http断点续传简单实现（java)

/* T|8:_4/l  
**SiteFileFetch.java |Fz ^(US  
*/ ;4U"y8PVTh  
package NetFox; d~AL4~}  
import java.io.*; q
u1+.z=|  
import java.net.*; ? cXW\A(  
3&>0'h  
CY*o"@-o5)  
public class SiteFileFetch extends Thread { 76bMy4re  

|h}4J  
,-hbwd~M  
SiteInfoBean siteInfoBean = null; //文件信息Bean r;xy/*%Mtj  
long[] nStartPos; //开始位置 m}u)C&2>  
long[] nEndPos; //结束位置 Vpne-PW  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 =&6sU{j*  
long nFileLength; //文件长度 S)g:+P  
boolean bFirst = true; //是否第一次取文件 }zks@7kf  
boolean bStop = false; //停止标志 >+Ig<}p  
File tmpFile; //文件下载的临时信息 T60pw  
DataOutputStream output; //输出到文件的输出流 &8w# 4*W  
x!fG%o~h  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） }tw+8YWkz  
public SiteFileFetch(SiteInfoBean bean) throws IOException 7*j!ZUzp  
{ zz[fkH3  
siteInfoBean = bean; T>]T=  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 6_<~]W&  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); S.4+tf7+  
if(tmpFile.exists ()) 3
<Zp+rD  
{ i(pHJP:a:  
bFirst = false; 3:MJKS02OD  
read_nPos(); ~uH_y
-  
} 1cv~_jFh  
else L-}J=n\  
{ t/Y0e#9,  
nStartPos = new long[bean.getNSplitter()]; jQzl!f1c3  
nEndPos = new long[bean.getNSplitter()]; zPND$3&'  
} u -P !2vT  
 *<W8j[?  
mM72>1~L*  
BO#tn{(#  
} ,5"(m?[m  
\7i_2|w  
5LB{b]w7m  
public void run() #H w(w  
{ 9M;t4Um  
//获得文件长度 @`dg:P*[  
//分割文件 k`Ifl)  
//实例FileSplitterFetch ,bXZ<RY$  
//启动FileSplitterFetch线程 ^e_LnJ+  
//等待子线程返回 3q}j"x?  
try{ oR&z,%0wMK  
if(bFirst) ] re=8s6  
{ o^vX\a?`u  
nFileLength = getFileSize(); u30D`sky  
if(nFileLength == -1) k1q/L|')  
{ jZzTnmm&?  
System.err.println("File Length is not known!"); ^APtV6
g  
} @2/|rq  
else if(nFileLength == -2) I7oA7@zv  
{ zk FX[-'O  
System.err.println("File is not access!"); 8rH6L:]S  
} ];LFv5"  
else N o6!gZ1  
{ M&j|5UH%.  
for(int i=0;i<nStartPos.length;i++) YND}P9 h  
{ Zt!A!Afu  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); NC%hsg^0/  
} ^sD M>OHp  
for(int i=0;i<nEndPos.length-1;i++) WJOoDS!i  
{ ^iMr't\b  
nEndPos = nStartPos[i+1]; qK a}O*  
} Q+=pP'cV  
nEndPos[nEndPos.length-1] = nFileLength; & "&s,  
} );h(D!D,  
} uqC#h,~ 0  
3&+dyhL'w  
Bz/Vzc(  
//启动子线程 z}ar$}T  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];  f\<r1  
for(int i=0;i<nStartPos.length;i++) i]%f94  
{ ;Zd_2CZ  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {siOa%;*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), }_]AQN$'G  
nStartPos,nEndPos,i); c4Zpt%:}h  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); yV!4Im.>  
fileSplitterFetch.start(); 2K91E}  
} Hw]E#S  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {R!yw`#^B  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ;o!p9MEpz;  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", sgp.;h'  
nEndPos = " + nFileLength); "l56?@-x  
// fileSplitterFetch[nPos.length-1].start(); '`P%;/z  
L/"};VI  
KGy3#r;Q
 
