http断点续传简单实现（java)

/* 7[8PSoo  
**SiteFileFetch.java N]5-#  
*/ !rwv~9I  
package NetFox; 0P!6 .-XU  
import java.io.*; QRa>W/N  
import java.net.*; !qy/'v4  
7 bpV=  
:.Np7[~{  
public class SiteFileFetch extends Thread { G-T:7  
,!Q2^R  
'GNT'y_  
SiteInfoBean siteInfoBean = null; //文件信息Bean 1'}~;?_  
long[] nStartPos; //开始位置 zs7K :OlkA  
long[] nEndPos; //结束位置 K72U0}$B  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 4Kx;F 9!%~  
long nFileLength; //文件长度 wLNO\JP'  
boolean bFirst = true; //是否第一次取文件 !v94FkS>  
boolean bStop = false; //停止标志 b^FB[tZ\x  
File tmpFile; //文件下载的临时信息 RELLQpz3  
DataOutputStream output; //输出到文件的输出流 CxwZ$0  
/(XtNtO*  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） $0{c=r9  
public SiteFileFetch(SiteInfoBean bean) throws IOException >D*L0snjV  
{ +]Ydf^rF  
siteInfoBean = bean; NbfV6$jo  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); -4"E]
f  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); qM]eK\q 1  
if(tmpFile.exists ()) up`!r;5-  
{ /Wk\6  
bFirst = false; LUJKR6oT{>  
read_nPos(); l*/I ;a$  
} @@_f''f$  
else @Vc*JEW  
{ XG*Luc-v  
nStartPos = new long[bean.getNSplitter()]; {bl^O  
nEndPos = new long[bean.getNSplitter()]; rFdovfb   
} gNN{WFHQX:  
@e+QGd;}  
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mZ*!$P:vy"  
} A=E1S{C  
mmEr2\L  
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public void run() e=TB/W_  
{ b6
Dve]  
//获得文件长度 X8p-VCkV  
//分割文件 BPe5c :z  
//实例FileSplitterFetch h_Q9c  
//启动FileSplitterFetch线程 fY$M**/,  
//等待子线程返回 jj.iW@m  
try{ !{"{(h)+@  
if(bFirst) mq su8ti  
{ 0Ocy$  
nFileLength = getFileSize(); ojUBa/
 
if(nFileLength == -1) j:\MrYt0H  
{ 9:IVSD&"Rf  
System.err.println("File Length is not known!"); GnkNoaU  
} jL>IX`,+6  
else if(nFileLength == -2) 8?h-H#h  
{ +P81&CaY  
System.err.println("File is not access!"); Hh4$Qr;R  
} BUuNI_?M#5  
else PiP\T.XANa  
{ -6(C^X%  
for(int i=0;i<nStartPos.length;i++) E9YR *P4$  
{ , 0MDkXb  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 8|OsVIe%  
} j"9bt GX  
for(int i=0;i<nEndPos.length-1;i++) nYLq%7}k  
{ u4, p.mZtb  
nEndPos = nStartPos[i+1]; U;Y{=07a@  
} ^#9 &Rk!t  
nEndPos[nEndPos.length-1] = nFileLength; "VRcR  
} 00[Uk'Q*5  
} n0:'h}^  
oMM`7
wJw  
HSE9-c=  
//启动子线程 @GK0j"_  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; /Z94<}C6b  
for(int i=0;i<nStartPos.length;i++) nGZZCsf <  
{ %l(qyH)*  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), R6r'[-B2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Cq(dj^/~m  
nStartPos,nEndPos,i); Xk8+m>   
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )xy1DA  
fileSplitterFetch.start(); (:4N#p  
} #qtAFIm'  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), a4Qr\"Qm  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ]<V[H  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 4RGEg;]S  
nEndPos = " + nFileLength); @b
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// fileSplitterFetch[nPos.length-1].start(); {m.l{<H  
yF8 av=<{  
K*xqQ]&  
//等待子线程结束 P4-`<i]!S  
//int count = 0; q;3.pRw(  
//是否结束while循环 N0,wT6.  
