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http断点续传简单实现(java)

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/* |r ue=QZ  
**SiteFileFetch.java $VAx:Y|  
*/ 6s,uXn  
package NetFox; ^@P1 JNe  
import java.io.*; I8oo~2Q w  
import java.net.*; =_j vk.  
FYs)M O  
umz;F  
public class SiteFileFetch extends Thread { xw{-9k-~  
gOgps:  
`[o)<<}  
SiteInfoBean siteInfoBean = null; //文件信息Bean )9,  
long[] nStartPos; //开始位置 'c\iK=fl  
long[] nEndPos; //结束位置 I%|>2}-_U  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ntNI]~z&  
long nFileLength; //文件长度 R1&unm0  
boolean bFirst = true; //是否第一次取文件 f= >O J!:  
boolean bStop = false; //停止标志 (SSRY9  
File tmpFile; //文件下载的临时信息 N@B9 @8h  
DataOutputStream output; //输出到文件的输出流 r "$.4@gc  
.xf<=ep  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) !+u"3;%h  
public SiteFileFetch(SiteInfoBean bean) throws IOException 2Q;9G6p  
{ e1//4H::t  
siteInfoBean = bean; IwGqf.!.>  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); NM)k/?fA  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); **69rN  
if(tmpFile.exists ()) {M,,npl  
{ ^Rm  
bFirst = false; (&$VxuJ+6y  
read_nPos(); !lo/xQ<  
} 6c0>gUQx-  
else CJ}5T]WZ  
{ @FdSFQ/9  
nStartPos = new long[bean.getNSplitter()]; #plY\0E@  
nEndPos = new long[bean.getNSplitter()]; ~>9_(L  
} q2HYiH^L  
4k./(f2+  
&.TTJsKG h  
U%0Ty|$Y   
} gGfoO[B  
UH7jP#W%=  
Z{?G.L*/  
public void run() s3Cc;#  
{ JTi!Xu5Jq  
//获得文件长度 5zON}"EC  
//分割文件 :qC '$dO!  
//实例FileSplitterFetch r1RGTEkD  
//启动FileSplitterFetch线程 1CLL%\V  
//等待子线程返回 5nbEf9&  
try{ )O:0 ]=#))  
if(bFirst) 26CS6(sn  
{ 6(P M'@i  
nFileLength = getFileSize(); 0'nikLaKy  
if(nFileLength == -1) tHLrhH<w  
{ &/,|+U[  
System.err.println("File Length is not known!"); \9-"M;R.d  
} !!Z?[rj  
else if(nFileLength == -2) dz Zb  
{ `~eUee3b.~  
System.err.println("File is not access!"); QeF3qXI  
} FVh U^  
else N&@}/wzZ  
{ gv5*!eI  
for(int i=0;i<nStartPos.length;i++) Q_l'o3  
{ $1ndKB8)`J  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); +S Jd@y@fR  
} \W1/p`  
for(int i=0;i<nEndPos.length-1;i++) [9:9Ql_h  
{ a&vY!vx 3  
nEndPos = nStartPos[i+1]; 4tY ss  
} 6;b~Ht  
nEndPos[nEndPos.length-1] = nFileLength; ]l8^KX'  
} W456!OHa  
} |JCU<_<  
(XoH,K?{z  
F2X0%te  
//启动子线程 RejQ5'Neh  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; bV/jfV"%E  
for(int i=0;i<nStartPos.length;i++) Jaz?Ys|S  
{ p,"g+ MwP  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6Aocm R0D'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), EYA,hc  
nStartPos,nEndPos,i); .bio7c6  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1^gl}^|B  
fileSplitterFetch.start(); Z1"v}g  
} hpU2  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2;w*oop,O  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 5h;+Ky!I  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ~Jf{4*>y  
nEndPos = " + nFileLength); k1Q ?'<`  
// fileSplitterFetch[nPos.length-1].start(); j&k6O1_  
0Fu~%~#E$  
4>J   
//等待子线程结束 y+7PwBo%e  
//int count = 0; oY, %Iq  
//是否结束while循环 Nz)l<S9>  
boolean breakWhile = false; u{L!n$D7  
<_Q1k>  
d^`?ed\1  
while(!bStop) %j7XEh<'  
{ @V!r"Bkg.  