//等待子线程结束 [s>3xWZ+a  
//int count = 0; il5C9ql$  
//是否结束while循环 ]nhh|q9r{  
boolean breakWhile = false; [tpiU'/Zl  
*y*tI}  
*p}mn
#ru-  
while(!bStop) /I`TN5~  
{ a;HAuy`M x  
write_nPos(); fwFJe(.  
Utility.sleep(500); ~T1W-ig4[*  
breakWhile = true;  + Q-b}  
exb} y  
2I-d.{  
for(int i=0;i<nStartPos.length;i++) 
b/'bhE=  
{ ^c\O,*:  
if(!fileSplitterFetch.bDownOver) 1>J.kQR^  
{ kv:9Fm\$  
breakWhile = false; +~^S'6yB  
break; XN df  
} ku]5sd >b  
} ]8p{A#1  
if(breakWhile) Mn0.!J "  
break; *2/Jg'de  
@{y'_fw  
X1^VdJE  
//count++; yfG;OnkZ  
//if(count>4) *g(d}C!  
// siteStop(); -r\jIO_  
} PtfG~$h?  
LDlYLsF9  
P<]U  
System.err.println("文件下载结束！"); N*Aw-\Bk  
} A,~3oQV  
catch(Exception e){e.printStackTrace ();}
'UhoKb_p  
}  FOiwA.:0  
l9.`2d]o
 
W:r[o%B  
//获得文件长度 Cj0r2^`  
public long getFileSize() Af|h*V4Xu  
{ o*KAS
@&  
int nFileLength = -1; cIU2qFn[  
try{ ziM{2Fs>  
URL url = new URL(siteInfoBean.getSSiteURL()); =3bk=vy  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); n8,%<!F^  
httpConnection.setRequestProperty("User-Agent","NetFox"); HWjJ.;k}a  
1w>[&#7  
{<-s&%/r  
int responseCode=httpConnection.getResponseCode(); I-#!mFl  
if(responseCode>=400) O/~T+T%  
{ Id=
20og  
processErrorCode(responseCode); /uw@o9`~2-  
return -2; //-2 represent access is error [+[W\6
 
} c~T{;  
v^C\ GDH  
(PpY*jKR  
String sHeader; ?
'V78N sA  
<exCK*G  
#(]D]f[@  
for(int i=1;;i++) >@N.jw>#T  
{ ^A ]4  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); x.1=QF{!  
//Utility.log(in.readLine()); +wQ5m8E  
sHeader=httpConnection.getHeaderFieldKey(i); LW=qX%o{  
if(sHeader!=null) TXB!Y!RG#  
{ YdI6|o@vc  
if(sHeader.equals("Content-Length")) u$w.'lK  
{ ckX8eg!f  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); #hBqgG:>  
break; U#f*  
} Gb^63.}  
} SrA6}kS  
else Md6u4c  
break; >Iij,J5i  
} {A}T^q!m]  
} sD3Ts;k  
catch(IOException e){e.printStackTrace ();} C?. ;3 h  
catch(Exception e){e.printStackTrace ();} RrLiH>  
mpYBMSLM  
&wNr2PHd#  
Utility.log(nFileLength); Pr>$m{ Z  
puOMtCI  
-IIrrY O  
return nFileLength; 5T/+pC$e=  
} 2`i&6iz  
@#wG)TA  
@.e4~qz\  
//保存下载信息（文件指针位置） fTmJDUv+  
private void write_nPos() y1`%3\  
{ Mx}r! Q  
try{ %YxKWZ/?  
output = new DataOutputStream(new FileOutputStream(tmpFile)); `@Z$+  
output.writeInt(nStartPos.length); [<+T
@"y  
for(int i=0;i<nStartPos.length;i++) qRT5|\l  
{ aR6~r^jB  
// output.writeLong(nPos); K*~xy bA  
output.writeLong(fileSplitterFetch.nStartPos); Xk:x=4u&  
output.writeLong(fileSplitterFetch.nEndPos); ''2:ZXX  
} z%fjG}z  
output.close(); L<  
} HmXxM:[4;  
catch(IOException e){e.printStackTrace ();} :|l0x a  
catch(Exception e){e.printStackTrace ();} d3oRan}z  
} >>=zkPy  
o<|u4r={s  
"+
Ks#  
//读取保存的下载信息（文件指针位置） lyowH{.N"3  
private void read_nPos() :t;\`gQoS  
{ a;i}<n7  
try{ i39_( )X  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); a#0*#&?7@  
int nCount = input.readInt(); iR4"I7J  
nStartPos = new long[nCount]; f`}u9!jVR  
nEndPos = new long[nCount]; e{: -N  
for(int i=0;i<nStartPos.length;i++) $7-4pW$y  
{ /0L]Pf;  
nStartPos = input.readLong(); p3%cb?G%w  
nEndPos = input.readLong(); sI)jqHZG  
} }Ej^"T:H_;  
input.close(); jJ>I*'w  
} gd)VL}
k  
catch(IOException e){e.printStackTrace ();} 'mU\X!- 4<  
catch(Exception e){e.printStackTrace ();} nQw, /Lk  
} BQMo*I>I  
4YMUkwh  
,|O|gh$s  
private void processErrorCode(int nErrorCode) 3qfQlqJ&3  
{ <t*3w  
System.err.println("Error Code : " + nErrorCode); eET1f8B=L  
} u_=>r_J[b  
7r3EMX\#Qm  
f+Bv8 g  
//停止文件下载 uCFpH5>  
public void siteStop() cMUmJ

