http断点续传简单实现（java)

/* p:))ne:7  
**SiteFileFetch.java #a:C=GV;4  
*/ ij^!TY[0  
package NetFox; G}*B`m  
import java.io.*; 'z:p8"h}  
import java.net.*; rY.:}D  
4dAhJjhgD  
pj6Cvq4bD  
public class SiteFileFetch extends Thread { !8].Z"5J  
T~E83Jw  
l|{<!7a  
SiteInfoBean siteInfoBean = null; //文件信息Bean }vIm C [  
long[] nStartPos; //开始位置 hFv}JQJw<  
long[] nEndPos; //结束位置 m~A/.t%=  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 t=#)3C`Q}  
long nFileLength; //文件长度 I 3PnyNZ  
boolean bFirst = true; //是否第一次取文件 PHkvt!
uH  
boolean bStop = false; //停止标志 "AVc^>  
File tmpFile; //文件下载的临时信息 !T)>q%@ai  
DataOutputStream output; //输出到文件的输出流 3[4]
G@  
P8f-&(  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） mLSAi2Y  
public SiteFileFetch(SiteInfoBean bean) throws IOException +l\Dp  
{ ZWH
`s  
siteInfoBean = bean; Ns_d10rZ.  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); mUxD.;P  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); HN+z7Q8hH  
if(tmpFile.exists ()) G 2##M8:U0  
{ *k -UQLJ  
bFirst = false; _JS'~JO3{  
read_nPos(); &V$R@~x  
} @,vSR
ns  
else Yc}b&  
{ \
T?O.  
nStartPos = new long[bean.getNSplitter()]; ;Xns9  
nEndPos = new long[bean.getNSplitter()]; tti.-  
} $6N.ykJ  

0Qz \"gr  
p*Cbe\  
U<x3=P  
} RD^o&VXO  
2#!D"F  
3h&s=e!  
public void run() Z)<>d.  
{  <_~`)t  
//获得文件长度 cl:YN]BK  
//分割文件 &x3y.}1
 
//实例FileSplitterFetch x8[8z^BV?e  
//启动FileSplitterFetch线程 pH%K4bV)8  
//等待子线程返回 |NqQK
ot1  
try{ !TcjB;q'  
if(bFirst) "F&uk~ b$  
{ 827N?pU$)  
nFileLength = getFileSize(); |8"HTBb\CW  
if(nFileLength == -1) ofJ@\xS  
{ 2rk_ ssvs  
System.err.println("File Length is not known!"); z3,z&Ra  
} %PpB$  
else if(nFileLength == -2) %/7`G-a.B  
{ B^ h!F8DC  
System.err.println("File is not access!"); P06K0Fxf  
} 1<*-,f  
else " 1Bn/Q  
{ Q_Rr5/  
for(int i=0;i<nStartPos.length;i++) OoE@30+  
{ eL.S="  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); &AzA0r&,  
} d 9|u~3  
for(int i=0;i<nEndPos.length-1;i++) PF~&!~S>W  
{ 4D8q
Gti  
nEndPos = nStartPos[i+1]; f`Nu]#i  
} {,m!%FDL  
nEndPos[nEndPos.length-1] = nFileLength; L_(|5#IDw  
} .3[YOM7h  
} |b@-1  
"-9YvB#  
.._wTOSq  
//启动子线程 B*{CcQ<5  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; KQk;:1
hW  
for(int i=0;i<nStartPos.length;i++) $ _zdjzT  
{ wS4zAu  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), F=cO=5Iz  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), g#e"BBm=A  
nStartPos,nEndPos,i); IzG7!K  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); i<l)To-  
fileSplitterFetch.start(); g$ h!:wW  
} X- zg  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _.j KcDf  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); MDRSI g  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", z~F!zigNAc  