write_nPos(); bV"G~3COy  
Utility.sleep(500); 5 (A5Y-B  
breakWhile = true; cp h:y  
NFv>B>  
^Ox3XC  
for(int i=0;i<nStartPos.length;i++) 0V?F'<qy  
{ 8g7<KKw  
if(!fileSplitterFetch.bDownOver) -44&#l^}_u  
{ j)q\9#sI/(  
breakWhile = false; Dl}$pN  
break; Dwzg/F(  
} |ZQ@fmvL/p  
} X]'7Ov  
if(breakWhile) aM;W$1h  
break; ]LM-@G+Jz  
7 x<i :x3  
- |gmQG  
//count++; n93=8;&  
//if(count>4) A%^ILyU6c  
// siteStop(); 0x!2ihf  
} Fgh]KQ/5  
QPq7R  
KZeQ47|  
System.err.println("文件下载结束!"); 0Zg%+)iy@  
} '}9JCJ  
catch(Exception e){e.printStackTrace ();} Lco& Fp  
} {%C7EAq*  
\J6j38D5  
F;>!&[h}G  
//获得文件长度 \nP>:5E1  
public long getFileSize() D$x_o!JT  
{ (IPY^>h  
int nFileLength = -1; PsZ >P|e1  
try{ |n] d34E  
URL url = new URL(siteInfoBean.getSSiteURL()); 'g{9@PkGn  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); jQ)T67  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^,]B@ t2  
.c$316  
}-@`9(o`)  
int responseCode=httpConnection.getResponseCode(); }RP @!=  
if(responseCode>=400) d \35a4l  
{ GDuMY\1  
processErrorCode(responseCode); dc rSz4E|>  
return -2; //-2 represent access is error )Qvk*9OS  
} x)_0OR2lkp  
n\Lb.}]1~  
l\n@cQR  
String sHeader; kTvd+TP4  
9 '2_  
ERN>don2  
for(int i=1;;i++) !e?.6% %   
{ R,Vd.-5M  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); c?@T1h4  
//Utility.log(in.readLine()); OiP!vn}k  
sHeader=httpConnection.getHeaderFieldKey(i); n-@j5w+k4  
if(sHeader!=null) -xP!"  
{ q?ix$nKOv  
if(sHeader.equals("Content-Length")) NhYLt w^u  
{ Q6r7.pk"SU  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); pn^ d]rou?  
break; G2FXrkU  
} J^g!++|2P  
} |.3DD"*  
else S)/_muP  
break; to$h2#i_  
} a.zpp'cEb  
} j.@\3'  
catch(IOException e){e.printStackTrace ();} ,#kIr  
catch(Exception e){e.printStackTrace ();} pt}X>ph{  
wLH] <k  
nxl[d\ap+n  
Utility.log(nFileLength); VZl6t;cn  
+) m_o"hl  
Pp5^@A  
return nFileLength; lO_UPC\@fw  
} $-*!pRaVU  
"%x<ttLl  
h?azFA~  
//保存下载信息(文件指针位置) C;vtY[}<  
private void write_nPos() Vkc#7W(  
{ w/K_B:s  
try{ HC}YY2  
output = new DataOutputStream(new FileOutputStream(tmpFile)); :]1 TGfS  
output.writeInt(nStartPos.length); 2Roc|)-47  
for(int i=0;i<nStartPos.length;i++) Kp,M"Y  
{ -Zz$~$  
// output.writeLong(nPos); w4d--[Q  
output.writeLong(fileSplitterFetch.nStartPos); .>IhN 5  
output.writeLong(fileSplitterFetch.nEndPos); MHC^8VL  
} wg]j+r@  
output.close(); yYH0v7vx+  
} $ <#KA3o\  
catch(IOException e){e.printStackTrace ();} 8M`#pN^  
catch(Exception e){e.printStackTrace ();} HF.^ysI  
} 82DmG@"s2  
KkE9KwZ]W  
}7.PH'.8  
//读取保存的下载信息(文件指针位置) 1[vi.  
