http断点续传简单实现（java)

/* )9@Ftzg|  
**SiteFileFetch.java $e<3z6  
*/ I^lb;3uR  
package NetFox; jfgAI7;b  
import java.io.*; M+nz~,![  
import java.net.*; \idg[&}l}  
*!.'1J:YJ(  
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public class SiteFileFetch extends Thread { ii~~xt1  
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SiteInfoBean siteInfoBean = null; //文件信息Bean }0f[x ?V  
long[] nStartPos; //开始位置 ~Jq<FVK  
long[] nEndPos; //结束位置 %2qvK}  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 b`%/*  
long nFileLength; //文件长度 =\_MJ?A$  
boolean bFirst = true; //是否第一次取文件 2;6p2GNSh  
boolean bStop = false; //停止标志 NFc<%#H  
File tmpFile; //文件下载的临时信息 ea7v:#O[S  
DataOutputStream output; //输出到文件的输出流 n]_8!NU  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） j7uiZU;3Rx  
public SiteFileFetch(SiteInfoBean bean) throws IOException yNI}=Z  
{ >Wy@J]Y#  
siteInfoBean = bean; qY0GeE>N  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 6'?Y]K  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); P_i2yhpK  
if(tmpFile.exists ()) ,hX03P-X  
{ >F@7}Y(  
bFirst = false; 7?cZ9^z`w  
read_nPos(); j7O7P+DmS  
} tQUp1i{j\  
else mJWl#3  
{ 5v>(xl  
nStartPos = new long[bean.getNSplitter()]; A!@D }n  
nEndPos = new long[bean.getNSplitter()]; # {!Qf\1M  
} v>0xHQD*<M  
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} G|X1c}zAL  
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public void run() rWSw1(sAA  
{ _X;5ORH"  
//获得文件长度 KqaeRs.u  
//分割文件 ^9"|tWf6O  
//实例FileSplitterFetch ae#7*B  
//启动FileSplitterFetch线程 %n!s{5:F  
//等待子线程返回 blxH`O!  
try{ H}JH339  
if(bFirst) &*L:4By)]  
{ (q3(bH~T)  
nFileLength = getFileSize(); mVU(u_lh  
if(nFileLength == -1) i>0I '~V  
{ m5f/vb4l  
System.err.println("File Length is not known!"); ~])\xC  
} [#uX{!q'  
else if(nFileLength == -2) (zye Ch  
{ QT\S>}  
System.err.println("File is not access!"); #).om*Xh  
} U*v//@WbH  
else ){R_o
5  
{ 3(6i6 vV  
for(int i=0;i<nStartPos.length;i++) >y%$]0F1  
{ 1 dI  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); \wO)w@"  
} MdZ7Yep  
for(int i=0;i<nEndPos.length-1;i++) ZK3?"|vhC  
{ Y( D d7`c  
nEndPos = nStartPos[i+1]; >0:h(,?V  
} GEIMCg(TRj  
nEndPos[nEndPos.length-1] = nFileLength; =@V4V} ?  
} )v8;\1`s:  
} )^g}'V=vIr  
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h'w9=Pk~6y  
//启动子线程 LQNu]2  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Zdj~B1  
for(int i=0;i<nStartPos.length;i++) Rm)vY}v  
{ mmr>"`5.  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), m'oVqA&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), E9%xSMS8@  
nStartPos,nEndPos,i); 26.iFt/:  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); u=#LY$  
fileSplitterFetch.start(); HSp*lHU  
} _N9yC\  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), M+)%gnq`u  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 9BNAj-Xa  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", iN+p>3w^l  
nEndPos = " + nFileLength); :14O=C  
// fileSplitterFetch[nPos.length-1].start(); KW^s~j  
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$//18+T  
//等待子线程结束 ~}z p}Pt  
//int count = 0; D\N-ye1LE  
//是否结束while循环 Qf7]t-Kp  
boolean breakWhile = false; _Vj O [hx  
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7 fqK{^L  
while(!bStop) XV). cW|.a  
{ /o+, =7hY  
write_nPos(); \qV5mD]"M  
Utility.sleep(500); d7$H})[^  
breakWhile = true; 06 K8|K  
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for(int i=0;i<nStartPos.length;i++) 9SC#N5V  
{ u0w2v+  
if(!fileSplitterFetch.bDownOver) =lr*zeHLC  
{ VGWqy4m  
breakWhile = false;  f==o  
break; $-M1<?5  
} r7JILk  
} WI[6l6  
if(breakWhile) p^5B_r:  
break; E Jq=MP  
~k|~Q\  
\ $X3n\  
//count++; (@uQ>dR:  
//if(count>4)
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// siteStop();
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} htMsS4^Kvd  
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System.err.println("文件下载结束！"); im*QaO%a4  
} J);1Tpm  
catch(Exception e){e.printStackTrace ();} 3`SLMPI  
} ehOF@IA_  
>(`|oD`,Y  
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//获得文件长度 1
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public long getFileSize() rTDx|pvYx  
{ s:jr/ j!  