nEndPos = " + nFileLength); yuND0,e  
// fileSplitterFetch[nPos.length-1].start(); 3E#acnqn*  
(g 8K?Q  
?/;<32cE,  
//等待子线程结束 T"$"`A"  
//int count = 0; =
T1i(M#  
//是否结束while循环 tw;`H( UZ^  
boolean breakWhile = false;  H='`#l1  
B;EdLs}  
TR#5V@e.m  
while(!bStop) 1:-$mt_*  
{ +m"iJW0  
write_nPos(); QDU^yVa_  
Utility.sleep(500); 7%X$6N-X  
breakWhile = true; -" DI,o  
#JVcl $0Y  
j0Q;OKu  
for(int i=0;i<nStartPos.length;i++) yd2ouCUV  
{ 8g<3J-7Mm  
if(!fileSplitterFetch.bDownOver) ^ H'|iju  
{ $Uzc  
breakWhile = false; @r#>-p  
break; &.d~ M
1Mz  
} )ZT&V I  
} JV@>dK8  
if(breakWhile)
ce@(Ct  
break; -IPc;`<  
2rA`y8g(L  
sx6` g;  
//count++; k1X<jC]P  
//if(count>4) )+{'p0  
// siteStop(); C; ! )<(Vw  
} |XeuqZa  
zdr?1=  
zD?<m J`  
System.err.println("文件下载结束！"); :
z.<||T  
} JIK;/1  
catch(Exception e){e.printStackTrace ();} &D/_@\ 0  
} yHCBf)N7\  
2Ddrxc>48  
hF6EOCY6D  
//获得文件长度 )4j#gHN\  
public long getFileSize() &0M^UvO  
{ 98x(2fCvF(  
int nFileLength = -1; Q+S>nL!*#1  
try{ $AoN,B>  
URL url = new URL(siteInfoBean.getSSiteURL()); =\tg$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); % nJ'r?+h  
httpConnection.setRequestProperty("User-Agent","NetFox"); 07CGHAxJ`  
U:ZklDW  
#\w~(Nm-  
int responseCode=httpConnection.getResponseCode(); Rf7py)  
if(responseCode>=400) ^}9Aq $R  
{ -BR&b2  
processErrorCode(responseCode); Ucv-}oa-?  
return -2; //-2 represent access is error HZR~r:_ i  
} NX$$4<A1  
\s[Uq  
 F`f#gpQ  
String sHeader; R7+k=DI  
UAa2oY&  
2uz<n}IV  
for(int i=1;;i++) yt$V<8a  
{ lepgmQ|oY  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); R(3V !ph  
//Utility.log(in.readLine()); K5b8lc  
sHeader=httpConnection.getHeaderFieldKey(i); X=-pNwO   
if(sHeader!=null) jh9^5"vQ  
{ "{|9Yis=  
if(sHeader.equals("Content-Length")) r%F{1.  
{ 'H:lR1(,  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); H=EvT'g  
break; BB9Z
?}
  
} HnrT;!C~  
} K" Y,K  
else #AE'arT<  
break; 9MVW~V  
} X#IVjc:&L  
} W&)OiZN  
catch(IOException e){e.printStackTrace ();} t[%9z6t  
catch(Exception e){e.printStackTrace ();} DqbN=[!X~n  
[K,&s8N5  
R|Y)ow51  
Utility.log(nFileLength); Bx2E9/S3  
Q']:k}y  
\3Ys8umKq  
return nFileLength; |0BmEF  
} 3Cq17A 9  
(',G Ako  
;DBO  
//保存下载信息（文件指针位置） {}[S,L  
private void write_nPos() .F&\xa{  
{ H"6:!;9,  
try{ P6
dIU/w  
output = new DataOutputStream(new FileOutputStream(tmpFile)); !ZHPR:k|  
output.writeInt(nStartPos.length); FX 0
^I 0  
for(int i=0;i<nStartPos.length;i++) n~k;9`  
{ (yn!~El3  
// output.writeLong(nPos); L3'o2@$  
output.writeLong(fileSplitterFetch.nStartPos); 5YJ
LR;  
output.writeLong(fileSplitterFetch.nEndPos); Lr_+)l  
} @zW'!Ol  
output.close(); d2Bn`VI  
} 1P@&xcvS\  
catch(IOException e){e.printStackTrace ();} J8~3LE )G  
catch(Exception e){e.printStackTrace ();} WADNr8.  
