http断点续传简单实现（java)

/* F V8K_xj  
**SiteFileFetch.java *{t{/^'y  
*/ &ah!g!o3  
package NetFox; P9~7GFas|  
import java.io.*; 0Fr
mZ$  
import java.net.*; fD3}s
#M*G  
c:0nOP  
?mxBMtc  
public class SiteFileFetch extends Thread { #9Z\jW6b  
-lr)z=})  
A;nrr1-0  
SiteInfoBean siteInfoBean = null; //文件信息Bean "oZ-W?IKE  
long[] nStartPos; //开始位置 ?;pw*s1Atz  
long[] nEndPos; //结束位置 VG*Tdaua~  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ezRhSN?  
long nFileLength; //文件长度 FA-""]  
boolean bFirst = true; //是否第一次取文件 3.M<ATe^  
boolean bStop = false; //停止标志 i3~"qbU%z[  
File tmpFile; //文件下载的临时信息 USLG G}R  
DataOutputStream output; //输出到文件的输出流 rQ -pD  
0 1U/{D6D  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） \}SA{)  
public SiteFileFetch(SiteInfoBean bean) throws IOException \.+.VK  
{ 4.|-?qG  
siteInfoBean = bean; _5'OQ'P2  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); C$o#zu q-  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ~kUdHne(  
if(tmpFile.exists ()) 8Fy$'Zx'  
{ KI
~BjP\e  
bFirst = false; h|h-<G?>  
read_nPos(); '\qd{mM\r  
} c,a+u  
else t(69gF\"  
{ (R)\  
nStartPos = new long[bean.getNSplitter()]; \
.HX7v  
nEndPos = new long[bean.getNSplitter()]; EgO=7?(pW  
} LB}y,-vX>  
@+LkGrDP  
2 2K:[K  
|_Vi8Ly  
} iXN"M` nhm  
ad^7t<a}<  
yi`Z(j;
 
public void run() EsR_J/:Qe  
{ d&K2\n  
//获得文件长度 EU?)AxH^  
//分割文件 sM)qzO2wh  
//实例FileSplitterFetch 4naL2 Y!  
//启动FileSplitterFetch线程 ~IvAnwQ'  
//等待子线程返回 2Cd#~  
try{ L'k)  
if(bFirst) Dohq@+] O  
{ <eRE;8C-  
nFileLength = getFileSize(); rZ<n0w  
if(nFileLength == -1) S#+Dfa`8X  
{ .{+<o  
System.err.println("File Length is not known!"); ]jNv}{  
} \Z0-o&;w  
else if(nFileLength == -2) /mLOh2T  
{ -V@vY42  
System.err.println("File is not access!"); d~f_wN&r  
} PLDg'4DMg  
else NoS|lT  
{ IQ_2(8Kv  
for(int i=0;i<nStartPos.length;i++) ab?   
{ }RX[J0Prq~  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); yRt]i>  
} hKP7p  
for(int i=0;i<nEndPos.length-1;i++) bdh6ii  
{ ~"eos~AuW  
nEndPos = nStartPos[i+1]; tr8a_CV  
} e|x1Dq  
nEndPos[nEndPos.length-1] = nFileLength; r\J"|{)e  
} rEwEdyK  
} 5S4kn.3  
L{y%\:]  
9\
9:)q  
//启动子线程 _t[RHrs  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; G gmv(!  
for(int i=0;i<nStartPos.length;i++) aewVq@ngq!  
{ \9Nd"E[B  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (V2~txMh  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), jd<`W  
nStartPos,nEndPos,i); !1 :%!7  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); QcBuUFf!c  
fileSplitterFetch.start(); px6[1'|g  
} 6Y4sv5G  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $10"lM[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); /VFh3n>I2  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", o^P/ -&T  
nEndPos = " + nFileLength); ZmSe>}B=  
// fileSplitterFetch[nPos.length-1].start(); G9'Wo.$ t  
;T1OXuQ  
= GUgb2TAT  
//等待子线程结束 S<Z]gY @c  
//int count = 0; o6LeC*  
//是否结束while循环 J3Ipk-'lx  
boolean breakWhile = false; \;&WF1d`ac  
v@_}R_pX  
;vM&se63  
while(!bStop) $['_m~ 2  
{ :x"Q[079  
write_nPos(); *E$&  
Utility.sleep(500); HRX}r$  
breakWhile = true; ~>8yJLZ.7  
F@ Sw
  
