http断点续传简单实现（java)

/* fOkB|E]  
**SiteFileFetch.java ZKco  
*/ Z&Ao;=Gp1  
package NetFox; F|&=\Q  
import java.io.*; f%cbBx^;  
import java.net.*; 5B,HJax  
>J>|+W  
z1`z k0  
public class SiteFileFetch extends Thread { @(_f}SgfE  
F-I\x  
8@J5tFJ&%  
SiteInfoBean siteInfoBean = null; //文件信息Bean ![CF >:e  
long[] nStartPos; //开始位置 n9N'}z  
long[] nEndPos; //结束位置 QB|D_?]  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 N_qKIc_R  
long nFileLength; //文件长度 |{JJ2c\W  
boolean bFirst = true; //是否第一次取文件 qk=0ovUzg  
boolean bStop = false; //停止标志 ?QfomTT  
File tmpFile; //文件下载的临时信息 %2t#>}If!  
DataOutputStream output; //输出到文件的输出流 g"o),$tm  
&nX,)"  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） RRBBz7:~  
public SiteFileFetch(SiteInfoBean bean) throws IOException Oxq} dX7S  
{ ?7CHHk  
siteInfoBean = bean; JHIXTy__  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); z(dX<  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); B@@j-  
if(tmpFile.exists ()) <rAk"R^  
{ q26%Z)'nf  
bFirst = false; 6A \Z221E  
read_nPos(); ps=+wg?]  
} /'g"Ys?3  
else 1ps_zn(  
{ At=l>  
nStartPos = new long[bean.getNSplitter()]; xPJ kadu  
nEndPos = new long[bean.getNSplitter()]; X*Dt<i};v  
} 5xF R7%_&  
@mu2,%  
?B`Yq\L)  
#ZS8}X*S  
} n]+v Eu|  
Y^P'slY{%  
RS`~i8e'  
public void run() 06peo d  
{ }4M4D/=  
//获得文件长度 maopr$r  
//分割文件 OlI{VszR  
//实例FileSplitterFetch A7X-),D  
//启动FileSplitterFetch线程 7TN94@kCF  
//等待子线程返回 SXI3y  
try{ Ap[}[:U  
if(bFirst) baVSQtda  
{ oI6o$C  
nFileLength = getFileSize(); ~0~f  
if(nFileLength == -1) HD95>%  
{ :$"L;"  
System.err.println("File Length is not known!"); 4;hgi[  
} ; 3WA-nn  
else if(nFileLength == -2) kW=GFj)L  
{ YN@4.&RP  
System.err.println("File is not access!"); _^)<d$R<  
} td6$w:SN,l  
else T)NnWEB  
{ C*I~14  
for(int i=0;i<nStartPos.length;i++) #
=hI}%n  
{ G$"$k=[  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); /\_wDi+#  
} @Ja8~5:  
for(int i=0;i<nEndPos.length-1;i++) AqzPwO^  
{ o?$
B<Cb"  
nEndPos = nStartPos[i+1]; _@47h86Q  
} 01nbR+e  
nEndPos[nEndPos.length-1] = nFileLength; #+- /0{HT  
} -b4#/q+bb+  
} M9/c8zZ  
!awfxH0  
{G D<s))  
//启动子线程 NZyGC Vh@  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 6O>GVJ
bw  
for(int i=0;i<nStartPos.length;i++) t TAqln|  
{ hF!t{ Lf3  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~Zc=FP:1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), W5_:Q@  
nStartPos,nEndPos,i); @L-3&~=  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @KhDQ0v]5  
fileSplitterFetch.start(); %`P6a38j  
} v){&g5djl  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %\ i 7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); SJtQK-%wK>  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", bnz2\C9^  
nEndPos = " + nFileLength); na&?Cw  
// fileSplitterFetch[nPos.length-1].start(); ]mN'Qoc  
5xm^[o2#y  
. _5g<aw;  
//等待子线程结束 p. eq N  
//int count = 0; 3U<\s=1?X  
//是否结束while循环 N;9m&)@JR'  
boolean breakWhile = false; 0Jh^((i*  
' {L5 3cH=  
+h}>UK\  
while(!bStop) vap,)kILF  
{ +ou ]|  
write_nPos(); UvSvgDMl  
Utility.sleep(500); K 9ytot  
breakWhile = true; TX96 ^EoH  
Gk9Y{  
3iHUG^sLW  
for(int i=0;i<nStartPos.length;i++) y\DR,$Py  
{ cuO)cj]@e  
if(!fileSplitterFetch.bDownOver) SO#NWa<0|  
{ !1tHg Z2\  
breakWhile = false; 0,a;N%K-  
break; <n4T*  
} Q`"gKBN1  
} prvvr;Ib  
if(breakWhile) 7cGc`7  
break; /STFXR1@.u  
,9I %t%sb  
wo($7'.@  
//count++; u%J04vG"D  
//if(count>4) la7VeFT  
// siteStop(); ]d$:R`;  
} M]O _L  
jN\} l|;q  
:}\w2W E[  
System.err.println("文件下载结束！"); w-%V9]J1  
} Y40`~  
catch(Exception e){e.printStackTrace ();} ,m| :U  
} 'D ,efTq  
x;&01@m.  
