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http断点续传简单实现(java)

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/* ) OE!vA  
**SiteFileFetch.java JW2~ G!@  
*/ $v\o14 v  
package NetFox; VSDG_:!K  
import java.io.*; .Gcs/PN   
import java.net.*; gNaB^IY  
~a06x^=j  
A>B_~=  
public class SiteFileFetch extends Thread { ;Ob`B@!=b  
lBZhg~{  
:YUQKy  
SiteInfoBean siteInfoBean = null; //文件信息Bean :(TOtrK@  
long[] nStartPos; //开始位置 yk0#byW`  
long[] nEndPos; //结束位置 J5#shs[M:  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ,b'QL6>`  
long nFileLength; //文件长度 \sc's7  
boolean bFirst = true; //是否第一次取文件 u d$*/ )/  
boolean bStop = false; //停止标志 Z~Vups#+f  
File tmpFile; //文件下载的临时信息 5-B %08T  
DataOutputStream output; //输出到文件的输出流 5~H}%W,P  
1<E:`,Mn?  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) kNC]q,ljt5  
public SiteFileFetch(SiteInfoBean bean) throws IOException bPMkBm  
{ Rdj/n :  
siteInfoBean = bean; $/|2d4O:{  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); SUaXm#9  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 9 lH00n+'  
if(tmpFile.exists ()) SadffAvSA{  
{ .?dYY;P  
bFirst = false; ?5Q_G1H&  
read_nPos(); "]kq,j^]  
} f~Ve7   
else R.)w l  
{ `CqF&b  
nStartPos = new long[bean.getNSplitter()]; )D8V;g(7F  
nEndPos = new long[bean.getNSplitter()]; Yu e#  
} R7NE= X4  
1 R,?kUa  
g'<ekY+V:  
MgrJ ;?L  
} h$_5)d~  
pUm|e5  
,4Qct=%L_  
public void run() 5o2vj8::  
{ t(r}jU=qw  
//获得文件长度 4fgYO]  
//分割文件 [e?vqm .  
//实例FileSplitterFetch NKRI|'Y,  
//启动FileSplitterFetch线程 E0_S+`o2y  
//等待子线程返回 mj|TWDcj+  
try{ g>;u} +lO  
if(bFirst) JzZ@Z8%a;  
{ OiJz?G:m  
nFileLength = getFileSize(); K/IG6s;Xj  
if(nFileLength == -1) vi~NfD@s  
{ qN@0k>11?  
System.err.println("File Length is not known!"); ]>H'CM4JR  
} %Z!3[.%F  
else if(nFileLength == -2) |N%#;7  
{ i=aK ?^+  
System.err.println("File is not access!"); O0=}: HM  
} rlP?Uh  
else Uk<2XGj  
{  ;)ji3M  
for(int i=0;i<nStartPos.length;i++) Eq/oq\(/6  
{ h-6zQs   
nStartPos = (long)(i*(nFileLength/nStartPos.length)); u~\l~v^mj  
} 3Ued>8Gv  
for(int i=0;i<nEndPos.length-1;i++) `R@b`3*%v  
{ 6o=Q;Mezl  
nEndPos = nStartPos[i+1]; R,f"2 k  
} dH_g:ocA  
nEndPos[nEndPos.length-1] = nFileLength; -YJ4-]Z  
} )L/o|%r!  
} (^mpb  
Rr"D)|Y;C(  
29kR7[k  
//启动子线程 5sI9GC  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; %mr6p}E|  
for(int i=0;i<nStartPos.length;i++) .V.ga2+  
{ <MzXTy3\  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), i[ 40p!~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 6 TSC7jO  
nStartPos,nEndPos,i); c!Wj^  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <EM'|IR?  
fileSplitterFetch.start(); (c|Ry[$|  
} '-NHu +  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), d8% sGH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); WR5W0!'Tf  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 5KRI}f  
nEndPos = " + nFileLength); x A"V!8C  
// fileSplitterFetch[nPos.length-1].start(); WeE1 \  
S?e*<s9k  
Q5>]f/LD  
//等待子线程结束 7kq6VS;p  
//int count = 0; rO7[{<97m  
//是否结束while循环 cC7&]2X +f  
boolean breakWhile = false; J8#3?Lp  
Dx>~^ ^<  
]5sU =\  
while(!bStop) \Ws$@ J-M  
{ :,1 kSM%r  
write_nPos(); Mv7=ZAm  
Utility.sleep(500); ,@r 0-gL  
breakWhile = true; IfzZ\x .  
