http断点续传简单实现（java)

/* DC~1}|B"  
**SiteFileFetch.java kXgc'w6EhF  
*/ ,_UTeW6M  
package NetFox; vd[?73:C  
import java.io.*; Y<t(
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import java.net.*; VBtdx`9  
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public class SiteFileFetch extends Thread { O9*l6^Scw  
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SiteInfoBean siteInfoBean = null; //文件信息Bean "
.{
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long[] nStartPos; //开始位置 z.~jqxA9  
long[] nEndPos; //结束位置 (j-_iOQ]i+  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 m@W>ku  
long nFileLength; //文件长度 Eq=j+ch7  
boolean bFirst = true; //是否第一次取文件 gle<{ `  
boolean bStop = false; //停止标志 48,uO!  
File tmpFile; //文件下载的临时信息 3ESrd"W=  
DataOutputStream output; //输出到文件的输出流 !A:d9 k  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ]m :Y|,:6  
public SiteFileFetch(SiteInfoBean bean) throws IOException xnDst
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{ 6@;sOiN+  
siteInfoBean = bean; HPXJRQBE  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); uE}$ZBiq  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); cR=o!2O  
if(tmpFile.exists ()) y q!{\@-  
{ 1pz-jo,2'  
bFirst = false; h2y<vO  
read_nPos();
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} L1kAAR  
else mgTzwE_\  
{ MnP+L'|  
nStartPos = new long[bean.getNSplitter()]; TSH'OW !b  
nEndPos = new long[bean.getNSplitter()]; X.V4YmZ-;  
} #fDM{f0]R  
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} 8 q>  
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public void run() r%9=75HA  
{ Wjli(sT#-  
//获得文件长度 hlfdmh?/  
//分割文件 {TvB3QOsj  
//实例FileSplitterFetch CY\D.Eow  
//启动FileSplitterFetch线程 Mzw:c#  
//等待子线程返回 M6j~`KSE  
try{ z<_a4ffR  
if(bFirst) lV9  
{ Svdmg D!  
nFileLength = getFileSize(); >=86*U~  
if(nFileLength == -1) _K B%g_{  
{ VNs3.  
System.err.println("File Length is not known!"); =imJ0V~RW  
} /i{V21(%  
else if(nFileLength == -2) ^mouWw)a_  
{ C%|m[,Gx  
System.err.println("File is not access!"); }lP`3e  
} BZ(DP_}&D  
else "y60YYn-#J  
{ ZcN#jnb0/  
for(int i=0;i<nStartPos.length;i++) 2$'bOo
 
{ Fd<eh(g9P  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); JL[!8NyU  
} a+j"8tHu$  
for(int i=0;i<nEndPos.length-1;i++) O"#/>hmv-  
{ 5n[''#D  
nEndPos = nStartPos[i+1]; k\r^GB  
} lx7]rkWo|a  
nEndPos[nEndPos.length-1] = nFileLength; e|q~t {=9S  
} ornU8H`  
} V{fG~19  
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//启动子线程 ltKMvGEF  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; EeGTBVms  
for(int i=0;i<nStartPos.length;i++) i v.G  
{ :x3xeVtY  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7nsovWp  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), UjMWSPEBy  
nStartPos,nEndPos,i); #|T2`uYotf  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0lOR.}]q  
fileSplitterFetch.start(); xUTTRJ(\  
} }D-jTZlC  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), '.jYu7   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); PsZ>L  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", g@.e%  
nEndPos = " + nFileLength); 99"8d^{z  
// fileSplitterFetch[nPos.length-1].start(); \uO^wJ}  
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//等待子线程结束 FV{XPr%   
//int count = 0; n:f&4uKoG<  
//是否结束while循环 AY;[v.Ff4  
boolean breakWhile = false; R:rols"QM  
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while(!bStop) 5~d=,;yE  
{ pK ^$^*#  
write_nPos(); Xc4zUEO9  
Utility.sleep(500); <+<Nsza  
breakWhile = true; IZGRQmi"  
//RD$e?h~  
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for(int i=0;i<nStartPos.length;i++) yMC6 Gvp  
{ s5V|.R  
if(!fileSplitterFetch.bDownOver) Vt,P.CfdC  
{ !N!AO(Z  
breakWhile = false; )Cat$)I#,  
break; qj
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} w"W;PdH)  
} P#V}l'j(<a  
if(breakWhile) lPrAx0m13%  
break; h6}rOchj  
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//count++; d\zUtcJwC  
//if(count>4) `xZ,*G7(*  
// siteStop(); |9p0"#4u  
} ^+0>,-)F  
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System.err.println("文件下载结束！"); R&$fWV;'  
} V(g5Gn
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catch(Exception e){e.printStackTrace ();} `5"3Cj"M  
} 9m\Yi  
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//获得文件长度 l%p,m[  
public long getFileSize() m77!i>V)  
{ jfVw{\l  
int nFileLength = -1; sk*vmxClY  
try{ 73nM9  
URL url = new URL(siteInfoBean.getSSiteURL()); nwzyL`kF  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ))nTd=  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;/kmV~KG  
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int responseCode=httpConnection.getResponseCode(); gdg``U;)p  
if(responseCode>=400) '4,IGxIq  
{ -s1.v$g  
processErrorCode(responseCode); OJhMM-  
return -2; //-2 represent access is error awjAv8tPO!  