sb Wn1 T U  
//获得文件长度 <l/QS3M  
public long getFileSize() v71j1Q}6  
{ :+%"kgJNL  
int nFileLength = -1; \K$
9r=!(  
try{ F)ak5  
URL url = new URL(siteInfoBean.getSSiteURL()); Arg604V3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +gZg7]
!Z  
httpConnection.setRequestProperty("User-Agent","NetFox"); !^{0vFWE  
W(h].'N  
.TcsXYL.`,  
int responseCode=httpConnection.getResponseCode(); = GN1l[X  
if(responseCode>=400) BI\ )vr$  
{ ~*OQRl6F  
processErrorCode(responseCode); (twwDI  
return -2; //-2 represent access is error td*1  
} J!O{.
v  
)Gf"#TM[  
97 Oi}   
String sHeader; HeV
6=&#  
~#z8Q{!O  
tPv3nh  
for(int i=1;;i++) F];"d0O#5  
{ i2. +E&3v  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); x$:>W3?T=^  
//Utility.log(in.readLine()); V}?*kx~T2C  
sHeader=httpConnection.getHeaderFieldKey(i); (v<l9}!  
if(sHeader!=null) 6n[O8^  
{ ^HJvT)e4  
if(sHeader.equals("Content-Length")) sGg=4(D  
{ lD`@{A  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); (OA-Mgyc  
break; W6~aL\[  
} 'o D31\@I  
} $1aJdZC7  
else ]i$
<<u  
break;
>K|<hzZ  
} I-?PTr  
} .[%
^~q7  
catch(IOException e){e.printStackTrace ();} =t[hsl  
catch(Exception e){e.printStackTrace ();} I},]Y~Y3  
9'1XZpM1  
]]sy+$@~  
Utility.log(nFileLength);  fP+RuZ  
g8=j{]~C  
1L~y!il  
return nFileLength; C)x>/Qr~  
} $&fP%p  
'?j[hhfB-  
xIOYwVC  
//保存下载信息（文件指针位置） w'[^RZW:j  
private void write_nPos() sBN"eHg  
{ +c7e[hz  
try{ 3pzp6o2  
output = new DataOutputStream(new FileOutputStream(tmpFile)); s5`CV$bz  
output.writeInt(nStartPos.length); T^z  
for(int i=0;i<nStartPos.length;i++) [-ONs
 
{ %4bGI/\/  
// output.writeLong(nPos); [h5~1N
 
output.writeLong(fileSplitterFetch.nStartPos); 4q9+a7@  
output.writeLong(fileSplitterFetch.nEndPos); Z-md$=+}w  
} |:H 9#=  
output.close(); ~__r-z  
} 9Dat oi  
catch(IOException e){e.printStackTrace ();} `_MRf[Z}  
catch(Exception e){e.printStackTrace ();} ";kwh8wB  
} [6ycs[{!  
