh  
} ?eu=0|d  
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