http断点续传简单实现（java)

/* $@xkKe"  
**SiteFileFetch.java E%'DIs  
*/ 9D<HJ(  
package NetFox; <uvshZv  
import java.io.*; E%e-R6gl  
import java.net.*;
B8&@Qc@~  
okv7@8U#p  
~!;3W!@(E  
public class SiteFileFetch extends Thread { zk]~cG5dT/  
K?>&Mr  
l\5NuCgRY  
SiteInfoBean siteInfoBean = null; //文件信息Bean f[RnL#*xJU  
long[] nStartPos; //开始位置 <Zi
O[dEV  
long[] nEndPos; //结束位置 h(L5MZs  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 kel {9b=i  
long nFileLength; //文件长度 PEWzqZ|!;  
boolean bFirst = true; //是否第一次取文件 $Yka\tS'  
boolean bStop = false; //停止标志 87Kx7CKF"  
File tmpFile; //文件下载的临时信息 d !H)voX  
DataOutputStream output; //输出到文件的输出流 :NLNxK  
twn@~$  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） tFwlx3  
public SiteFileFetch(SiteInfoBean bean) throws IOException \ C^D2Z6  
{ ka*UyW}  
siteInfoBean = bean; yV. P.Q  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); l0_V-|x  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); SS`
C0&I@p  
if(tmpFile.exists ()) nAzr!$qbNv  
{ by<2hLB9Q  
bFirst = false; (tgaH,G  
read_nPos(); hqBRh+[  
} `+uXL9
mo  
else |
`nVr>QF&  
{ h2>0#Vp3j  
nStartPos = new long[bean.getNSplitter()]; -&?-  
nEndPos = new long[bean.getNSplitter()]; - \QtE}|4  
} `FwAlYJK  
krA))cP  
El%(je,|  
-}J8|gwwp  
} F\I^d]#,[  
k-U/x"Pl  
&u8c!;y$b  
public void run() "DpQnhvbB  
{ JF gN  
//获得文件长度 | QA8"&r  
//分割文件 v4$,Vt:7  
//实例FileSplitterFetch H/$q]i*#K  
//启动FileSplitterFetch线程 *v+ fkg  
//等待子线程返回 zYL^e @  
try{ +[ zo2lBx  
if(bFirst) To`?<]8  
{ kQ8WO|
bA  
nFileLength = getFileSize(); tpN}9N  
if(nFileLength == -1) UwU]l17~  
{ zMKL: Um"  
System.err.println("File Length is not known!"); (a?Ip)`I  
} oB9m\o7$  
else if(nFileLength == -2) E`|qFG<  
{ r.^&%D  
System.err.println("File is not access!"); A3_9MO   
} yH^*Fp8V  
else R 6Em^A/>  
{ u
i1
m+  
for(int i=0;i<nStartPos.length;i++) RHbw
q
]  
{ w.f[
)  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); t3G'x1  
} \4k*Zk  
for(int i=0;i<nEndPos.length-1;i++) wNZ7(W.U  
{ In&vh9Lw  
nEndPos = nStartPos[i+1]; fsd>4t:"\  
} .Q@"];wH  
nEndPos[nEndPos.length-1] = nFileLength; B
*IDx`^Y  
} 6K}=K?3Z  
} ;^]A
@WN6_  
=HHg:"  
Ne 4*MwK  
//启动子线程 
v%5(-  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; (#]KjpIK  
for(int i=0;i<nStartPos.length;i++) 3)Y:c2  
{ <.ky1aex7  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(),  Dfia=1A  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Fev3CV$  
nStartPos,nEndPos,i); T#7^6Ks+1  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ks
(U]G"V  
fileSplitterFetch.start(); S)yV51^B  
} ]||=<!^kn  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 'QF>e  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ]6 wi  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", !`lqWO_/ :  
nEndPos = " + nFileLength); ;kBies>V  
// fileSplitterFetch[nPos.length-1].start(); sA}R!  
e%6{P  
!$Z"\v'b  
//等待子线程结束 \<**SSN  
//int count = 0; m{c#cR  
//是否结束while循环 -::%9D}P|  
boolean breakWhile = false; CN(4;-so)  
sfE8b/Z8  
HU
9y{H  
while(!bStop) c ?XUb[  
{ .Er/t"Qs;  
write_nPos(); Z"X*FzFo  
Utility.sleep(500); 8 -A7  
breakWhile = true; AW5g (  
JxJntsn  
mC92J@m/L!  
for(int i=0;i<nStartPos.length;i++) PBtU4)  
{ E e>j7k.G.  
if(!fileSplitterFetch.bDownOver) 2]=I'U<E!  