} }Oqt=Wm  
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String sHeader; m&z(2yb1  
.$ YYN/+W  
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for(int i=1;;i++) `~=NBN=tiL  
{ zbGZ\pz  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ;lSsy  
//Utility.log(in.readLine()); L)1\=[Ov  
sHeader=httpConnection.getHeaderFieldKey(i); k8l7.e*  
if(sHeader!=null) -F 9xPw  
{ 3}fhU{
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if(sHeader.equals("Content-Length")) G}LV"
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{ b|;h$
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); NqveL<r`  
break; {wgq>cb  
} O1wo KkfV  
} TB=_r(:l+  
else Y\+LBbB8  
break; UJ(UzKq8  
} vp9wRGd  
} E|jU8qz>P  
catch(IOException e){e.printStackTrace ();} l2YA/9.  
catch(Exception e){e.printStackTrace ();} ,?HM5c{'[Y  
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Utility.log(nFileLength); .}uri1k"@k  
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return nFileLength; jw 5 U-zi  
} HLdHyK/S  
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//保存下载信息（文件指针位置） B(5>H2  
private void write_nPos() ^SW9J^9  
{ SoHaGQox  
try{ k*!iUz{]  
output = new DataOutputStream(new FileOutputStream(tmpFile)); +@H{H2J4  
output.writeInt(nStartPos.length); M{jq6c  
for(int i=0;i<nStartPos.length;i++) YpRhl(|  
{ GV28&!4sS  
// output.writeLong(nPos); UX<)hvKj  
output.writeLong(fileSplitterFetch.nStartPos); @,-D P41g  
output.writeLong(fileSplitterFetch.nEndPos); ^,)nuUy  
} bI_MF/r''  
output.close(); @; I9e  
} 9\T9pjdZE  
catch(IOException e){e.printStackTrace ();} M4CC&?6\  
catch(Exception e){e.printStackTrace ();} ^dsj1#3z  
} ^zS;/%  
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//读取保存的下载信息（文件指针位置） Ta/u&t4  
private void read_nPos() *"4l}&  
{ pU[yr'D.r  
try{ {`T^&bk  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,nGQVb   
int nCount = input.readInt(); TtKKU4yp  
nStartPos = new long[nCount]; ez)Ks`  
nEndPos = new long[nCount]; Li$2 Gpc/  
for(int i=0;i<nStartPos.length;i++) {,Rlq  
{ N8x.D-=gG  
nStartPos = input.readLong(); fO .=i1 E}  
nEndPos = input.readLong(); B@VAXmCaoV  
} 6`bR' 0D  
input.close(); ]*Q,~uV^|  
} <P6d-+  
catch(IOException e){e.printStackTrace ();} H*+7{;$  
catch(Exception e){e.printStackTrace ();} VZ y$0*  
} {^^LeUd#V  
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private void processErrorCode(int nErrorCode) UO!} 0'  
{ e$JC
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System.err.println("Error Code : " + nErrorCode); t}?-ao  
} bR~5 :A^  
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//停止文件下载 b& -8/t  
public void siteStop() bd% M.,  
{ $bfmsCcHL  
bStop = true; +dRRMyxe4  
for(int i=0;i<nStartPos.length;i++) KrHKM3<  
fileSplitterFetch.splitterStop(); 9zrTf%mF  
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} o)x&|0_  
} <RY!Mc  
//负责部分文件的抓取 ;ceg:-Zqo  
**FileSplitterFetch.java l~Ka(*[!U  
*/ O=lRI)6w@e  
package NetFox; J&}1=s  
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import java.io.*; 7~'%ThUb$-  
import java.net.*; LnN:;h  
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public class FileSplitterFetch extends Thread { s0/m qZ]s  
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String sURL; //File URL Aayd3Ph0%  
long nStartPos; //File Snippet Start Position ,dw\y/d
n  
long nEndPos; //File Snippet End Position {;z
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int nThreadID; //Thread's ID o@]n<ZYo  
boolean bDownOver = false; //Downing is over _x#y   
boolean bStop = false; //Stop identical TXS`ey  
FileAccessI fileAccessI = null; //File Access interface 3>73s}3  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 0Zo><=  
{ vv<\LN0  
this.sURL = sURL; p9mGiK4!  
