http断点续传简单实现（java)

/* x*'H@!!G  
**SiteFileFetch.java Fp@>(M#3  
*/ F7*)u-4Yn  
package NetFox;
^M
q@} 0  
import java.io.*; [pmIQ228  
import java.net.*; ~+
t@7A=  
lOeX5%$Z  
!1i-"rR  
public class SiteFileFetch extends Thread { R-NM ~gp  
^t7u4w!  
S ;rd0+J  
SiteInfoBean siteInfoBean = null; //文件信息Bean 0(f+a_2^Q  
long[] nStartPos; //开始位置 DW9MX`!Xc  
long[] nEndPos; //结束位置 o_mjI:  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 'm6bfS^T  
long nFileLength; //文件长度 Lp(`m=;O  
boolean bFirst = true; //是否第一次取文件 hbvcIGaT  
boolean bStop = false; //停止标志 Nr$78] o9  
File tmpFile; //文件下载的临时信息 R_+:nCB@,  
DataOutputStream output; //输出到文件的输出流 82EvlmD  
Z#Nw[>NN*  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） WrDFbcH  
public SiteFileFetch(SiteInfoBean bean) throws IOException 7rRI-wZ  
{ f"j9C%'*  
siteInfoBean = bean; 1_f+! ns#  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Udtz zka  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); k,=<G,  
if(tmpFile.exists ()) ]N'%l]_$  
{ m3pDFI  
bFirst = false; W3>9GY90R  
read_nPos(); ]j
VE
 
} OOXSJE1  
else 2P8wvNDG  
{ 1?|"33\03R  
nStartPos = new long[bean.getNSplitter()]; oNPvksdC;  
nEndPos = new long[bean.getNSplitter()]; P)f8lU^z  
} Ot\[Ya''  
Y ?n4#J<  
d ([~o  
.(cpYKFX  
} &}P#<"Fo8Q  
=d ;#Nu-  
5rck]L'  
public void run() |36%B7H  
{ Bx5xtJ|!  
//获得文件长度 |J:r]);@K  
//分割文件 #CI0G  
//实例FileSplitterFetch X,3\c:  
//启动FileSplitterFetch线程 FA{Q6fi:2  
//等待子线程返回 $3p48`.\  
try{ 9^n0<(99b  
if(bFirst) ]*k ~jY,  
{ F>#F@j^c  
nFileLength = getFileSize(); I9+h-t  
if(nFileLength == -1) j][&o-Ev  
{ XPMUhozV
 
System.err.println("File Length is not known!"); o jxK8_kl  
} wH@S$WT  
else if(nFileLength == -2) [@VzpVhXz  
{ G[ #R1'  
System.err.println("File is not access!"); @Z'i7Z  
} d@{12hq  
else <^5$))r  
{ NI,>$@{  
for(int i=0;i<nStartPos.length;i++) p\;8?x  
{ %RtL4"M2j  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); F::Ki4{jJ  
} rL"]m_FK  
for(int i=0;i<nEndPos.length-1;i++) 2%R.~9HtA  
{ [efU)O&  
nEndPos = nStartPos[i+1]; b?iPQ$NyQ  
} Nb ~J'"  
nEndPos[nEndPos.length-1] = nFileLength; b,+KXx  
} U7n#TPet  
} #>:S&R?2t  
Os>&:{D4!  
My
g;2.  
