http断点续传简单实现（java)

/* L?KEe>;r  
**SiteFileFetch.java 3)0*hq&83  
*/ vn}Vb+@R  
package NetFox; ^@X =v`C  
import java.io.*; JpS:}yyJ>N  
import java.net.*; Pn7oQA\  
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public class SiteFileFetch extends Thread { _rjCwo\  
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SiteInfoBean siteInfoBean = null; //文件信息Bean <\zb*e&vr  
long[] nStartPos; //开始位置 , is
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long[] nEndPos; //结束位置 z eIBB  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 UQW;!8J#R(  
long nFileLength; //文件长度 Y,E:?  
boolean bFirst = true; //是否第一次取文件 AS;{O>}54  
boolean bStop = false; //停止标志 k )){1O  
File tmpFile; //文件下载的临时信息 B u4N~0
 
DataOutputStream output; //输出到文件的输出流 *QLl jGe  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） -JwH^*Ad  
public SiteFileFetch(SiteInfoBean bean) throws IOException sOJ"~p  
{ -QS_bQG%  
siteInfoBean = bean; 2~]c`/M3  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); e`}|*^-  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); v/yk T9@;  
if(tmpFile.exists ()) /.WD'*H  
{ ;oR-\;]/.  
bFirst = false; =:a3cr~  
read_nPos(); pM VeUK?  
} ;yk@`<  
else TR)'I  
{ 1YnDho;~  
nStartPos = new long[bean.getNSplitter()]; C5sV-UMR  
nEndPos = new long[bean.getNSplitter()]; 2! wz#EC  
} 3U:0,-j"  
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} 3*arW|Xm  
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public void run() G0*$&G0nb  
{ ,sLV6DM  
//获得文件长度 5gJQr%pS  
//分割文件 SH}O?d\Q:  
//实例FileSplitterFetch b$gDFNa  
//启动FileSplitterFetch线程 S%%>&^5  
//等待子线程返回 CB|z{(&N  
try{ j@9nX4Z  
if(bFirst) l_f"}l  
{ {I2jLc  
nFileLength = getFileSize(); kc"U)>  
if(nFileLength == -1) ![Jxh,f  
{ *2@q=R-1  
System.err.println("File Length is not known!"); <,cDEN7  
} 8@$QN4^u^  
else if(nFileLength == -2) $rjv4e}7  
{ cIgFS
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System.err.println("File is not access!"); jJ?3z,h  
} J-,T^Wv  
else bq ~'jg^#  
{ 45-pJf8F  
for(int i=0;i<nStartPos.length;i++) /-4%ug tD$  
{ O>k.sO <  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); DTr0u}m  
} i,bFe&7J  
for(int i=0;i<nEndPos.length-1;i++) 9CL&tpqv f  
{ ?NHh=H\7u  
nEndPos = nStartPos[i+1]; '-v~HwC+/T  
} #4"
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nEndPos[nEndPos.length-1] = nFileLength; oEi+S)_  
} 7z+NR&'M$  
} a>Q7Qn  
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//启动子线程 ^AEg?[q  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; /Hd\VI  
for(int i=0;i<nStartPos.length;i++) O~xc> w  
{ cxmr|-^  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4`*jF'N[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), lv8tS-  
nStartPos,nEndPos,i); bo@1c0  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (nV/-#*  
fileSplitterFetch.start(); q+m&V#FT%  
} -i;#4@^t  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7v\OS-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); khEHMvVH  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", h<uRlTk  
nEndPos = " + nFileLength); n ~ =]/  
// fileSplitterFetch[nPos.length-1].start(); n$~RgCf  
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//等待子线程结束 w\\   
//int count = 0; 8taaBM`:  
//是否结束while循环 OY@
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boolean breakWhile = false; u37+B  
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while(!bStop) 4lz9z>J.V  
{ duwZe+  
write_nPos(); $%!]tNGS  
Utility.sleep(500); 61wGIN2,  
breakWhile = true; u/,m2N9cL  
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for(int i=0;i<nStartPos.length;i++) < Gu s9^_  
{ \9 ^wM>U  
if(!fileSplitterFetch.bDownOver) UHxXa*HyI  
{ GadD*psD2  
breakWhile = false; `[`eg<xj  
break; b9"Q.*c<Z^  
} jI y'mGaG  
} Q4Cw{2r  
if(breakWhile) G2em>W_n  
break; Ejn19{  
*VL-b8'A<  
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//count++; = [:ruE  