this.nStartPos = nStart; Q)qJ6-R|HD  
this.nEndPos = nEnd; ^Jdg%U?  
nThreadID = id; #o9CC)q5G  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ITi#p%  
} !|]k2=+I  
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 cz>)6#&O  
public void run() D`X<b4e8/  
{ a2i:fz=[  
while(nStartPos < nEndPos && !bStop) jsr
)  
{ :`"-Jf  
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try{ 0Js5 ' 9}H  
URL url = new URL(sURL); rg]b$tL~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @\xEK5SG  
httpConnection.setRequestProperty("User-Agent","NetFox"); }1+2&Ps50  
String sProperty = "bytes="+nStartPos+"-"; 3u^wK  
httpConnection.setRequestProperty("RANGE",sProperty); qe(C>qjMbG  
Utility.log(sProperty); :,
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InputStream input = httpConnection.getInputStream(); @T>^ >  
//logResponseHead(httpConnection); @,6*yyO  
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byte[] b = new byte[1024]; ~|ZAS]  
int nRead; 3pL4Zhf  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) QR8]d1+GV  
{ nGc'xQy0  
nStartPos += fileAccessI.write(b,0,nRead); W$J.B!O  
//if(nThreadID == 1) _FS #~z'j  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); nU\.`.39 +  
} T2)CiR-b  
8oRq3"  
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Utility.log("Thread " + nThreadID + " is over!"); |E||e10wR  
bDownOver = true; uGW#z_{(n  
//nPos = fileAccessI.write (b,0,nRead); Z("N *`VP;  
} \_(0V"  
catch(Exception e){e.printStackTrace ();} qNrLM!Rj  
} Fl{~#]  
} xy$aFPH!-  
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//打印回应的头信息 :P+7ti@  
public void logResponseHead(HttpURLConnection con) f4NN?"W)  
{ vS3Y9
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for(int i=1;;i++) V$Oj@vI  
{ R"
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String header=con.getHeaderFieldKey(i); _+7P"B|\  
if(header!=null) g}a+%Obb  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); OPqhdqo  
Utility.log(header+" : "+con.getHeaderField(header)); ]iFW>N*a  
else D@[#7:rHL  
break; -HuIz6  
} HJpx,NU'  
} (dO0`wfM  
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public void splitterStop() cd=H4:<T5  
{ p?P.BU\CR  
bStop = true; xUa9>=JU{  
} UCFFF%  
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} vMn$lT@  
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/* VAyAXN~  
**FileAccess.java ~YviXSW  
*//文件访问(定位，写) 4 EA$<n(A-  
package NetFox; {CVZ7tU7]  
import java.io.*; C$LRX7Z`o  
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public class FileAccessI implements Serializable{ qvhG^b0h  
0%IZ -])  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 bun_R-  
RandomAccessFile oSavedFile; /6\uBy"Xt  
long nPos; ?@Tsd@s~r  
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public FileAccessI() throws IOException PG|Zu3[  
{ Py+ B 2G|  
this("",0); M;KeY[u  
} u3&#UN  
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public FileAccessI(String sName,long nPos) throws IOException ;>X;cZMd  
{ _)3C_G1!  
oSavedFile = new RandomAccessFile(sName,"rw"); fJ\u8  
this.nPos = nPos; q%/.+g2-\  
oSavedFile.seek(nPos); ('d,Sh  
} JlEfUg#*  
;4v`FC>  
,,)'YhG(  
public synchronized int write(byte[] b,int nStart,int nLen) w&]$!g4  
{ {%,4P_m  
int n = -1; PtL8Kd0`C  
try{ .uN(44^+x  
oSavedFile.write(b,nStart,nLen); uLI;_,/:  
n = nLen; JZ-64OT  
} G[OJ<px  
catch(IOException e) qk0cf~gz  
{ c@4$)68  
e.printStackTrace (); 2t{Tz}g*  
} XZ8]se"C  
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return n;
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} X .K*</(g  
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} j*1MnP3/8Y  
^ ~Tn[w W_  
;vpq0t`  
/* n4H'FZ  
**SiteInfoBean.java =~)rT8+)  
*/ -G=.3 bux  
package NetFox; Y2g%{keo  
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public class SiteInfoBean { #D>:'ezm  
#}tdA( -  
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private String sSiteURL; //Site's URL 65mfq&"P?  
