http断点续传简单实现（java)

/* Fo86WP}  
**SiteFileFetch.java `PVr;&  
*/ {u4=*>?G  
package NetFox; yQ{xRtNO  
import java.io.*; V(A p|I:G  
import java.net.*; IS9}@5`'  
u{SJ#3C5  
@4%
a  
public class SiteFileFetch extends Thread { *6b$l.Vs  
5^W},:3R  
Sgy_?Y  
SiteInfoBean siteInfoBean = null; //文件信息Bean Jfs$VGZP;  
long[] nStartPos; //开始位置 Pm*N!:u  
long[] nEndPos; //结束位置 q;{# ~<"+  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Kf!8PR
$  
long nFileLength; //文件长度 ~=xS\@UY =  
boolean bFirst = true; //是否第一次取文件 ?!$uMKyt  
boolean bStop = false; //停止标志 >lg-j-pV  
File tmpFile; //文件下载的临时信息 ,&X7D]  
DataOutputStream output; //输出到文件的输出流 }&I^1BHZs  
yu>DVD  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ~ d!F|BH4  
public SiteFileFetch(SiteInfoBean bean) throws IOException (&y~\t]H  
{ )n&@`>vm  
siteInfoBean = bean; Spt]<~  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); =5QP'Qt{O  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 6JYVC>i  
if(tmpFile.exists ()) w?LDaSz\t  
{ Np?%pB!Q  
bFirst = false; 6)B6c. 5o  
read_nPos(); [LHx9(,NM  
} A^9RGz4=  
else %1Pn;bUU!  
{ !L)~*!+Gf  
nStartPos = new long[bean.getNSplitter()]; as%ab[ fX  
nEndPos = new long[bean.getNSplitter()]; E"|LA[o  
} kUp[b~  
.7"]/9oB  
|z`kFil%  
<,S5(pZ  
} ~
VqDh*0  
wx,yx3c (  
t"]+}
]O  
public void run() t
|ih{0  
{ _3lci  
//获得文件长度 ,%zU5hh  
//分割文件 `?H yDny  
//实例FileSplitterFetch :"pA0oB  
//启动FileSplitterFetch线程 ,iQRf@#W_b  
//等待子线程返回 ?C[W~m P  
try{ )Uk!;b  
if(bFirst) `=zlS"dQ  
{ qkEre  
nFileLength = getFileSize(); M!9gOAQP  
if(nFileLength == -1) \.`;p  
{ XmK2Xi;=b  
System.err.println("File Length is not known!"); :&{:$-h!  
} 4zRz U  
else if(nFileLength == -2) i`Tp +e@a>  
{ VJeoO)<j  
System.err.println("File is not access!"); _shoh  
} BXCB/:0  
else r^m8kYezQ  
{ `k 5'nnyP  
for(int i=0;i<nStartPos.length;i++) zree}VqD;5  
{ fnwhkL#8  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ~q.a<B`,t  
} 9uNkd2#  
for(int i=0;i<nEndPos.length-1;i++) kma)DW  
{ /5l"rni   
nEndPos = nStartPos[i+1]; GbLuXU  
} ?OYK'p.  
nEndPos[nEndPos.length-1] = nFileLength; <:,m  
} ^{IF2_h"  
} )H'SU_YU  
$E j;CN59  
$mV1K)ege  
//启动子线程 907N;r  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; VDyQv^=#  
for(int i=0;i<nStartPos.length;i++) k`5jy~;  
{ "x+o(jOy  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1^x"P#u  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), #s\HiO$BT  
nStartPos,nEndPos,i); C3XB'CL6  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [%);N\o2Y  
fileSplitterFetch.start(); P0B`H7D  
} v/fo`]zP  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), TQ{rg2_T  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Vw^2TRU  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Tke3X\|  
nEndPos = " + nFileLength); CWTPf1?eB  
// fileSplitterFetch[nPos.length-1].start(); x'4q`xDa  
.d JX,^  
GV+K] KDI  
//等待子线程结束 -|
"[S"e  
//int count = 0; y.O
%  
//是否结束while循环 m>H+noc^  
boolean breakWhile = false;  ?)_?YLi  
fbG+
.'  
