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http断点续传简单实现(java)

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/* I#Y22&G1  
**SiteFileFetch.java X Swl Tg  
*/ g#pr yYz  
package NetFox; W dK #ZOR  
import java.io.*; ?DS@e@lx  
import java.net.*; f M :]&  
(?1y4M  
ouvA~/5  
public class SiteFileFetch extends Thread { %ufN8w!p  
Af~$TyX  
t:x\kp  
SiteInfoBean siteInfoBean = null; //文件信息Bean %8B}Cb&2c  
long[] nStartPos; //开始位置 A7Cm5>Y_S  
long[] nEndPos; //结束位置 kYP#SH/  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 CAig ]=2'  
long nFileLength; //文件长度 :S{BbQ){]  
boolean bFirst = true; //是否第一次取文件 \j}ZB<.>  
boolean bStop = false; //停止标志 K^)Eb(4  
File tmpFile; //文件下载的临时信息 FJ GlP&v<  
DataOutputStream output; //输出到文件的输出流 !I{0 _b{  
p}z<Fdu 0  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) hn7# L  
public SiteFileFetch(SiteInfoBean bean) throws IOException ~f&E7su-6+  
{ + /4A  
siteInfoBean = bean; 64 wv<r]5j  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); )Yh+c=6 ?  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); i(rL|d+'  
if(tmpFile.exists ()) >;aWz%-  
{ z3{G9Np  
bFirst = false; n:I,PS0H<  
read_nPos(); c)6m$5]  
} fZGX}T<)p-  
else .ljnDL/  
{ pGP7nw_g  
nStartPos = new long[bean.getNSplitter()]; jh?H.;**  
nEndPos = new long[bean.getNSplitter()]; Y #ap*  
} :DK {Vg6  
8?B!2  
K e;E1S-~  
.FP$m?  
} q<x/Hat)  
g>E LGG |Q  
TM__I\+Q  
public void run() n$A9_cHF7  
{ imhwY#D  
//获得文件长度 M!siK2  
//分割文件 58}U^IW  
//实例FileSplitterFetch 6IN e@  
//启动FileSplitterFetch线程 wQ:)KjhHH  
//等待子线程返回 +[6G5cH  
try{ /wGM#sFH  
if(bFirst) '|6]_   
{ @(EAq<5{  
nFileLength = getFileSize(); 1SQ3-WU s  
if(nFileLength == -1) h6L&\~pf  
{ D%[mWc@1I  
System.err.println("File Length is not known!"); 1 fp?  
} F$y$'Rzu_B  
else if(nFileLength == -2) NR$3%0 nC6  
{ W 8<&gh+  
System.err.println("File is not access!"); Co9^OF-k  
} ;>%r9pz ~  
else rK 8lBy:<  
{ 9!ngy*\x  
for(int i=0;i<nStartPos.length;i++) RN1y^`  
{ ].avItg  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); r8t}TU>C  
} j7Yu>cr  
for(int i=0;i<nEndPos.length-1;i++) h ]5(].  