H#FH '@J  
A_}6J,*u  
for(int i=0;i<nStartPos.length;i++) E0aJ~A(Hv  
{ ,<O|Iis  
if(!fileSplitterFetch.bDownOver) L2{b~`UvP  
{ J[jzkzSu`  
breakWhile = false; K\y W{y1  
break; 6<m9guv  
} |P(8T'  
} )bR`uV9<  
if(breakWhile) Yrmd hSY  
break; S/)yi  
Ys+NIV#Q  
A? T25<}  
//count++; 3"p'WZ>  
//if(count>4) NNn sq@?6  
// siteStop(); *rv7#!].  
} #55_hY#  
!G~`5?CvE  
EVW\Z 2N.  
System.err.println("文件下载结束!"); *TC#|5  
} 6![}Jvu>  
catch(Exception e){e.printStackTrace ();} E4qQ  
} e(Y5OTus  
Uo=_=.GQ  
rYPj3!#  
//获得文件长度 xY<*:&  
public long getFileSize() `IH*~d]  
{ {I]>!V0j!  
int nFileLength = -1; p%ZAVd*|#V  
try{ NXSjN~aG2  
URL url = new URL(siteInfoBean.getSSiteURL()); v9XevLs  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /f]'_t0\.  
httpConnection.setRequestProperty("User-Agent","NetFox"); ZfnJ&H'  
;(Kj-,>  
l?:S)[:  
int responseCode=httpConnection.getResponseCode(); lnv&fu`1P  
if(responseCode>=400) &*9 ' 0  
{ Z:.*fs5  
processErrorCode(responseCode); h_\OtoRa  
return -2; //-2 represent access is error *IIuGtS  
} `{  ` W-C  
 .F/0:)  
)| 0(#R  
String sHeader; zCI.^^<?  
kWbD?i-  
O[W/=j[  
for(int i=1;;i++) O1Nya\^g<I  
{ lc\%7-%:5  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); LjPpnjU  
//Utility.log(in.readLine()); w<Ot0&&  
sHeader=httpConnection.getHeaderFieldKey(i); rH9[x8e  
if(sHeader!=null) k]~|!`  
{ g4}K6)@  
if(sHeader.equals("Content-Length")) F`M`c%  
{ g^[BnP)I  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); v?s%qb=T  
break; npMPjknl  
} x/uC)xm  
} *nlDN4Y[  
else }T&~DVM  
break; 2!? =I'uMA  
} 1R"Z+tNB  
} y)mtSA8  
catch(IOException e){e.printStackTrace ();} $ Qcr8~+a  
catch(Exception e){e.printStackTrace ();} rn RWL4  
lX/:e=  
%OJq(}  
Utility.log(nFileLength); !+_X q$9_  
F5%IsAH  
%:yVjb,Yf  
return nFileLength; ^ wb9n  
} `qhZZ{s)1U  
Pa-{bhllu)  
S3gd'Bahq  
//保存下载信息(文件指针位置) 2-beq<I  
private void write_nPos() `c?8i  
{ X1o=rT  
try{ =O>E>Q  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Ti$_V_  
output.writeInt(nStartPos.length); nTCwLnX(O  
for(int i=0;i<nStartPos.length;i++) kerBy\^  
{ %a|m[6+O  
// output.writeLong(nPos); Ue(\-b\)  
output.writeLong(fileSplitterFetch.nStartPos); S3ZI C\2  
output.writeLong(fileSplitterFetch.nEndPos); t)hi j&wzu  
} l(d3N4iz  
output.close(); VF:95F;@  
} PGhYkj2  
catch(IOException e){e.printStackTrace ();} `Hd~H  
catch(Exception e){e.printStackTrace ();} U:uF rb,  
} v)<|@TD)  
WT jy"p*  
1"~$(@oxG  
//读取保存的下载信息(文件指针位置) S^A+Km3VB  
private void read_nPos() .~fov8  
{ yny1i9 y  
try{ Bb.U4#  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); nx@,oC4  
int nCount = input.readInt(); ?Lbn R~/J  
nStartPos = new long[nCount]; <\oD4EE_  
nEndPos = new long[nCount]; J }|6m9k!  