9!C
D25u  
for(int i=0;i<nStartPos.length;i++) ?` ?HqR0  
{ 3d<Z##`{4  
if(!fileSplitterFetch.bDownOver) AQAZ+g(I
K  
{ y5>X0tT  
breakWhile = false; alr'If@7  
break;  ! @EZ  
} p'SclH[
 
} [2h4%{R&  
if(breakWhile) }Xa1K;KM{  
break; [wp(s2=  
FU]jI[  
{lv@V*_Y0  
//count++; Z=c&</9e  
//if(count>4) .7GTL  
// siteStop(); <L!9as]w  
} Whd.AaD\  
}:QQ{h_  
pNt,RRoR  
System.err.println("文件下载结束！"); iX]tL:,~i  
} %%uvia=e  
catch(Exception e){e.printStackTrace ();} 2~ [  
} Q)mYy
  
>#u9W'@|  
}\#u~k!l  
//获得文件长度 H\r- ;,&  
public long getFileSize() \mp2LICQg  
{ t=(d, kf  
int nFileLength = -1; q8m[ S4Q]g  
try{ o5h*sQ9  
URL url = new URL(siteInfoBean.getSSiteURL()); fYgEiap  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); oy[>`qyz  
httpConnection.setRequestProperty("User-Agent","NetFox");  4:Ton  
s~i73Qk/  

ro}WBv  
int responseCode=httpConnection.getResponseCode(); lVptA3
F  
if(responseCode>=400) .DrGr:UW  
{ %4$J.6M
 
processErrorCode(responseCode); '
&LH9r  
return -2; //-2 represent access is error (fqU73  
} y8.3tp  
~rfUqM]I   
qu`F,OG  
String sHeader; )x&4 Q=  
qsG}A  
M&SY2\\TB  
for(int i=1;;i++) !n^7&Y[N;  
{ 7W.z8>p  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); K3;~|U-l  
//Utility.log(in.readLine()); Ewq7oq5:  
sHeader=httpConnection.getHeaderFieldKey(i); ?910ki_  
if(sHeader!=null) k
*ZYT6Z?  
{ wl Nl|+ K  
if(sHeader.equals("Content-Length")) !QsmT3  
{ ],|
;  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 1$n!Lj=5  
break; cv7.=*Kb;  
} k &6$S9  
} 3kJ7aBiR<  
else dTVh{~/  
break; ,<O|#`?"@G  
} tGwQUn  
} SU7 erCHX  
catch(IOException e){e.printStackTrace ();} 5?HoCz]l  
catch(Exception e){e.printStackTrace ();}  K)P].htw  
Q`HG_n@?  
*@E&O^%cO  
Utility.log(nFileLength); S{S.H?{F  
9Itj@ps  
OV`#/QL  
return nFileLength; MT^krv(G  
} ? oQ_qleuo  
C<E;f]d  
h,x'-]q  
//保存下载信息（文件指针位置） 28,g'k!  
private void write_nPos() w1,6%?p(O  
{
'-[?iF@l  
try{ I,7n-G_'  
output = new DataOutputStream(new FileOutputStream(tmpFile)); iUOGuiP  
output.writeInt(nStartPos.length); ]}9D*V  
for(int i=0;i<nStartPos.length;i++) osPrr QoH  
{ ~+anI  
// output.writeLong(nPos); 7b hJt_`Q  
output.writeLong(fileSplitterFetch.nStartPos); 6B&ERdoX  
output.writeLong(fileSplitterFetch.nEndPos); OcZ8:`=%  
} ;#n+$Q#:  
output.close(); 9D H
}6fO  
} WXX08"  
catch(IOException e){e.printStackTrace ();} ;oJCV"y6$  
catch(Exception e){e.printStackTrace ();} "a]Ff&T-  
} 9RnXp&w  
/u pDbP.O  
822jZ sb  
//读取保存的下载信息（文件指针位置） 11BfJvs:  
private void read_nPos() zf?U q  
{ ^<v]
x; 3  
try{ O;SD90
  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); iNEE2BPp  
int nCount = input.readInt(); @W
O>F G3  
nStartPos = new long[nCount]; {PQ!o^7y  
nEndPos = new long[nCount]; DS>qth  
for(int i=0;i<nStartPos.length;i++) XFrgnnt  
{ ">'`{mXew  
nStartPos = input.readLong(); J/ZC<dkYQ  
nEndPos = input.readLong(); !/6KQdF  
}
'/
GZ,~q  
input.close(); rEY5,'?YHv  
} lPOcX'3\  
catch(IOException e){e.printStackTrace ();} 2R`/Oox   
catch(Exception e){e.printStackTrace ();} @>Ul0&Mf?  
} zH1:kko  
Q2RO&dL 9  
vw
/X  
private void processErrorCode(int nErrorCode) x[1(cj  
{ BZs?tbf  
System.err.println("Error Code : " + nErrorCode); \"AzT{l!;  
} )d"s6i
 