{ Q^P}\wb>  
nEndPos = nStartPos[i+1]; 9 &dtd  
} S3C]AhW;  
nEndPos[nEndPos.length-1] = nFileLength; )rIwqUgp6\  
} j.[.1G*("  
} zF`0J  
>.Pnkx*  
L8@f-Kk  
//启动子线程 c`)\Pb/O  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; KWbI'}_z  
for(int i=0;i<nStartPos.length;i++) ;HfmzY(  
{ ~p6 V,Q  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), EgEa1l!NSQ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), &C5_g$Ma.Z  
nStartPos,nEndPos,i); IV~>I-rd  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +zqn<<9  
fileSplitterFetch.start(); 7uqzm  
} A;q9rD,_  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "m):Y;9iQ?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ZuzEg*lb  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Y sC>i`n9  
nEndPos = " + nFileLength); ,C\i^>=  
// fileSplitterFetch[nPos.length-1].start(); Gq)]s'r2  
#Qw0&kM7I  
.fqN|[>  
//等待子线程结束 c1(RuP:S  
//int count = 0; dZl5Ic  
//是否结束while循环 )N{Pw$l_  
boolean breakWhile = false; G{~J|{t\yz  
(Bb5?fw  
'`[&}R  
while(!bStop) oi7@s0@  
{ E:_ZA  
write_nPos(); n t;m+by  
Utility.sleep(500); 3)wN))VBX  
breakWhile = true; b<[Or^X ]  
*uRBzO}  
PA{PD.4Du  
for(int i=0;i<nStartPos.length;i++) ^]Y> [[  
{ 2 0h} [Q(  
if(!fileSplitterFetch.bDownOver) 4&lv6`G `  
{ D(op)]8  
breakWhile = false; C\3rJy(VJ  
break; FW;?s+Uyx  
} ] Jg&VXrH  
} S&5&];Ag  
if(breakWhile) Wx%H%FeK  
break; *\a4wZ6<3  
wD}l$ & +  
& bm 1Fz  
//count++; BN5[,J  
//if(count>4) |)DGkOtd  
// siteStop(); dh\'<|\K  
} 8mrUotjS  
F@jZ ho  
tmYz R%i  
System.err.println("文件下载结束!"); ;W )Y OT  
} <]t%8GB2V  
catch(Exception e){e.printStackTrace ();} z]y.W`i   
} kPG-hD  
%g$o/A$  
?#G$=4;i  
//获得文件长度 LKB$,pR~1l  
public long getFileSize() @l5"nBs<_:  
{ ,.8KN<A2]'  
int nFileLength = -1; :uS\3toj  
try{ ;%9|k U  
URL url = new URL(siteInfoBean.getSSiteURL()); Y;M|D'y+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ] IQ&>z}<  
httpConnection.setRequestProperty("User-Agent","NetFox"); a$OE0zn`  
N0Lw}@p  
'3tCH)s  
int responseCode=httpConnection.getResponseCode(); Tn e4  
if(responseCode>=400) Wq&if_  
{ k@J&IJ  
processErrorCode(responseCode); ,AFu C <  
return -2; //-2 represent access is error BoWg0*5xb  
} xwq (N_  
nPl?K:(  
ql{ OETn#  
String sHeader; #&aqKV Y  
'[:D$q;  
Cctu|^V  
for(int i=1;;i++) }@+0/W?\.  
{ :U%W%  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); $k%2J9O  
//Utility.log(in.readLine()); %s|Ely)  
sHeader=httpConnection.getHeaderFieldKey(i); 9~XA q^e  
if(sHeader!=null) "?xHlYj@+  
{ (m/G(wg  
if(sHeader.equals("Content-Length")) ,!y$qVg'\f  
{ sIGMA$EK  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); xs bE TP?  
break; %T%sGDCV  
} KL57# gV  
} <0&*9ZeD  
else JIOR4'9  
break; zKJ#`OhT  
} )23H1  
} [D4SW#  
catch(IOException e){e.printStackTrace ();} BLiF 5  
catch(Exception e){e.printStackTrace ();} k"iOB-@B+  
_op}1   
X51:  
Utility.log(nFileLength); |&)dh<  
{@{']Y  
9vc2VB$  
return nFileLength; {qJ1ko)$  
} jcf7n`L  
`0gyr(fES  
,i`,Oy(BI  
//保存下载信息(文件指针位置) A[{yCn`tM  
private void write_nPos() F/kWHVHU[  
{ 29] G^f>  
try{ EUX\^c]n  