//启动子线程 g7hI9(8+  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; m`8{arz2  
for(int i=0;i<nStartPos.length;i++) J>T98y/))  
{ JS m7-p|E  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0H4|}+e  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), e4I
bj/  
nStartPos,nEndPos,i); P
nE7}  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 
9{A4>  
fileSplitterFetch.start(); *?1\S^7R  
} oVHe<zE.  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), j96}E/gF  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); #Ox@[Z1I  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ._]Pz6  
nEndPos = " + nFileLength); hV,T889'  
// fileSplitterFetch[nPos.length-1].start(); s Y1@~v  
wI 7gHp  
<h#W
*a  
//等待子线程结束 l(Hz9  
//int count = 0; H"w;~;h  
//是否结束while循环 )_j(NX-C:  
boolean breakWhile = false; !'# D~  
sDg1nKw(  
3
p HI+a  
while(!bStop) WO%pX+PoH  
{ d\3 %5Y  
write_nPos(); 1QmOUw}yj  
Utility.sleep(500); 2Uf/'  
breakWhile = true; %?+Lkj&  
!a\v)R  
zTMLE~w  
for(int i=0;i<nStartPos.length;i++) T&6>Eb0{  
{ .Y7Kd+)s)L  
if(!fileSplitterFetch.bDownOver) X0j>g^b8  
{ W(ryL_#;  
breakWhile = false; fNx!'{o"  
break; ~V?z!3r-)  
} @ls/3`E/5E  
} fATVAv  
if(breakWhile) nJv=kk1|o  
break; T<Y*();Zo  
aLW3Ub{h  
Sw>>]UjU  
//count++; D[]0/+,  
//if(count>4) ipGxi[Vav  
// siteStop(); 9wf"5c  
} ZZHQ?p-  
Tzjv-9^V  
+Z_VF30pa  
System.err.println("文件下载结束！"); alzdYiGf  
} G~&8/ s  
catch(Exception e){e.printStackTrace ();} 58HAl_8W  
} [ t8]'RI%  
,37<FXX,  
;q%z\gA  
//获得文件长度 YSPUQ  
public long getFileSize() uUq= L  
{ oBub]<.J  
int nFileLength = -1; {)b  
try{ -:r<sv$  
URL url = new URL(siteInfoBean.getSSiteURL()); 0>-}c>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); t~ I;IB  
httpConnection.setRequestProperty("User-Agent","NetFox"); xuqG)HthRS  
w1zMY
:9  
|%XcI3@*  
int responseCode=httpConnection.getResponseCode(); |[#Qk 4Ttf  
if(responseCode>=400) %o\+R0K  
{ [+A]E,pv]1  
processErrorCode(responseCode); 9v
DOSwU*  
return -2; //-2 represent access is error {=d}04i)E"  
} 2a
uJp .  

J1gnR  
$A,YQH+  
String sHeader; iE;F=Rb  
oVp/EQ  
8#,_%<?UVy  
for(int i=1;;i++) Au)~"N~p?  
{ ^A\(M%*F  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); M(\{U"%@?  
//Utility.log(in.readLine()); "B+F6  
sHeader=httpConnection.getHeaderFieldKey(i); Pz D30VA  
if(sHeader!=null) 4IY|<  
{ ]3 GO_tL  
if(sHeader.equals("Content-Length")) AG%[?1IXW  
{ /4 Kd
  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); +zDRed_]=_  
break; zHNBX Rx  
} DS@Yto  
} RTg\c[=w  
else "|&3z/AUh  
break; oXk6,b"  
} oz
]3 Tx  
} v/~&n  
catch(IOException e){e.printStackTrace ();} 6~{'\Z  
catch(Exception e){e.printStackTrace ();} "G*$#  
\AoqOC2u  
)J+OyR=  
Utility.log(nFileLength); &'Nzw2  
T]/>c  
Ax=)J{4v  
return nFileLength; }z9v*C  
} F+BCzsm7$  
GZx*A S]+  
:YkAp9civ  
//保存下载信息（文件指针位置） /7+b.h])^  
private void write_nPos() !L9]nO 'BL  
{ c}),yQ|!:  
try{ |-*50j l  
output = new DataOutputStream(new FileOutputStream(tmpFile)); S{MB$JA  
output.writeInt(nStartPos.length); U%BtBPL  
for(int i=0;i<nStartPos.length;i++) )OQ<H.X  
{ ?0sTx6x@  
// output.writeLong(nPos); GCr]x '  
output.writeLong(fileSplitterFetch.nStartPos); ld|GY>rH  
output.writeLong(fileSplitterFetch.nEndPos); X+u1p?  
} vQ2{+5!|  
output.close(); e~'z;%O~  
} /d"@$+  
catch(IOException e){e.printStackTrace ();} PX23M|$!  
catch(Exception e){e.printStackTrace ();} /ET+`=n  
} SEi\H$!  