private void read_nPos() oTuOw|[  
{ .?Gd'Lp  
try{ jav#f{'  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 1wP-  
int nCount = input.readInt(); #"5 Dk#@  
nStartPos = new long[nCount]; a qc?pqM  
nEndPos = new long[nCount]; v3jg~"!  
for(int i=0;i<nStartPos.length;i++) $"H{4 x`-  
{ bG(3^"dS  
nStartPos = input.readLong(); AlIpsJ[UU  
nEndPos = input.readLong(); ut I"\1hQ  
} Aj4T"^fv  
input.close(); UTH_^HAN#G  
} Sh8"F@P8  
catch(IOException e){e.printStackTrace ();} " _ka<R..  
catch(Exception e){e.printStackTrace ();} ;h jwD  
} vt9)pMs  
e;[F\ov %  
Pw61_ZZ4B\  
private void processErrorCode(int nErrorCode) @>U-t{W  
{ KSN Pkd6  
System.err.println("Error Code : " + nErrorCode); N D2L_!g:(  
} mA=i)Ga  
Oal3rb  
<h'5cO  
//停止文件下载 oT>(V]*5  
public void siteStop() Yn G_m]  
{ 2mGaD\?K  
bStop = true; q CnZhJ  
for(int i=0;i<nStartPos.length;i++) wGP;Vbk  
fileSplitterFetch.splitterStop(); 6Z%U`,S  
sU{NHC)5  
(X3Tav  
} x" L20}  
} :FTMmW,>'  
//负责部分文件的抓取  D 'Zt  
**FileSplitterFetch.java AQ[GO6$,%H  
*/ C .~+*"Vw  
package NetFox; % V8U (z  
#I bp(  
2P@sn!*{1  
import java.io.*; uvG]1m#  
import java.net.*; dKxyA"@  
_`:1M2=  
csW43&  
public class FileSplitterFetch extends Thread { trp0 V4b8  
[S>2ASj  
AGYc |;  
String sURL; //File URL 7*Ej. HK  
long nStartPos; //File Snippet Start Position j+,d^!  
long nEndPos; //File Snippet End Position @-!}BUs?  
int nThreadID; //Thread's ID suzZdkMA  
boolean bDownOver = false; //Downing is over 65aK2MS@  
boolean bStop = false; //Stop identical !74S  
FileAccessI fileAccessI = null; //File Access interface W|g4z7Pb  
hj.a&%  
b KN@j'M  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException <yH4HY  
{ J.xPv)1'  
this.sURL = sURL; *=I}Qh(1  
this.nStartPos = nStart; #/<&*Pu5t  
this.nEndPos = nEnd; U5.LDv;  
nThreadID = id; /q`xCS  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 0p}D(m2B  
} 2 Cv4=S  
?1K#dC52#  
vbC\?\_  
public void run() W1|0Yd ;P  
{ zIu E9l  
while(nStartPos < nEndPos && !bStop) 7B\Vs-d  
{ zPjHsulK  
9E>|=d|(d  
xY^ %&n  
try{ NP/Gn6fr  
URL url = new URL(sURL); f m)pulz  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 'g m0)r  
httpConnection.setRequestProperty("User-Agent","NetFox"); A"G 1^8wvX  
String sProperty = "bytes="+nStartPos+"-"; ^Uf]Q$uCjE  
httpConnection.setRequestProperty("RANGE",sProperty); G'ei/Me6{  
Utility.log(sProperty); .@@?Pj?)  
K)DDk9*  
j;-1J_e5  
InputStream input = httpConnection.getInputStream(); ?-dX`n  
//logResponseHead(httpConnection); 6&!PmKFO.  
Pu*6"}#~  
lY?QQ01D  
byte[] b = new byte[1024]; F.=2u"[*&  
int nRead; C8V/UbA /  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) BlA_.]Sg$  
{ :<bB?N(  
nStartPos += fileAccessI.write(b,0,nRead); #0P$M!%  
//if(nThreadID == 1) :?g:~+hfO  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); $',K7%y  
} V4'YWdTi  
HoRg^Ai?\  
)quM4=u'  
Utility.log("Thread " + nThreadID + " is over!"); j)/nKh4O  
bDownOver = true; c*L0@Ak%  
//nPos = fileAccessI.write (b,0,nRead); Y STv\y  
} 'kL#]  
catch(Exception e){e.printStackTrace ();} <~n"m  
} @oV9)  
} <FcG oGK  
e} P I^bc  
06c>$1-?  
