http断点续传简单实现（java)

/* RrUBpqA  
**SiteFileFetch.java `w I/0  
*/ !Z VU,b>  
package NetFox; )i+2X5B`S  
import java.io.*; ~{sG| ;/!*  
import java.net.*; !EUan  
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public class SiteFileFetch extends Thread { w 4[{2  
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SiteInfoBean siteInfoBean = null; //文件信息Bean *
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long[] nStartPos; //开始位置 Y0?5w0{  
long[] nEndPos; //结束位置 ()&
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 R.=}@oPb  
long nFileLength; //文件长度 CLvX!O(~  
boolean bFirst = true; //是否第一次取文件 l Va &"  
boolean bStop = false; //停止标志 y.KO :P?5{  
File tmpFile; //文件下载的临时信息 rZ8`sIWQt  
DataOutputStream output; //输出到文件的输出流 *m?/O}R  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） PkI:*\R  
public SiteFileFetch(SiteInfoBean bean) throws IOException Q.K,%(^;a  
{ &0f5:M{P  
siteInfoBean = bean; vfVj=DYj  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 9z6XF]A  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); y;/VB,4V  
if(tmpFile.exists ()) (o3 Iy  
{ jKt7M>P  
bFirst = false; Eke5Nb  
read_nPos(); |:8bNm5[  
} 2-Y<4'>  
else TB0 5?F  
{ !K|5bK  
nStartPos = new long[bean.getNSplitter()]; (5]}5W*  
nEndPos = new long[bean.getNSplitter()]; <b,~:9*?  
} oudxm[/U  
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}  w@,zFV  
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public void run() 8OgLn?"P  
{ H;
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//获得文件长度 "AE5 V'  
//分割文件 Omd .9  
//实例FileSplitterFetch #%DE;  
//启动FileSplitterFetch线程 *}P~P$q%  
//等待子线程返回 H%D$(W  
try{ 21"1NJzP  
if(bFirst) eJg8,7WC  
{ %c4Hse#Y  
nFileLength = getFileSize(); X&kp;W  
if(nFileLength == -1) Y]&j,j&  
{ l\i)$=d&g  
System.err.println("File Length is not known!"); ;^Dpl'v%\  
} gEjdN.  
else if(nFileLength == -2) 
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{ ]\
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System.err.println("File is not access!"); -B +4+&{T  
} 0Vx.nUQ
  
else M3.do^ss  
{ 4<BjC[@~Z{  
for(int i=0;i<nStartPos.length;i++) |ZmUNiAa  
{ VVlr*`  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); nrjE.+v  
} a|X a3E  
for(int i=0;i<nEndPos.length-1;i++) /'/Xvm3  
{ &v
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nEndPos = nStartPos[i+1]; L
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} B6={&7U2  
nEndPos[nEndPos.length-1] = nFileLength; 'dn]rV0(C  
} !z>6Uf!{  
} ]9^sa-8  
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0  
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//启动子线程 }~L.qG  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; E 7{U|\  
for(int i=0;i<nStartPos.length;i++) H*}y^)x  
{ ~A\G
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), > ;*b|Ik  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), F%RRd/'  
nStartPos,nEndPos,i); |!4K!_y  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); o4Om}]Ti  
fileSplitterFetch.start(); c24dSNJg,  
} d$1@4r  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,5h)x"s  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); I`!<9OTBj  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 6
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nEndPos = " + nFileLength); F'21jy&  
// fileSplitterFetch[nPos.length-1].start(); BI%$c~wS  
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//等待子线程结束 )?anOD[  
//int count = 0; t7aefV&_,  
//是否结束while循环 HMNLa*CL'  
boolean breakWhile = false; 2fL;-\!y(  
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while(!bStop) %WjXg:R  
{ fbe[@#:  
write_nPos(); MDnua  
Utility.sleep(500);  R[D{|K@"  
breakWhile = true; do>wwgr  
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for(int i=0;i<nStartPos.length;i++) ;@oN s-  
{ YIG~MP  
if(!fileSplitterFetch.bDownOver) xqu}cz  
{ K &N  
breakWhile = false; {'NvG  
break; cQ R]le%(  
} ]>5/PD,wWy  
} 5Odhb
 
if(breakWhile) vg32y /l]S  
break; b gK}-EU  
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//count++; u. F9g #  
//if(count>4) VY7[)  
// siteStop(); zHM(!\8K  
} \!.B+7t=I  
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System.err.println("文件下载结束！"); +nFu|qM}  
} W{ q U  
catch(Exception e){e.printStackTrace ();} lR6@ xJd:@  
} n{argI8wF  
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Q+{xZ'o"Z  
//获得文件长度 Rl?_^dPx  
public long getFileSize() f.KN-f8<F  
{ YJT&{jYi  
int nFileLength = -1; ~:s>aQ`!  