`Mh3v@K:  
while(!bStop) &!xePKvO6k  
{ ko2T9NI:S  
write_nPos(); YKUb'D:t]  
Utility.sleep(500); $j+RUelFY  
breakWhile = true; 9?jD90@ }  
|2$wJ$I  
V>$A\AWw  
for(int i=0;i<nStartPos.length;i++) ?F^$4
:  
{ }f~:>N#  
if(!fileSplitterFetch.bDownOver) + Z7 L&BI  
{ ,[} XK9  
breakWhile = false; ,R-T( <r  
break; 9_h V1:  
} _i/x4,=xv  
} (mNNTMe  
if(breakWhile) 0:CIM  
break; a7]wPXKq  
nRE(RbRe  
.qN|.:6a  
//count++; Yq$KYB j  
//if(count>4) <r@w`G  
// siteStop(); xF#'+Y  
} H n^)Xw  
tyW5k(>  
tFi'RRZ  
System.err.println("文件下载结束！"); v_ U$jjO1  
} >-%}'iz+  
catch(Exception e){e.printStackTrace ();} @L9C_a  
} pL& Zcpx  
,cesQ ou  
<-]qU}-  
//获得文件长度 JNJ96wnX1  
public long getFileSize() N<$dbqoT|  
{ V,*<E&+  
int nFileLength = -1; RZ6[+Ygn  
try{ (uxe<'Co|  
URL url = new URL(siteInfoBean.getSSiteURL()); $ouw*|<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |=o)|z2  
httpConnection.setRequestProperty("User-Agent","NetFox"); L&I8
lG  
I*SrKZb  
Un~8N  
int responseCode=httpConnection.getResponseCode(); $ #*";b)QY  
if(responseCode>=400) C8xxR~mq  
{ j& H4L  
processErrorCode(responseCode); v!>(1ROQ.=  
return -2; //-2 represent access is error e}PJN6"5  
} SqF `xw  
H;~Lv;,g,  
|#G
ug('  
String sHeader; F=B[%4q`%  
(/^s?`1{N?  
k6}M7&nY  
for(int i=1;;i++) *K57($F  
{ zAZ+'9LB  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); '1 }ybSG  
//Utility.log(in.readLine()); S.I3m-  
sHeader=httpConnection.getHeaderFieldKey(i); n&n WY+GEo  
if(sHeader!=null) j6JK4{  
{ .:b&$~<  
if(sHeader.equals("Content-Length"))  Fhk 8  
{ >iKbn  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); jO5,PTV  
break; Nuebxd
 
} U
G!528;7  
} zUI
h^hbFf  
else [Zpx :r}  
break; ~0 PR>QJ  
} l!d |luqbA  
} &
>xd6-  
catch(IOException e){e.printStackTrace ();} S#:yl>2  
catch(Exception e){e.printStackTrace ();} TpSv7kT]  
-r'/PbV0  
Fcz}Gs4  
Utility.log(nFileLength); 'bb*$T0=  
Xa
xM$  
moOc G3=9  
return nFileLength; +NT8dd  
} 4%GwCEnS  
2LTMt?  
`q$a p$?  
//保存下载信息（文件指针位置） YaT6vSz  
private void write_nPos() %*A|hK+G:W  
{ =-m"y~{>3  
try{ &*JU N}86  
output = new DataOutputStream(new FileOutputStream(tmpFile)); &Rp/y%9  
output.writeInt(nStartPos.length); )ZQ>h{}D  
for(int i=0;i<nStartPos.length;i++) gic!yhsS_  
{ ]_EJ "'x  
// output.writeLong(nPos); \,ko'48@  
output.writeLong(fileSplitterFetch.nStartPos); JS^QfT,zE  
output.writeLong(fileSplitterFetch.nEndPos); ceUhCb  
} v\3 \n3[u  
output.close(); ,8`CsY^1  
} ;S5J"1)O~  
catch(IOException e){e.printStackTrace ();} +@"Ls P  
catch(Exception e){e.printStackTrace ();} e*!0|#-  
} g.wDg  
I;g>r8N-Bu  
(oxMBd+n1  
//读取保存的下载信息（文件指针位置） 0zHMtC1,  
private void read_nPos() |lG7/\A  
{ G &QGQ  
try{ /7CV7=^d,  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); EW~M
,+?  