//打印回应的头信息 O Hb[qX\  
public void logResponseHead(HttpURLConnection con) +RYls|f  
{ '":lB]hS  
for(int i=1;;i++) ]pNvxXbeW  
{ y)W@{@{kl  
String header=con.getHeaderFieldKey(i); %'s>QF]'  
if(header!=null) D*gFV{ Ws  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ;U.hxh;+  
Utility.log(header+" : "+con.getHeaderField(header)); d(:8M  
else iB%gPoDCL@  
break; w~"KA6^  
} Kgi<UkFP  
} X[&Wkr8x '  
ymx>i~>7J  
DVB{2~7 4  
public void splitterStop() -ZRO@&tMD  
{ N343qU  
bStop = true; Py@wJEo  
} OZ |IA:,}  
qUob?| ^   
2\jPv`Ia  
} LWz&YF#T-  
/ zB0J?  
b\$}>O  
/* Rv$[)`&T  
**FileAccess.java &U5{Hm9Ynr  
*//文件访问(定位,写) _m gHJ0v'  
package NetFox; {B?Wu3-  
import java.io.*; !'&n -Q  
jv%kOovj  
-EkWs/'h  
public class FileAccessI implements Serializable{ D6>2s\:>vp  
CF&6J$ZBgJ  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 z$/_I0[  
RandomAccessFile oSavedFile; ;*:]*|bw  
long nPos; f78An 8  
.<x&IJ /  
gv)P]{%^  
public FileAccessI() throws IOException lOuHVa*}  
{ \{Z; :,S  
this("",0); T arIPp  
} ,9}h  
ES.fOdx  
ZniB]k1  
public FileAccessI(String sName,long nPos) throws IOException  -QM: q  
{ #h8Sq~0  
oSavedFile = new RandomAccessFile(sName,"rw"); zF8dKFE~  
this.nPos = nPos; :Q $K<)[  
oSavedFile.seek(nPos); 9F)z4  
} J'SZ  
4'g;TI^  
wVicyiY]  
public synchronized int write(byte[] b,int nStart,int nLen) ;t<QTGJ  
{ PE}:ybsX  
int n = -1; l_P-j 96WD  
try{ {*0<T|<n  
oSavedFile.write(b,nStart,nLen); w)kNkD  
n = nLen; dZ  rAn  
} aqRhh=iS  
catch(IOException e) 2 Ga7$q  
{ =BSzsH7  
e.printStackTrace (); "a ueL/dgN  
} F)&@P-9+  
aY'C%^h]  
]iN'x?Fo  
return n; _aFl_\3>  
} rz wF~-m +  
Oiz ,w7LRh  
Ljxz.2LGr  
} tyXuG<  
4C<j dv_J  
JJ}0gZ   
/* ^)(bM$(`  
**SiteInfoBean.java z3&]%Q&  
*/ ,SynnE68  
package NetFox; -8:&>~4`  
Ghx3EVqnx"  
E^ P,*s  
public class SiteInfoBean { q|o}+Vr  
DoJ\ q+  
J&[@}$N  
private String sSiteURL; //Site's URL ,0*&OXt  
private String sFilePath; //Saved File's Path t2F _uCr  
private String sFileName; //Saved File's Name zVXC1u9B  
private int nSplitter; //Count of Splited Downloading File Ir`eL  
/<@SFF.  