int nFileLength = -1; f^:9gRt  
try{ P.&,nFIg3  
URL url = new URL(siteInfoBean.getSSiteURL()); FL(gwfL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); k-b_ <Tbo|  
httpConnection.setRequestProperty("User-Agent","NetFox"); ',*I=JW;  
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int responseCode=httpConnection.getResponseCode(); ,UH`l./3DX  
if(responseCode>=400) ) ;-AT^  
{  5t:4%  
processErrorCode(responseCode); JQQD~J1)E  
return -2; //-2 represent access is error ,yAvLY5P  
} g#9KG  
]*sXISg1  
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String sHeader; 1,,o_e\nn3  
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for(int i=1;;i++) .IYOt
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{ sBZKf8@/  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); "%qGcC
8  
//Utility.log(in.readLine()); <3Co/.VQd  
sHeader=httpConnection.getHeaderFieldKey(i); Z^>3}\_v  
if(sHeader!=null) afGb}8 Q9  
{ JgYaA*1X  
if(sHeader.equals("Content-Length")) -[0)n{AVvU  
{ Eq~&d.j  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 'u_'y  
break; M!!W>A@T[g  
} S[X bb=n  
} W O|2x0K  
else s-o0N{b?#'  
break; kTc'k  
} ,t*
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} _d %H;<_  
catch(IOException e){e.printStackTrace ();} 'WxcA)z0cQ  
catch(Exception e){e.printStackTrace ();} 2+sNt6B2  
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Utility.log(nFileLength); _4xX}Z;  
 \AoM'+  
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return nFileLength; MFiX8zwhx+  
} }`h)+Im=  
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Y.[
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//保存下载信息（文件指针位置） &AZr(>  
private void write_nPos() /DQoM@X  
{ EoIP#Cnd1  
try{ I/pavh  
output = new DataOutputStream(new FileOutputStream(tmpFile)); T AwA)Zg  
output.writeInt(nStartPos.length); o*'J8El\y^  
for(int i=0;i<nStartPos.length;i++) v?
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{ BqCBH!^x  
// output.writeLong(nPos); aOyAP-m,  
output.writeLong(fileSplitterFetch.nStartPos); 2\CFt;fk  
output.writeLong(fileSplitterFetch.nEndPos); tm#T8iF  
} $*9h\W-)`Q  
output.close(); .Rd@,3  
} H.'MQ  
catch(IOException e){e.printStackTrace ();} b@/z^k{%  
catch(Exception e){e.printStackTrace ();} #gUM%$  
} VbKky1a@  
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//读取保存的下载信息（文件指针位置） ?UcW@B{  
private void read_nPos() UStZ3A'  
{ 9fzbR~s  
try{ ]+ XgH#I  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Uj(,
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int nCount = input.readInt(); R1&(VK{  
nStartPos = new long[nCount]; #J\
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nEndPos = new long[nCount]; bJx{mq  
for(int i=0;i<nStartPos.length;i++) 6}K|eUak/  
{ e7{3:y|]d3  
nStartPos = input.readLong(); x5c pv  
nEndPos = input.readLong(); D?)"Z$  
} k8GcHqNHx  
input.close(); S^c5  
} [6FCbzS_W  
catch(IOException e){e.printStackTrace ();} rk-}@vp  
catch(Exception e){e.printStackTrace ();} 4IG'Tm  
} >(<OhS(  
oi::/W|A+  
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private void processErrorCode(int nErrorCode) "6gu6f  
{ : N>5{  
System.err.println("Error Code : " + nErrorCode); dp&4G6Y<A  
} 2(\~z@g  
*QG>U[  
H
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//停止文件下载 "e&S*8QhM  
public void siteStop() $83TA><a  
{ w5bD  
bStop = true; W&;X+XA_W  
for(int i=0;i<nStartPos.length;i++) ^;Nu\c  
fileSplitterFetch.splitterStop(); B;SYO>.W  
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} 6w0/;8(_m  
} `$JPF Z  
//负责部分文件的抓取 C
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**FileSplitterFetch.java &y;('w  
*/ &DYHkG  
package NetFox; Sl/[9-a)  
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import java.io.*; V&-pgxf;  
import java.net.*; b%2+g<UKh  