H  
{ )q+;+J`>  
bStop = true; Yu9(qRK  
for(int i=0;i<nStartPos.length;i++) xqVIw!J?/}  
fileSplitterFetch.splitterStop(); EU7mP MxJ  
~:A=o?V2  
gdBH\K(\  
} 0Q/BTT%X  
} +_fxV|}P  
//负责部分文件的抓取 w##$SaT
I  
**FileSplitterFetch.java &ZPyZj  
*/ }!vJ+  
package NetFox; 4H%Ai(F}_  
|P=-m-W  
$Jy1=/W&  
import java.io.*; tw]Q5:6  
import java.net.*; "IdN*K  
>x1?t  
#c1c%27cmm  
public class FileSplitterFetch extends Thread { pL'+sW  
x_KJCU  
G Y ]bw  
String sURL; //File URL &14Er,K  
long nStartPos; //File Snippet Start Position %wux#"8  
long nEndPos; //File Snippet End Position =qTmFszT  
int nThreadID; //Thread's ID $]]|#}J  
boolean bDownOver = false; //Downing is over /4-6V d"8  
boolean bStop = false; //Stop identical sZPA(N?  
FileAccessI fileAccessI = null; //File Access interface [,ns/*f3R  
d#3
E'8  
|Xk>a7X  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ~Wj. 4b*  
{ 6<C|O-  
this.sURL = sURL; 2~*.X^dR  
this.nStartPos = nStart; 0=KyupwXC  
this.nEndPos = nEnd; 8d"Ff  
nThreadID = id; <@2g.+9  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 EJ`"npU  
} gflu!
C6  
>FM2T<.;  
-|A`+1-R+  
public void run() YeCS`IXm  
{ 4XXuj  
while(nStartPos < nEndPos && !bStop) S U$U  
{ if
y}xv  
$Q< >MB7  
|.Y}2>{  
try{ P+nd?:cz  
URL url = new URL(sURL); aqzIMOAf  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;/g Bjp]H  
httpConnection.setRequestProperty("User-Agent","NetFox"); a$ FO5%o  
String sProperty = "bytes="+nStartPos+"-"; {]6Pd`-  
httpConnection.setRequestProperty("RANGE",sProperty); /KH,11)yc  
Utility.log(sProperty); jou741  
m3E`kW|  
ev;R; 0<  
InputStream input = httpConnection.getInputStream(); wz=c#}0dB  
//logResponseHead(httpConnection); Ryrvu1 k  
Zw<\^1  
DqGm
 
byte[] b = new byte[1024]; ^J-\s_)"  
int nRead; Doj>Irj?7  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) qz<>9n@o  
{ MYVgi{
 