*c~T@m~DR  
public SiteInfoBean() !46RGU:I  
{//nSplitter的缺省值为5 k9  "[H'  
//default value of nSplitter is 5 {1V($aBl  
this("","","",5); "= 6_V?&w  
} :3XA!o&.T3  
@&%'4j&+  
2z6yn?'&L  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) \>jLRb|7Ts  
{ (]0%}$Fo  
sSiteURL= sURL; SB1upTn  
sFilePath = sPath; @.b+av4J  
sFileName = sName; ])|d"[ur=  
this.nSplitter = nSpiltter; //T>G_1  
)PG6gZYW  
T]t+E'sQ  
} A )^`?m3  
GN ]cDik  
]ndvt[4L  
public String getSSiteURL() _hRcc"MS`  
{ f!oT65Vmi  
return sSiteURL; %+8F'&X  
} P_?gq>E8  
';TT4$(m  
b8V~S'6VqO  
public void setSSiteURL(String value) tZ} v%3  
{ o7J  
sSiteURL = value; PZE0}>z  
} 0Fk5kGD,&K  
:*ing  
0y 7"SiFY  
public String getSFilePath() -BRc8 /  
{ bSfpbo4(  
return sFilePath; 6|aKL[%6  
} a:"Uh**  
^* J2'X38I  
UUzYbuS>&l  
public void setSFilePath(String value) =NnNN'}  
{ CK,7^U  
sFilePath = value; _d"b;4l  
} ^HV>`Pjd}=  
(eCJ;%%k  
}`W){]{k O  
public String getSFileName() J6U$qi  
{ \R|4( +]x  
return sFileName; HG+%HUO$  
} ]bj&bk#  
.q `Hjmg<  
Xe<sJ. &Wf  
public void setSFileName(String value) ]$Yvj!K*Q  
{ Fs{x(_LOr  
sFileName = value; q;<h[b?  
} _CW(PsfY  
:uWw8`  
v}1QH  
public int getNSplitter() ] 8Q4BW  
{ k 8UO9r[  
return nSplitter; 1u: gFUb  
} 6^]!gR#B  
E"+QJ~!  
Svondc 4  
public void setNSplitter(int nCount) cW i}V  
{ T(f/ ?_%  
nSplitter = nCount; Po ZuMF  
} -u2P ?~  
} SS$[VV  
*a58ZI@  
k p<OJy  
/* 3[O=x XB  
**Utility.java pPcTrN'  
*/ |/09<F:L[  
package NetFox; x$1]M DAGb  
fb{`` ,nO  
RLb KD>  
public class Utility { m=}B,']O  
P"W2(d  
 c|M6 <}  
public Utility() U@-^C"R  
{ ;?8_G%va  
zx-81fx+k  
|QU <e  
} vU767/  
f7=((5N  
//线程睡眠 MrDc$p W G  
public static void sleep(int nSecond) @&1ZB6OCb:  
{ G*-b}f  
try{ BaSZ71>9]r  
Thread.sleep(nSecond); !{^PO <9  
} huJ&]"C  
catch(Exception e) d5oIH  
{ '=Rs/EDME  
e.printStackTrace (); z"0I>gl  
} 8Le||)y,\  
} (>r[- Bft  
Cq%IE^g<  
//日志 )rekY;  
public static void log(String sMsg) <$X3Hye  
{ BZR:OtR^  
System.err.println(sMsg); nPye,"A Ol  
} CitDm1DXt/  
_NMm/]mN /  
oZ!m  
public static void log(int sMsg) MO n  
{ 8P1=[i]  
System.err.println(sMsg); ',:*f8Jk  
} CE/Xfh'44  
} mT.u0KUIy  
[/e<l&y  
bI:zp!-.  
/* hJZV}a|  
**TestMethod.java y *fDwd~  
*/ fp+gyTnd3  
package NetFox; H[S%J3JI  
qYlhlHD  
T~Gvp0r}h  
public class TestMethod { U-R6xxPZ  
jpO7'ivG  
BK,{N0  
public TestMethod() 4iKgg[)7`=  
{ ///xx/weblogic60b2_win.exe X{\F;Cb*  
try{ `NgAT 3zq  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); b/C`J p  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ><gG8MH0'  
SiteFileFetch fileFetch = new SiteFileFetch(bean); pKit~A,Q  
fileFetch.start(); bT^I"  
} %?p1d!  
catch(Exception e){e.printStackTrace ();} ~v6OsH%vx  
px}|Mu7z~  
>_|O1H./4  
} EUN81F?  
$shoasSuI  
:9^;Qv*  
public static void main(String[] args) ,u`B<heoLU  
{ { S3ZeN,kZ  
new TestMethod(); $`)/0{qY-  
} ug+io mZ  
} MLRK74D  
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