{ 79H+~1Az  
breakWhile = false; (}1f]$V  
break; VAGMI+ -  
} 4tJ4X' U  
} _`>7 Q),7  
if(breakWhile) rJp6d:M  
break; <|3v@  
/g'-*:a  
XWpnZFjE  
//count++; ^1=|(Z/  
//if(count>4) GK?R76d  
// siteStop(); pIiED9  
} vfJk? (  
4uAafQ`@H  
-oBas4J  
System.err.println("文件下载结束！"); yX3H&F
6  
} )OC[;>F7  
catch(Exception e){e.printStackTrace ();} 3z92Gy5cr  
} y4We}/-<  
H^;S}<pxW  
U^BXCu1km  
//获得文件长度 z/k~+-6O  
public long getFileSize() &\|<3sd(  
{ NP'Ke:  
int nFileLength = -1; g4aX  
try{ {))S<_yN  
URL url = new URL(siteInfoBean.getSSiteURL()); OG7v'vmY  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); w*%$ lhp!  
httpConnection.setRequestProperty("User-Agent","NetFox"); h\*rv5\M  
%L>nXj  
`)M\(_  
int responseCode=httpConnection.getResponseCode(); iCRw}[[  
if(responseCode>=400) '8kjTf#g<l  
{ Sx9:$"3.X  
processErrorCode(responseCode); I{e^,oc  
return -2; //-2 represent access is error vr;Br-8  
} w })Pedg  
xWz;5=7a]  
_ZM9 "<M-X  
String sHeader; "4uUI_E9F;  
kjC{Zr  
XW_xNkpL5c  
for(int i=1;;i++) Tv,.  
{ 9$V_=Bo  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 9^#gVTGXv  
//Utility.log(in.readLine()); 0gD59N'C  
sHeader=httpConnection.getHeaderFieldKey(i); K6*UFO4}i  
if(sHeader!=null) vq:OH H  
{ i2a"J&,6O  
if(sHeader.equals("Content-Length")) J&ECm+2  
{ [2 w<F[  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ]q[  
break; \*!%YTZ~  
} 3J~kiy.nfW  
} 3hf;4Mb  
else ZHD0u)ri=J  
break;  Am%a4{b  
} 6Y_O^f  
} dN\P&"`  
catch(IOException e){e.printStackTrace ();} |+xtFe  
catch(Exception e){e.printStackTrace ();} ca3BJWY}J  
yb{{ z@  
GHC?Tp  
Utility.log(nFileLength); (<R\  
|5B,cB_  
FWpN:|X BS  
return nFileLength; 4:eq{n  
} 1;kG[z=A  
l&??2VO/t  
K*U=;*p)  
//保存下载信息（文件指针位置） P[I*%  
private void write_nPos() d?&!y]RS#  
{ =#Cf5s6qt  
try{ h3]@M$Y[  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Q@W|GOH3  
output.writeInt(nStartPos.length); %f_OP$;fc  
for(int i=0;i<nStartPos.length;i++) UG"6RW @  
{ "ex~LB  
// output.writeLong(nPos); :7Z\3_D/  
output.writeLong(fileSplitterFetch.nStartPos); opcR~tg@r  
output.writeLong(fileSplitterFetch.nEndPos); DPS1GO*  
} J={OOj  
output.close(); H")N_BB  
} /=YqjZTCq  
catch(IOException e){e.printStackTrace ();} B#k3"vk#  
catch(Exception e){e.printStackTrace ();} g\\1C2jG  
} HEB/\  
mB^I@oZ*  
#S53u?JV8  
//读取保存的下载信息（文件指针位置） 5}MlZp  
private void read_nPos() ELrZ8&5G  
{ "gbnLKs  
try{ q?Ku}eID3  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); UC+7-y,
  
int nCount = input.readInt(); le^_6|ek  
nStartPos = new long[nCount]; x<*IF,o  
nEndPos = new long[nCount]; aEEz4,x_  
for(int i=0;i<nStartPos.length;i++) uVq5fT`B  
{ V3 _b!  
