http断点续传简单实现（java)

/* gQ'zW  
**SiteFileFetch.java >O*IQ[r-  
*/ 8u6:=fxb  
package NetFox; VH9dleZ  
import java.io.*; /{+y2.{j  
import java.net.*; mRL"nC  
95 ;x=ju  
B@&4i?yJ  
public class SiteFileFetch extends Thread { CG0 M  
DI:]GED"=  
NdMb)l)m  
SiteInfoBean siteInfoBean = null; //文件信息Bean pR(jglm7-  
long[] nStartPos; //开始位置 NidIVbT.A  
long[] nEndPos; //结束位置 v|uAzM{73  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 `|{-+m  
long nFileLength; //文件长度 oW ::h
B  
boolean bFirst = true; //是否第一次取文件 s5CXwM6cx  
boolean bStop = false; //停止标志 7 n8"/0kc:  
File tmpFile; //文件下载的临时信息 fI&t]  
DataOutputStream output; //输出到文件的输出流 06O2:5zF  
Q.l}NtHwV  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） uJzG|$;  
public SiteFileFetch(SiteInfoBean bean) throws IOException TW)c#P43K  
{ (s.0PO`  
siteInfoBean = bean; c6h.iBJ
'  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ,K9*%rW)  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); WI-&x '  
if(tmpFile.exists ()) lAb*fafQy  
{ 2oVSn"  
bFirst = false; O(fM?4w  
read_nPos(); w>pq+og&  
} \-h%O jf4  
else h2Ld[xvCu%  
{ )
J2mM  
nStartPos = new long[bean.getNSplitter()];  gbF+WE  
nEndPos = new long[bean.getNSplitter()]; 'u*DA|HC  
} ]V^iN=(_5  
Xe$I7iKD  
RRmz"j>  
ULs\+U  
} ;_c;0)  

]Lf{Jboo  
e?0l"  
public void run()
Q6PHpaj  
{ 4!Fo$9  
//获得文件长度 cpL7!>^=  
//分割文件 '@o;-'b  
//实例FileSplitterFetch ]<ldWL  
//启动FileSplitterFetch线程 }AB,8n`  
//等待子线程返回 4ezEW|S  
try{ _ TiuY  
if(bFirst) wH>a~C:  
{ VCV"S>aVf  
nFileLength = getFileSize(); Q-_N2W?  
if(nFileLength == -1) CAfGH!l!  
{ ((H^2KJn  
System.err.println("File Length is not known!"); u(@$a4z  
} '))0Lh l  
else if(nFileLength == -2) L-ET<'u  
{ ??^5;P{yx  
System.err.println("File is not access!"); xN5)  
} `, OG7hg  
else @5N]ZQ9  
{ smlpD3?va  
for(int i=0;i<nStartPos.length;i++) ;rF\kX&Jh  
{ 2;k*@k-t  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Sdp&jZY  
} x-$&g*<  
for(int i=0;i<nEndPos.length-1;i++) VJeu8ZJ.  
{ VEWi_;=J1  
nEndPos = nStartPos[i+1]; \:b3~%Fz  
} >")Tf6zw&  
nEndPos[nEndPos.length-1] = nFileLength; z>LUH  
} Nv#t:J9f  
} ;Y00TGU  
2^r<{0@n  
6</xL9#/  
//启动子线程 zBCtd1Xrni  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; A 9(

x  
for(int i=0;i<nStartPos.length;i++) 3x`|  
{ "
un]Gc   
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), umjt]Gu[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), V3&RJ k=b  
nStartPos,nEndPos,i); ]] !VK  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ). <-X^@  
fileSplitterFetch.start(); qraSRK5  
} nr95YSH  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,c;Kzp>e  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); H3z:

ZTI  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", `.E[}W
  
nEndPos = " + nFileLength); X3{G:H0\p  
// fileSplitterFetch[nPos.length-1].start(); yQU{zY  
Lf16j*}-Q  
Xnt~]k\"  
//等待子线程结束 G? ]
)o5  
//int count = 0; t>L;kRujVJ  
//是否结束while循环 FtpK)9/4  
boolean breakWhile = false; QX!-B  
m,VOx7%n  
V[RF</2T  
while(!bStop) {:Orn%Q  
{ ( Z619w  
write_nPos(); y^;#&k!
 
