http断点续传简单实现（java)

/* gbP]!d:I  
**SiteFileFetch.java ;~&F}!pQ  
*/ aS^ 4dEJ  
package NetFox; Q@]QPpe  
import java.io.*; `0@onDQVc=  
import java.net.*; /8Sg<  
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public class SiteFileFetch extends Thread { nf,R+oX  
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SiteInfoBean siteInfoBean = null; //文件信息Bean jhd&\z-  
long[] nStartPos; //开始位置 $^ \8-k "  
long[] nEndPos; //结束位置 mnKSO  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 y.$/niQ%  
long nFileLength; //文件长度 efj[7K.h  
boolean bFirst = true; //是否第一次取文件 ZzU3j^  
boolean bStop = false; //停止标志 }9w?[hXW"  
File tmpFile; //文件下载的临时信息 P
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DataOutputStream output; //输出到文件的输出流 3I87|5V,Z  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） by 'P}  
public SiteFileFetch(SiteInfoBean bean) throws IOException 9oOr-9t3  
{ _*d8:|qw  
siteInfoBean = bean; o!q3+Pp;}  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); D4e*Wwk  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); U)Cv_qe  
if(tmpFile.exists ()) i%jti6z$Hr  
{ F iZe4{(p  
bFirst = false; -YF]k}|  
read_nPos(); 
,
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} &xKln1z'  
else rJ2yi6TB\  
{ \'z&7;px  
nStartPos = new long[bean.getNSplitter()]; *v+xKy#M  
nEndPos = new long[bean.getNSplitter()]; lTl-<
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} tI2V)i!  
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} oBfh1/<<a  
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public void run() c{YBCWA  
{ aRPpDSR?l  
//获得文件长度 W(^R-&av  
//分割文件 FsZW,  
//实例FileSplitterFetch #G'Y2l  
//启动FileSplitterFetch线程 qmNgEz%  
//等待子线程返回 ,(h:0L2v7d  
try{ oD_n+95B  
if(bFirst) T$ <l<.Qd  
{ q J)[2:.G  
nFileLength = getFileSize(); ELh`|X  
if(nFileLength == -1) PL;PId<9w  
{ [1pWg^  
System.err.println("File Length is not known!"); `a$-"tW~j  
} drr W?U  
else if(nFileLength == -2) JQ-O=8]  
{ s&T"/4  
System.err.println("File is not access!"); .UxbwTup  
} YVcFCl  
else 5](-(?k}~  
{ 6Vr:?TI7  
for(int i=0;i<nStartPos.length;i++) |?zFm mh  
{ tOQ29
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); d
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} A .]o&S}  
for(int i=0;i<nEndPos.length-1;i++) : ,0F_["3  
{ _!vxX]  
nEndPos = nStartPos[i+1]; }/dGC;p"  
} O$<m(~[S  
nEndPos[nEndPos.length-1] = nFileLength; K9{]v=#I  
} '@~\(SH  
} \Y37wy4  
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cV=0)'&<`_  
//启动子线程 O+8]y4%5  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; u"WqI[IV  
for(int i=0;i<nStartPos.length;i++) "x;|li3;  
{ K)e;*D  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {#-I;I:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), qfRsp rRI"  
nStartPos,nEndPos,i); 2)_Zz~P^f  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); IP#w  
fileSplitterFetch.start(); BZ2frG\0&I  
} 0rnne L  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Z/Vb_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Me*woCos'  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", oP[R?zN  
nEndPos = " + nFileLength); Y~FN`=O  
// fileSplitterFetch[nPos.length-1].start(); Bo)N<S_=^  
%E1_)^^  
uT")j,tz  
//等待子线程结束 }f/xMp-Y  
//int count = 0; FLWQY,  
//是否结束while循环 w.AF7.X`1  
boolean breakWhile = false; 6p=OM=R  
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while(!bStop) x{
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{ l"T{!Oq  
write_nPos(); OI@;ffHSW  
Utility.sleep(500); {x&"b-  
breakWhile = true; A.f!SYV6  
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for(int i=0;i<nStartPos.length;i++) S"}G/lBx.  
{ @ V_@r@A  
if(!fileSplitterFetch.bDownOver) ;v}f7v '  
{ G<dWh.|`=  
breakWhile = false; dV~d60jOF  
break; 28u3B2\$  
} 71g\fGG\  
} <1^\,cI2  
if(breakWhile) -XbO[_Wf  
break; f( %r)%  
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$|0?$U7!  
//count++; N:4oVi@Je  
//if(count>4) AK$h S
M  
// siteStop(); t<UtSkE1  
} 3#d?  