int nCount = input.readInt(); b3M`vJ+{  
nStartPos = new long[nCount]; ?nCo?A  
nEndPos = new long[nCount]; w2(pgWed  
for(int i=0;i<nStartPos.length;i++) ^Mmsja5K  
{ unB`n
'L  
nStartPos = input.readLong(); 579<[[6~d2  
nEndPos = input.readLong(); '~\\:37+  
} iRIO~XVo  
input.close(); )7jJ3G*  
} !SPu9:  
catch(IOException e){e.printStackTrace ();} =A]*r9  
catch(Exception e){e.printStackTrace ();} sd,KB+)  
} ;xQNa}"V  
>>b <)?3Rv  
+}eH,  
private void processErrorCode(int nErrorCode) Py~1xf/  
{ h0oe'Xov  
System.err.println("Error Code : " + nErrorCode); b9Mp@I7Q-  
} r^v1_u,1I  
crbph.0  
/=K(5Xd  
//停止文件下载 '5xvR G  
public void siteStop() 3Ow bU  
{ Kk\TW1w3  
bStop = true; n|N?[)^k  
for(int i=0;i<nStartPos.length;i++) 8svN*`[  
fileSplitterFetch.splitterStop(); oB$c-!&  
L:_GpZ_  
mFgrT  
} Z'!i"Jzq|{  
} ?_t_rF(?6  
//负责部分文件的抓取 :lBw0{fP  
**FileSplitterFetch.java Ju@8_ ?8=  
*/ A:4?Jd>  
package NetFox; [aF"5G
  
%5ovW<E:  
WS6;ad;|  
import java.io.*; + usB$=kJ  
import java.net.*; )&s9QBo{b  
5kik+  
ey@{Ng#  
public class FileSplitterFetch extends Thread { TFG0
~"4Cz  
`V2doV)  
HJ+Q7)  
String sURL; //File URL v83@J~  
long nStartPos; //File Snippet Start Position ' +f(9/  
long nEndPos; //File Snippet End Position X6Q\NJ"
B  
int nThreadID; //Thread's ID H{4_,2h=m  
boolean bDownOver = false; //Downing is over QJF_ "  
boolean bStop = false; //Stop identical "DC L Z  
FileAccessI fileAccessI = null; //File Access interface g-4j1yJV<  
}B ?_>0  
M)"'Q6ck=  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException @gnLY  
{ Vj[hT~{f  
this.sURL = sURL; W+I""I*mV  
this.nStartPos = nStart; bk|?>yd  
this.nEndPos = nEnd; !<vy!pXg  
nThreadID = id; 0WSOA[R%[b  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 L_Xbca=  
} nIWY<Z"  
Vtv~jJ{m  
6&;h+;h  
public void run() D!V~g72j  
{ `4-N@h  
while(nStartPos < nEndPos && !bStop) RpwDOG  
{ U'LPaf$O  
kD me>E=  
t\WU}aKML  
try{ fb[? sc  
URL url = new URL(sURL); b#(X+I  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); tTbfyI  
httpConnection.setRequestProperty("User-Agent","NetFox"); UCo`l~K)qg  
String sProperty = "bytes="+nStartPos+"-"; rV fZ_\|  
httpConnection.setRequestProperty("RANGE",sProperty); {8"Uxj_6V  
Utility.log(sProperty); 8[H bg  
3/ '5#$  
.sSbU^U  
InputStream input = httpConnection.getInputStream(); jbe_r<{  
//logResponseHead(httpConnection); TDX~?>P  
'iU+mRLp  
'?Xf(6o1  
byte[] b = new byte[1024]; ^fj30gw7\5  
int nRead; A_Y5{6@  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) XzBlT( `w  
{ #sE:xIR  
nStartPos += fileAccessI.write(b,0,nRead); #y f  
//if(nThreadID == 1) &ZL4/e  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); aA]wFZ  
} :W#?U yo  
D `av9I  
{s
0!hp  
Utility.log("Thread " + nThreadID + " is over!"); a1shP};pK  
bDownOver = true; OkMAqS  
//nPos = fileAccessI.write (b,0,nRead); Gi\Z"MiBZ  
} SB`xr!~A]  
catch(Exception e){e.printStackTrace ();} P2F8[o!<  
} d~q7!  