?< yYm;B  
;0 +Dx~  
//读取保存的下载信息（文件指针位置） 0/!0W%f[}  
private void read_nPos() SS_6VE*sI  
{ .ej+?QYwC  
try{ p9\*n5{  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); IW@phKz  
int nCount = input.readInt(); {w"Cr0F,  
nStartPos = new long[nCount]; }$uwAevP{y  
nEndPos = new long[nCount]; `@,V
bn^_  
for(int i=0;i<nStartPos.length;i++) G[_Z|Xi1  
{ \WdSj  
nStartPos = input.readLong(); x\:KfYr4Y;  
nEndPos = input.readLong(); br k
*;  
} +`mI\+y,  
input.close(); <rui\/4NJ  
} e$Yvy>I'tS  
catch(IOException e){e.printStackTrace ();} G^VOA4  
catch(Exception e){e.printStackTrace ();} Sj/v:  
} F9las#\J  
s?9Y3]&+&M  
#k>A,  
private void processErrorCode(int nErrorCode)
L>7@!/9L  
{ qJonzFp7  
System.err.println("Error Code : " + nErrorCode); \x4:i\Fx@  
} # SJJ@SM  
_"t>72 `  
cCx{ ")  
//停止文件下载 ,-(D(J;}1  
public void siteStop() 7D 3-/_v  
{ TOa6sB!H  
bStop = true; s!MD8ia  
for(int i=0;i<nStartPos.length;i++) kj4=Q\Rfm  
fileSplitterFetch.splitterStop(); 5X5UUdTM  
@;hdZLG]`&  
`*kl>}$  
} H=Cj/jE  
} !SnLvW89Z  
//负责部分文件的抓取 '<ZHzDW@  
**FileSplitterFetch.java kou
7_4oS  
*/ 4 540Lw'A  
package NetFox; ${wp}<u_  
=_@) KWeX$  
ug;\`.nT^  
import java.io.*; ;
9ChBA  
import java.net.*; -^7 $HD  
Tj<B;f!u  
W*(- *\1[  
public class FileSplitterFetch extends Thread { 9OY ao  
SwO$UqYU=  
61gyx6v  
String sURL; //File URL DYgB_Iak  
long nStartPos; //File Snippet Start Position K@Q%NK,  
long nEndPos; //File Snippet End Position iG~&uEAJ  
int nThreadID; //Thread's ID @8A[HP  
boolean bDownOver = false; //Downing is over O%F*i2I:+k  
boolean bStop = false; //Stop identical ouFKqRs;  
FileAccessI fileAccessI = null; //File Access interface <1*\ ~CX  
R4k+.hR  
=i;T?*@  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException k:@N6K/$P^  
{ UH\{:@GjNO  
this.sURL = sURL; VUHf-bKl  
this.nStartPos = nStart; E GZiWBr  
this.nEndPos = nEnd; 7#
9%,6Yi  
nThreadID = id; $T7 qd  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 #O8=M(- V  
} >w.%KVBJ  
vW?/:  
@B(E&  
public void run() F:Ps>  
{ L=C#E0{i  
while(nStartPos < nEndPos && !bStop) :!?Fq/!  
{ t6\--lk_  
#mK?:O\-1  
Gui[/iY,F  
try{ uf (_<~  
URL url = new URL(sURL); Lz:FR*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %4YSuZg  
httpConnection.setRequestProperty("User-Agent","NetFox"); EQ
:>]O  
String sProperty = "bytes="+nStartPos+"-"; -XwS?*O  
httpConnection.setRequestProperty("RANGE",sProperty); eT(X Ri0  
Utility.log(sProperty); &uBfsa$  
B8.}9  
a+a6P5kJ  
InputStream input = httpConnection.getInputStream(); /nX_Q?mo  
//logResponseHead(httpConnection); IX<9_q  
l]&x~K}  
nvNF~)mu  
byte[] b = new byte[1024]; + DE/DR:  
int nRead; 8xhx*A  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) A2A_F|f  
{ <$25kb R5K  
nStartPos += fileAccessI.write(b,0,nRead); Xrpvq(]  
//if(nThreadID == 1) C>,> _  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ! R3P@,j  
} R?- zJ ;  
=#<bB)59  
X{6a  
Utility.log("Thread " + nThreadID + " is over!"); BB(v,W  
bDownOver = true; DVKb`KJ"  
//nPos = fileAccessI.write (b,0,nRead); `R.Pz _
oe  
} T,vh=UF%]  
catch(Exception e){e.printStackTrace ();} UTN[!0[  
} .P?n<n#  
} 2Yd@V}  
"*W# z  
)N1iGJO)  
//打印回应的头信息 A^LS^!Jz  
public void logResponseHead(HttpURLConnection con) 5IFzbL#q#f  
{ N`N?1!fM<}  
for(int i=1;;i++) Zkqq<  
{ ~ L>M-D4o  
String header=con.getHeaderFieldKey(i); Q1|zX@,  
if(header!=null) PDC
b(5  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Ze#DFe$  
Utility.log(header+" : "+con.getHeaderField(header)); Y> }\'$\b  
else EIyFGCw|U  
break; uZ>q$ F  
} *">CEQ[MT  
} k#8`996P  
bw7gL\*  
u7Ix7`
V  
public void splitterStop() 3?L[ohKH?:  
{ r )_*MPY  
bStop = true; {d0-.  