nStartPos = input.readLong(); Q3Z%a|3W  
nEndPos = input.readLong(); 9oje`Ay  
} #7~tL23}]  
input.close(); I*:qGr+ WJ  
} J|"nwY}a9  
catch(IOException e){e.printStackTrace ();} x?f0Hk+  
catch(Exception e){e.printStackTrace ();} o[6vxTH  
} Q@e*$<3  
/nY).lSH  
4kaE}uKU  
private void processErrorCode(int nErrorCode) xOVA1pb,  
{ o!s%h!%L  
System.err.println("Error Code : " + nErrorCode); $d2kHT  
} $h,&b<-  
xgtJl}L  
B%eDBu ")  
//停止文件下载 ^Cc8F3os=  
public void siteStop() k_K,J6_)  
{ M$&WM{Pr^  
bStop = true; |B%BwE  
for(int i=0;i<nStartPos.length;i++) zM_
DE   
fileSplitterFetch.splitterStop(); x5fgF;  
rb *C-NutE  
J})$  
} @~$F;M=.*  
} c_qcb7<~.  
//负责部分文件的抓取 -- i&"  
**FileSplitterFetch.java 9raHSzK@d  
*/ qab) 1ft  
package NetFox; VBbUl|X\  
%="~\1y  
u>,lf\Fgz  
import java.io.*; XN~#gm#  
import java.net.*; e0v9u
Q%F5  
dysX  
DOF?(:8Y  
public class FileSplitterFetch extends Thread { Z]x5!  
:kME  
FE8+E\ U?  
String sURL; //File URL ){O1&|z-
 
long nStartPos; //File Snippet Start Position qE#&)  
long nEndPos; //File Snippet End Position qPXANx<^  
int nThreadID; //Thread's ID zdLVxL>87  
boolean bDownOver = false; //Downing is over Jw:Fj{D  
boolean bStop = false; //Stop identical ub`z7gL  
FileAccessI fileAccessI = null; //File Access interface .8T\Nr\~2  
*Nvy+V  
k_*XJ<S!Y  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException CF3E]dt  
{ Ynv9&P  
this.sURL = sURL; lFiq<3Nk  
this.nStartPos = nStart;
'GV&]   
this.nEndPos = nEnd; ER~T'-YMS  
nThreadID = id; \#\`!L[1  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 3AdP^B<  
} x1 ;rb8  
&5kZ{,-eM  
gB/;clCdX)  
public void run()  &7L~PZ  
{ /e.FY9  
while(nStartPos < nEndPos && !bStop) ur/Oc24i1n  
{ `"xk,fVYd  
\3t,|%v  
:kWZSN8.D  
try{ I;Al?&uw  
URL url = new URL(sURL); -@%t"8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); U9<_6Bsd  
httpConnection.setRequestProperty("User-Agent","NetFox"); _-@ZOhw&  
String sProperty = "bytes="+nStartPos+"-"; *C4~}4WT\  
httpConnection.setRequestProperty("RANGE",sProperty);
q?;N7P  
Utility.log(sProperty); I6K7!+;2  
-!XrwQyk  
3 R5%N ~  
InputStream input = httpConnection.getInputStream(); F
f[H>Lp~  
//logResponseHead(httpConnection); u{g]gA8s  
?JuX~{{.L  
~8jThi U  
byte[] b = new byte[1024]; **T:eI+  
int nRead; /Qr
A8  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 'fS?xDs-v  
{ Rz`@N`U  
nStartPos += fileAccessI.write(b,0,nRead); v\fzO#vj  
//if(nThreadID == 1) gXq!a|eH  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); q$MHCq;  
} @ \!KF*v  
H,(F1+~d  
96vj)ql  