output = new DataOutputStream(new FileOutputStream(tmpFile)); )' cMYC  
output.writeInt(nStartPos.length); @:vwb\azVD  
for(int i=0;i<nStartPos.length;i++)  DA,?}  
{ S g![Lsj  
// output.writeLong(nPos); Ka V8[|Gn,  
output.writeLong(fileSplitterFetch.nStartPos); 4!yzsPJL  
output.writeLong(fileSplitterFetch.nEndPos); !F'YDjTot  
} *P=VFP  
output.close(); .?sx&2R2  
} jLm ;ty2;  
catch(IOException e){e.printStackTrace ();} ~HsJUro  
catch(Exception e){e.printStackTrace ();} ^k">A:E2  
} z$. 88 ^  
O m2d .7S  
x g  
//读取保存的下载信息(文件指针位置) YPk fx  
private void read_nPos() 7[XRd9a5(  
{ >KhOz[Zg  
try{ bK&+5t&  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); <`r>h  
int nCount = input.readInt(); h3 }OX{k  
nStartPos = new long[nCount]; VjZ|$k  
nEndPos = new long[nCount]; 4vB<fPN  
for(int i=0;i<nStartPos.length;i++) Eo]xNn/g  
{ B[?Ng}<g`  
nStartPos = input.readLong(); 7~.9=I'A  
nEndPos = input.readLong(); `+:`_4  
} ]Q)OL  
input.close(); v`Oc,  
} <R=Zs[9M1  
catch(IOException e){e.printStackTrace ();} R!gEwTk  
catch(Exception e){e.printStackTrace ();} h J)h\  
} .4!=p*Y  
tFOhL9T  
cIOlhX@  
private void processErrorCode(int nErrorCode) p6!x=cW  
{ ` 7V]y -  
System.err.println("Error Code : " + nErrorCode); R8Fv{7]c  
} 'e'cb>GnA  
Cj lk  
z_4J)?3  
//停止文件下载 BuXqd[;K%  
public void siteStop() $}<e|3_  
{ PIS2Ed]  
bStop = true; VQOezQs\  
for(int i=0;i<nStartPos.length;i++) <$Yd0hxjU  
fileSplitterFetch.splitterStop(); oV78Hq6  
59;KQ  
1f=gYzuO)  
} pG;U2wE  
} w@w(-F!%l  
//负责部分文件的抓取 t&e{_|i#+  
**FileSplitterFetch.java ~6LN6}~|.  
*/ )|# sfHv7  
package NetFox; &`2)V;t  
5M*:}*  
]Gq !`O1  
import java.io.*; }`m/bgtFX  
import java.net.*; /R wjCUf  
0{-q#/  
_u QOHwn  
public class FileSplitterFetch extends Thread { tf`^v6m%]  
L$M9w  
Se =`N  
String sURL; //File URL ,.FxIl ]  
long nStartPos; //File Snippet Start Position %6f*{G w  
long nEndPos; //File Snippet End Position /aZ`[m2  
int nThreadID; //Thread's ID z*% q@]ym  
boolean bDownOver = false; //Downing is over smo~7;  
boolean bStop = false; //Stop identical fVpMx4&F   
FileAccessI fileAccessI = null; //File Access interface ; kI134i=  
ge8ZsaiU  
amY!qg0P*  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException {&1/V  
{ f9{Rb/l!BQ  
this.sURL = sURL; [Y| t]^M  
this.nStartPos = nStart; Z4 =GMXj  
this.nEndPos = nEnd; JY(WK@  
nThreadID = id; 1#+S+g@#  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 p H2Sbs:Tk  
} v):Or'$~M  
;>7De8v@@  
Q*~]h;6\{d  
public void run() z!9-:  
{ >e$PP8&i_T  
while(nStartPos < nEndPos && !bStop) .eVG:tl\  
{ t;\Y{`  
7WZ+T"O{I  
ePo}y])2  
try{ { 9q4)R}G  
URL url = new URL(sURL); ##"HF  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Oxd]y1  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]~3V}z,T*  
String sProperty = "bytes="+nStartPos+"-"; -6B4sZpzD  
httpConnection.setRequestProperty("RANGE",sProperty); 8FY?!C  
Utility.log(sProperty); 6qnzBA7  
$yNS pNmT0  
C1QA)E['V  
InputStream input = httpConnection.getInputStream(); 0flRh)[J  
//logResponseHead(httpConnection); $*fMR,~t&  
|@4' <4t  
7hPY_W y  
byte[] b = new byte[1024]; zy }$i?  