` EgO&;1D)  
kz?
m `~1  
//停止文件下载 FX:'38-fk  
public void siteStop() X.hVMX2B  
{ K0z@gWGE  
bStop = true; 2[TssJQ  
for(int i=0;i<nStartPos.length;i++) jLgx(bM
n  
fileSplitterFetch.splitterStop(); -?PX
j)<  
-A;4""  
7?EC kuSv  
} YR
s32vVz  
} _5SA(0D#9  
//负责部分文件的抓取 "%fvA;  
**FileSplitterFetch.java D$PR<>=y  
*/ 8VLD yX2-  
package NetFox; .80L>0  
(d$ksf_[%f  
Kk<MS$Ov  
import java.io.*;  4xnM7t\  
import java.net.*; 4Q5c'  
rhvTV(Bz  
_)F0oC {  
public class FileSplitterFetch extends Thread { 4&/m>%r  
EE[JXoke  
/{+77{#Qn  
String sURL; //File URL nN[gAM (  
long nStartPos; //File Snippet Start Position .m \y6  
long nEndPos; //File Snippet End Position _.G p}0a  
int nThreadID; //Thread's ID 1)N{!w`  
boolean bDownOver = false; //Downing is over k{d)'\FM  
boolean bStop = false; //Stop identical BuIly&qbm<  
FileAccessI fileAccessI = null; //File Access interface r4(Cb_  
ju%t'u\'  
P},d`4Ty@  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException {fAj*,pzl  
{ fY{&W@#g  
this.sURL = sURL; 'k9dN \ev  
this.nStartPos = nStart; OX*5 yT{  
this.nEndPos = nEnd; @gHWU>k,A  
nThreadID = id; - |j4u#z  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 TWk1`1|  
} kG70j{gf  
\`$RY')9|!  
Fu6~8uDV{{  
public void run() CxW-lU3G`  
{ 7d"gRM;  
while(nStartPos < nEndPos && !bStop) >djTJ>dl_u  
{ Rr3<ln  
k| Ye[GM*  
hY-;Vh0J  
try{ SFRQpQ06  
URL url = new URL(sURL); pu9ub.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Bh*7uNM  
httpConnection.setRequestProperty("User-Agent","NetFox"); Lr}>Md  
String sProperty = "bytes="+nStartPos+"-"; xBW{Wy
h  
httpConnection.setRequestProperty("RANGE",sProperty); p.J+~s4G  
Utility.log(sProperty); Nq=r404  
A-XWG9nL  
t:<dirw,o  
InputStream input = httpConnection.getInputStream(); f*Dy>sw  
//logResponseHead(httpConnection); |)\{Rufb  
4_B1qN
 