} nLv~)IQ}:  
cx&\oP  
n4}e!  
} 6
v~nEw  
zDbO~.d  
aIrM-c8.O  
/* U[8F{LX  
**FileAccess.java ^&8hhxCPu|  
*//文件访问(定位，写) {~s\a2YH  
package NetFox; I;eoy,  
import java.io.*; eO*s,*  
;$gV$KB:xA  
i1m>|
[@k  
public class FileAccessI implements Serializable{ F[!%,-*  
tm2
lxt  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ,Oy$q~.  
RandomAccessFile oSavedFile; EBz4k)@m  
long nPos; Z2H bAI8  
U,61 3G  
d%epM5  
public FileAccessI() throws IOException cs9h\]ZA  
{ s8P3H|0.-  
this("",0); hlze]d?z  
} bqp^\yu-E  
2k^rZ^^"  
}Q]-Y :  
public FileAccessI(String sName,long nPos) throws IOException @pYC!;n+  
{ 3]9Rmx  
oSavedFile = new RandomAccessFile(sName,"rw"); ,9_O4O%  
this.nPos = nPos; wAX;)PLg  
oSavedFile.seek(nPos); dGkw%3[  
} 8e
,F{>N  
N mxh zjJ  
lcjOBu  
public synchronized int write(byte[] b,int nStart,int nLen) 4>vO9q  
{ j6XHH&ZEb  
int n = -1; m.1-[2{8~  
try{ J:&.[  
oSavedFile.write(b,nStart,nLen); v>Kh5H5e~  
n = nLen; g;6/P2w  
} B, H9EX  
catch(IOException e) D_~;!^  
{ -;&I
S  
e.printStackTrace (); ZX1/6|_  
} '-[hy>t  
m6$&yKQ-=h  
DLqH*U  
return n; Vw
h;QJxb  
} bDJ!Fc/  
_od /)#  
G e]NA]<  
} tgi%#8ZDpz  
@U1|?~M%s  
r=vY-p  
/* 5$HG#2"Kb#  
**SiteInfoBean.java R9
#ar{  
*/ y%61xA`#  
package NetFox; bu_@A^ys  
d,(q3  
|uw48*t  
public class SiteInfoBean { Fw{@R
Qf8  
.35~+aqC  
V\{@c%xW  
private String sSiteURL; //Site's URL M<*Tp^Y'  
private String sFilePath; //Saved File's Path ~OPBZ#  
private String sFileName; //Saved File's Name ytjZ7J['{  
private int nSplitter; //Count of Splited Downloading File !t"/w6X1I  
{#,5C H')  
t&=bW<6  
public SiteInfoBean() <#nU 06 fN  
{//nSplitter的缺省值为5 b$fmU"%&|  
//default value of nSplitter is 5 O2pE"8=4Q  
this("","","",5); +_cigxpTc  
} &|
ne!wu  
p5vQ.Ni*\-  
L[Z^4l_!  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Us'JMZ~  
{ z~3ubta8(@  
sSiteURL= sURL; a{^z= =  
sFilePath = sPath; ]w _&%mB  
sFileName = sName; I]+ zG  
this.nSplitter = nSpiltter; .FgeAxflP  
)j~
{P  
K{/i2^4  
} t,8?Tf+i  
"#7Q}d!x  
<3@nv%  
public String getSSiteURL() !-470
J  
{ F1-"yX1B  
return sSiteURL; 7z1@XO<D  
} LmqSxHs0
Q  
r0lI&25
w  
Tgtym"=xd  
public void setSSiteURL(String value) DzE^FY  
{ Y<VX.S2kf  
sSiteURL = value; eaDZ^Z Er  