Utility.sleep(500); x.]i}mt  
breakWhile = true; Q8T]\6)m  
O8+7g+J=!  
r/YMLQ  
for(int i=0;i<nStartPos.length;i++) 1ct;A_48  
{ /$i.0$L  
if(!fileSplitterFetch.bDownOver) vUN22;Z\  
{ %P<hW+P!  
breakWhile = false; p)jk>j B  
break; rV2WnAb[H&  
} :y
+2*lV  
} ]s]vZ  
if(breakWhile) RmI]1S_=  
break; <lgYcdJ   
u8'Zl8g  
#H)vK"hF  
//count++; tClg*A;|B  
//if(count>4) QiQ_bB!\  
// siteStop(); B\=L3eL<D  
} Ok|*!
!T  
8hu<E4]L  
Dl<bnx;0  
System.err.println("文件下载结束！"); @D.}\(  
} tWJZoD6}h  
catch(Exception e){e.printStackTrace ();} 2POXj!N  
} 44gPCW,u  
cA2V2S)  
- \5v^l  
//获得文件长度 O@tU.5*$5  
public long getFileSize() lsgh#x  
{ ],>@";9u"  
int nFileLength = -1; 2L:_rR#w  
try{ q['Euy  
URL url = new URL(siteInfoBean.getSSiteURL()); J28
M@cn  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Tre]"2l  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;%B(_c  
bk[
U/9Z\  
Pj[PIz  
int responseCode=httpConnection.getResponseCode(); wu7Lk3  
if(responseCode>=400) srPWE^&  
{ VEH&&@d  
processErrorCode(responseCode); xmNB29#  
return -2; //-2 represent access is error -Y1e8H ='  
} Z)e/!~""]  
i
/65v  
@GPCwE1  
String sHeader; o@r7 n>G  
Hn7_FOC  
Mz9r5
 
for(int i=1;;i++) ~xbe~$$Q@  
{ %d1,a$*3}  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); tnV/xk#!  
//Utility.log(in.readLine()); QHDXW1+|^  
sHeader=httpConnection.getHeaderFieldKey(i); ,MdV;j~"'  
if(sHeader!=null) m.JBOq=  
{ j5QuAU8  
if(sHeader.equals("Content-Length")) .sx
cCrQE  
{ O)C\vF#  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); zE336  
break; hP=WFD&  
} 1[mXd  
} 7P%%p3  
else G|[=/>~B  
break; .\\DKh%  
} aKV$pC<[o  
} q VjdOY:z  
catch(IOException e){e.printStackTrace ();} +cD<:"L'
g  
catch(Exception e){e.printStackTrace ();} !xzeMVI  
P!~MZ+7#&  
BIb4h   
Utility.log(nFileLength); $Ad{Z  
Eav[/cU  
-<c=US  
return nFileLength; y>R=`A1b  
} 6h>wt-tRC  
00<cYy
  