private String sFilePath; //Saved File's Path aouYPxA`  
private String sFileName; //Saved File's Name Rdj^k^V+a1  
private int nSplitter; //Count of Splited Downloading File @x*,fk  
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public SiteInfoBean() V%zo[A  
{//nSplitter的缺省值为5 0B~x8f  
//default value of nSplitter is 5 C}9|e?R[Rz  
this("","","",5); {q;_Dd  
} .I^Y[_.G  
;2sP3!*  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) %S>6Q
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{ C 8d9(u  
sSiteURL= sURL; PdRDUG{Jy  
sFilePath = sPath;
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sFileName = sName; |0_5iFAB|  
this.nSplitter = nSpiltter; E?Qg'|+_  
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} 'S=eW_ 0/  
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,1vFX$  
public String getSSiteURL() vEt+^3=  
{ r& :v(  
return sSiteURL; OO,%zwgt  
} #Ny+6XM  
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'3E25BsL  
public void setSSiteURL(String value) ?dCJv_w  
{ wx2 z9Q  
sSiteURL = value; QG@Z%P~,E  
} lJS3*x#H  
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public String getSFilePath() FEV Ya#S  
{ G('UF1F  
return sFilePath; v|3mbApv  
} C9>^!?>  
-Gm}i8;  
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public void setSFilePath(String value) ~ntDzF  
{ 4v#s!W  
sFilePath = value; =~21.p  
} eX0[C0#  
v\}{eP'  
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public String getSFileName() :"Rx$;a  
{ dw| VH1fS  
return sFileName; 98UI]? 4  
} w`zS`
+4  
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}5B\:*yW  
public void setSFileName(String value) koj*3@\p/  
{ gf/<sH2}  
sFileName = value; fA),^  
} /\E3p6\*  
A "'h0D  
1IK*j+%  
public int getNSplitter() F9q!Upr_+  
{ LftGA7uGJ)  
return nSplitter; Ve40H6Ox  
} ]2iEi`"[  
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public void setNSplitter(int nCount) OgCNqW d-  
{ bhfC2@  
nSplitter = nCount; '\"5qB  
} 81)i>]  
} (>*L-&-  
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/* Sa:;j4  
**Utility.java W/%9=g$m  
*/ D\DwBZ>  
package NetFox; 5hDPX\  
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public class Utility { veS) j?4  
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public Utility() o9OCgP`Y  
{ NezE]'}  
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mCQ:<#  
} ~/2OK!M  
B}N1}i+  
//线程睡眠 (Hs,Tj  
public static void sleep(int nSecond) 'GLpSWL+*  
{ V2'5doo  
try{ Ghar hJ>v  
Thread.sleep(nSecond); 6E_YUk?KW  
} =(v'8?--  
catch(Exception e) zV"'-iP  
{ Mh@
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e.printStackTrace (); LeNSjxB  
} m'uFj !  
} 7{NH;U t  
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//日志 Z!l]v.S  
public static void log(String sMsg) Nema>T]  
{ G"Hj$  
System.err.println(sMsg); n ON]YDg  
} Cli:;yi&n  
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\\`(x:\  
public static void log(int sMsg) akWOE}5#  
{ lLU8eHf\  
System.err.println(sMsg); }!m}?  
} ?Q"1zcX  
} ?0lz!Nq'S  
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/* 1*trtb4F  
**TestMethod.java 2_)gJ_kP  
*/ @H}Hjg_>m  
package NetFox; ?^`fPH=  
nt%p@e!,  
Hv%$6,/*v  
public class TestMethod { V$dhi
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#IU^(W  
public TestMethod() ;ssI8\LG  
{ ///xx/weblogic60b2_win.exe y8} /e@&  
try{ J_9[xmM  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); XcL%0%`  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); mo&9=TaG  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ]3 QW\k~  
fileFetch.start(); \=o0MR  
} "ZFH_5<  
catch(Exception e){e.printStackTrace ();} #WAX&<m  
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} o1uM(  
6.6?Rp".  
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public static void main(String[] args) "w__AYHV  
{ K'f2S  
new TestMethod(); `Io#440;  
} h,,B"vPS  
} 4b6)+*[O  
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