nStartPos += fileAccessI.write(b,0,nRead);
TcM;6h`  
//if(nThreadID == 1) I c 2R\}q  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); . +  
} r0fxEYze&  
&nyJ :?  
NP^j5|A*"  
Utility.log("Thread " + nThreadID + " is over!"); Yy3g7!K5E  
bDownOver = true; 4V9S~^v|  
//nPos = fileAccessI.write (b,0,nRead); q71~Y:7f  
} Hlj_oDL  
catch(Exception e){e.printStackTrace ();} 7lH3)9G;  
} kI|7o>}<   
} $"[5]{'J  
zt|DHVy  
r(VznKSx  
//打印回应的头信息 yrVk$k#6}  
public void logResponseHead(HttpURLConnection con) s7>a  
{ r#X6jU  
for(int i=1;;i++) rCp'O\@S  
{ fS#I?!*}  
String header=con.getHeaderFieldKey(i); C_ 4(-OWq  
if(header!=null) $WS?/H0C  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); g/f^|:  
Utility.log(header+" : "+con.getHeaderField(header)); #M~6A^)  
else _(%;O:i  
break; O=E?m=FR"  
} WAqH*LB  
} QRKr2:o{  
`+0K~k|DC  
qb1JE[2F  
public void splitterStop() Ew
X:^1f  
{ `ZhS=ezgr  
bStop = true; w1J%%//(h  
} !<#,M9 EA&  
Sxzt|{  
uoi~JF  
} cfhiZ~."T  
' |Ia-RbX  
rMEM$1vPU  
/* Nm4 h  
**FileAccess.java GA+#'R  
*//文件访问(定位，写) 'S#D+oF(1~  
package NetFox; gO%oA} !i  
import java.io.*; w)7s]Ld  
GX0S9s  
caD)'FSES  
public class FileAccessI implements Serializable{ $*q^7ME  
L<W2a(  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 HVH<S  
RandomAccessFile oSavedFile; i)=dp!Bx^  
long nPos; `RHhc{  
A3eus
 
`/RcE.5n\@  
public FileAccessI() throws IOException w 21g&  
{ @5tGI U;1  
this("",0); HA`qU  
} ul^VGW>i  
\#7@"~<  
n@_aTY  
public FileAccessI(String sName,long nPos) throws IOException L=9^Y/8Q  
{ kO/]mNLG  
oSavedFile = new RandomAccessFile(sName,"rw"); 8Os: SC@Q  
this.nPos = nPos; O/Mx$Q3re  
oSavedFile.seek(nPos); H7CWAQPfj  
} (8Q*NZ  
wq:"/2p1  
)SzgMbF6  
public synchronized int write(byte[] b,int nStart,int nLen) V(
wANvH  
{ m<I>NYfE  
int n = -1; H$rNT/C  
try{ WY$c^av<  
oSavedFile.write(b,nStart,nLen); %4^NX@1jV  
n = nLen; @&9,0x  
} #u/5 nm  
catch(IOException e) U0@Qc}y  
{ {66P-4Ev(  
e.printStackTrace (); }NY! z^  
} ^SWV!rrg  
YckLz01jh  
W0k7(v)  
return n; -)9aY.  
} >)6k)$x%%  
"U|u-ka8B  
H8V@KB  
} |Ng}ZLBM  
L "5;<  
b^R_8x  
/* =^mBj?(V7  
**SiteInfoBean.java x:iLBYf  
*/ CPci 'SO  
package NetFox; +o|I@7f  
o?/fObV@(  
y`a]##1j$M  
public class SiteInfoBean { _g%,/y 9y  
S7(tGD  
z<OfSS_]R  
private String sSiteURL; //Site's URL *:"p*qV*  
private String sFilePath; //Saved File's Path K;*B$2Z#k  
private String sFileName; //Saved File's Name 5 51p* B2  
private int nSplitter; //Count of Splited Downloading File .f9&.H#  
8fA8@O}  
_18Aek  
public SiteInfoBean() @*=eqO  
{//nSplitter的缺省值为5 @dc4v_9  
//default value of nSplitter is 5 !@[@&.  
this("","","",5); K'oy6$B  
} $_O;yz  
r#NR3_@9  
;8g[y"I  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) G;AJBs>Y}  
{ an)Z.x  
sSiteURL= sURL; %mRnJgV5k  
sFilePath = sPath; 4^7*R  
sFileName = sName; VJS1{n=;k  
this.nSplitter = nSpiltter; I]Ws
  