} MZ-;'w&Z  
#-G@p  
Ot`%5<E^  
public String getSFilePath() fx(8 o+  
{
&&P9T/Zks  
return sFilePath; uj.$GAtO)  
} $p0D9mF  
3!gz^[!?EN  
#t(/wa4  
public void setSFilePath(String value) { >[
]iX  
{ V61oK  
sFilePath = value; /4pYhJ8S  
} lqL5V"2Y  
 ArAe=m!u  
@YH>|{S&  
public String getSFileName() 4_j_!QH87  
{  ov,  
return sFileName; @#t<!-8d  
} nKr'cb  
.u#Hg'oP  
wUr(i*  
public void setSFileName(String value) (UjaL@G  
{ yGt[Qvx#  
sFileName = value; Ew PJ|Z^  
} ?;`GCE  
JcmMbd&B  
36+/MvIT  
public int getNSplitter() R(^Sse  
{ m]MR\E5]By  
return nSplitter; 5Wa)_@qI)`  
}  XA;PWl5!  
\M@IKE  
2SD Z  
public void setNSplitter(int nCount) &R4?]I  
{ Tb?XKO,  
nSplitter = nCount; _zM?"16I}  
} KNQj U-A  
} Y_ne?/sZE  
t!/~_}eDJ  

FO^6c  
/* M*3G  
**Utility.java [j@i^B &  
*/ zzI,iEG  
package NetFox; 9M9Fif.  
F#<:ZByjJ@  
2D"my]FnF  
public class Utility { `V V>AA5  
M$ieM[_T  
*'aJO}$  
public Utility() +,)k@OI  
{ ll$mRC  
uuFQTx))  
&ot^+uVH  
} <>n|_6'$90  
7ixG{yu  
//线程睡眠 kDmuj>D  
public static void sleep(int nSecond) 0Q7<;'m  
{ }[PwA[k'  
try{ [3-u7Fx!  
Thread.sleep(nSecond); .Er+*j;&w  
} N5;z5E  
catch(Exception e) DKMkCPX%  
{ P8dMfD*"E  
e.printStackTrace (); s,[I_IiPf  
} RbxQTM_:M  
} e> 9X  
7lwI]/ZH*  
//日志 CckfoJ 9  
public static void log(String sMsg) Sft vN-  
{ |-\anby<  
System.err.println(sMsg); DPW^OgL;  
} Lc}hjK  
W9c&"T9JT  
,D`jlY-1l  
public static void log(int sMsg) 6<S-o|Xw  
{ R||$Rfe  
System.err.println(sMsg); x<!]#**;  
} wj}LVyV  
} oP56f"BE(  
!L9|iC:8  
^vG<Ma.yk  
/* C7m/<  
**TestMethod.java v ,h
"u  
*/ JP\jhkn  
package NetFox; dPpQCxf  
>T[Y>]  
`fEzE\\!*  
public class TestMethod { [
|*7"Q(  
u?SwGXi~8  
zJ8T.+qJ  
public TestMethod() dT7fyn  
{ ///xx/weblogic60b2_win.exe Wkk(6gS,  
try{ 3)=ix. wW  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); |-/@3gPO  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); L6nsVL&  
SiteFileFetch fileFetch = new SiteFileFetch(bean); F^Jz   
fileFetch.start(); k^K76mB  
} {*hFG:u  
catch(Exception e){e.printStackTrace ();} 7)#JrpTj%  
@YaI5>,/  
pd:YR;  
} lj&\F|-i  
ol_\ "  
td\gk  
public static void main(String[] args) 8lqmd1v  
{ W!XBuk-  
new TestMethod(); 3*%+NQIj  
} RfvvX$  
} #X*);cn  
点击下载更多相关资料