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http断点续传简单实现(java)

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/* RXDk8)^  
**SiteFileFetch.java R!=XMV3$PH  
*/ >8##~ZuF+  
package NetFox; v3B ^d}+.  
import java.io.*; h?b{{  
import java.net.*; \[BnAgsF  
E4Sp^,  
Hs9uDGWp  
public class SiteFileFetch extends Thread { 7%tn+  
6ZE] 7~X  
Nb6HM~  
SiteInfoBean siteInfoBean = null; //文件信息Bean W*0KAC`m  
long[] nStartPos; //开始位置 { !w]t?h  
long[] nEndPos; //结束位置 l6~eb=u;9g  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 d@<XR~);  
long nFileLength; //文件长度 Ok@5`?08  
boolean bFirst = true; //是否第一次取文件 R *U>T$  
boolean bStop = false; //停止标志 Z-:`{dns/  
File tmpFile; //文件下载的临时信息 F {[Q  
DataOutputStream output; //输出到文件的输出流 8[k-8h|  
|7argk+  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) j'W)Nyw$[  
public SiteFileFetch(SiteInfoBean bean) throws IOException Pz?O_@Ln  
{  :JlJB  
siteInfoBean = bean; *\/UT  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); B?]^}r  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); `?)i/jko"  
if(tmpFile.exists ()) ??F{Gli"C`  
{ #KIHq2:.4  
bFirst = false; yC -4wn*  
read_nPos(); C-M op,w  
} 5)vXmAD/0  
else l"+=z.l6;  
{ > ,[(icyzn  
nStartPos = new long[bean.getNSplitter()]; <(v!Xj^yO  
nEndPos = new long[bean.getNSplitter()]; C$P3&k#W  
} 8ViDh  
ms?h/*E<H  
J-U}iU|  
V\ |b#?KL  
} (efH>oY[  
0wx`y$~R  
4x:fOhtP  
public void run() S&a 44i  
{ g {00i  
//获得文件长度 7"gy\_M  
//分割文件 t((0]j^  
//实例FileSplitterFetch vm(% u!_P  
//启动FileSplitterFetch线程 X/Ae-1!  
//等待子线程返回 :G!Kaa,r  
try{ js{ RaR=  
if(bFirst) ]!/1qF  
{ &0 @2JS/!  
nFileLength = getFileSize(); `0L!F"W  
if(nFileLength == -1) DV. m({?  
{ @~"0|,6VC  
System.err.println("File Length is not known!"); /as1  
} d+_qBp  
else if(nFileLength == -2) yJ^}uw  
{ }{[F+|\>,e  
System.err.println("File is not access!"); P%1s6fjU  
} xHf l>C'  
else noacnQ_I$  
{ JLjx4B\  
for(int i=0;i<nStartPos.length;i++) sV-9 xh)i  
{ 4FYws5]$  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); NEX\+dtE~0  
} k?_Miqr  
for(int i=0;i<nEndPos.length-1;i++) hE>Mo$Q(  
{ ;&iQNXL  
nEndPos = nStartPos[i+1]; o/Z?/alt4  
}  3N;X|pa  
nEndPos[nEndPos.length-1] = nFileLength; }%%| '8  
} pBHr{/\5  
} u|+O%s TQ  
Z yIn>]{  
lO:[^l?F  
//启动子线程 (`T:b1  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 8tsW^y;S  
for(int i=0;i<nStartPos.length;i++) I(C_}I>Wb  
{ LNe- ]3wB  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !dZC-U~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), N/Z<v* i"  
nStartPos,nEndPos,i); g4Tc (k#  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +YP,LDJ!v  
fileSplitterFetch.start(); N O'-HKHj  
} )jn xR${M  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,<%],-Lt[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 7dAa~!/(  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", &QvWT+]c'0  
nEndPos = " + nFileLength); ^!=+$@<  
// fileSplitterFetch[nPos.length-1].start(); @@+\  
y6$5meh.T  
qPWYY  
//等待子线程结束 #\fAp RL  
//int count = 0; [N{Rd[{QTL  
//是否结束while循环 z55P~p  
boolean breakWhile = false; ?L'ijzP  
2nk}'HBe  
0nBAO  
while(!bStop) zg[ksny  
{ euQ d  
write_nPos(); J3C"W7 94}  
Utility.sleep(500); 3rs=EMz:w  
breakWhile = true; >*EcX3  
- v`;^X  
L~~;i'J  
for(int i=0;i<nStartPos.length;i++) qL(Qmgd  
{ 8hdd1lVKO8  
if(!fileSplitterFetch.bDownOver) Wa ,  #  
{ 9[/Gd{`XC  
breakWhile = false; `*N2x\+X  
break; lr=*Ty(V  
} ZfS-W&6Z  
} iGM-#{5  
if(breakWhile) 6:@tHUm  
break; uS3J^=>@(a  
@va6,^)  
7|*|xLrVY  
//count++; (C1]R41'  
//if(count>4) D[ny%9 :  
// siteStop(); 5ZUqCl(PX)  
} F?3a22Zg#  
#TRPq>XzD  
7h,SX]4Q  
System.err.println("文件下载结束!"); %*zgN[/w  
} m;k' j@:  
catch(Exception e){e.printStackTrace ();} UfXqcyY(  
} [/6IEt3}B  
nx8 4l7<  
g?)9zJ9  
//获得文件长度 S'lZ'H/  
public long getFileSize() A6= Um%T  
{ q8`JRmt)H  
int nFileLength = -1; ! p458~|  
try{ qa2QS._m  
URL url = new URL(siteInfoBean.getSSiteURL()); NJwcb=*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #X`j#"Ov2(  
httpConnection.setRequestProperty("User-Agent","NetFox"); % ?@PlQ  
%\2 ll=p1  
Z#%4QIz ?  