boolean breakWhile = false; BxS\"W  
]Nz~4ebB  
0GK<l  
while(!bStop) <Wn={1Ts"  
{ =* oFs|v  
write_nPos(); zxTcjC)y  
Utility.sleep(500);  yl0&|Ub  
breakWhile = true; s`B]+  
!`LaX!bmp  
,]+P#eXgE  
for(int i=0;i<nStartPos.length;i++) cah1'Y  
{ ^mz&L|h  
if(!fileSplitterFetch.bDownOver) ]h3<r8D_#  
{ S='AA_jnw  
breakWhile = false; ^I*</w8  
break; t;!vjac  
} hy3j8?66  
} ;}"_hLX  
if(breakWhile) q|;_G#4  
break; 61L vT"  
8QDs4Bv|  
U` uP^  
//count++; ViIt'WX  
//if(count>4) $hZb<Xz  
// siteStop(); sEP-jEuwG  
} ~8L*N>Y  
osPJ%I`^  
G0Q}
 1  
System.err.println("文件下载结束！"); aw&:$twbM  
} KCu@5`p  
catch(Exception e){e.printStackTrace ();} =NMT H[  
} y!)  
Y&!M#7/'J3  
?f<JwF<  
//获得文件长度 nk|j(D  
public long getFileSize() /n;Ll](ri  
{ :34]}`-  
int nFileLength = -1; rH Et]Xa  
try{ FKRO0%M4}Z  
URL url = new URL(siteInfoBean.getSSiteURL()); #}*w &y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,#:*dl  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6;6a.iZ  
qkVGa%^  
\n$s5i-  
int responseCode=httpConnection.getResponseCode(); G- wQ weJ9  
if(responseCode>=400) +RWP;rk  
{ HI)MBrj;r  
processErrorCode(responseCode); qDHiyg^u  
return -2; //-2 represent access is error 03$-U0.;-  
} ky>0  
3NAU|//J  
*y<Ru:D  
String sHeader; __o`+^FS  
]wFKXZeK  
H'7AIY}  
for(int i=1;;i++) |W4 \  
{ q_S`@2Dzz,  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); S81Z\=eK  
//Utility.log(in.readLine()); z(V?pHv+  
sHeader=httpConnection.getHeaderFieldKey(i); D#Fe\8!l  
if(sHeader!=null) acr@erk  
{ AT Dm$ *  
if(sHeader.equals("Content-Length")) U ?'$E\  
{ E`s9SE  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Rj6:.KEJ  
break; GPlAQk  
} :
?W {vV  
} *qdf?'R  
else hd{Vz{;W  
break; jm9J-%?  
} ]AkHNgW  
} ]4~- z3=y  
catch(IOException e){e.printStackTrace ();} 9QE|
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catch(Exception e){e.printStackTrace ();} #vh1QV!Ho  
2c:H0O 0o  
Dlz||==  
Utility.log(nFileLength); :aHD'K  
6QS[mWU  
!9|)v7}  
return nFileLength; DE
"KbA0}  
} D>"U0*h
 
*I,3,zO  
`~|8eKFq!  