'[T#d!T  
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System.err.println("文件下载结束！"); |._9;T-Yde  
} cH==OM7&-  
catch(Exception e){e.printStackTrace ();} KNI* :  
} ?3=D-Xrb  
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Y6&B%t<b
o  
//获得文件长度 zi7>!#(  
public long getFileSize() ,JLY oE+  
{ E#5$O2b#  
int nFileLength = -1; Rt%3\?rf  
try{ E0SP  
URL url = new URL(siteInfoBean.getSSiteURL()); @c>a  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); o?9k{  
httpConnection.setRequestProperty("User-Agent","NetFox"); equ|v~@y  
r[u@[  
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int responseCode=httpConnection.getResponseCode(); sKIpL(_I$  
if(responseCode>=400) 7KB:wsz^  
{ -5&|"YYjr{  
processErrorCode(responseCode); 1@i 8ASL  
return -2; //-2 represent access is error
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} &EZq%Sd  
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String sHeader;  q#=}T~4j  
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for(int i=1;;i++) A_:YpQ07@  
{ }@+{;"  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); W5&;PkhQ6  
//Utility.log(in.readLine()); 0E
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sHeader=httpConnection.getHeaderFieldKey(i); ;aI`4;  
if(sHeader!=null) $L@os
2  
{ z 8w&;Ls  
if(sHeader.equals("Content-Length")) MO1t0Myc  
{ ;Wo\MN  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); +!'rwD  
break; .b3cn  
} v?9  
} e>FK5rz  
else UNc[h&@_  
break; H&yK{0H  
} ec$kcD!  
} cb9ndZ)v.  
catch(IOException e){e.printStackTrace ();} {[i 37DN  
catch(Exception e){e.printStackTrace ();} D:r+3w:l]  
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Utility.log(nFileLength); >f !
 
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return nFileLength; *8a8Ng  
} H*h7Y*([  
+OM9v3qJ  
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//保存下载信息（文件指针位置） _Di";fe?  
private void write_nPos() O|Z5SSlk  
{ mvCH$}w8&  
try{ NrNxI'MG  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ++Z
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output.writeInt(nStartPos.length); &~6W!w  
for(int i=0;i<nStartPos.length;i++) [q<Vm-  
{ Z2%ySO  
// output.writeLong(nPos); |z5`h  
output.writeLong(fileSplitterFetch.nStartPos); O.9r'n4f  
output.writeLong(fileSplitterFetch.nEndPos); %GY U$aA  
} U|NVDuo{{x  
output.close(); X}Oo5SNgff  
} I Ceb2R  
catch(IOException e){e.printStackTrace ();} R _c! ,y  
catch(Exception e){e.printStackTrace ();} NDmTxW#g  
} (B0tgg^jj,  
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//读取保存的下载信息（文件指针位置） 3~r>G  
private void read_nPos() {cYS0%Go  
{ G(;C~kHX  
try{ 6oQSXB@  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); -=+@/@nV  
int nCount = input.readInt(); {p70( ]v  
nStartPos = new long[nCount]; G!^}z(Mgi  
nEndPos = new long[nCount]; w7;,+Jq  
for(int i=0;i<nStartPos.length;i++) Q;'{~!=  
{ l1EI4Y9KG  
nStartPos = input.readLong(); +ROwk  
nEndPos = input.readLong(); YyF=u~l  
} `u *:wJsv  
input.close(); TsvF~Gdp  
} >@mvb@4*  
catch(IOException e){e.printStackTrace ();} DO^K8~]
 
catch(Exception e){e.printStackTrace ();} $?e_l  
} E&wz0d;gf  
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private void processErrorCode(int nErrorCode) v Mi&0$  
{ qkLp8/G>pO  
System.err.println("Error Code : " + nErrorCode); 6UXDIg=  
} zj+.MG04  
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//停止文件下载 da,Bnze0  
public void siteStop() A:?|\r  
{ y9#r SA*  
bStop = true; }3Mnq?.-  
for(int i=0;i<nStartPos.length;i++) j\uh]8N3<  
fileSplitterFetch.splitterStop(); q\`0'Z,  
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} j&c YRKpz  
} B F,8[|%#  
//负责部分文件的抓取 RAh4#8]  
**FileSplitterFetch.java whoQA}X>  
*/ @C?.)#  
package NetFox; A\1X-Mm  
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import java.io.*; S=N3qBH6  
import java.net.*; ?|`Ba-  
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public class FileSplitterFetch extends Thread { zD9gE  
1h[xVvo<L  
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String sURL; //File URL 8(b C.  