for(int i=0;i<nStartPos.length;i++) eDY)i9"W  
{ }X~"RQf9  
nStartPos = input.readLong(); lQ#='Jqfp  
nEndPos = input.readLong(); Zw_'u=r >  
} S#nW )=   
input.close(); v$#l]A_D  
} Ch73=V  
catch(IOException e){e.printStackTrace ();} mq+<2 S  
catch(Exception e){e.printStackTrace ();} \ {;3'<  
} @k)[p+)E  
$^`@lyr  
._TN;tR~'  
private void processErrorCode(int nErrorCode) \e~5Dx1  
{ a;=IOQ  
System.err.println("Error Code : " + nErrorCode); w#{S=^`}  
} I-m Bj8^;  
aole`PD,l  
_kdt0Vr,L  
//停止文件下载 l<:\w.Gl  
public void siteStop() RKy!=#;17  
{ qm< mw"]  
bStop = true; C/MQY:X4  
for(int i=0;i<nStartPos.length;i++) AA0\C_W0p  
fileSplitterFetch.splitterStop(); #~[{*[B+  
vrIWw?/z?  
JC iB;!y  
} ^9 ^DA!'  
} t]E@AJO K  
//负责部分文件的抓取 VcLzv{  
**FileSplitterFetch.java +h8`8k'}-2  
*/ jmF)iDvjuZ  
package NetFox; p\DSFB  
h}Lrpr2r  
w9675D+  
import java.io.*; DA>TT~L  
import java.net.*; y7x*:xR[  
r9n:[A&HE  
MH|R@g  
public class FileSplitterFetch extends Thread { +asO4'r  
R#ZO<g%'  
7G%:ckg  
String sURL; //File URL 1} ~`g ED  
long nStartPos; //File Snippet Start Position ijgm-1ECk3  
long nEndPos; //File Snippet End Position \LM.>vJ  
int nThreadID; //Thread's ID p3 V?n[/}  
boolean bDownOver = false; //Downing is over d ;i@9+  
boolean bStop = false; //Stop identical qWD(rq+9  
FileAccessI fileAccessI = null; //File Access interface B`:l;<&jX  
_gw paAJ  
I8Y #l'z  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException \- 8aTF  
{ WZ=$c]gG  
this.sURL = sURL; 3~?m?vj|Y  
this.nStartPos = nStart; *!ecb1U5  
this.nEndPos = nEnd; 73JrK_h  
nThreadID = id; tac\Ki?  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 a\}` f=T  
} klnk{R.>|  
8vQR'<,  
A=wG};%_  
public void run() u:H:N]  
{ ZS[Ut  
while(nStartPos < nEndPos && !bStop) HSVl$66  
{ lIPz "  
L%+mD$@u  
Pbt7T Q  
try{ dSe d 6  
URL url = new URL(sURL); Dt(xj}[tC  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =|dHD  
httpConnection.setRequestProperty("User-Agent","NetFox"); ij1YV2v  
String sProperty = "bytes="+nStartPos+"-"; 5 v^tPGg4  
httpConnection.setRequestProperty("RANGE",sProperty); a'A<'(yv  
Utility.log(sProperty); 45&Rl,2  
3,n"d-  
MG~bDM4  
InputStream input = httpConnection.getInputStream(); v-wZHkdd1  
//logResponseHead(httpConnection); Z\cD98B#  
Ss_}@p ^  
kK/XYC 0D  
byte[] b = new byte[1024]; eD7qc1*G  
int nRead; d{"@<0i?  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) <W+9 h0c  
{ u60RuP&  
nStartPos += fileAccessI.write(b,0,nRead); XlnSh<e  
//if(nThreadID == 1) wB&5q!{!  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); i[:cG  
} }F"98s W  
&x;n^W;#  
20}w . V  
Utility.log("Thread " + nThreadID + " is over!"); )j\_*SoH  
bDownOver = true; J4@-?xj=\q  
//nPos = fileAccessI.write (b,0,nRead); 1}Y3|QxF  
} `?b'.Z_J  
catch(Exception e){e.printStackTrace ();} M8/:PmR<  
} +(y 8q  
} N9*:]a  
XyiaRW  
K$w;|UJc  
//打印回应的头信息 R_\o`v5  
public void logResponseHead(HttpURLConnection con) { {:Fs  
{ 6P:fM Y  
for(int i=1;;i++) sG)aw`_j  
{ FBbaLqgVF{  
String header=con.getHeaderFieldKey(i); uB#U( jl  
if(header!=null) BC\W`K  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); pWq+`|l$  
Utility.log(header+" : "+con.getHeaderField(header)); r-yUWIr S  
else %V+"i_{m  
break; T]nAz<l),  
} #<Lv&-U<KT  
} <XQwu*_\  
W6_ rSVm  
jU* D  
public void splitterStop() j9l32<h7]  
{ P+=m.  