Utility.log("Thread " + nThreadID + " is over!"); qAUaF;{  
bDownOver = true; ge^!F>whr  
//nPos = fileAccessI.write (b,0,nRead); h^%GE;N  
} @AvM  
catch(Exception e){e.printStackTrace ();} IM[54_I  
} AU0$A403  
} Q8 -3RgAw  
ZvUp#8x(3  
P-[fHCg~  
//打印回应的头信息 (YAI,Xnw  
public void logResponseHead(HttpURLConnection con) +7Sf8tg\  
{ !c\7  
for(int i=1;;i++) X"kXNKV/n  
{ `if
b<T  
String header=con.getHeaderFieldKey(i); .KFA218h*x  
if(header!=null) ?O!]8k`1$  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); :L]-'\y  
Utility.log(header+" : "+con.getHeaderField(header)); G5!|y#T  
else B`LD7]ew  
break; 3|q2rA  
} &K06}[J  
} +*n]tlk  
USE   
ah 4kA LO  
public void splitterStop() P\.WXe#j  
{ :[L{KFQU  
bStop = true; ~@xT]D!BQ  
} S
2Zx &D/_  
!)NYW4"  
Dz,uS nnm  
} ';_1rh  
Po!oN~r  
et@">D%;]  
/* '^hsH1  
**FileAccess.java k - FB  
*//文件访问(定位，写) ,
(6)ghr  
package NetFox; dI!8S  
import java.io.*; \$'R+k-57;  
:eSc;  
R_maNfS]Z  
public class FileAccessI implements Serializable{ <[bQo&B2 E  
K-Re"zsz  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 8098y,mQe  
RandomAccessFile oSavedFile; bi+9R-=&  
long nPos; KCE=|*6::|  
HB%K|&!+  
QQ*gFP.Ao  
public FileAccessI() throws IOException 6j_ 678  
{ ol50d73B  
this("",0); : -E,  
} wc"9A~  
 "";=DH  
J)_>%.
 
public FileAccessI(String sName,long nPos) throws IOException wqcDAO(  
{ 6Ux[,]GK  
oSavedFile = new RandomAccessFile(sName,"rw"); '[%jjUU  
this.nPos = nPos; 1bd$XnU  
oSavedFile.seek(nPos); dQ,Q+ON>  
} CdZnD#F2  
i)=m7i  
X|,["Az 8  
public synchronized int write(byte[] b,int nStart,int nLen) gglf\)E;}E  
{ B4@fY

 
int n = -1; >#INEO  
try{ x9h?e`  
oSavedFile.write(b,nStart,nLen); ;r3}g"D@  
n = nLen; )Q~C4C-j  
} 2H6:np|O  
catch(IOException e) \/
n+j!  
{ 7vw;Egd@@-  
e.printStackTrace (); ~)_K"h.DY  
} 2.ew^D#
 
^1R"7h  
Vu=] O/ =P  
return n; $_wo6/J5+D  
} {aoMJJq  
0fA=_=A,  
B& "RS  
} 04~}IbeJ  
u >4ArtF  
>[EBpYi  
/* >G&^?5  
**SiteInfoBean.java ;ed#+$Na  
*/ w;~>k%}j  
package NetFox; r|<6Aae&  
r5[4h'f  
C\OECVT  
public class SiteInfoBean { pp<E))&R  
o OQ'*7_  
ewpig4  
private String sSiteURL; //Site's URL @cPflb  
private String sFilePath; //Saved File's Path Vu%n&uF  
private String sFileName; //Saved File's Name l~NEGb  
private int nSplitter; //Count of Splited Downloading File z"EWj73  
5\xr?`VZ  
H$Kw=kMw  
public SiteInfoBean() C!5I?z&  
{//nSplitter的缺省值为5 P<vo;96JT  
//default value of nSplitter is 5 ##v`(#fu  
this("","","",5); 7LfcF  
} )(lJT&e  
<1K7@Tu  
3-iD.IAUm@  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) IytDvz*|  
{ ?,>5[Ha^?  