} X!6$<8+1OV  
P8[k1"c!  
\A6}=  
//打印回应的头信息 _BoA&Ism  
public void logResponseHead(HttpURLConnection con) ]:}7-;$V  
{ p]qz+Z/  
for(int i=1;;i++) !ScEA=  
{ p}e|E!  
String header=con.getHeaderFieldKey(i); 1'H!S%fS  
if(header!=null) QT=i>X  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); qIxe)+.  
Utility.log(header+" : "+con.getHeaderField(header)); .O SQ8W}  
else o$#q/L  
break; t$b5,"G1  
} b3ys
"Vyn  
} Z>~7|v
l  
:1;"{=Yx}  
6]mAtA`Y  
public void splitterStop() d4)0G-|  
{ MkWbPm)  
bStop = true; p^w_-(p  
} H`,t"I  
b#*"eZj
 
t]T't='
  
} K1w:JA6(  
L) UCVm  
iI;np+uYk  
/* hW`o-'  
**FileAccess.java j Y(|z*|  
*//文件访问(定位，写) 89{`GKWX  
package NetFox; zYM0?O8pJ~  
import java.io.*; -XnOj2  
4
?]s%2U6  
gYloY=.Z$'  
public class FileAccessI implements Serializable{ gX|\O']6  
>vXS6`;  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 [
~kS)  
RandomAccessFile oSavedFile; 6Ilj7m*  
long nPos; 4wWfaL5"  
L\R(//V  
4>/i,_&K K  
public FileAccessI() throws IOException xZ(d*/6E  
{ 53?Ati\Y)  
this("",0); iba8G]2  
} z/nW;ow  
gGx<k3W^  
ND/oKM+?  
public FileAccessI(String sName,long nPos) throws IOException h gu\~}kD  
{ wYDdy gS  
oSavedFile = new RandomAccessFile(sName,"rw"); Lt i2KY}/%  
this.nPos = nPos; |{RCvm  
oSavedFile.seek(nPos); 9v1Snr  
} {;Oj  
9m<%+S5&  
U;*O7K=P  
public synchronized int write(byte[] b,int nStart,int nLen) WXG0Z  
{ s#(7D3Pr#  
int n = -1; L* ScSxw  
try{ p.H`lbVY  
oSavedFile.write(b,nStart,nLen); IJC]Al,df  
n = nLen; ]=59_bkD:s  
} 5H,(\Xd  
catch(IOException e) i^8w0H<-@v  
{ /B|"<`-H  
e.printStackTrace (); CAmIwAx6;  
} ff=RKKnN  
k5*Z@a  
x3F94+<n{  
return n; 7%G&=8tq  
} _#uRKy<`N  
jUDE)~h  
%cJdVDW`L  
} q29d=  
J4s`U/F  
(j(9'DjP  
/* 1~j,A[&|<  
**SiteInfoBean.java U ,!S1EiBs  
*/ 1bHQB$%z  
package NetFox; {:KPEN  
tgHN\@yj  
$e.Bz`  
public class SiteInfoBean { 0_,un^  
{bG.X?b  
xk3)#*  
private String sSiteURL; //Site's URL qQ1D}c@  
private String sFilePath; //Saved File's Path _ q AT%.  
private String sFileName; //Saved File's Name ~f( #S*Ic  
private int nSplitter; //Count of Splited Downloading File s>[Oe|`  
=h|7bYLy  
)\kNufP  
public SiteInfoBean() ~#)9Kl7<X  
{//nSplitter的缺省值为5 bJkFCI/  
//default value of nSplitter is 5 1lJ^$U  
this("","","",5); k(v &+v  
} Do5{t'm3  
i[w&!mn%  
54/ZGaonz  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)
j^e
Mi  
{ kBY#=e).  