} b2duC  
PKty'}
KF  
3@_je)s  
//读取保存的下载信息（文件指针位置）  Jcy  
private void read_nPos() UIIR$,XB  
{ 3L/>=I{5  
try{ JmtU>2z\
 
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); w*OZ1|  
int nCount = input.readInt(); D\bW' k]!  
nStartPos = new long[nCount]; i` n,{{x&4  
nEndPos = new long[nCount]; rV54-K;`0  
for(int i=0;i<nStartPos.length;i++) pu=Q;E_f[  
{ l0 rZril  
nStartPos = input.readLong(); bw ' yX  
nEndPos = input.readLong(); xLPyV&j-  
} 4L(axjMYU  
input.close(); O\-cLI<h2  
} 48Z{wV,  
catch(IOException e){e.printStackTrace ();} kbOdg:  
catch(Exception e){e.printStackTrace ();} LEKN%2  
} WEZ(4ah  
zH.DyD5T;  
SzMh}xDh2  
private void processErrorCode(int nErrorCode) H@.j@l  
{ !Yz~HO,u+  
System.err.println("Error Code : " + nErrorCode); 'cu( Sd}  
} Gmf.lHr$%  
y/
'2WO[  
It!PP1$   
//停止文件下载 >x eKO2o  
public void siteStop() p3qlVE  
{ 4hr;k0sD  
bStop = true; !Z`~=n3bk  
for(int i=0;i<nStartPos.length;i++) :OUNZDL  
fileSplitterFetch.splitterStop(); .TSj8,  
n'U*8ID  
"
9>~O`l,  
} IF(W[J  
} y}R{A6X)  
//负责部分文件的抓取 Ot`jjZ&  
**FileSplitterFetch.java @
q}.BcSg  
*/ j_H{_Ug  
package NetFox; s 'u6Ep/V  
^8a,gA
8.  
ck){N?y  
import java.io.*; ?sfA/9"  
import java.net.*; Nc,"wA  
2kp.Ljt@  
kVCSFF*  
public class FileSplitterFetch extends Thread { |[)t4A"}  
=hH>]$J[  
kS%FV;9>(  
String sURL; //File URL G29PdmY$<  
long nStartPos; //File Snippet Start Position O$V 6QJ  
long nEndPos; //File Snippet End Position @(,k%84z  
int nThreadID; //Thread's ID hbD@B.PD  
boolean bDownOver = false; //Downing is over -SGR)  
boolean bStop = false; //Stop identical Hp
C|dtro  
FileAccessI fileAccessI = null; //File Access interface Ks(+['*S  
. Zrt/;  
pLE|#58I  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 2G=Bav\n+  
{ NIY0f@1z-  
this.sURL = sURL; >2_BL5<S  
this.nStartPos = nStart; MS)#S&  
this.nEndPos = nEnd; J}Bg<[n  
nThreadID = id; ka0T|$ u(s  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 3J7TWOJVw  
} :_~UO^*h  
:Ag]^ot  
z| Hl*T  
public void run() (wdE@/V  
{ #I'W[\l~+  
while(nStartPos < nEndPos && !bStop) `(vgBz`e[  
{ x}[/A;N  
<UQaRI[55  
/V+&#N  
try{ tO~DA>R  
URL url = new URL(sURL); 7[rn ,8@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); UeIu -[R  
httpConnection.setRequestProperty("User-Agent","NetFox"); >0k7#q}O  
String sProperty = "bytes="+nStartPos+"-"; 7hZCh,O  
httpConnection.setRequestProperty("RANGE",sProperty); 2Vxr  
Utility.log(sProperty); @NWjYHM[`  
2`Ub;Nn29  
4_TxFulX.  
InputStream input = httpConnection.getInputStream(); WO?EzQ ?  
//logResponseHead(httpConnection); R
]VY PNns  
zW,m3~XX:  
O8(;=exA  
byte[] b = new byte[1024]; I\&..e0l  
int nRead; q(M[ij  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) .h~M&d!  