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public class FileSplitterFetch extends Thread { HpiP"Sl  
 O3bo3Cm$  
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String sURL; //File URL bJ*jJl x  
long nStartPos; //File Snippet Start Position 4yV}4f$q  
long nEndPos; //File Snippet End Position \S{ise/U  
int nThreadID; //Thread's ID OxqK}%=Bw  
boolean bDownOver = false; //Downing is over 5}x^0 LY  
boolean bStop = false; //Stop identical >)YaWcI  
FileAccessI fileAccessI = null; //File Access interface %G1kkcdH<  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Wsyq  
{ h.gj4/g  
this.sURL = sURL; C:\BvPoO  
this.nStartPos = nStart; ftw\oGrS  
this.nEndPos = nEnd; 4eMNKIsvY$  
nThreadID = id; 3Kc  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 IGeXj%e  
} -&I
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public void run() L=nyloz,0  
{ GD<xmuo  
while(nStartPos < nEndPos && !bStop) n dgG1v%  
{ -.~Dhk  
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vY&[=2=  
try{ AP&mr1_  
URL url = new URL(sURL); AC;ja$A#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;^za/h>r  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6,"86  
String sProperty = "bytes="+nStartPos+"-"; ^"WrE(3  
httpConnection.setRequestProperty("RANGE",sProperty); B~K@o.%  
Utility.log(sProperty); tu8n1W  
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InputStream input = httpConnection.getInputStream(); 0\*[7!`s  
//logResponseHead(httpConnection); M}2a/}4
 
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byte[] b = new byte[1024]; Goa0OC,  
int nRead; w7aC=B/{?i  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) mxUM&`[  
{ ,$BbJQ5  
nStartPos += fileAccessI.write(b,0,nRead); |zhVl  
//if(nThreadID == 1) &Jw]3U5J  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {+r0Nikx_  
} ,U':=8  
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Utility.log("Thread " + nThreadID + " is over!"); Qz6Ry\u  
bDownOver = true; sTeW4Hnp  
//nPos = fileAccessI.write (b,0,nRead); =w&JDj  
} J<J_yRg2  
catch(Exception e){e.printStackTrace ();} w$%d"Jm#X  
} gbF^m`A>%+  
} X.TsOoy  
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//打印回应的头信息 /sHWJ?`&/,  
public void logResponseHead(HttpURLConnection con)  zE$KU$  
{ zq\YZ:JC  
for(int i=1;;i++) 7S+_eL^  
{ \H <k  
String header=con.getHeaderFieldKey(i); <Sw>5M!j  
if(header!=null) 6%'bo`S#  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); M;s r1C  
Utility.log(header+" : "+con.getHeaderField(header)); H
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else T#&tf
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break; ;#c=0*.  
} |cKo#nfzZ  
} 
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public void splitterStop() (vL-Z[M!  
{ Cbw@:+%J{  
bStop = true; yc ize2>q  
} Hqsj5j2i  
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} @0js=3!2  
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/* Q#+y}pOLP  
**FileAccess.java k.UQT^.  
*//文件访问(定位，写) UvwO/A\Gv  
package NetFox; !cblmF;0  
import java.io.*; !{hC99q6  
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public class FileAccessI implements Serializable{ ji'NR  
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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 <K6:"  
RandomAccessFile oSavedFile; "DWw]\xO](  
long nPos; }V@ * :3w8  
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public FileAccessI() throws IOException ey icMy`7{  
{ 7bC1!x*qw  
this("",0); ?_hKhn%K9  
} j%7N\Vb  
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public FileAccessI(String sName,long nPos) throws IOException s"tyCDc.c  
{ W Z!?O0.A  
oSavedFile = new RandomAccessFile(sName,"rw"); u1@&o9  
this.nPos = nPos; 6p;G~,bd~  
oSavedFile.seek(nPos); CJn{tP  
} ^T^l3B[  
`>.^/SGu>?  