try{ 12b(A+M   
URL url = new URL(siteInfoBean.getSSiteURL()); MP Y[X[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); nFHUy9q  
httpConnection.setRequestProperty("User-Agent","NetFox"); "R;U/+  
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int responseCode=httpConnection.getResponseCode(); 6d<r= C=  
if(responseCode>=400) aC8} d  
{ 65J
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processErrorCode(responseCode); V]lLw)  
return -2; //-2 represent access is error KQ% GIz x  
} {k TEHe  
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String sHeader; s+$ Q}|?u  
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; F"g$_D0  
for(int i=1;;i++) *&^Pj%DX  
{ B"1c  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); yg<R=$n,Q  
//Utility.log(in.readLine()); rr],DGg+B]  
sHeader=httpConnection.getHeaderFieldKey(i); 0d)M\lG  
if(sHeader!=null) IL#"~D?
  
{ wDal5GJp  
if(sHeader.equals("Content-Length")) l[0RgO*S  
{ k8&;lgO'  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); HdUQCugxx:  
break; |"8b_Cq{  
} X9W@&zQ  
} XpB_N{v9w  
else 5H<m$K4z  
break; 6 $4[gcL'  
} y}" O U  
} l*Gvf_UH  
catch(IOException e){e.printStackTrace ();} @<hb6bo,N
 
catch(Exception e){e.printStackTrace ();} -A^_{4X  
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Utility.log(nFileLength); _7Ju  
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return nFileLength; P9^Xm6QO  
} q$d>(vbq  
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//保存下载信息（文件指针位置） @e.C"@G  
private void write_nPos() X:"i4i[}{9  
{ _Eo[7V{NY  
try{ ?Jm^<  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ].w4$OJ?  
output.writeInt(nStartPos.length); v!~fs)cdE|  
for(int i=0;i<nStartPos.length;i++) G:<aB  
{ &AeX   
// output.writeLong(nPos); 'x#~'v
*  
output.writeLong(fileSplitterFetch.nStartPos); :'X&bn  
output.writeLong(fileSplitterFetch.nEndPos); >C>.\  
} ?=Z?6fw  
output.close(); UmP/h@8  
} @1roe G  
catch(IOException e){e.printStackTrace ();} _aSxc)?  
catch(Exception e){e.printStackTrace ();} K<3A1'_  
} X]TG<r  
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//读取保存的下载信息（文件指针位置） w3ResQ   
private void read_nPos() EeE7#$l  
{ D0-3eV-  
try{ z#wkiCRYm  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); T4Uev*A  
int nCount = input.readInt(); <44G]eb  
nStartPos = new long[nCount]; hD 82tr  
nEndPos = new long[nCount]; oWT3apGO  
for(int i=0;i<nStartPos.length;i++) *w`sM%]Rq  
{ Z"xvh81P  
nStartPos = input.readLong(); 2*& ^v  
nEndPos = input.readLong(); q 'yva  
} A:%`wX}  
input.close(); -l*|M(
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} &jJL"gq"  
catch(IOException e){e.printStackTrace ();} 6Pl<'3&  
catch(Exception e){e.printStackTrace ();} F0TB<1  
} AO4U}?  