)9pRT dT  
^ gy"$F3{`  
//读取保存的下载信息（文件指针位置） TnuaP'xZ  
private void read_nPos() QPD[uJ(I  
{ 4!vovt{  
try{ U"qR6  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); !7rk>YrY  
int nCount = input.readInt(); >'eY/>n{  
nStartPos = new long[nCount]; 8I>'xf  
nEndPos = new long[nCount]; rtjUHhF  
for(int i=0;i<nStartPos.length;i++) q0m>NA   
{ u5'jIq
lU  
nStartPos = input.readLong(); zfsGf'U  
nEndPos = input.readLong(); YcRo>:I  
} 5bj9S  
input.close(); 6"o,)e/z  
} F `4a0~?  
catch(IOException e){e.printStackTrace ();} sahXPl%;U  
catch(Exception e){e.printStackTrace ();} lH%%iYBM  
} Ii.?| u  
Il4R R  
za,JCI  
private void processErrorCode(int nErrorCode) ov 'g'1}  
{ VYo2m  
System.err.println("Error Code : " + nErrorCode); r|ID]}w  
} &6@#W]_  
x/d(" Bb  
mNQ~9OJ1  
//停止文件下载 5/E7@h ,  
public void siteStop() {W' 9k  
{ n:8<Ijrh  
bStop = true; h,fC-+H5  
for(int i=0;i<nStartPos.length;i++) IaHu$` v  
fileSplitterFetch.splitterStop(); Y& p ~8  
"9v4'"  
W<c95Q
D.  
} EyDH-}Y  
} q; ?Kmk  
//负责部分文件的抓取 xTGdh  
**FileSplitterFetch.java gucgNpX  
*/ KW@][*\uC  
package NetFox; '}, 8x?  
!+)5?o  
Qn!KL0w  
import java.io.*; Q`zW[Y&]  
import java.net.*; WNK)IC~c  
S\S31pYT  
dcH@$D@~S  
public class FileSplitterFetch extends Thread { QFg{.F?3q>  
?ZAynZF|#  
jr2wK?LbB  
String sURL; //File URL 6 =H]p1p~O  
long nStartPos; //File Snippet Start Position
..fbRt  
long nEndPos; //File Snippet End Position hQ80R B  
int nThreadID; //Thread's ID >$:_M*5  
boolean bDownOver = false; //Downing is over ^|lw~F  
boolean bStop = false; //Stop identical {%BPP{OFk  
FileAccessI fileAccessI = null; //File Access interface F T$x#>  
w{"ro~9o  
1~
ZFkcV_C  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException *3A)s O  
{ H$k2S5,,z  
this.sURL = sURL; `9&~fWu  
this.nStartPos = nStart; L(q~
%  
this.nEndPos = nEnd; '&!:5R59  
nThreadID = id; 2o<aEn&7|e  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 .H}#,pQ}l  
} .YlhK=d4  
$g!iy'4n*  
q^eLbivVE  
public void run() A(D3wctdr  
{ :I(d-,C  
while(nStartPos < nEndPos && !bStop) m9mkZ:r(kV  
{ Lk]W?  
62 9g_P)  
K)#6&\0tT  
try{ eZ|_wB'r  
URL url = new URL(sURL); i'3)5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;$g?W"  
httpConnection.setRequestProperty("User-Agent","NetFox");
$Ned1@%[  
String sProperty = "bytes="+nStartPos+"-"; F
nCMr_  
httpConnection.setRequestProperty("RANGE",sProperty); dYZB> OS  
Utility.log(sProperty); .s%dP.P:i1  
5"&=BD~D  
u,JUMH]@  
InputStream input = httpConnection.getInputStream(); l9z{pZ\KM  
//logResponseHead(httpConnection); ]Q -.Y-J/O  
>9,LN;Ic
 
i?D)XXB85  
byte[] b = new byte[1024]; I_is3y0  
int nRead; tR<L9h  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) S{nBQB<  
{ e
QJyO9$G  
nStartPos += fileAccessI.write(b,0,nRead); XB<Q A>dLh  
//if(nThreadID == 1) 
oA+'9/UY  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6E$ET5p&l  
} /hYFOZ  
=%d.wH?dZ/  
FKy2C:R(]  
Utility.log("Thread " + nThreadID + " is over!"); +&[X7r<  
bDownOver = true; H^XTzE  
//nPos = fileAccessI.write (b,0,nRead); 3 (F+\4aRm  
} 9P
*p{O{_  
catch(Exception e){e.printStackTrace ();}  g^))  
} NdB:2P  
} ?~X^YxWsY  
W#foVAi .  