int nRead; sd|).;s}  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 1p=]hC  
{ qY!Zt_Be6  
nStartPos += fileAccessI.write(b,0,nRead); HN|%9{VeB  
//if(nThreadID == 1) 5$C-9  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 11;MN  
} #AQV(;r7@  
/IMFO:c  
$qj2w"'  
Utility.log("Thread " + nThreadID + " is over!"); I b5rqU\  
bDownOver = true; Ig>(m49d  
//nPos = fileAccessI.write (b,0,nRead); %1+4_g9  
} Xc&9Glf  
catch(Exception e){e.printStackTrace ();} )+9Uoe~6  
} h@ry y\9  
} EXqE~afm2  
}0Ed ]  
e$rZ5X  
//打印回应的头信息 b d!Y\OD  
public void logResponseHead(HttpURLConnection con) },-H"Qs  
{ I-l_TpM)  
for(int i=1;;i++) &{t,'[ u  
{ M9%$lCl   
String header=con.getHeaderFieldKey(i); 5:_}zu|!u  
if(header!=null) e+fN6v5pU  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 1bwOm hkS  
Utility.log(header+" : "+con.getHeaderField(header)); ^^ixa1H<  
else ' S/gmn  
break; fe_5LC"  
} 3%b6{ie/=  
} GnJt0{  
G]&qx`TBK  
}Jj}%XxKs  
public void splitterStop() nAlQ7 '  
{ KVa  
bStop = true; bV3|6]k^  
} R.<g3"Lm>  
 rjnrju+  
e$Pj.>-<=  
} mQ"-,mMI  
pOoEI+t  
DZtsy!xA  
/* [ub e6  
**FileAccess.java KF:78C  
*//文件访问(定位,写) \YrUe1  
package NetFox; ,r_Gf5c  
import java.io.*; bW(0Ng  
4;2uW#dG"  
e~"U @8xk~  
public class FileAccessI implements Serializable{ (X*^dO  
M kXmA`cP  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Y(Hs#Kn{  
RandomAccessFile oSavedFile; QQc -Ya!v  
long nPos; 1EX;MW-p<T  
E}Uc7G  
*MW\^PR?  
public FileAccessI() throws IOException >uEzw4w  
{ &s>Jb?_5Mx  
this("",0); S)"Jf?  
} ,f?*{Q2  
{(Es(Sb}c  
k)TpnH! "  
public FileAccessI(String sName,long nPos) throws IOException XfIJ4ZM5  
{ 5~DJWi,  
oSavedFile = new RandomAccessFile(sName,"rw"); Xne1gms  
this.nPos = nPos;  uHRsFlw  
oSavedFile.seek(nPos); !&@615Vtw  
} WcbiqxK7-  
t\O16O7S  
}4X0epPp;:  
public synchronized int write(byte[] b,int nStart,int nLen) rEz^  
{ zX i 'kB  
int n = -1; i SQu#p@  
try{ 1s;S aq+  
oSavedFile.write(b,nStart,nLen); ~v6D#@%A  
n = nLen; @oGcuE  
} < I``&>  
catch(IOException e) DzRFMYBR  
{ +Vdpy (  
e.printStackTrace (); X2'0PXv>!  
} Q22 GIr  
<9b &<K:  
V>3X\)qu  
return n; )0k53-h&  
} @IZnFHN  
)fAUum  
ql~J8G9  
} e&>2 n  
2MK-5 Kg  
dqcL]e  
/* 8H`[*|{'  
**SiteInfoBean.java MiX43Pk]  
*/ RT8 ?7xFc  
package NetFox; w&.a QGR#  
Rf% a'b  
 05^h"  
public class SiteInfoBean { yaX iE_.  
qmP].sA  
B`sAk %  
private String sSiteURL; //Site's URL tO&^>&;5  
private String sFilePath; //Saved File's Path DVeE1Q  
private String sFileName; //Saved File's Name asqV~n  
private int nSplitter; //Count of Splited Downloading File iN.n8MN=I  
zKK9r~ M  
bW:!5"_{H  
public SiteInfoBean() ]I6  J7A[  
{//nSplitter的缺省值为5 |1Z)E+q*:  
//default value of nSplitter is 5 =i3n42M#  
this("","","",5); 5`_SN74o  
} dgP3@`YS  
J9 I:Q<;  
u]G\H!Wk Q  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) A?0Nm{O;3v  
{  f)<6  
sSiteURL= sURL; K.yb ^dg5  
sFilePath = sPath; [PbOfxxgA  
sFileName = sName; o;R I*I  
this.nSplitter = nSpiltter; kSo"Ak!  