//if(count>4) t/nu/yz5E  
// siteStop(); iXXgPapz  
} PY) 74sa  
9v/1>rziE  
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System.err.println("文件下载结束！"); eLl;M4d  
} RX#:27:  
catch(Exception e){e.printStackTrace ();} 3ne=7Mj  
} (Kx3:gs  
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//获得文件长度 5 kQC  
public long getFileSize() sx|=*j,_  
{ Z
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int nFileLength = -1; g9 g &]  
try{ HQ4o^WC  
URL url = new URL(siteInfoBean.getSSiteURL()); Wny{qj)=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); edbzg#wy  
httpConnection.setRequestProperty("User-Agent","NetFox"); iao_w'tJ  
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int responseCode=httpConnection.getResponseCode(); DQwbr\xy\  
if(responseCode>=400) Xo$(zGb  
{ ^F
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processErrorCode(responseCode); 7eZ,; x  
return -2; //-2 represent access is error +jQW6k#  
} ~|+  

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String sHeader; ALPZc:  
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for(int i=1;;i++) *\-6p0~A  
{ j
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 7)<&,BWc  
//Utility.log(in.readLine()); NouT~K`'  
sHeader=httpConnection.getHeaderFieldKey(i); Sh=z  
if(sHeader!=null) n{=vP`V_  
{ ~#OnA1)  
if(sHeader.equals("Content-Length")) <Y<%=`  
{ ".~,(
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); F d *p3a  
break; C+jlIT+  
} {ge^&l  
} O &;Cca
 
else Un@dWf6'  
break; A"d=,?yE  
} yP6^&'I+  
} 7'CdDB6&.  
catch(IOException e){e.printStackTrace ();} E%2]c?N5  
catch(Exception e){e.printStackTrace ();} V+-%$-w>  
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Utility.log(nFileLength); g2BE-0,R  
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return nFileLength; c7,p5[  
} Qne@Vf kA  
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={B%qq  
//保存下载信息（文件指针位置） 4Zo.c* BZ  
private void write_nPos() <D%.'=%pZ  
{ 6 -N 442  
try{ (gQP_Oa(  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 4*P#3 B'@V  
output.writeInt(nStartPos.length); 2V:`':  
for(int i=0;i<nStartPos.length;i++) \0). ODA(  
{ fl9`Mgu  
// output.writeLong(nPos); 3fM8W> *7  
output.writeLong(fileSplitterFetch.nStartPos); Iw~R@,  
output.writeLong(fileSplitterFetch.nEndPos); C[6} 8J|  
} :Ugf3%sQ  
output.close(); kZ>_m&g  
} ))66_bech  
catch(IOException e){e.printStackTrace ();} kc-=5l  
catch(Exception e){e.printStackTrace ();} ,K 8R
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} h'jc4mu0  
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//读取保存的下载信息（文件指针位置） j4k\5~yzS  
private void read_nPos() gF#HNv  
{ Py y!B  
try{ 3K!(/
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); S6Y2(qdP  
int nCount = input.readInt(); T\?$7$/V  
nStartPos = new long[nCount]; .o8Sy2PaV  
nEndPos = new long[nCount]; -n FKP&P  
for(int i=0;i<nStartPos.length;i++) ]l>LU2 sx  
{ ^m~&2l\N=  
nStartPos = input.readLong(); r2yJ{j&s  
nEndPos = input.readLong(); ti'B}bH>'  
} 70Jx[3vr  
input.close(); jVi>9[rz  
} oq${}n<  
catch(IOException e){e.printStackTrace ();} 3>M%?d  
catch(Exception e){e.printStackTrace ();} B\S}*IE  
} B>.x@(}V~  
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private void processErrorCode(int nErrorCode) %|j`z
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{ y^Uh<L0M  
System.err.println("Error Code : " + nErrorCode); Kv0V`}<Yc  
} lg"aB  
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<yl%q*gls  
//停止文件下载 z_93j3#  
public void siteStop() O,6Wdw3+-3  
{ ~=va<%
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bStop = true; ;NU-\<Q{  
for(int i=0;i<nStartPos.length;i++) .
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fileSplitterFetch.splitterStop(); (Zg'])  
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} J-#V_TzJ?  