int responseCode=httpConnection.getResponseCode(); NbSkauF~b  
if(responseCode>=400) X^7bOFWE  
{ = T!iM2  
processErrorCode(responseCode); y.HE3tH  
return -2; //-2 represent access is error ZF>zzi+@  
} b1R%JY7/S  
6l<q  
X*/j na"*  
String sHeader; ZU5hHah.t  
gM '_1zs U  
[YLaR r  
for(int i=1;;i++) ['Hl$2 j  
{ 0PjWfM8%  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); \GEFhM4)  
//Utility.log(in.readLine()); "o+< \B~  
sHeader=httpConnection.getHeaderFieldKey(i); I5 "Z  
if(sHeader!=null) 9m/v^  
{ p$0G EYwM  
if(sHeader.equals("Content-Length"))  (0bvd  
{ amK"Z<V F  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); TkM8GK-3  
break; TW" TgOfd  
} n>" 0y^v  
} 5(]=?$$*t  
else  mR)Xq=  
break; _Y?p =;  
} nn5tOV}QE  
} eF823cH2x_  
catch(IOException e){e.printStackTrace ();} *0^!%Y'/4  
catch(Exception e){e.printStackTrace ();} >,yE;zuw  
tt $DWmm  
9@9(zUS|  
Utility.log(nFileLength); ,6uON@  
|#^wYZO1U  
T@ (MSgp9  
return nFileLength; @FKm_q  
} Z%E;*R2+:>  
4V@raI-  
$WED]X@X!  
//保存下载信息(文件指针位置) i 3?=up!  
private void write_nPos() N =FX3Z  
{ dDK4I3a  
try{ #N.W8mq  
output = new DataOutputStream(new FileOutputStream(tmpFile)); |4^us|XY  
output.writeInt(nStartPos.length); US[{ Q  
for(int i=0;i<nStartPos.length;i++) 2~h! ouleY  
{ fkbHfBp[(A  
// output.writeLong(nPos); 1tw>C\  
output.writeLong(fileSplitterFetch.nStartPos); roSdcQTeT  
output.writeLong(fileSplitterFetch.nEndPos); 3#<b!Yz  
} |`B*\\1  
output.close(); ^lud2x$O^C  
} 4jbqV  
catch(IOException e){e.printStackTrace ();} <=[,_P6|  
catch(Exception e){e.printStackTrace ();} FrT.<3  
} {]BPSj{B  
ek\8u`GC  
+L03. rf  
//读取保存的下载信息(文件指针位置) 6[b'60CuZL  
private void read_nPos() jeXP|;#Una  
{ -}#=L@  
try{ Jh`Pq,B:  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); dCc"Qr[k  
int nCount = input.readInt(); ?-C=_eZJ  
nStartPos = new long[nCount]; g?&_5)&  
nEndPos = new long[nCount]; =;A p+}  
for(int i=0;i<nStartPos.length;i++) s&&8~ )H  
{ z=%&?V  
nStartPos = input.readLong(); :59fb"^$  
nEndPos = input.readLong(); ;\-f7!s  
} Hj(ay4 8  
input.close(); Lu?MRF f  
} }x!=F<Q!r  
catch(IOException e){e.printStackTrace ();} ]z3!hgTj  
catch(Exception e){e.printStackTrace ();} Ck.LsL-  
} rH Y SS0*3  
G8AT] =  
}.*"ezaZw  
private void processErrorCode(int nErrorCode) Jy<hTd*q  
{ +U9m  
System.err.println("Error Code : " + nErrorCode); b* (~8JxZ  
} n@%Q 2_  
{&7%wZ"t_  
M:TN^ rA|  
//停止文件下载 3kqO5+,C  
public void siteStop() KTLq~Ru  
{ Rn?Yz^ 1q  
bStop = true; 3lr9nBR  
for(int i=0;i<nStartPos.length;i++) \"k[y+O],4  
fileSplitterFetch.splitterStop(); I "Qf};n  
|p_\pa1&  
@>:V?  