I\f\k>;  
//打印回应的头信息 .RPh#FI6J  
public void logResponseHead(HttpURLConnection con) Hv</Xam  
{ l%#z  
for(int i=1;;i++) DpIk$X  
{ +TN*6V{D  
String header=con.getHeaderFieldKey(i); "\qm+g  
if(header!=null) QG 1vP.K  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 6SEq 2  
Utility.log(header+" : "+con.getHeaderField(header)); ztC>*SX  
else z q@"qnr  
break; -H$C3V3]  
} c3N,P<#  
} [fg-"-+:M  
2U) 0k*  
v\R-G  
public void splitterStop() '~E=V:6  
{ AQ)J|i  
bStop = true; }^azj>p5  
} Q+dLWFI  
\vgM`32<  
yK0iW  
} Q
1P=A:*]9  
Mh=j^ [4Q  
 uE'Kk8  
/*
{YEGy  
**FileAccess.java %18%T{|$e  
*//文件访问(定位，写) !BN@cc[%  
package NetFox; z0?IQzR^T  
import java.io.*; ^
=y%s  
y>]Yq-  
> mEB,  
public class FileAccessI implements Serializable{ VVk8z6W  
{`V ^V_  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Jm,
tN/o*  
RandomAccessFile oSavedFile; WU~L#Ih.V  
long nPos; Nq#B4Zx  
A }d\ND  
ageTv/  
public FileAccessI() throws IOException (1Klj+"p%  
{ y0,>_MS  
this("",0); 2 @t?@,c  
}
hx8.  
@j=rSS  
wpcqgc  
public FileAccessI(String sName,long nPos) throws IOException 6!v$"u|[!'  
{ yw*| HT  
oSavedFile = new RandomAccessFile(sName,"rw"); cnj32H^+  
this.nPos = nPos; "8/BVW^bv  
oSavedFile.seek(nPos); ,&s%^I+CC  
} Gq{);fq  
w9C?wT  
HH|N~pBJB  
public synchronized int write(byte[] b,int nStart,int nLen) J6Nhpzp  
{ LQJC]*b1  
int n = -1; NB3ar&.$S  
try{ fiW2m=h_  
oSavedFile.write(b,nStart,nLen); O8/r-?4.  
n = nLen; 4c@_u
8  
} ;jFUtG  
catch(IOException e) kn}bb*eZ  
{ C&;m56  
e.printStackTrace (); @Wa,  
} E6fs&  
,Gy2$mglB  
KU;J2Kt  
return n; b 4A1M  
} a2B9 .;F  
$.3J1DU  
S>y}|MG  
} eJE!\ucS2W  
lFa?l\jLXZ  
cRP!O|I`]  
/* hpo*5Va  
**SiteInfoBean.java Ys8D|
HIk  
*/ dUkZ_<5''  
package NetFox; c=33O,_  
Fz2CXC  
#Ht;5p>5  
public class SiteInfoBean { %XH%.Ps/  
IgPU^?sp  
tkW7wP;  
private String sSiteURL; //Site's URL B* k|NZj  
private String sFilePath; //Saved File's Path Q; BD|95nl  
private String sFileName; //Saved File's Name R{q<V uN  
private int nSplitter; //Count of Splited Downloading File SyIi*dH  
W$:D#;jz`h  
L | #"Yn  
public SiteInfoBean() Tfw5i,{  
{//nSplitter的缺省值为5 lKV7IoJ&;  
//default value of nSplitter is 5 aMaqlqf  
this("","","",5); !r4
B1fX  
} OZ}o||/Rc  
'25zb+-  
%S<))G  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) m.c2y6<=  
{ 1l\.>H\E  
sSiteURL= sURL; :
b<<  
sFilePath = sPath; P7*?E*   
sFileName = sName; Iy Vmz'  
this.nSplitter = nSpiltter; )TwA?kj  
n1rJ^q-G  
;TboS-Y  
} CQ'4 ".7  
+q] kpkG!  