bStop = true; 1z-A3a/-  
} kD?@nx>  
3W]gn8  
0{ ~2mggh  
} l1KgPRmEP  
'nBP%  
_>rM[\|X  
/* wc. =`Me  
**FileAccess.java 9[;da  
*//文件访问(定位,写) &1R#!|h1W  
package NetFox; aKWxLe  
import java.io.*; <oV[[wl  
>TY;l3ew  
x^EW'-a  
public class FileAccessI implements Serializable{ G"OP`OMDc  
+ima$a0Zyt  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 FO%pdLs,  
RandomAccessFile oSavedFile; 'Grii,  
long nPos; J-<_e??  
C\~}ySQc.e  
6h2keyod  
public FileAccessI() throws IOException q?dd5JzZy,  
{ ydo9 P5E  
this("",0); [P =P8-5  
} BQ)>}YHk  
()bQmNqmO=  
Qrg- xu=  
public FileAccessI(String sName,long nPos) throws IOException -Dx3*ZhP  
{ X%j`rQk`  
oSavedFile = new RandomAccessFile(sName,"rw"); 4=/jh:h  
this.nPos = nPos; ZTV)D  
oSavedFile.seek(nPos); |Z{#DOT  
} A|S)cr8z  
T3@2e0u )  
jwa6`u  
public synchronized int write(byte[] b,int nStart,int nLen) #dL,d6a  
{ t(6]j#5   
int n = -1; E+qLj|IU  
try{ R[j?\#  
oSavedFile.write(b,nStart,nLen); A,~KrRd  
n = nLen; 4 ZnQpKg  
} 5X=1a*2']  
catch(IOException e) ]vvA]e  
{ I9qFXvqL  
e.printStackTrace (); yRyXlZC  
} F |BY]{  
N6"sXw m  
,v K%e>e&  
return n; cZ|*Zpk  
} 41<h|WA  
T`":Q1n  
F:T(-,  
} B qX"La,  
?Y3i-jY  
4@3\Ihv  
/* Dg.~"h5mT  
**SiteInfoBean.java e'A_4;~@s  
*/ r=0PW_r:  
package NetFox; # o/;du  
x\8g ICf  
oSD=3DQ;  
public class SiteInfoBean { (WC =om  
6E-eD\?I&  
P"^Yx8L#  
private String sSiteURL; //Site's URL <q$Tk,  
private String sFilePath; //Saved File's Path jH9PD8D\  
private String sFileName; //Saved File's Name 2|lR@L sr  
private int nSplitter; //Count of Splited Downloading File )/@KdEA:  
X^N6s"2  
nUpj+F#  
public SiteInfoBean() nt$P A(Y  
{//nSplitter的缺省值为5 f&4+-w.:V|  
//default value of nSplitter is 5 jn|NrvrX  
this("","","",5); aOGoJCt C  
} 3WF]%P%  
y,`n9[$K\  
#~nXAs]Q  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) @[9  
{ gi,7X\`KQ  
sSiteURL= sURL; -%MXt  
sFilePath = sPath; A?#i{R  
sFileName = sName; ]sb?lAxh{  
this.nSplitter = nSpiltter; 0SYJ*7lPX  
[;,E cw^  
#Mn?Nn  
} #~-Xt! I  
pP":,8Q{  
=@M9S  
public String getSSiteURL() 2[`n<R\  
{ V[kJ;YLPN  
return sSiteURL; bT2c&VPCE  
} vw!7f|Pg ~  
siCi+Y  
l hYJectJa  
public void setSSiteURL(String value) kR %,:   
{ %/w-.?bX  
sSiteURL = value; )yb~ kbe  
} z_xy*Iif  