} ["O/%6b9+  
} (B+CI%= D  
//负责部分文件的抓取 Q+bZZMK5,U  
**FileSplitterFetch.java :DWvH,{+&  
*/ |z.x M>  
package NetFox; E3hql3=  
p} }pq~EH/  
&k53*Wo  
import java.io.*; [Ey[A|g  
import java.net.*; a9LK}xc={  
=f~8"j  
_EHz>DJ9  
public class FileSplitterFetch extends Thread { omd oH?  
M9~eDw'Pr  
+;#z"m]  
String sURL; //File URL B|I9Ex~L  
long nStartPos; //File Snippet Start Position =bKz$ _W  
long nEndPos; //File Snippet End Position XS#Jy n  
int nThreadID; //Thread's ID &<dC3o!  
boolean bDownOver = false; //Downing is over g}@W9'!  
boolean bStop = false; //Stop identical ^lvYj E  
FileAccessI fileAccessI = null; //File Access interface 9f=L'{  
srL|Y&8p  
<[l0zE5Z8'  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException !m {d6C[  
{ <b.O^_zQF  
this.sURL = sURL; yj$a0Rgkv  
this.nStartPos = nStart; 2eC`^  
this.nEndPos = nEnd; t@(:S6d  
nThreadID = id; t_xO-fT)  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 S"=y >.#  
} U~CG(9  
WNnB s  
SH ow~wxw  
public void run() vQH 6CB"  
{ ) t#>fnN  
while(nStartPos < nEndPos && !bStop) ]`+J!G,  
{ "5wer5? t  
Ty&Ok*  
,vcg%~-  
try{ y,/Arl}yc  
URL url = new URL(sURL); W^e"()d/Z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); JX)%iJq#  
httpConnection.setRequestProperty("User-Agent","NetFox"); wjzR 8g0bQ  
String sProperty = "bytes="+nStartPos+"-"; Qr.SPNUFK  
httpConnection.setRequestProperty("RANGE",sProperty);  Uf,fd  
Utility.log(sProperty); OK] _.v}  
rbt/b0ET  
?z pN09e  
InputStream input = httpConnection.getInputStream(); 6lAHB*`  
//logResponseHead(httpConnection); 8el\M/u{  
uD=FTx  
*`]#ntz9  
byte[] b = new byte[1024]; D[H #W[  
int nRead; eo [eN.  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) U0m 5Rc  
{ c3__=$)'kP  
nStartPos += fileAccessI.write(b,0,nRead); zk++#rB  
//if(nThreadID == 1) Hd_W5R  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zNo>V8B(  
} 1CmjEAv%/  
Ht,+KbB  
b'O>qQ  
Utility.log("Thread " + nThreadID + " is over!"); \cx==[&(  
bDownOver = true; OF1fS\P<>  
//nPos = fileAccessI.write (b,0,nRead); af-  
} -dyN Ah?=  
catch(Exception e){e.printStackTrace ();} x=I|O;"><  
} 5 (cgHr"  
} CT0 ~  
a%YohfsY?U  
lKSd]:3Xm  
//打印回应的头信息 S_ER^Pkg  
public void logResponseHead(HttpURLConnection con) 1@Gmzh  
{ o"gtWAGH  
for(int i=1;;i++) Dg=!d)\  
{ u*6Y>_iA  
String header=con.getHeaderFieldKey(i); umuE5MKY<  
if(header!=null) $! R]!s  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); %AJTU3=0  
Utility.log(header+" : "+con.getHeaderField(header)); !Y,*Zc$R  
else &;2@*#,  
break; I .> SC  
} 5Tg[-tl  
} ozOvpi:k3%  
($T"m-e  
elDt!9Pu  
public void splitterStop() _&R lR  
{ #qDMUN*i  
bStop = true; TbQ5  
} Y;"rJxHD  
@b3jO  
cii! WCu  
} NpAZuISD!  
X3zpU7`Av+  
0`Hr(J`F  
/* T$IwrTF@?  
**FileAccess.java M "\j7(  
*//文件访问(定位,写) f=--$o0U~  
package NetFox; lL;SP&  
import java.io.*; J/xbMMb   
3/s" ;Kg,  
Ad)::9K?J  
public class FileAccessI implements Serializable{ 6 k+4R<  
WlHK  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 X:kr$  
RandomAccessFile oSavedFile; > }fw7X  
long nPos; Bm$(4  
_^MkC} 8  
xcM*D3  
public FileAccessI() throws IOException b^^ .$Gu  
{ Q:^.Qs"IK  
this("",0); TfnBPO  
} I6vy:5d  
U'p-Ko#  
UAEu.AT  
public FileAccessI(String sName,long nPos) throws IOException UlQS]f~  
{ tDQuimYu7  
oSavedFile = new RandomAccessFile(sName,"rw"); ]9PQKC2&  
this.nPos = nPos; Me2qOc^Z-  
oSavedFile.seek(nPos); VdOcKP.  