{ qAUqlSP5  
nStartPos += fileAccessI.write(b,0,nRead); \K
.i8f,  
//if(nThreadID == 1) IHZ WNT2  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7Vr .&`l  
} iA3d[%tBb  
j0B, \A  
yv=LT~  
Utility.log("Thread " + nThreadID + " is over!"); DmEmv/N=  
bDownOver = true; &W:Wv,3
 
//nPos = fileAccessI.write (b,0,nRead); tSV}BM,  
} ~O;!y%  
catch(Exception e){e.printStackTrace ();} Z$ Fh4  
} >*(4evU  
} 'g$~ij ;x  
Q:&,8h[  
~Z!xS  
//打印回应的头信息 <6Q]FH!6  
public void logResponseHead(HttpURLConnection con) W
p/!;  
{ *[*LtyCQt4  
for(int i=1;;i++) R/R[r> 1)6  
{ \[Op:^S  
String header=con.getHeaderFieldKey(i); i;;CU9`E2q  
if(header!=null) dE!{=u(!i  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); B(wk $2  
Utility.log(header+" : "+con.getHeaderField(header)); W"?|OQ'  
else <?kr"[cQeP  
break; fQi7e5  
} $IX>o&S@|  
} v|t_kNX;v*  
ge)g?IP4  
-l8n0P1+  
public void splitterStop() tuo'4%]i  
{ M7^PWC  
bStop = true; [X0Wfb}{  
} JM!rop^  
3P3x^NI  
XeX0\L')R  
} :BKY#uH~  
>gM|:FG  
V|zz
j[c  
/* I gcVl/d  
**FileAccess.java IE.JIi^w  
*//文件访问(定位，写) d!7cIYVZ  
package NetFox; KT~J@];Fb  
import java.io.*; 5|f[evQj<S  
7r 07N'  
7D\#1h  
public class FileAccessI implements Serializable{ Rcs7 'q5  
]IMBRZQqb  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 fqZqPcT
0  
RandomAccessFile oSavedFile; hAi50q;z  
long nPos; )[yM4QFl  
u6IEBYG ((  
\!j{&cJ  
public FileAccessI() throws IOException S9d+#6rn  
{ gm~Ka%O|F  
this("",0); NX&mEz  
} km,}7^?F0r  
mV^+`GWvo  
hu%rp{m^,  
public FileAccessI(String sName,long nPos) throws IOException cG1-.,r  
{ oNY;z-QK  
oSavedFile = new RandomAccessFile(sName,"rw"); \g< M\3f  
this.nPos = nPos; PeEf=3  
oSavedFile.seek(nPos); VFz(U)._  
} 2#~5[PtP^  
z #c)Q  
3ddH@Y|  
public synchronized int write(byte[] b,int nStart,int nLen) TzmoyY  
{ = q9>~E{}  
int n = -1; LL|$M;S  
try{ Z7% |'E R  
oSavedFile.write(b,nStart,nLen); -1d2Qed  
n = nLen; Bi/=c
I  
} 4]0|fi3}>  
catch(IOException e) 5jD2%"YUV  
{ 9$8B)x  
e.printStackTrace (); +:pjQ1LsJ  
} ~f0Bu:A)  
NF&R}7L  
gfG Mu0FjB  
return n; )pLde_ k  
} Zc(uK{3W-  
wG6>.`:  
hd1(q33  
} iIji[>qz  
O`5PX(J1&  
Sx?IpcPSm  
/* jR`q  y<  
**SiteInfoBean.java
Tm~a&p  
*/ L^uO.eI"m  
package NetFox; $
50A!h
 
e}Cp;c]=  
"- @{ )  
public class SiteInfoBean { fa9c!xDt  
3Xyu`zS&  
wR +C>  
private String sSiteURL; //Site's URL *>,8+S33r{  
private String sFilePath; //Saved File's Path :td6Mywl  
private String sFileName; //Saved File's Name y<jW7GNt  
private int nSplitter; //Count of Splited Downloading File Z8$n-0Ww  
d?^bCf+<  
{eA0I\c(C  
public SiteInfoBean() @T[}]e  
{//nSplitter的缺省值为5 aal5d_Y  
//default value of nSplitter is 5 aF1i!Z  
this("","","",5); !PJD+SrG  
} v MTWtc!6  
\9TCP;{  
H"lq!C`  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) kSoa'  
{ }bIbMEMn  
sSiteURL= sURL; ee}&~%  
sFilePath = sPath; E uxD,(  
sFileName = sName; s"*ZQ0OaD  
this.nSplitter = nSpiltter; 8$9<z  
?CIMez(h  
vpu20?E>5z  
} FJJ+*3(  
_tDSG]  
a<-NB9o~v  
public String getSSiteURL() N9@@n:JT  
{ uLXMEx<^  
return sSiteURL; ^x(BZol
km  
} E-jL"H*  
V("@z<b|  
gFlUMfKh  
public void setSSiteURL(String value) `Mx&,;x  
{ at"-X?`d  
sSiteURL = value; e]F4w(*=  
} A (z lX_  
t@(S=i7}-  
3>;zk#b2  
public String getSFilePath() MQ7d IUs  
{ bso l>M[<  
return sFilePath; 'Vq_/g!?1  
} x[l_dmq  
.:gZ*ks~  
zzOc # /  
public void setSFilePath(String value) nP`#z&C  
{ _"Yi>.{]  
sFilePath = value; Mg3>/!  