//保存下载信息（文件指针位置） vQf'lEFk  
private void write_nPos() v\7k  
{ s33< }O0  
try{ M7z>ugk"  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ]yu,YZ@7  
output.writeInt(nStartPos.length); 3l5rUjRwj  
for(int i=0;i<nStartPos.length;i++) #;cDPBv*wS  
{ ]=ar&1}J  
// output.writeLong(nPos); gNkx]bm  
output.writeLong(fileSplitterFetch.nStartPos); Y^5X>  
output.writeLong(fileSplitterFetch.nEndPos); c*MSd  
} +9Z RCmV  
output.close(); R7aS{8nn  
} eveGCV
;@  
catch(IOException e){e.printStackTrace ();} ]}z;!D>  
catch(Exception e){e.printStackTrace ();} :(tSL{FO  
} lOp/kGmn+  
E-h`lDoJ  
VesW7m*z  
//读取保存的下载信息（文件指针位置） s)Sa KE*d  
private void read_nPos() _J^q|  
{ 7+]T}4;  
try{ `L0aQ$'>z  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); XP'Mv_!Z  
int nCount = input.readInt(); <jdS0YT  
nStartPos = new long[nCount]; %4QCUc*lr  
nEndPos = new long[nCount]; dLOUL9hf  
for(int i=0;i<nStartPos.length;i++) KI(9TI*  
{ 7s:`]V%  
nStartPos = input.readLong(); }G n2%  
nEndPos = input.readLong(); AU1P?lk  
} L8-
  
input.close(); =uKGh`^[  
} _i [.5  
catch(IOException e){e.printStackTrace ();} : sIZ+3  
catch(Exception e){e.printStackTrace ();} 3$f%{
~3  
} *UVjN_na5  
7O5`&Z'-  
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private void processErrorCode(int nErrorCode) 8>q:Q<BB2  
{ fM8kS  
System.err.println("Error Code : " + nErrorCode); BcV;EEi  
} a(CZGIB  
#sit8k`GR8  
w7\:S>;(O"  
//停止文件下载 zSta!]  
public void siteStop() c)Ft#vzg&e  
{ Mi'Q5m  
bStop = true; lh
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for(int i=0;i<nStartPos.length;i++) X'N4a  
fileSplitterFetch.splitterStop(); <LM<,  
 iqf+rBL  
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} )f#@`lf[<  
} aM'0O![d  
//负责部分文件的抓取 ,-u | l  
**FileSplitterFetch.java &H\$O.?f  
*/ [o&Vr\.$  
package NetFox; A?Jm59{w  
GEP YSp  
'N,3]Soi  
import java.io.*; 2L.UEAt  
import java.net.*; |E@Gsw  
JA7HO|  
&|<~J(L;  
public class FileSplitterFetch extends Thread { R=HN>(U  
tF)K$!GR[  
dtjaQsJM^  
String sURL; //File URL xD#PM |I  
long nStartPos; //File Snippet Start Position lD2>`s5  
long nEndPos; //File Snippet End Position @Zd+XWFw  
int nThreadID; //Thread's ID %_+9y??  
boolean bDownOver = false; //Downing is over KmV#% d  
boolean bStop = false; //Stop identical :7Mo0,Bw,  
FileAccessI fileAccessI = null; //File Access interface RLY Ae  
k1>%wR  
{npKdX  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException aA%$<ItH  
{ r5[om$|*  
this.sURL = sURL; C|"T!1MlY4  
this.nStartPos = nStart; f ;|[  
this.nEndPos = nEnd; q,d]i/T  
nThreadID = id; xt +fuL  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 h./cs'&  
} ?zUV3Qgzj  
(]j*)~=V  
Fy-nV%P  
public void run() heZ)+}U~  
{ P&| =  
while(nStartPos < nEndPos && !bStop) `u:U{m  
{ #c4LdZu9  
;3\Fb3d  
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try{ (d993~|h  
URL url = new URL(sURL); do*`-SDy  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); R#tz"T@  
httpConnection.setRequestProperty("User-Agent","NetFox"); WlP@Tm5g/  
String sProperty = "bytes="+nStartPos+"-"; jLvI!q   
httpConnection.setRequestProperty("RANGE",sProperty); L
Yh5f#  
Utility.log(sProperty); P;KbS~ SlC  
[OG-ZcNu?  