Y_Eb'*PY  
//保存下载信息（文件指针位置） wGU*:k7p  
private void write_nPos() 3T31kQv{  
{ x
qXo0  
try{ \K_ET> !  
output = new DataOutputStream(new FileOutputStream(tmpFile));
x[4`fM.m*  
output.writeInt(nStartPos.length); AG3>V+k{Lv  
for(int i=0;i<nStartPos.length;i++) n+! AnKq  
{ Gn22<C/  
// output.writeLong(nPos); E_gD:PPU5  
output.writeLong(fileSplitterFetch.nStartPos); "HX<,l8f%  
output.writeLong(fileSplitterFetch.nEndPos); Qf58ig-vCY  
} 2{M^,=^>  
output.close(); Q;MT"=RW  
} t$+?6E  
catch(IOException e){e.printStackTrace ();} @M<|:Z %.@  
catch(Exception e){e.printStackTrace ();} 7@C<oy_bb  
} x9NEFtqjm  
".f ;+wH  
[N FFB
96  
//读取保存的下载信息（文件指针位置） LO'**}vm  
private void read_nPos() -Q2, "  
{ cy*?&~;  
try{ *EI6dD"  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 5VRYO"D:  
int nCount = input.readInt(); /xG*,YL/q  
nStartPos = new long[nCount]; 'z );  
nEndPos = new long[nCount]; TvwZW!@jc  
for(int i=0;i<nStartPos.length;i++) Z<U6<{b  
{ `+`Z7  
nStartPos = input.readLong(); I\hh8abAp  
nEndPos = input.readLong(); l_3`G-`2  
}  ,t}vz 7  
input.close(); s|@6S8E  
} -)s qc P  
catch(IOException e){e.printStackTrace ();} KTK <gV9:  
catch(Exception e){e.printStackTrace ();} (w&F/ynO:  
} %/EVUN9=  
/TE_W@?^  
}L &^xe  
private void processErrorCode(int nErrorCode) X#d~zk[r2  
{ J2d.f}-  
System.err.println("Error Code : " + nErrorCode); s.EI`*xylY  
} eD-#b|  
R|JC1f8P5  
`id
9j  
//停止文件下载 nvca."5y  
public void siteStop() ?m![Pg%  
{ PxF<\pu&  
bStop = true; U!T~!C^  
for(int i=0;i<nStartPos.length;i++) WJ)z6m]  
fileSplitterFetch.splitterStop(); w'L\?pI  
mrTlXXz  
A+HF@Uw}^  
} <Q$@r?Mu]  
} r[1i*b$  
//负责部分文件的抓取 $GYm6x\4  
**FileSplitterFetch.java ko1J094Y%  
*/ 0,r}o  
package NetFox; tzZ63@cm  
J5*tJoCYS  
ckV`OaRw4  
import java.io.*; F8hw#!Aq  
import java.net.*; aGK?x1_  
)@N2  
r$5i Wu  
public class FileSplitterFetch extends Thread { .#wqXRd  
mt9.x  
Pf*^ZB%  
String sURL; //File URL s~X+*@.  
long nStartPos; //File Snippet Start Position yphS'AG  
long nEndPos; //File Snippet End Position _,q)hOI  
int nThreadID; //Thread's ID AoY-\E  
boolean bDownOver = false; //Downing is over X7[^s $VK  
boolean bStop = false; //Stop identical YNYx>Ue  
FileAccessI fileAccessI = null; //File Access interface og4UhP^UET  
?MXejE
C  
.id)VF-l  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException NxSu3e~PS  
{ @|LBn6q  
this.sURL = sURL; *Kyw^DI  
this.nStartPos = nStart; f5F@^QXQ  
this.nEndPos = nEnd; Z:ni$7<.  
nThreadID = id; #G|qD  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;_8#f%Y#R  
} VQY&g;[d  
(Lo%9HZ1Mx  
b:=TB0Fx?n  
public void run() r
I^zB mrr  
{ r~+\ Y"rM  
while(nStartPos < nEndPos && !bStop) |\_^B  
{ [qdRUV'  
;g6M%;1-  
*eIJwXE  
try{ .R)PJc5^  
URL url = new URL(sURL); m1n.g4Z&*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); } $uxJB  
httpConnection.setRequestProperty("User-Agent","NetFox"); ZPc@Zr`z  
String sProperty = "bytes="+nStartPos+"-"; Wf>zDW^"R  
httpConnection.setRequestProperty("RANGE",sProperty); :k7uGD  
Utility.log(sProperty); 6`!Fv-  
9k9_mjLZ  
RZ6xdq}>  
InputStream input = httpConnection.getInputStream(); 6Ztq  
//logResponseHead(httpConnection); F&])P- !3  
!(qsD+  
t^`O{m<  
byte[] b = new byte[1024]; 6``'%S'#  
int nRead; z?>D_NLX6  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) :1
(p.q=  
{ $|]" W=h  
nStartPos += fileAccessI.write(b,0,nRead); e`d%-9  
//if(nThreadID == 1) ,REJt  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); V<D.sd<  
} /y A7%2  
!E,A7s  
KQ`qpX^d  
Utility.log("Thread " + nThreadID + " is over!"); _8Z_`@0  
bDownOver = true; j>]nK~[ka  
//nPos = fileAccessI.write (b,0,nRead); kgy:Q'  
} 4VHqBQ4  
catch(Exception e){e.printStackTrace ();} ;^La"m  
} xBUya4w  
} HODz*pI  
o[v\|Q`d  
Z-8Yd6 4  
//打印回应的头信息 ?9! Z<H  
public void logResponseHead(HttpURLConnection con) *\(r+>*x*  
{ -6Oz^   
for(int i=1;;i++) 6&DX] [G  
{ i O
/K nH  
String header=con.getHeaderFieldKey(i); 4Y,R-+f
 