sSiteURL= sURL; |tz{Es<`B  
sFilePath = sPath; _X@ Q`d  
sFileName = sName; 88 ca  
this.nSplitter = nSpiltter; t{`-G*^  
BqdGU-Q  
9;rZ)QD  
} ;yCtk ~T%  
6z
i Mf  
Zu>CR_C  
public String getSSiteURL() XpA|<s  
{ &)|f|\yh"  
return sSiteURL; lwo,D}  
} B B^81{A  
:qV|rih_Q  
>SS^qjh/  
public void setSSiteURL(String value) A0Q1"b=  
{ J7~Kjl  
sSiteURL = value; u'gsIuRJ  
} {UF|-VaG  
RB;2  
75A60Uw  
public String getSFilePath() U
o[`AzD3  
{ ]iZ-MG)J  
return sFilePath; ;<%d^   
} PW
yFys  
+eop4
|Z  
y+izC+  
public void setSFilePath(String value) q!q=axfMD  
{ w(ic$  
sFilePath = value; I;9DG8C&v*  
} JD AX^]  
KqNsCT+j  
C\|HN=2eh  
public String getSFileName() 2d<`dQY{l3  
{ Xob(4  
return sFileName; D2io3Lo$ov  
} }/g1  
v[a4d&P  
Yi19VU|/  
public void setSFileName(String value) GB>T3l"  
{ akwS;|SZ  
sFileName = value; h(^[WSa  
} maV*+!\  
a`Q-5*\;z  
9Z3Vf[n5\  
public int getNSplitter() eO{2rV45O  
{ WckWX]};S  
return nSplitter; pwF])uf*{\  
} zCu+Oi6  
eEeK ]8@  
gV'=uz v  
public void setNSplitter(int nCount) 7'@~TM  
{ wB<cW>6  
nSplitter = nCount; tcI Z 2H%  
} t~Ic{%bdA  
} ZKi?;ta=  
Yof]  
VY0-18 o  
/* -or)NE  
**Utility.java '47E8PIJ|  
*/ ffa
MF~+  
package NetFox; &@qB6!^  
V~t; J  
c{jTCkzq  
public class Utility { t /lU
*  
pz.fZV  
5)gC<  
public Utility() a JQ_V  
{ 2}5@:cwR+  
YCyh+%Q(  
nNRc@9Lt  
} 2V$YZSw6q  
WTZuf9:  
//线程睡眠 |s!n7%|,7  
public static void sleep(int nSecond) e^hI[LbNC  
{ I3Ad+]v  
try{ p >nKNd_aQ  
Thread.sleep(nSecond); B<,
AI7  
} Nxm '* -A  
catch(Exception e) Wa%p+(\<uB  
{ X C'|  
e.printStackTrace (); <h`}I3Ao  
} =
z}M(<G  
} T`Xz*\}Zb  
>~T2MlRux  
//日志 [kI[qByf  
public static void log(String sMsg) ,4(m.P10  
{ WX$AOnEv  
System.err.println(sMsg); ?nf4K/IjZ!  
} MhN8'y(  
?6:e%YT  
jf& oN]sZ  
public static void log(int sMsg) Ys
td[  
{ hTQ]xN)  
System.err.println(sMsg); e ,A9N%M  
} @%6"xnb`  
} ?C_Y2JY  
DF"*[]^[  
So#>x5dL  
/* ~B`H5#  
**TestMethod.java 1*B'o<?P1  
*/ .L_ Hk  
package NetFox; $XFFNE`%  
No]#RvEd3  
fc%C!^7  
public class TestMethod { dewN\  
<@qJsRbhK  
Ia>~ph#]{`  
public TestMethod() T?D]]x  
{ ///xx/weblogic60b2_win.exe  +qyx3c+  
try{ WhDNt+uk)  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); A)nE+ec1  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); l,j0n0h.  
SiteFileFetch fileFetch = new SiteFileFetch(bean); fyv S1_  
fileFetch.start(); @Sz7*p  
} ,L8(Vo`-  
catch(Exception e){e.printStackTrace ();} IVG77+O# }  
/ASpAl[J  
[uu<aRAg3O  
} alZ83^YN'  
YU1z\pK  
f7 zGz  
public static void main(String[] args) aOW$H:b  
{ 5K$d4KT  
new TestMethod(); sHHu<[psM  
} vNAQ/Q  
} FX/f0C3CK  
点击下载更多相关资料