s"(F({J  
public String getSSiteURL() jV(b?r)eT{  
{ bDnT><eH  
return sSiteURL; pXK-,7-  
} _vUId?9@+e  
Y.E]U!i*  
=r^Pu|  
public void setSSiteURL(String value) wPaM
YxO/  
{ rvPmd%nk-  
sSiteURL = value; QPKY9.Rvv  
} 3#Xv))w1  
=/(R_BFna  
-"}nm!j /5  
public String getSFilePath() %[BOe4[  
{ _A6e|(.ll  
return sFilePath; 2E@g#:3  
} ;;mr?'R  
?F9c6$|  
ab>>W!r@!  
public void setSFilePath(String value) i?6#>;f  
{ Em/? 4&
 
sFilePath = value; +lw1v  
} sDjbvC0  
(4C_Ft*~j  
L+.-aB2!d  
public String getSFileName() :@^
T^  
{ sNsWz.DLT#  
return sFileName; @%I-15Jz  
} <+AvbqDe  
I04c7cDp  
5N$O  
public void setSFileName(String value) }nMp.7b  
{ DVw 04ay%  
sFileName = value; @MfZP~T+  
} fDKV`  
Vs, &  
B0m2SUC,H  
public int getNSplitter() `bjPOA(g  
{ ah15,<j  
return nSplitter; \)2~oN  
} i=\`
f& B  
$TFWum9wO  
r^;1Sm  
public void setNSplitter(int nCount) }/aqh;W  
{ !5K5;M_Ih"  
nSplitter = nCount; gS.,V!#t  
} T49^  
} y#-~L-J_R  
lnt}l  
$zJ!L  
/* ;oVFcZSA  
**Utility.java /`b`ai8`8  
*/ $mut v=IO  
package NetFox; [*d<LAnuWP  
?pkGejcQ  
z{A~d  
public class Utility { dWVm'd  
Z1R{'@Y0Z  
y1kI^B  
public Utility() z;Dc#SZnO(  
{ xGt>X77  
b*<Fi#x1=  
b2UqN]{  
} epxbTJfc  
[Ee <SB{  
//线程睡眠 c>L#(D\\  
public static void sleep(int nSecond) @T&w nk  
{ ~o8x3`CoF  
try{ X?n($z/{  
Thread.sleep(nSecond); q;9OqArq  
} T!QAcO  
catch(Exception e) M6"a w6  
{ :djbZ><  
e.printStackTrace (); i} ?\K>BWq  
} 1|oE3  
} (\CH;c
-@  
PQ(/1v   
//日志 TJz} 8-#t  
public static void log(String sMsg) _!^2A3c<  
{ ~A,(D-  
System.err.println(sMsg); Hzojv<c  
} mjJ/rx{kbw  
M`Q
K{$1p  
/R[PsB  
public static void log(int sMsg) QUz_2rN^  
{  @zSj&4  
System.err.println(sMsg); \_AoG8B  
} A4f;ftB  
} x)-n[Fu  
NU.YL1  
qWb8"  
/* AJ)N?s-=  
**TestMethod.java |#x]/AXa0/  
*/ hpzDQ6-Y  
package NetFox; Rj~y#m  
zN7Ou .  
GW!%DT  
public class TestMethod { P B"nf|pm  
]vq=~x  
,Zb_Pu   
public TestMethod() )C%S`d<%,  
{ ///xx/weblogic60b2_win.exe ANXN.V  
try{ rwY{QBSf  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); d?>pcT)G_  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 48[b1#q]  
SiteFileFetch fileFetch = new SiteFileFetch(bean); js)I%Z  
fileFetch.start(); yr34&M(a  
} iK9#{1BpML  
catch(Exception e){e.printStackTrace ();} E9:p A5H-j  
Z~HLa  
T*zy^we  
} LGPg\g`  
x}H%NzR  
8|-064i>  
public static void main(String[] args) P*9L3R*=N  
{ Pc=:j(  
new TestMethod(); 5c-'m?k  
} ~ ]^<*R  
} }
BLT2]y0  
点击下载更多相关资料