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private void processErrorCode(int nErrorCode) `Y$4 H,8L  
{ *~e?TfG  
System.err.println("Error Code : " + nErrorCode); eF$x1|  
} JGrWHIsNV  
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//停止文件下载 s/#!VnU6  
public void siteStop() By!o3}~g  
{ C ;W"wBz9  
bStop = true; S9y}  
for(int i=0;i<nStartPos.length;i++) 'n3uu1C  
fileSplitterFetch.splitterStop(); :P~6~ Kum  
+~$ ]}%  
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} Ee! 4xg  
} *i%.;Z"  
//负责部分文件的抓取 zwjgE6  
**FileSplitterFetch.java aB&&YlR=n<  
*/ !*N@ZL&X  
package NetFox; ]w8(&,PP  
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import java.io.*; \
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import java.net.*; cdT7 @  
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public class FileSplitterFetch extends Thread { Bj;'qB
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String sURL; //File URL '-~~-}= sJ  
long nStartPos; //File Snippet Start Position 7R\<inCQ  
long nEndPos; //File Snippet End Position @qAS*3j  
int nThreadID; //Thread's ID JPw.8|V)y  
boolean bDownOver = false; //Downing is over ?N9u
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boolean bStop = false; //Stop identical +=</&Tm  
FileAccessI fileAccessI = null; //File Access interface bWU'cw  
}19\.z&J  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException )3EY;  
{ xi}skA  
this.sURL = sURL; 0M[EEw3  
this.nStartPos = nStart; OQJ6e:BGt  
this.nEndPos = nEnd; W/h[A3 `3N  
nThreadID = id; @:#eb1<S  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 +cN8Y}V  
} UZ+<\+q3^  
%*}(}~  
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public void run() -[.[>&`/  
{ eng'X-x  
while(nStartPos < nEndPos && !bStop) `b$.%S8uj=  
{ MQ6KN(?\ZL  
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try{  }.6[qk  
URL url = new URL(sURL); S"H2 7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <RL]  
httpConnection.setRequestProperty("User-Agent","NetFox"); <)D$51 &0  
String sProperty = "bytes="+nStartPos+"-"; 9\7en%(M  
httpConnection.setRequestProperty("RANGE",sProperty); zTU0HR3A  
Utility.log(sProperty); 'D1xh~  
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InputStream input = httpConnection.getInputStream(); +6+i!Sip  
//logResponseHead(httpConnection); eJ-nKkg~a  
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byte[] b = new byte[1024]; sfl<qD+?  
int nRead; \'O"~W  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) S?2
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{ UkFC~17P  
nStartPos += fileAccessI.write(b,0,nRead); {)sdiE  
//if(nThreadID == 1) _H@DLhH|=  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .7X^YKR  
} sFRQe]zCcP  
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Utility.log("Thread " + nThreadID + " is over!"); Xsa].  
bDownOver = true; 3!_XEN[  
//nPos = fileAccessI.write (b,0,nRead); 3=oDQ&UFt  
} dSHDWu&  
catch(Exception e){e.printStackTrace ();} G18b$z  
} 2D5StCF$O  
} La[V$+Y  
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//打印回应的头信息 493*{  
public void logResponseHead(HttpURLConnection con) 7b+6%fV  
{ hM
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for(int i=1;;i++) 5|)W.*Q  
{ d&>^&>?$zh  
String header=con.getHeaderFieldKey(i); 5)X=*I  
if(header!=null) cFXp  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); [dz _R  
Utility.log(header+" : "+con.getHeaderField(header)); B%68\  
else I7]8Y=xf  
break; ftSW (og  
} v`T c}c '  
} Zv{'MIv&v  
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public void splitterStop() *{5fq_  
{ (/$^uWj  
bStop = true; RxQ*  
} E"IZ6)Q  
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} Q/Rqa5LI:  
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/* #<x
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**FileAccess.java ^<6[.)  
*//文件访问(定位，写) gRzxLf`K  
package NetFox; VIb
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import java.io.*; E{vbO/|kf  
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public class FileAccessI implements Serializable{ s>c=c-SP.  
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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 }6ldjCT/,  
RandomAccessFile oSavedFile; % ]U  
long nPos; vP,n(reM  
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public FileAccessI() throws IOException "J1 4C9u   
{ "r2 r  
this("",0); 2fS:- 8N  
} U$UIN#  
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public FileAccessI(String sName,long nPos) throws IOException B<C&xDRZ0  
{ 2`-Bs  
oSavedFile = new RandomAccessFile(sName,"rw"); ,]D,P  
this.nPos = nPos; w!XD/jN  
oSavedFile.seek(nPos); QZ8IV>  
} -Qe'Y
By:  
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public synchronized int write(byte[] b,int nStart,int nLen) |vC~HJpuv'  
{ E" vS $  
int n = -1; 2KZneS`  
try{ ;FEqe49  
oSavedFile.write(b,nStart,nLen); [fyLV`  
n = nLen; K)P%;X  
} ptaKf4P^r  
catch(IOException e) lLIAw$  
{ @}ZVtrz  
e.printStackTrace (); 6dY
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} "Y.y:Vv;  
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return n; H"F29Pu2  
} mp3s-YfRc  
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} dF2RH)Ud  
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o !7va"  
/* w2J<WC+_<  
**SiteInfoBean.java 6w77YTJ  
*/ @j/&m]6%-D  
package NetFox; f *)Z)6E  
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public class SiteInfoBean { @o.I;}*
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private String sSiteURL; //Site's URL A%-6`>  
private String sFilePath; //Saved File's Path Qwc"[N4H  
private String sFileName; //Saved File's Name ?h2}#wg  
private int nSplitter; //Count of Splited Downloading File `y0FY&y=  
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public SiteInfoBean() V43H/hl  
{//nSplitter的缺省值为5 )`}:8y?  