} NNt n  
//负责部分文件的抓取 i/j53towe  
**FileSplitterFetch.java CRBj>  
*/ 0vETg'r  
package NetFox; vj
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import java.io.*; }@eIO|  
import java.net.*; :*f  2Bn  
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public class FileSplitterFetch extends Thread { d~1uK-L]*  
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String sURL; //File URL _Jy7` 4B.  
long nStartPos; //File Snippet Start Position F~q(@.b  
long nEndPos; //File Snippet End Position 1U% /~  
int nThreadID; //Thread's ID Kv<f<>|L  
boolean bDownOver = false; //Downing is over  ^M{,{bG  
boolean bStop = false; //Stop identical j$K*R."  
FileAccessI fileAccessI = null; //File Access interface AbxhNNK  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException [\AOr`7  
{ 
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this.sURL = sURL; c/Xg ARCO  
this.nStartPos = nStart; rtS' 90`  
this.nEndPos = nEnd; l+[:Cni  
nThreadID = id; R&9FdM3K`:  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 'IG@JL'  
} _0(%^5
Y  
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public void run() !$A/.;0$  
{ DY -5(6X  
while(nStartPos < nEndPos && !bStop) 3/>7b(  
{ 1rJ2}d\y  
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try{ 2 /FQ;<L  
URL url = new URL(sURL); (J[Xryub  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); lDTHK2f  
httpConnection.setRequestProperty("User-Agent","NetFox"); -QroT`gy  
String sProperty = "bytes="+nStartPos+"-"; 3V<@Vkf5  
httpConnection.setRequestProperty("RANGE",sProperty); .4p3~r?=S  
Utility.log(sProperty); AH|gI2  
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InputStream input = httpConnection.getInputStream(); '`3#FCg  
//logResponseHead(httpConnection); @@)2 12  
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byte[] b = new byte[1024]; PD)"od  
int nRead; ,
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) )P$|9<_q7x  
{ tO&ffZP8$  
nStartPos += fileAccessI.write(b,0,nRead); v8)"skVnFG  
//if(nThreadID == 1) CuWJai:nQ;  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); fC[za,PXaE  
} EHk\Q\  
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Utility.log("Thread " + nThreadID + " is over!"); H+4j.eVzZU  
bDownOver = true; P.}d@qD{)  
//nPos = fileAccessI.write (b,0,nRead); J#zr50@@  
} 3''Sx8p  
catch(Exception e){e.printStackTrace ();} ]1|P|Jp  
} hq)1YO  
} >#w;67he2  
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//打印回应的头信息 ;f=m+QXU  
public void logResponseHead(HttpURLConnection con) <eoie6@3  
{ |^6{3a  
for(int i=1;;i++) EU$.{C_O(  
{ Ks-$:~?5":  
String header=con.getHeaderFieldKey(i); j,.\QwpU  
if(header!=null) %up?70  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ;f[lq^eV  
Utility.log(header+" : "+con.getHeaderField(header)); E5w;75,  
else }d<R 5  
break; 7uF|Z(  
} 7;s#QqG`I  
} Y()"2CCV  
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public void splitterStop() 8R,<S-+v  
{ p49]{2GXb  
bStop = true; cJ;Nh>ey  
} k, HC"?K  
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} x4oWZEd  
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/*  lN,?N{6s  
**FileAccess.java j]Jgz<  
*//文件访问(定位，写) BAf$tyh  
package NetFox; 8]ZzO(=@{  
import java.io.*; .T| }rB<c  
(N7uaZ?Z  

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public class FileAccessI implements Serializable{ qCV<-o  
|'Fe?~P`  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 9}(w*>_L  
RandomAccessFile oSavedFile; 558P"w0"X  
long nPos; 9a}9cMJ^"  
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public FileAccessI() throws IOException CKYg!\g(:  
{ CM;b_E)9)f  
this("",0); =p+y$  
} CSO'``16  
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public FileAccessI(String sName,long nPos) throws IOException EB~]6.1  
{ ?sf<cFF  
oSavedFile = new RandomAccessFile(sName,"rw"); 1E+12{~m"i  
this.nPos = nPos; g!'R}y  
oSavedFile.seek(nPos); >|$]=e,Z  
} l<6u@,%s  
2 !s&|lI  
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public synchronized int write(byte[] b,int nStart,int nLen) T@ c~ql  
{ 0j.K?]f)h  
int n = -1; E}@C4pS  
try{ " kDiK`i  
oSavedFile.write(b,nStart,nLen); J2YQdCL  
n = nLen; z3oi(  
} 3k Ci5C  
catch(IOException e) (l{
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{ '!