if(header!=null) _2k]3z?  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 1^_U;O:I  
Utility.log(header+" : "+con.getHeaderField(header)); |l&vkRrN  
else -:Fe7c  
break; SF}<{x_  
} WX}xmtLs  
} uum;q-"  
F.-R r  
lE!a  
public void splitterStop() GM<BO8Y.  
{ @mE)|.f  
bStop = true; %YSpCI  
} ?q(\=;Y  
&ZghMq~  
`6 /$M!4$  
} XO-Prs  
u$*56y  
fGw^:
,B  
/* y_*PQZ$c<  
**FileAccess.java {88gW\GL  
*//文件访问(定位，写) UbEb&9}  
package NetFox; CPVjmRUF|  
import java.io.*; [cTe54n  
JT "B>y>  
vo\fUT@k  
public class FileAccessI implements Serializable{ 2-=\~<)  
j<2m,~k`V  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 w?zKjqza=v  
RandomAccessFile oSavedFile; 56e r`=ms  
long nPos; ~/8M 3k/  
4(Ov1a>  
.
!1S[  
public FileAccessI() throws IOException Q:|l`*.R  
{ K=C!b?  
this("",0); oY1';&BO9  
} rj6tZJZ#o0  
Ma'_e=+A  
c9kzOQ2n  
public FileAccessI(String sName,long nPos) throws IOException 2pzF5h  
{ NE/m-ILw  
oSavedFile = new RandomAccessFile(sName,"rw"); W%.v.0  
this.nPos = nPos; nSF``pp+  
oSavedFile.seek(nPos); uch>AuF:  
} p8kr/uMP ;  
R)M_|ca  
f6_];]yP  
public synchronized int write(byte[] b,int nStart,int nLen) Xcrk;!IB?  
{ t~E<j+<2B  
int n = -1; t6,wjN-J  
try{ e'*`.^  
oSavedFile.write(b,nStart,nLen); yz-,)GB6  
n = nLen; Di@GY!  
} N[<H7_/3  
catch(IOException e) r'dr9"-{  
{ "p/j; 6H  
e.printStackTrace (); /,MJq#@K  
} d~/q"r1"  
JCPUM*g8  
 t^xTFn  
return n; z-@=+4~  
} 3I!?e!y3(  
-29gL_dk.  
B!dU>0&Ct  
} kloR#?8A  
R*oXmuOsYA  
Vs)--t  
/* >_c5r?]SG  
**SiteInfoBean.java -DN8Yb  
*/ (x"BR  
package NetFox; *\wp?s>-t  
d{3@h+zL  
oT{@_U{*J  
public class SiteInfoBean { QJ F=UB  
)mJf|W!Z#  
U
9&k;`  
private String sSiteURL; //Site's URL tV_t6x_.  
private String sFilePath; //Saved File's Path Tx1vL  
private String sFileName; //Saved File's Name ?E9DXg  
private int nSplitter; //Count of Splited Downloading File &O)
&k  
?9HhG?_x  
RP2_l$  
public SiteInfoBean() DbZ0e5  
{//nSplitter的缺省值为5 7R3fqU.Rq  
//default value of nSplitter is 5 PN$X N<  
this("","","",5); osOVg0Gyj  
} +B'8|5tPX  
Z<#hS=eY  
4<lQwV6=  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ( 7ws{)  
{ ^pS+/ZSi^  
sSiteURL= sURL; !PMU O\y  
sFilePath = sPath; &SAH2xR  
sFileName = sName; \XF}?*8  
this.nSplitter = nSpiltter; |+:h|UIUQ  
(=16PYs  
y8s!M  
} [3W*9j  
;uqx@sx ;  
`:wvh(  
public String getSSiteURL() f`8OM}un&  
{ Q\Gq|e*  
return sSiteURL; WKrX,GF  