//default value of nSplitter is 5 aQ~s`^D  
this("","","",5); xN(|A}w  
} !!ya  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) i mM_H;-X  
{ eDB;cN  
sSiteURL= sURL; -{A<.a3P}=  
sFilePath = sPath; J8D,ZfPN`d  
sFileName = sName; o"SMbj  
this.nSplitter = nSpiltter; GKCroyor  
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} @ .KGfNu  
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public String getSSiteURL() 8Xb
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{ S[QrS7  
return sSiteURL; I2DpRMy  
} J8~ha
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public void setSSiteURL(String value) A\;U3Zu  
{ .sA.C]f  
sSiteURL = value; O'~+_ykTl  
} hzC>~Ub5  
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{:W$LWET  
public String getSFilePath() Vz[C=_m  
{ -.3w^D"l  
return sFilePath; @|)Z"m7  
} lRdChoL$2  
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public void setSFilePath(String value) FgI3   
{ 1nOCQ\$l  
sFilePath = value; Np)lI
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} lys#G:H]  
*owU)  
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public String getSFileName() u-C)v*#L  
{ fn!KQ`,#  
return sFileName; 39jG8zr=Z[  
} TB^$1C  
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wdZ/Xp9]  
public void setSFileName(String value) t0I{q0  
{ =rK+eG#,  
sFileName = value; >OK^D+v"j  
} 8.~kK<)!  
3k?X-|O8AZ  
{}x^ri~  
public int getNSplitter() ]+$?u&0?w  
{ [trwBZ^D~  
return nSplitter; bJ;'`sw1  
} ;UP$yM;  
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public void setNSplitter(int nCount) Tac$LS\Q  
{ m#F`] {  
nSplitter = nCount; 9)=ctoZ'  
} ei{eTp4HpV  
}  f V(J|  
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/* #5j\C+P}|  
**Utility.java Hq 188<  
*/ T,tdL N-  
package NetFox; j8`BdKg  
u~-8d;+?y  
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public class Utility { ;({W#Wa  
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public Utility() /H==Hm/  
{ *WT`o>  
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} 6MkP |vr6  
w+{LAS  
//线程睡眠
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public static void sleep(int nSecond)
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{ +?!(G}5  
try{ 0K2`-mL  
Thread.sleep(nSecond); L,@lp  
} xZv#Es%#  
catch(Exception e) ?3xzd P  
{ N8FF3}> g  
e.printStackTrace (); t`mV\)fa
 
} #Vha7  
} I.k *GW  
.VzT:4-<Q"  
//日志 1y4  
public static void log(String sMsg) ^`>/.gL  
{ $p?aVO  
System.err.println(sMsg); {!dVDf_  
} !I Qck8Y  
Y.r+wc]  
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public static void log(int sMsg) 5[u]E~Fl}  
{ ,WB{i^TD  
System.err.println(sMsg); (*)hD(C5  
} }!C)}.L<  
} > "=>3  
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1 Ya`| ?FS  
/* .h4 \Y A  
**TestMethod.java >&5DsV.B  
*/ ]wG{!0pl  
package NetFox; NPe%F+X  
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public class TestMethod { 7VFLJrt  
 YVanW  
Fun^B;GA:  
public TestMethod() ';=O 0)u  
{ ///xx/weblogic60b2_win.exe '(L7;+E  
try{ e;}7G  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); q
(2'\ _`u  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); nK%LRcAs  
SiteFileFetch fileFetch = new SiteFileFetch(bean); R[x_j  
fileFetch.start(); }@+:\   
} ~1vDV>dpE  
catch(Exception e){e.printStackTrace ();} [^98fAlz6  
7Da`   
}2<7%FL  
} SJ>vwmA4  
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public static void main(String[] args) (c &mCJN  
{ sI^Xb@'09$  
new TestMethod(); K}MK<2vU  
} <;Zmjeb+#  
} cP_.&!T  
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