long nStartPos; //File Snippet Start Position KH~o0 W  
long nEndPos; //File Snippet End Position 'Y%@fZf x  
int nThreadID; //Thread's ID 2#1G)XI  
boolean bDownOver = false; //Downing is over ^_Ap?zn  
boolean bStop = false; //Stop identical 0[O."9  
FileAccessI fileAccessI = null; //File Access interface +'@j~\>^yJ  
6N<v&7cSB  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ]m(C}}  
{ \?VNr
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this.sURL = sURL; eL`}j9  
this.nStartPos = nStart; 'T7=.Hq<4  
this.nEndPos = nEnd; [ljC S  
nThreadID = id; {wNNp't7  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 \%! t2=J!  
} }=fVO<Rv  
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public void run() B}&9+2M  
{ v"K #  
while(nStartPos < nEndPos && !bStop) q5UD!&W  
{ n$03##pf  
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try{ ^s;xLGl]  
URL url = new URL(sURL); *2
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,2R7AHk  
httpConnection.setRequestProperty("User-Agent","NetFox"); TB@0j ;g  
String sProperty = "bytes="+nStartPos+"-"; {+SshT>J  
httpConnection.setRequestProperty("RANGE",sProperty); b;K];o-/f  
Utility.log(sProperty); keMfK]9  
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InputStream input = httpConnection.getInputStream(); XS&oW  
//logResponseHead(httpConnection); c2,;t)%@E  
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byte[] b = new byte[1024]; 0YApaL+jt  
int nRead; Ny6 daf3f  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) iem@K  
{ 0]._|Ubn6)  
nStartPos += fileAccessI.write(b,0,nRead); 9eh9@~mU"l  
//if(nThreadID == 1) XeJ|Z)qZ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `-J$7)d@  
} WYayr1  
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Utility.log("Thread " + nThreadID + " is over!"); {f12&t  
bDownOver = true; M< 1rQW'  
//nPos = fileAccessI.write (b,0,nRead); DJGq=*  
} v Wt{kg;  
catch(Exception e){e.printStackTrace ();}
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} uh8+Y%V p  
} OZ9ud ]@\  
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//打印回应的头信息 =/6rX"\P  
public void logResponseHead(HttpURLConnection con) nbhzLUK  
{ n1mqe*Mvs/  
for(int i=1;;i++) wBbJ \  
{ rF*L@HI  
String header=con.getHeaderFieldKey(i); D|lm,  
if(header!=null) S7A[HG;  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); M*xt9'Yd  
Utility.log(header+" : "+con.getHeaderField(header)); pVGH)6P>|  
else ER)<Twj  
break; P_Bhec|#fT  
} [&B}{6wry  
} <.N337!  
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public void splitterStop() 2!y%nkO*  
{ vvDaL$  
bStop = true; 
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} 4NN81~v 4  
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} TfFuHzZZ  
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/* :AzP3~BI  
**FileAccess.java F:P&hK  
*//文件访问(定位，写) ndY1j5  
package NetFox; *a2
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import java.io.*; Z#i5=,Bk  
! 54(K6a[  
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public class FileAccessI implements Serializable{ ~:|qdv%\  
u>cU*E4/  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 S(b5Gj
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RandomAccessFile oSavedFile; OGC|elSM  
long nPos; (ru9Ke%Dx  
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public FileAccessI() throws IOException (_Ld^^|  
{ S[_Hc$7U  
this("",0); lZq`,E_L  
} >h+G$&8[y  
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public FileAccessI(String sName,long nPos) throws IOException s)e'}y  
{ =u+.o<  
oSavedFile = new RandomAccessFile(sName,"rw"); N-+`[8@(P<  
this.nPos = nPos; 6kc/  
oSavedFile.seek(nPos); P!Mz5QZ+  
} A)X 'We  
"E><:_,\  
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public synchronized int write(byte[] b,int nStart,int nLen) 9m:qQ1[\  
{ 3}}#'5D  
int n = -1; 9kkYD  
try{ GsG9;6c+u  
oSavedFile.write(b,nStart,nLen); `T;M=S^y*E  
n = nLen; ?D^l&`S  
} }g?9/)z  
catch(IOException e) wJb\Q  
{ 05+uBwH
 
e.printStackTrace (); &;)6G1X1  
} _*.Wo"[%[X  
}+_Z|>qv  
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return n; =}12S:Qhj  
} h2Pvj37  
Ef
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} `B^HW8  
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/* &f\ng{  
**SiteInfoBean.java Q\>Kd N{  
*/ p:,(r{*?  
package NetFox; $g|/.XH%  
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public class SiteInfoBean { 0CYm%p8!  