sSiteURL= sURL; oPsK:GC`U  
sFilePath = sPath; NCn`}QP  
sFileName = sName; "H$@b`)  
this.nSplitter = nSpiltter; \ADLMj`F|  
<<sE`>)  
#jm@N7OZ  
} m<3w^mww  
x)_r@l`$ix  
NJm-%K  
public String getSSiteURL() ioWo ]  
{ l~D\;F  
return sSiteURL; z+ ZG1\  
} 85D? dgV  
^&MK42,\  
SB/3jH  
public void setSSiteURL(String value) n+rM"Gxz  
{ 'BhwNuW\"  
sSiteURL = value; @D]lgq[  
} yPN+W8}f  
"Vy WT  
Mb.4J2F?  
public String getSFilePath() H{%H^t>  
{ T pD;  
return sFilePath; *{|$FQnR>(  
} oqYt/4^Q  
ceG&,a$\  
A?r^V2+j  
public void setSFilePath(String value) 'g hys1H  
{ NH4?q!'G  
sFilePath = value; SO_>c+Dw  
} s4bv;W  
5z Kqb  
[,b)YjO~Xd  
public String getSFileName()
QZ~0o7  
{ 03_pwB)^  
return sFileName; mf9hFy*<4  
} #kci=2q_  
E30Z`$cz:  
i
D714+N(  
public void setSFileName(String value) ]-bQNYKX  
{ (;ADW+.`J  
sFileName = value; M)O[j}N  
} 6.19g'{sB  
1qZG`Vz  
NO4Z"3Pd_  
public int getNSplitter() S/7l/DFb  
{ pV=@sz,G  
return nSplitter; 0>FE%  
} Y{+3}drJE  
*)D1!R<\,R  
jT-<IJh!o  
public void setNSplitter(int nCount) V{ |[oIp  
{ o(fyd)t  
nSplitter = nCount; fEwifSp.  
} OaaH$B  
} D5L{T+}Oi%  
i*CnoQH  
5\'AD^{  
/* d.AC%&W  
**Utility.java  :,~K]G  
*/ E}YIWTX  
package NetFox; 9!#EwPD$#  
gr+Pl>C{  
M*`hDdS  
public class Utility { c1#+Vse  
GHG,!C  
6|#g+&[  
public Utility() ) EXJ   
{ ]0-<>  
vQHpf>o  
FmD +8=  
} %b?uW]j:  
th 2<o5  
//线程睡眠 _ZyT3P&  
public static void sleep(int nSecond) u"Y]P*[k  
{ Nfaf;;J}  
try{ [K:29N9~4  
Thread.sleep(nSecond); vyU!+mlc  
} W.[BPR  
catch(Exception e) ArXl=s';s4  
{ ti2  
e.printStackTrace (); V.VJcx  
} !*vBW/  
} vD26;S.y[a  
X"<|Z]w  
//日志 {[^#h|U  
public static void log(String sMsg) ~kb{K;  
{ PeNF+5s/K  
System.err.println(sMsg); _ECB^s_  
} R=$Ls6z  
Qxq-Mpx{  

h<NRE0-  
public static void log(int sMsg) <\aU"_D   
{ ;?~ 9hN!  
System.err.println(sMsg); '[0YIn  
} Pa&4)OD  
} u)~s4tP4  
ab
4LTF|  
!y*oF{RZ  
/* U^?= 0+  
**TestMethod.java J?D\$u:  
*/ 1;&T^Gdj  
package NetFox; nk/vGa4
  
D=&K&6rr  
?,XC=}  
public class TestMethod { 9@y3IiZ"}  
6+PGwCS  
W[|[;{  
public TestMethod() 7'eh)[T  
{ ///xx/weblogic60b2_win.exe u-.L^!k  
try{ '[f
Zt#  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); hQ';{5IKvC  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); $E.XOpl&I  
SiteFileFetch fileFetch = new SiteFileFetch(bean);  SFpQ#  
fileFetch.start(); [{cC  
} HJ@5B"  
catch(Exception e){e.printStackTrace ();} m =k%,J_  
F1c&0*_A  
=x H~ww (D  
} 6N3@!xtpi  
*Hu
np Y  
\ja `c)x  
public static void main(String[] args) GYoseqZM  
{ .'lN4x  
new TestMethod(); &HL{LnLP@/  
} oD0EOT/E  
} H[nz]s  
点击下载更多相关资料