} rZoj
Y}dWJ  
6cdMS[_SD(  
?sBh=Ds  
public void setSSiteURL(String value) B/J>9||g  
{ hH
->%*  
sSiteURL = value; >t
G+?Y'{  
} `e]6#iJ^  
7l."b$U4yv  
!ph" mf$-  
public String getSFilePath() li] 6Pj,  
{ =39 ?:VoD  
return sFilePath; EQIUSh)M  
} `p0ypi3hn  
A])P1c. 7"  
KECElK3uj  
public void setSFilePath(String value) x1gx$P  
{ 6*n
Ao8gl  
sFilePath = value; HPQ/~0$  
} %d m-?`  
1|ZhPsD.}g  
++}\v9Er  
public String getSFileName() GIftrYr  
{ *U=]@I}J  
return sFileName; {ub/3Uh  
} :%JC^dV(  
T#!lPH :&h  
T;\^#1  
public void setSFileName(String value) ~AG$5!  
{ 0IT@V5Gdj  
sFileName = value; E2AW7f(/  
} S2C]?6cTq  
\aP6_g:N}  
9 L?;FY)_  
public int getNSplitter() ogeL[7  
{ h?UVDzI!O  
return nSplitter; V5D
2\n3A  
} 2UP,Tgn..  
i2Jq|9,g  
p|XA
l
ia  
public void setNSplitter(int nCount) HFo-4"  
{ OQ4c#V?  
nSplitter = nCount; !OcENV  
} ekQrW%\3  
} VY+>=!  
8cm@a*2%  
9.M{M06;  
/* kII7z;<^`  
**Utility.java VjbG(nB?_  
*/ U3#dT2U  
package NetFox; >O]s&34  
fP%Fyg^k  
$E(XjuS  
public class Utility { MZ#T^Y  
H
5nS%D  
0y%L-:/c|  
public Utility() 6ri#Lw  
{ dEp/dd~(&  
r
Ol6lQW  
S7n"3.k  
} ^[-> )  
[cU,!={  
//线程睡眠 0jB X5  
public static void sleep(int nSecond) ~!+h?[miV  
{ Ff"gadRXd  
try{ kI*UkM-  
Thread.sleep(nSecond); A
%ywj'|z  
} K%{ad1$c  
catch(Exception e) 5n:71$6[  
{ PDw{R]V+  
e.printStackTrace (); y7zkAXhJ  
} ~v:#zU  
} M%=P)cC  
#*%fu  
//日志 K&pM o.  
public static void log(String sMsg) T$b\Q  
{ /jrY%C  
System.err.println(sMsg); _J"mR]I+  
} gM_:l  
(Nz]h:}r  
b>q6:=((  
public static void log(int sMsg) e)pTC97^L  
{ k@qWig  
System.err.println(sMsg); =g0*MZ;
"  
} aR(E7mXQ  
} 'yT`ef  
:{CFTc5:A  
'\4fU%  
/* \JU ~k5j  
**TestMethod.java ABWb>EZ8  
*/ +rQg7a}  
package NetFox; URw!7bTz  
ZDlu1>Q  
PHkDb/HIx|  
public class TestMethod { ?Y`zg`  
A c:\c7M;  
 Rkv  
public TestMethod() >6K4b/.5w  
{ ///xx/weblogic60b2_win.exe m'.T2e.u  
try{ 4]"w b5%  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); fu>Qi)@6a1  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Fg@ ACv'@
 
SiteFileFetch fileFetch = new SiteFileFetch(bean); 3Wj,}  
fileFetch.start(); ~x+Ykq0  
} Hs<n^fyf  
catch(Exception e){e.printStackTrace ();} e 2*F;.)  
LV=^jsQ5  
-R@JIe_28f  
} ,^+#M{Z  
2E$i_jc  
s*{mT6s+T  
public static void main(String[] args) m3%
ef  
{ LY1KQuY  
new TestMethod(); ftW{C1,U7  
} +G\
0L_B  
} O2@" w23  
点击下载更多相关资料