O|,+@qtH  
InputStream input = httpConnection.getInputStream(); Fhn883  
//logResponseHead(httpConnection); `(;d+fof  
A4';((OXy  
V]H<:UE  
byte[] b = new byte[1024]; /(n)I  
int nRead; : ` F>B  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) D]y6*Ha  
{ }3:TPW5S  
nStartPos += fileAccessI.write(b,0,nRead); @babgP,  
//if(nThreadID == 1) y5a^xRDw  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); EN.yU!N.4  
} lGG
1d  
 g/+M&k$  
l@1f L%f  
Utility.log("Thread " + nThreadID + " is over!"); hl}#bZ8]  
bDownOver = true; KtEMH  
//nPos = fileAccessI.write (b,0,nRead); /G[y 24 Q  
} pRc(>P3;  
catch(Exception e){e.printStackTrace ();} y(.WK8  
} !nV
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} o~P8=1t  
c}Z,xop<P{  
rA*,)I_v@  
//打印回应的头信息 AG}' W  
public void logResponseHead(HttpURLConnection con) 9[T#uh!DC  
{ JPQ
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for(int i=1;;i++) Xki/5roCQ|  
{ (/"T=`3t  
String header=con.getHeaderFieldKey(i); q*{"6"4(  
if(header!=null) UMhM8m!=o  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 6El%T]^  
Utility.log(header+" : "+con.getHeaderField(header)); =q xcM+OX1  
else *kyy
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break; u6r-{[W}  
} fY%Sw7ql<  
} NBMY1Xgj  
D4#,9?us  
&KR@2~vE  
public void splitterStop() 3pDZ}{ZZU  
{ CQ,r*VAw  
bStop = true; E=s`$ A  
} iUI,r*  
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K&|zWpb  
} &<UOi@  
pNiqb+^nz  
7KM!\"PM  
/* _IlL'c5  
**FileAccess.java GMNf#;x  
*//文件访问(定位，写) GUN<ZOYb=  
package NetFox; Ds}6{']K  
import java.io.*; Wnf`Rf)1z  
|=%$7b\C  
&OzJ^G\o  
public class FileAccessI implements Serializable{ M$&>"%Oi  
cQ+,F2  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 :He:Bdk  
RandomAccessFile oSavedFile; /=r&9P@Ay<  
long nPos; \17)=W  
5~[Fh2+  
'M'LJ.,"/  
public FileAccessI() throws IOException y4?>5{`W  
{ \uPT-M*  
this("",0); 3K0J6/mc  
} a9qZI  
d
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3=K-+dhk|t  
public FileAccessI(String sName,long nPos) throws IOException 5 + Jy  
{ n&V(c&C  
oSavedFile = new RandomAccessFile(sName,"rw"); dF?pEet?2  
this.nPos = nPos; 4@W.{|2~  
oSavedFile.seek(nPos); #{?oUg>$  
}
_|Dt6  
!EW]:u  
oNh .Zgg  
public synchronized int write(byte[] b,int nStart,int nLen) R1m18GHQ  
{ ,}|V'y  
int n = -1; ?<}qx`+%Q  
try{ .ZJh-cd  
oSavedFile.write(b,nStart,nLen); d z\b]H]  
n = nLen; Wex4>J<`/
 
} ypifXO;m7  
catch(IOException e) 7SM/bJ-M#  
{ 6/n;u{|  
e.printStackTrace (); mcR!P~"i  
}
4{Ak|  
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return n; wGxLs>| 4  
} Ip0Zf?  
"bO]  
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} +I~?8*  
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g!QumRF  
/* aOuon0  
**SiteInfoBean.java W>Kwl*Cis"  
*/ *>#cs#)  
package NetFox; tsa6: D  
|% kK?!e+-  
)- \w  
public class SiteInfoBean { Xg)yz~Ug  
NR [VGZj  
hPH7(f|c{g  
private String sSiteURL; //Site's URL GJ$,@  
private String sFilePath; //Saved File's Path g-s@m}[T  
private String sFileName; //Saved File's Name V:+bq`  
private int nSplitter; //Count of Splited Downloading File p?h;Sv/  
INT2i8oU  
f_\-y&)+*  
public SiteInfoBean() JQCwI`%i  
{//nSplitter的缺省值为5 !K2[S J  
//default value of nSplitter is 5 W | }Hl{}  
this("","","",5); ]aR4U`  
} Ij8tBT?jlL  
e{O5y8,  
:Ry24X  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) z~_\onC  
{ -jy"?]ve.  