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e.printStackTrace (); *g/klK  
} =[6^NR(  
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return n; =Zd(<&B K  
}  is'V%q  
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} 4&/CES  
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/* j[>cv;h ;  
**SiteInfoBean.java *{g3ia  
*/ 3H,E8>Vd  
package NetFox; jvzioFCt  
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public class SiteInfoBean { N[%u>!  
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private String sSiteURL; //Site's URL x9_mlZ  
private String sFilePath; //Saved File's Path g@.$P>Bh  
private String sFileName; //Saved File's Name y.rN(  
private int nSplitter; //Count of Splited Downloading File (eHyas %X  
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/:{%X(8  
public SiteInfoBean() Cf{F"o  
{//nSplitter的缺省值为5 2]>O ZhS  
//default value of nSplitter is 5 zM'eqo>!c>  
this("","","",5); ^Q6J$"Tj  
} N]<(cG&p  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) :^;c(>u{  
{ oMh$:jR$
 
sSiteURL= sURL; 0RUk^  
sFilePath = sPath; $|K d<wv  
sFileName = sName; aeqz~z2~8s  
this.nSplitter = nSpiltter; VYvfx  
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} NvR{S /Z  
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public String getSSiteURL() 5>k:PKHL  
{ @u~S!(7.Wi  
return sSiteURL; baxZ>KNi  
} )*')  
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public void setSSiteURL(String value)
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{ rzjVUPdnh  
sSiteURL = value; c_lHj#A(l  
} )>volP  
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public String getSFilePath() Q&9
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{ P7x;G5'.  
return sFilePath; 3h:j.8Z  
} =ily=j"hK  
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public void setSFilePath(String value) *$f=`sj  
{ D3pz69W  
sFilePath = value; kfy!T rf  
} 6Q.S  
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public String getSFileName() q z)2a2C  
{ a#oROb-*~  
return sFileName;  Fr%#  
} ! 'zd(kv<  
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public void setSFileName(String value) m]p{]6h  
{ Q*ITs!~Z  
sFileName = value; \pmS*Dt  
} K$E3RB_F  
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public int getNSplitter() eUPa5{P  
{ 9&mSF0q  
return nSplitter; bO~y=Pa\  
} B(
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public void setNSplitter(int nCount) AGBV7Kk  
{ exRw, Nk4  
nSplitter = nCount; 7DB_Z/uU  
} ,_z79tC{s  
} {U4!sJSl1  
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/* FD=% 4#|  
**Utility.java c*USA eP  
*/ n<?U6~F&~  
package NetFox; qxL\G &~  
7qKz_O  
~!S3J2kG{  
public class Utility { )^(*B6;z5  
Zxk~X}K\P  
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public Utility() s%[F,hQRk  
{ |/.J{=E0K  
5Qgu:)}  
2"/MM2s  
} l#)X/(?;  
{UiSa'TR1b  
//线程睡眠 0G%9 @^B  
public static void sleep(int nSecond) #w$Y
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{ {Jr1K,  
try{ &L|oqXE0L  
Thread.sleep(nSecond); q'3{M]Tk  
} -V$|t<  
catch(Exception e) jNZ.Fb  
{ )u?f| D  
e.printStackTrace (); 8R~<$xz  
} =lacfPS  
} U,GSWMI/K  
VRo&1:  
//日志 \;;M")$  
public static void log(String sMsg) T,38Pu@r  
{ -t-f&`S||  
System.err.println(sMsg); 62xOh\(  
} `sjY#U
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4jT6
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public static void log(int sMsg) /2^L;#  
{ "2%z;!U1  
System.err.println(sMsg); aq,1'~8XR  
} xC76jE4  
} 0TN28:hcD  
so))J`ca)  
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/* .1QGNW  
**TestMethod.java +LHU}'|  
*/ *CN *G"  
package NetFox; d3%qYL_+a  
Y,L`WeQY.  
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public class TestMethod { c~|(j \FI  
!Vpi1N\  
)k<cd.MX  
public TestMethod() U1`5P!ov  
{ ///xx/weblogic60b2_win.exe J"gMm@#C4  
try{ ~E}kwF  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); zCs34=3D[  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); HcRw9,I'  
SiteFileFetch fileFetch = new SiteFileFetch(bean); dCx63rF`G  
fileFetch.start(); uYW4$6S3  
} &1\/B  
catch(Exception e){e.printStackTrace ();} ,GOIg|51  
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} zDFNx:h  
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public static void main(String[] args) ^sv|m"  
{ &X4anH>O  
new TestMethod(); 
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} ;@+|]I  
} Fg
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