BO3%p  
byte[] b = new byte[1024]; KW5u.phv  
int nRead; L4C_qb k;:  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) :w5p#+/,P  
{ e-.s63hm  
nStartPos += fileAccessI.write(b,0,nRead); "G,$Sqi@  
//if(nThreadID == 1) MEZc/Ru-[  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @5y ~A}Vd  
} hJcN*2\:  
x&PVsXdt5m  
,@*Srrw  
Utility.log("Thread " + nThreadID + " is over!"); uY'77,G_J  
bDownOver = true; i9%cpPrg8  
//nPos = fileAccessI.write (b,0,nRead); S0uEz;cE  
} !p#+I=  
catch(Exception e){e.printStackTrace ();} ddiBjp2.!  
} 07:N)y,  
} aur4Ky> :  
V=LJ_T"z0  
si|DxDx  
//打印回应的头信息 wqyrs|P  
public void logResponseHead(HttpURLConnection con) Q+]
9Glz9  
{ y@?t[A#v  
for(int i=1;;i++) "/MA.zEl0,  
{ v1Wz#oP  
String header=con.getHeaderFieldKey(i); 16N+  
if(header!=null) WMw]W&  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 4`Z8EV  
Utility.log(header+" : "+con.getHeaderField(header));
|-SImxV  
else -Bl!s^-'  
break; *U69rbYI  
} ejuw+@ _  
} k_}aiHdG  
Im*~6[  
Zg#VZg1 2  
public void splitterStop() h72#AN  
{ 78[5@U  
bStop = true; 0nbQKoF  
} *>,CG:`D  
V<+=t{  
@&G< Np
`  
} ZC\&n4~7  
[c=T)]E1  
n6f  
/* 5sc`L  
**FileAccess.java S`qa_yI)Ed  
*//文件访问(定位，写) n,E=eNc  
package NetFox; NLLLt  
import java.io.*; O5:2B\B  
'8|y^\  
rL=_z^.P  
public class FileAccessI implements Serializable{ UFLN/  
;F:~HrxT}  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 =gjq@N]lAW  
RandomAccessFile oSavedFile; S
)h0@;q  
long nPos; IV5B5Q'D  
=]auP{AlE  
|dxcEjcY_  
public FileAccessI() throws IOException A&:i$`m,  
{ 7kZ-`V|\.  
this("",0); s^n}m#T  
} V?*\ISB`}  
AKbrXKx  
*Ou)P9~-L  
public FileAccessI(String sName,long nPos) throws IOException ]tzO)c)w;  
{ zL<<`u?  
oSavedFile = new RandomAccessFile(sName,"rw"); [4_JK  
this.nPos = nPos; ;F;"Uw  
oSavedFile.seek(nPos); B?G!~lQ)o  
} TL?(0]Hfe  
2unaK<1s  
MzY~-74aF  
public synchronized int write(byte[] b,int nStart,int nLen) .-Xp]>f,  
{ 'K9{xI@N  
int n = -1; CfWtCA  
try{ %bp8VR sY  
oSavedFile.write(b,nStart,nLen); 7K|: 7e(  
n = nLen; F{g^4  
} {4@+ 2)l  
catch(IOException e) ;hsem,C h7  
{ )TmqE<[  
e.printStackTrace (); !)}3[h0  
} Y<vsMf_U  
YR{%pZp  
?y@RE  
return n; NPL(5@  
} &3nbmkM  
@4'bI)  
Q^iE,_Zq  
} $\DOy&e  
dHtbl\6  
kYVn4Wq  
/* soH
M5<U  
**SiteInfoBean.java 0(Hhb#WDh\  
*/ _7O;ED+  
package NetFox; I\BcG(hlJ  
GomTec9.  
(61_=,jv\h  
public class SiteInfoBean { ^zMME*G  
A@W/  
UA{tmIC\  
private String sSiteURL; //Site's URL h#o3qY  
private String sFilePath; //Saved File's Path ]7d~,<3R  
private String sFileName; //Saved File's Name Kc>C$}/}$  
private int nSplitter; //Count of Splited Downloading File x1$:u6YD22  
PyS~2)=B  
4r&S&^  
public SiteInfoBean() KVvzVQ1  
{//nSplitter的缺省值为5 h27awO Q  
//default value of nSplitter is 5 F%8W*Y699  
this("","","",5); vu&%e\gM  
} Zj*kHjn"
 