sSiteURL= sURL; Rju8%FRO  
sFilePath = sPath; Z8@]e}n  
sFileName = sName; u0e#iX  
this.nSplitter = nSpiltter; Rb0{t[IU  
y{sA["   
4ca-!pI0  
} R;yAqr29  
E6gEP0b  
*LVM}| f  
public String getSSiteURL() "10VN*)J}  
{ cmeyCyV*  
return sSiteURL; ? `KOW  
} w;(gi  
{|%O)fr,
 
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Pf  
public void setSSiteURL(String value) 8GP}g?%  
{ ( A)wcB  
sSiteURL = value; *J=ol  
} gK(4<PO'  
!O-+h0Z  
@FV;5M:I  
public String getSFilePath() .g~@e_;):  
{ a\w|tf  
return sFilePath; H^g<`XEgw  
} C] w< &o  
6~S0t1/t?  
ihWz/
qx&q  
public void setSFilePath(String value)  R'/wOE2  
{ }}_uN-m  
sFilePath = value; *PEuaRDN  
} pYG,5+g  
* 2%e.d3"M  
Uz|]}t5V  
public String getSFileName() \7/_+)0}'  
{ G= cxc_9  
return sFileName; {1
%ZyY  
} ->8q, W2A  
px
x(BE  
r\d:fot  
public void setSFileName(String value) clw91yrQn  
{ 5m42Bqy"  
sFileName = value; p'qH [<s  
}  G{.+D2  
HH?*"cKF~  
r<v%Zp  
public int getNSplitter() O:
)IRB3  
{ ~S6{VK.  
return nSplitter; B6\VxSX4{  
} (Y)h+}n5N  
?m1$*j  
]LTc)[5Zj  
public void setNSplitter(int nCount) <h=M Rw,l  
{ ssITe.,ny  
nSplitter = nCount; _
KVB~loT  
} }dJ ~Iy  
} x 5Dt5Yp"o  
*^6xt7  
%E"/]!}3  
/* SsX05>  
**Utility.java -/c1qLdQ  
*/ tQ JH'YV  
package NetFox; \)Z
X4rs{8  
t[,T}BCy.  
ddDJXk)!0  
public class Utility { Y&f[2+?2NK  
3b@1Zahz  
jA4v?(AO}#  
public Utility() $L8s/1up  
{ ,7jiHF  
*.%)rm  
x[W]?`W3r~  
} -#;VFSz,9*  
FR^wDm$  
//线程睡眠 ( L\G!pP.  
public static void sleep(int nSecond) 1r& ?J.z25  
{ HcVs(]tIW  
try{ EJaaW&>[  
Thread.sleep(nSecond); L_ qv<iM$  
} '3UIri
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catch(Exception e) a~>0JmM+N  
{ e=)
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e.printStackTrace (); rI66frbj  
} JvJ!\6Q@  
} T>Rf?%o  
5uJP)S?  
//日志 eKpxskbhZ  
public static void log(String sMsg) _<F@(M5  
{ ?Wz(f{Hm  
System.err.println(sMsg); k=~pA iRDN  
} >wk=`&+V@  
RyQ\5^z  
gc:p@<  
public static void log(int sMsg) Y1_6\zpA  
{ lPQ Ut!xI  
System.err.println(sMsg); nBIv{  
} '`~(Fkj  
} `{Di
*
 
LOUKUReE  
$17 v,  
/* -5,y 1_M  
**TestMethod.java =
"w8U'  
*/ (VI* c!N  
package NetFox; h:Mn$VR,  
p C2c(4  
^@LhUs>3  
public class TestMethod { V?V)&y] 4  
~v(M6dz~vk  
3g#=sd!0O@  
public TestMethod() IfmIX+t?  
{ ///xx/weblogic60b2_win.exe 9Bvn>+_K  
try{ ?]:EmP  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); nh&J3b}B!  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); e5>5/l]jsg  
SiteFileFetch fileFetch = new SiteFileFetch(bean); L!b0y7yR  
fileFetch.start(); k5%0wHpk=  
} MV;Y?%>  
catch(Exception e){e.printStackTrace ();} GKsL~;8"  
)bCG]OM7<  
Rw ao5l=x  
} >&Ui*  
0@e}hv;  
{Fp`l\,  
public static void main(String[] args) s8yTK2v2\  
{ #9hXZr/8  
new TestMethod(); QOh w  
} HSr"M.k5  
} 77&^$JpM  
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