$NO&YLS@  
;9'OOz|+1  
} ,iwp,=h=  
M'l ;:  
8JUwf  
public String getSSiteURL() -%4,@ x`  
{ ,wPr"U+7  
return sSiteURL; #Rr%:\*  
} >KKMcTOYY  
{fp[BF  
NyuQMU  
public void setSSiteURL(String value) S`]k>' l  
{ Q=dy<kg']  
sSiteURL = value; -D~%|).'  
} |vzl. ^"-  
h@wgd~X9  
HkVB80hv  
public String getSFilePath() !Xw5<J3L-  
{ Uoix  
return sFilePath; f`66h M[  
} .5{ab\_af  
wwcBsJ1{  
l}M!8:UzU  
public void setSFilePath(String value) 7Fsay+a  
{ dUdT7ixo  
sFilePath = value; |! "eWTJ  
} Yz)qcU  
}SCM I4\  
q- d:TMkc  
public String getSFileName() ?|Zx!z ($  
{ ""~ajy  
return sFileName; UJ6v(:z <  
} ?!/kZM_ts  
/; 85i6  
jmW7)jT8:  
public void setSFileName(String value) sdmT  
{ ENY+^7  
sFileName = value;  #:%/(j  
} @pU)_d!pJ  
a C)!T  
Wo=jskBrQ  
public int getNSplitter() ;i:d+!3XwC  
{ y4fdq7i~}9  
return nSplitter; "g8M0[7e3  
} uY'HT|@:{  
NQ2E  
)w%!{hn  
public void setNSplitter(int nCount) VVOd]2{  
{ l1Fc>:o{  
nSplitter = nCount; 5l*&>C[(i  
} iOO)Q\  
} iAU@Yg`pt  
du^J2m{f  
bA->{OPkT  
/* (Ep\Z 6*  
**Utility.java 7D5]G-}x.  
*/ #Mw8^FST  
package NetFox; i~J'%a<Qp  
f& '  
VP]%Hni]  
public class Utility { HyWCMK6b  
Th%Sjgsn  
HHsmLo c4  
public Utility() Z?QC!bWb  
{ ^y%T~dLkp'  
[cp+i^f  
L;I]OC^J  
} JaGtsi9%.  
~$?ZK]YOrx  
//线程睡眠 XOS[No~  
public static void sleep(int nSecond) I2 P@L?h  
{ E^eVvP4uC@  
try{ z' >_Mc6  
Thread.sleep(nSecond); E~oOKQ5W  
} Jg| XH L)  
catch(Exception e) Jze:[MYS  
{ 9-*uPK]m9  
e.printStackTrace (); s!7y  
} }U"&8%PZr  
} (JFWna0@  
yaH Zt`Y  
//日志 B_m8{44zM  
public static void log(String sMsg) NHZz _a=  
{ !d0kV,F:  
System.err.println(sMsg); I&W=Q[m  
} QB'aON\S  
Hja3a{LH  
ut7zVp<"  
public static void log(int sMsg) 81 sG  
{ fS78>*K  
System.err.println(sMsg); j+  0I-p  
} v #j$;  
} +!.^zp21  
Qn)a/w-  
XuM'_FN`A<  
/* Qjv}$`M  
**TestMethod.java ;@Y;g(bw:  
*/ GDiBl*D  
package NetFox; 1NA.nw.  
%aVq+kC h  
68WO~*  
public class TestMethod { lp%pbx43s  
IKilr'  
Vb]=B~^`  
public TestMethod() E92KP?i  
{ ///xx/weblogic60b2_win.exe [j/9neaye  
try{ z/@slT  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); A@{PZ   
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); K:# I  
SiteFileFetch fileFetch = new SiteFileFetch(bean); =R$u[~Xl2X  
fileFetch.start(); Iom'Y@x  
} nazZ*lC  
catch(Exception e){e.printStackTrace ();} A0 C,tVd  
<FkFs{(t  
]Wlco  
} gu.}M:u  
!9VY|&fHe  
hH8oyIC  
public static void main(String[] args) q Y? j#fzi  
{ 4*cEag   
new TestMethod(); =|y9UlsD  
} nBSYsp{  
} wc^tgE  
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