L+c7.l.yT  
&!y7PWHJ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) :< )"G&  
{ C{i9~80n  
sSiteURL= sURL; gm-I)z!tz  
sFilePath = sPath; vSt7&ec  
sFileName = sName; }|k_sx:  
this.nSplitter = nSpiltter; fY|Bc<,V9)  
|b@H]c;"  
fVU9?^0/)9  
} wz,T7L  
*q?-M"K  
HywT  
public String getSSiteURL() n>_EEw2/  
{ :N826_q  
return sSiteURL; 6
(Qr!<  
} tj:Q]]\M  
b)SU8z!NV&  
8fn7!  
public void setSSiteURL(String value) fI/?2ZH  
{ Y\.ds%G  
sSiteURL = value; _e ]jz2j  
} `sS\8~A  
uG|d7LS,%  
,+u.FQv~  
public String getSFilePath() =1JS6~CTLN  
{ t Z_ni}  
return sFilePath; sg.8Sd"]7  
} QW5S=7  

-`iXAyr)m  
Y7vTs
eq  
public void setSFilePath(String value)  Nn"[GB  
{ IZ$7'Mo86  
sFilePath = value; kHO2&"6  
} +@'{  
2\$P&L a  
|M*jo<C  
public String getSFileName() ,ZpcvK/S  
{ Zy}Qc")Z  
return sFileName; D^?jLfW8  
} `m~x*)L#  
_^)Wrf+  
*Cdw"n  
public void setSFileName(String value) LDj'L~H  
{ aUdbN&G  
sFileName = value; NF}QQwG3  
} $[L8UUHY<8  
$`2rtF  
fZ9EE3  
public int getNSplitter() yj^LX2x"  
{ ArFsr  
return nSplitter; Kk}|[\fW  
} <Rs#y:  
h\oAW?^  
kQ,#NR/q6  
public void setNSplitter(int nCount) }!5x1F!  
{ B!`Dj,_  
nSplitter = nCount; P87!+pB(  
} h>'9-j6B  
} F{:ZHCm  
0XrB+nt  
m])!'Pa(=  
/* >-2eZ(n)"  
**Utility.java Qy)+YhE  
*/ Wc}opp  
package NetFox; xbh4j!FD$  
]Qo.X~]  
Qz T>h  
public class Utility { 0_}^IiG  
Lx{bR=  
i6"/GSA  
public Utility() RL|13CG OP  
{ i+/:^tc;  
s6#@S4^=\  
b#**`Y  
} 49)A.Bh&!  
_(CuuP$`I  
//线程睡眠 ;2o+|U@  
public static void sleep(int nSecond) IrAc&Ehul  
{ \htL\m^$9  
try{ _%Hp
B=  
Thread.sleep(nSecond); XA cpLj]  
} @WppiZ$  
catch(Exception e) Bg^k~NX%  
{ rsbdDTy  
e.printStackTrace (); pNOVyyo>BW  
} GZL{~7n  
} r]XXN2[jO  
z3l=aAw8  
//日志 oDyrf"dl  
public static void log(String sMsg) 89I[Dg;"u  
{ *.
H1m{V  
System.err.println(sMsg); NF& ++Vr6  
} bYr;~ ^  
~R`Rj*Q2Y  
^
y.e Fz  
public static void log(int sMsg) jTNfGu0x  
{ -*[?E!F  
System.err.println(sMsg); .s4hFB^n  
} P]bq9!{1  
} \]y4e^FZZ  
KRS_6G],{  
PZ/gD  
/* FHNK%Ko  
**TestMethod.java $}d| ~q\  
*/ <1(:W[M  
package NetFox; zE{@
'  
X-oHQu5  
v1hrRf2<  
public class TestMethod { p100dJvq  
:kycIM]s  
0y$aGAUm  
public TestMethod() |Rr^K5hmD  
{ ///xx/weblogic60b2_win.exe aqvt
$u8  
try{ _VU/j9<+  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); /Kmzi9j+  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); "ei*iUBN:  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 
(>qX>  
fileFetch.start(); Az.k6)~  
} a:jRQ-F)  
catch(Exception e){e.printStackTrace ();} h+mM  
2[&3$-]  
Jji~MiMn  
} dhe?7r]u  
9wP_dJvb  
nZ>bOP+,  
public static void main(String[] args) (7RxCo=X  
{ Cc:4n1|]>  
new TestMethod(); q #f U*  
} :$&%Pxm  
} $tyF(RybG  
点击下载更多相关资料