r#(*x 2~,  
y*T@_on5  
} Dop,_94G  
KqvM5$3  
KJW^pAj$B  
public String getSSiteURL() z-m:l;  
{ Ygc.0VKMR  
return sSiteURL; E
n ]"^*  
} ,'byJlw_pv  
2#@-t{\3-p  
Id{Ix(O  
public void setSSiteURL(String value) Cf.(/5X  
{ h3V; J  
sSiteURL = value; GRAPv|u9[  
} BHR(B]EI  
P.3kcZ   
WD|pG;Gq  
public String getSFilePath() & sgzSX  
{ <*z9:jzQ  
return sFilePath; $.O(K4S  
} Hyc19|  
#J1a `}x  
M62V NYt  
public void setSFilePath(String value) \s+<
w3  
{ 1.jW^sM  
sFilePath = value; rS6iZp,  
} W99Fb+$I  
/:C"n|P7Z  
[ub,&j^  
public String getSFileName() a Se.]_  
{ .>h|e_E  
return sFileName; va#~ \%`  
} JWH}0+1*  
rP#@*{";  
&W|
'rA'r  
public void setSFileName(String value) 85Ms*[g  
{ /T*{Mo{B  
sFileName = value; cUS2*7h  
} ilpg()  
P'Rr5Xa  
RC\TPG/8!  
public int getNSplitter() */?L_\7  
{ lzl4pnj  
return nSplitter; )e]:T4*vo  
} qdUlT*fw  
@{XN}tWDOp  
e`8z1r  
public void setNSplitter(int nCount) P,tN
;c  
{ zKgW9j<(  
nSplitter = nCount; yvNYY
p2r  
} ,CwhpW\Y  
} `4l>%S8y:  
cCWOGd  
AB+Zc ]  
/* hoSk  
**Utility.java ?mgr#UN  
*/ m0
/J3  
package NetFox; v }P~g  
UDuKG\_J<y  
_VR4|)1g  
public class Utility { cF,u)+2b|6  
ZOS{F_2.  
hFQC%N.'  
public Utility() j>0S3P,  
{ |!IJ/ivEgw  
QZQ@C#PR;  
c.jnPVf:  
} TSE(K
t  
Zj`eR\7~  
//线程睡眠 M
(oW;^B  
public static void sleep(int nSecond) RTF{<,E.UX  
{ ?86h:9  
try{ ilFM+x@  
Thread.sleep(nSecond); a ,W5T8  
} @/|sOF;8W  
catch(Exception e) {SK8Mdn  
{ Fi*6ud\n!  
e.printStackTrace (); P`U5kNN  
} tDIzn`$z  
} =X+DC&]%!  
X3a:*1N  
//日志 ,0#OA*0B  
public static void log(String sMsg) $o]suF;3  
{ 7B7I'{d  
System.err.println(sMsg); azOp53zR  
} & qd:o}  
~49+$.2  
F!aYK2  
public static void log(int sMsg) {L<t6A  
{ DYzVV(_J"  
System.err.println(sMsg); %NxNZe  
} |fRajuA;  
} ;&:UxmTf  
E 8,53$  
Mc@p~5!M  
/* G_dia6  
**TestMethod.java 5Vut4px  
*/ _#N~$  
package NetFox; '@pav>UPD  
iW |]-Ba\  
p8F|]6Z  
public class TestMethod { :%!SzI?  
>1joCG~  
w(mn@Qc  
public TestMethod() ;B1}so1]  
{ ///xx/weblogic60b2_win.exe XtQ3$0{*%  
try{ ` qt4~rD  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); q:?g?v  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); urtcSq&H'  
SiteFileFetch fileFetch = new SiteFileFetch(bean);
!4*@H  
fileFetch.start(); u# %7>=  
} faMUd#o&  
catch(Exception e){e.printStackTrace ();}
jp[QA\  
+S3'ms  
X)nOY*  
} {P = {)  
6] <?+#uQ  
ef53~x  
public static void main(String[] args) sav2.w  
{ @br%:Nt  
new TestMethod(); ^//N-?Fx  
} 6j` waK  
} T-<^mX[}  
点击下载更多相关资料