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public synchronized int write(byte[] b,int nStart,int nLen) 4V2}'/|[  
{ !&8nwOG  
int n = -1; WAd5,RZ?  
try{ UG@9X/l}  
oSavedFile.write(b,nStart,nLen); tBJCfM  
n = nLen; 8mrB_B5  
} yJyovfJz.  
catch(IOException e) {>x6SVF  
{ *y6zwe !M  
e.printStackTrace (); -'q#u C  
} Z4&,KrV  
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return n; "L?h
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} [9hslk  
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} .el&\Jt  
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/* @pV~Q2%  
**SiteInfoBean.java ){D6E9  
*/ *VP-fyJp  
package NetFox; LBcnBo</v  
FV 0x/)<z  
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public class SiteInfoBean { vO?\u`vY  
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private String sSiteURL; //Site's URL B
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private String sFilePath; //Saved File's Path pW y+oZ  
private String sFileName; //Saved File's Name r bfIH":  
private int nSplitter; //Count of Splited Downloading File Ro2Ab^rQ|  
/s/\5-U7q  
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public SiteInfoBean() =ws iC'  
{//nSplitter的缺省值为5 y;GwMi$KI  
//default value of nSplitter is 5 E"/r*C+T  
this("","","",5); '5f6 M^}|2  
} l KdY!j"  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) p;x3gc;0  
{ ]%Db%A
 
sSiteURL= sURL; u/
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sFilePath = sPath; ,f[`C-\Q%  
sFileName = sName; ?=},%^  
this.nSplitter = nSpiltter; f"Z2,!Z;  
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} 17C"@1n-  
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public String getSSiteURL() x%`.L6rj  
{ W3gBLotdg  
return sSiteURL; 1y{@fg~..  
} 32S5Ai@Cd"  
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public void setSSiteURL(String value) &OXWD]5$6  
{ U4.-{.  
sSiteURL = value; -*nd5(lY&  
} .Bs~FIe^  
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public String getSFilePath() C4h4W3w  
{ C]f`  
return sFilePath; Ij_h #f   
} tB<2mjg  
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public void setSFilePath(String value) 0{k*SCN#  
{ = a54  
sFilePath = value; 8jdEx&K  
} ln*_mM/Q%  
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public String getSFileName() L>X39R~  
{ j-n-2:Q  
return sFileName; =K`]$Og}8  
} %AV[vr
,  
,^m;[Dl7  
:L&d>Ii|'  
public void setSFileName(String value) `/+PZqdC  
{ PpWn+''M  
sFileName = value; ,b!]gsds  
} k4!z;Yq  
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public int getNSplitter() R;3Tyn+  
{ kfQi}D'a  
return nSplitter; %.mHV7c)%  
} a]%>7yr4  
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public void setNSplitter(int nCount) okSCM#&:[2  
{ lr-:o@q{  
nSplitter = nCount; kM o7mkV  
} d2=Z=udd  
} ,K 1X/),  
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/* +^tw@b  
**Utility.java "U6:z M  
*/ *(*
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package NetFox; r[votdFo  
h}@)oSX }  
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public class Utility { P{{U  
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public Utility() lMW4SRk1C  
{ [T>a}}@  
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} Zyx92z9Y  
9p '#a:  
//线程睡眠 d%C:%d  
public static void sleep(int nSecond) mok%TK  
{ [ta3sEPjs  
try{ :4'Fq;%C  
Thread.sleep(nSecond); -|\SNbPTV  
} CTOrBl$70  
catch(Exception e) DTi\ 4&41  
{ e|&}{JP{[  
e.printStackTrace (); wO&2S-;_K  
} @*{sj`AS '  
} PRi3=3oF  
X&+*?Q^  
//日志 3Hg}G#]WS  
public static void log(String sMsg) H;(|&Asq>  
{ "2
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System.err.println(sMsg); 7\e96+j|f  
} /H m),9NN  
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tUR9ti  
public static void log(int sMsg) hr)CxsPoRQ  
{ &GetRDr  
System.err.println(sMsg); w6w'Jx  
} gY=Ry=w9  
} <F7g;s'q9  
v7kR]HU[y  
:(o6^%x  
/* RXDPT  
**TestMethod.java ~BJ~]~0P`  
*/ ^%<t^sE  
package NetFox; @T6Z3Zj}  
jj&4Sv#>  
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public class TestMethod { QoVRZ$!p  
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public TestMethod() S5$sB{\R  
{ ///xx/weblogic60b2_win.exe \h&ui]V  
try{ Z
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); M zbs#v0  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); J/o$\8tiMw  
SiteFileFetch fileFetch = new SiteFileFetch(bean); xO<
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fileFetch.start();  KOQ9K
 
} W6>SYa  
catch(Exception e){e.printStackTrace ();} },=0]tvZG#  

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} %488"  
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public static void main(String[] args) [v!TQwMU  
{ Y^(Sc4 W  
new TestMethod(); c T!L+zg  
} l6C^,xU~IX  
} |=Mn~`9p  
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