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private String sSiteURL; //Site's URL z]NN ^pIa  
private String sFilePath; //Saved File's Path y3 {om^ f  
private String sFileName; //Saved File's Name quB.A7~^=  
private int nSplitter; //Count of Splited Downloading File b!Q|0X.?  
).TQYrs  
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public SiteInfoBean() (u81
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{//nSplitter的缺省值为5 Tp.0@aC  
//default value of nSplitter is 5 r00 fvZyK  
this("","","",5); k0{5)Su"xr  
} *5k" v"NM(  
ZM/*cA!"  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) -X~VXeg  
{ I3QK~ V*j)  
sSiteURL= sURL; yz}Agc4.I  
sFilePath = sPath; F:.rb Ei  
sFileName = sName; (gQ^jmZPG  
this.nSplitter = nSpiltter; DFKU?#R  
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} RLN>*X  
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public String getSSiteURL() nz:I\yA  
{ `<Xq@\H  
return sSiteURL; Lrgv:n  
} PsTPG
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+(iM]L$Fw%  
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public void setSSiteURL(String value) P agzp%m  
{ R9o3T)9V  
sSiteURL = value; k:nR'TI  
} "q(#,,_  
PW"G]G,  
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public String getSFilePath() zhbp"yju7  
{ Z 55i
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return sFilePath; rxu 6 #v F  
} E~5r8gM,0  
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L;=:OX0  
public void setSFilePath(String value) ]%jlaXb  
{ ?y82S*sb#  
sFilePath = value; vr<6j/ty  
} $E@L{5Yt  
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public String getSFileName() !uLW-[F,  
{ lwhAF, '$  
return sFileName; |?6r
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} AK\X{>$a!  
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public void setSFileName(String value) /NCEZ@2BN,  
{ 'NF_!D  
sFileName = value; r+fR^hv  
} 3+_? /}<  
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)NJD+yQ%  
public int getNSplitter() 6%Ap/zvCZ>  
{ ; mF-y,E  
return nSplitter; ~TCz1UWV  
} &/*XA  
9,=3D2x&  
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public void setNSplitter(int nCount) i8pM,Ppi~  
{ mMm_=cfv  
nSplitter = nCount; 7ET^,6  
} +h^>?U,  
} O,6Upk  
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M7{w7}B0@  
/* y&Sl#IQ L  
**Utility.java ko\VDyt,  
*/ {aP5Mem  
package NetFox; )p'ZSXb  
{Y-<#U~iH  
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public class Utility { I*_@WoI*  
3RG*:9  
@sRRcP~  
public Utility() [YG\a5QK  
{ X[b=25Ct  
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} W]MKc&R  
@~%R%Vu  
//线程睡眠 J'9hzag  
public static void sleep(int nSecond) R=P=?U.  
{ -L@4da[]i  
try{ c'nEbelE  
Thread.sleep(nSecond); <EFA^,3t%  
} x? 3U3\W  
catch(Exception e) r'xZF~}k"~  
{ 8enlF\I8g  
e.printStackTrace (); ,.[T]37  
} $Kgw6  
} S~L$sqt  
d2s
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//日志 JVbR5"+.  
public static void log(String sMsg) s<VNW  
{ ^6j:
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System.err.println(sMsg); S0().2#  
} $qG;^1$  
!_CBf#0  
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public static void log(int sMsg) vI3L <[W  
{ 9}^nozR,I  
System.err.println(sMsg); y}5V3)P  
} |}s)Wo  
} eMyh&@7(F  
l&l&
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/* SV#$Cf g  
**TestMethod.java m  "'  
*/ /H.w0fu&.S  
package NetFox; 94 58.!3  
!h3$C\  
A\p'\@f  
public class TestMethod { ]OIB;h;3  
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:YaEMQJ^  
public TestMethod() D^ZG-WR  
{ ///xx/weblogic60b2_win.exe ;hb;%<xqT  
try{ e;L++D
 
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); =K'X:UM  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 5{nERKaPf  
SiteFileFetch fileFetch = new SiteFileFetch(bean); xR;>n[6  
fileFetch.start(); kt?G\H!}  
} y%%D="  
catch(Exception e){e.printStackTrace ();} {FRUB(68b  
;NNYJqWd^]  
uYVlF@]  
} CT5\8C  
l~P%mVC3m  
d-/{@   
public static void main(String[] args) 3cfJ(%'X  
{ 4/UY*Us&  
new TestMethod(); Wno{&I63  
} T DOOq;+  
} k4:$LFw@  
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