Ur< (TM  
{z_cczJ-  
public String getSFilePath() ];Noe9o  
{ 9D\E0YG X/  
return sFilePath; ZrEou}z(*  
} ]I,&Bme  
cI8\d 4/py  
2EpQ(G J  
public void setSFilePath(String value) ]@z!r2[  
{ jW8ad{  
sFilePath = value; V)~b+D  
} }rmr0Bh  
A2\hmp@A@7  
Zc_F"KJL  
public String getSFileName() )fXw~  
{ 2(GY k  
return sFileName; 1VFCK&  
} +sn0bi/rG  
n%36a(] t  
TxQsi"0c  
public void setSFileName(String value) 0N!rIz  
{ K{I"2c  
sFileName = value; WP\kg\o  
} B]yO  
,ov$` v  
bz nMD  
public int getNSplitter() W7|nc,i0\  
{ Z:h'kgG&  
return nSplitter; 09vVCM;DY  
} !U4YA1>>  
[g"nu0sOK  
Dj=$Q44  
public void setNSplitter(int nCount) "kcix!}&  
{ u8?$W%eW  
nSplitter = nCount; ux^rF  
} 4s|qxCks  
} (bI/s'?K  
)Az0.}  
L:&'z:,<  
/* ;>ml@@Z  
**Utility.java A?n5;mvq#  
*/ 7R5ebMW V  
package NetFox; DQu)?Rsk  
,tZL"  
jpYZ) So-  
public class Utility { "+O/OKfR0  
'e<8j  
N6BOUU]  
public Utility() s."N7F  
{ _ j'm2BA O  
{C]tS5$Z  
-0`n(`2  
} \goiW;b  
nZYO}bv\  
//线程睡眠 }vP(SF 6  
public static void sleep(int nSecond) H^o_B1  
{ vY4}vHH2  
try{ ~S~+'V,d  
Thread.sleep(nSecond); a)S6Z  
} <ir]bQT  
catch(Exception e) op-\|<i  
{ Vy/G-IASb  
e.printStackTrace (); ^u90N>Dvq  
} nRX'J5Q m<  
} 4;32 f`  
/i_FA]Go  
//日志 =_N $0  
public static void log(String sMsg) ?c"i V  
{ lOb(XH9  
System.err.println(sMsg); 7&jq  =  
} D\J.6W  
NTK9`#SA  
`{IL.9M!f  
public static void log(int sMsg) =?]S8cth  
{ .n.N.e  
System.err.println(sMsg); q!><:"#[G  
} k MV1$  
}  (t@!0_5  
E}0g  
c% wztP;L  
/* G|t0no\f  
**TestMethod.java ]i1OssV~>  
*/ }=gD,]2x8  
package NetFox; QAl4w)F  
muK.x7zyl  
y= 8SD7P'  
public class TestMethod { 0Q#}:  
ZifDU@J$t  
-I*vl  
public TestMethod() ,j(E>g3  
{ ///xx/weblogic60b2_win.exe Ck m:;q  
try{ {7$jwk  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); v/vPU  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Ui1s ]R  
SiteFileFetch fileFetch = new SiteFileFetch(bean); d|W=_7 z  
fileFetch.start(); 33~8@]b  
} *].qm g%  
catch(Exception e){e.printStackTrace ();} QWt3KW8)  
kPAg *  
|v#D}E  
} QaA?UzB  
k`z]l;:  
"|,KXv')  
public static void main(String[] args) $i!r> .Jo  
{ U ){4W0  
new TestMethod(); [P}mDX  
} DV>;sCMJ %  
} =C|^C3HK  
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