} i i&kfy  
sk*AlSlM  
\yDr  
public String getSFileName() A/pp
r.  
{ RMJq9a  
return sFileName; lS<T|:gz@  
} AA$+ayzx9{  
nGb%mlb  
h# R;'9*V  
public void setSFileName(String value) j$v2_q  
{ $&D$Uc`U>  
sFileName = value; vX|i5P0)8  
} 0'&N?rS  
h\C" ti2  
 %T9'dcM  
public int getNSplitter() fsd,q?{a:  
{ J3/2>N]/}  
return nSplitter; !F]7q]g  
} @~WSWlQW  
{[B^~Y>Lr  
g=iPv3MG  
public void setNSplitter(int nCount) =e\E{K'f@  
{ &oi*]:<FNe  
nSplitter = nCount; !<`}mE!:  
} e'%"G{(D  
} PEA<H0  
2|a@,TW}-  
tR`'( *wh  
/* x@^Kd*fo  
**Utility.java OJX* :Q  
*/ "h.-qQGU%  
package NetFox; B,rpc\_  
"p,TYjT?R  
xnz(hz6  
public class Utility { Th"0Cc)  
)1de<# qM  
uh,~CvXU]  
public Utility() A\Ax5eeL  
{ dt -EY  
^uZ!e+   
"`A@_;At`  
} @log=^  
_Nze="Pt  
//线程睡眠 eAkC-Fm  
public static void sleep(int nSecond) ]*fiLYe9  
{
&+"-'7
  
try{ -TL `nGF  
Thread.sleep(nSecond); @C\>P49  
} 47]?7GU,  
catch(Exception e) uLr9*nxd  
{ <\0+*`">g  
e.printStackTrace (); LHy-y%?i  
} X0G Mly  
} fK-tvP0}*  
lawjGI  
//日志 e[5=?p@|  
public static void log(String sMsg) \TchRSe  
{ >|Xy'ZR  
System.err.println(sMsg); kd0~@rPL  
} b \pjjb[  
4i<V^go"  
BNA`Cc1VV  
public static void log(int sMsg) YGAB2`!U  
{ zp
PzXQv]/  
System.err.println(sMsg); z xe6M~+  
} q ERdQ~M,  
} QY$Z,#V)  
l;u_4`1H  
Mq
A%hlq  
/* |ji={  
**TestMethod.java ?U}Ml]0~  
*/ bKAR}JM&  
package NetFox; fDq`.ZW)s  
c5KJ_Nfi  
o>3g<-ul  
public class TestMethod { #HgXTC  
oh>X/uj  
DM*GvBdR  
public TestMethod() nMz~.^Q-  
{ ///xx/weblogic60b2_win.exe B Q)1)8r  
try{ y7&8P8R  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); :)cn&'l(S  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); P:`tL)W_  
SiteFileFetch fileFetch = new SiteFileFetch(bean); e+_~a8 -|  
fileFetch.start(); 7&I+mw/X  
} RU r0K#]  
catch(Exception e){e.printStackTrace ();} y2XeD=_'  
CBj&8#8Z  
*F ya qJ)  
} V={`k$p  
fi/[(RBG  
Kzv*`  
public static void main(String[] args) sg=mkkD!g  
{ =%wwepz6  
new TestMethod(); }Y{aVn&C  
} L%3m_'6QP  
} xt{f+c@P  
点击下载更多相关资料