} ; S~  
oY<R[NYKu  
'`sZo1x%f  
public synchronized int write(byte[] b,int nStart,int nLen) [I 6&|Lz>  
{ nsN|[E8  
int n = -1; &rfl(&\oUi  
try{ ;hb_jW-0W  
oSavedFile.write(b,nStart,nLen); 6DT ^:LHS  
n = nLen; <5E: ,<  
} z)F<{]%  
catch(IOException e) RAU"  
{ A +41JMH  
e.printStackTrace (); c-oIP~,  
} py }`thx  
d}^G790  
AMre(lgh  
return n; L0X/  
} %4,v2K  
TGH"OXV*@  
)%wNVW 0C  
} 2+=:pc^  
$(fhO   
.K`EflN  
/* wCgi@\  
**SiteInfoBean.java wfQ^3HL  
*/ b Od<x >@  
package NetFox; FH)_L1n  
&w%--!T  
5 >\~jf  
public class SiteInfoBean { )>;V72  
952l1c!  
4A)@,t9+  
private String sSiteURL; //Site's URL h,zM*zA_  
private String sFilePath; //Saved File's Path l4$Iv:  
private String sFileName; //Saved File's Name /i)>|U 4  
private int nSplitter; //Count of Splited Downloading File @0 #JY:"  
CmxQb,Uls  
ybU_x  
public SiteInfoBean() c^1tXu|&  
{//nSplitter的缺省值为5 $*+IsP!  
//default value of nSplitter is 5 @hwe  
this("","","",5); sR;u#".  
} Xv<K>i>k  
({0:1*lF@  
*CCh\+S7m  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) VT [TE  
{ H b?0?^#  
sSiteURL= sURL; bbs'>D3  
sFilePath = sPath; :Z&<5  
sFileName = sName; ^v5<*uf%m  
this.nSplitter = nSpiltter; CB^.N>'  
xi[\2g+  
)F_nK f"a  
} -pW*6??+?  
./35_Vy/O  
5tl( $j  
public String getSSiteURL() Q 6n!u;  
{ 3IG<Ot9  
return sSiteURL; fj97_Q=  
} 1) Nj.#)  
#QNa| f#=  
y.$Ae1a=  
public void setSSiteURL(String value) hQ (84u  
{ t76B0L{  
sSiteURL = value; ^X;p8uBo  
} 6aKfcvf &  
nc^DFP  
fS$;~@p  
public String getSFilePath() :i>If:>g  
{ hgK 4;R  
return sFilePath; =Q*x=}NH  
} ckYT69U  
0.[tEnLZ  
qLV3Y?S!L  
public void setSFilePath(String value) VWK%6Ye0  
{ }<^QW't_Y  
sFilePath = value; "0 $UnR  
} _tRRIW"Vx"  
nJ}@9v F/  
yoH,4,!G  
public String getSFileName() K\FLA_J  
{ H128T8?r[  
return sFileName; b|-S;cw  
} m*.+9 6  
_:]g:F[ #  
3EHB~rL/C  
public void setSFileName(String value) :(iBLO<x  
{ "hk {"0E  
sFileName = value; xp}M5|   
} hp`ZmLq/[  
YQcaWd(  
&z#`Qa3NI  
public int getNSplitter() U$ 46=F|  
{ uUb`Fy9  
return nSplitter; x\oSD1t,  
} ;!A=YXB  
Y5c[9\'\  
Y/sZPG}4  
public void setNSplitter(int nCount) 03c8VKp'p  
{ ~owodc  
nSplitter = nCount; ?,i}Qr [Q  
} iK=QP+^VN  
} qOy0QZ#0  
[ eb k u_  
\CX6~  
/* adPd}rt;  
**Utility.java L2=:Nac  
*/ ( k,?)  
package NetFox; zdm2`D;~p  
 |nfMoUI  
KP&xk1 3)  
public class Utility { _+.JTk  
q ~^!Ck+#*  
[{`2FR:Cd  
public Utility() j^%N:BQ&  
{ \ef:H&r  
^HxIy;EQ<z  
I1 Otu~%d  
} %/ctt_p0x  
B77`azwF  
//线程睡眠 SsPZva  
public static void sleep(int nSecond) 9F[_xe@  
{ [X91nUz#  
try{ wh)F&@6 R!  
Thread.sleep(nSecond); 0*_E'0L8e  
} R a"hdxH  
catch(Exception e) {A'*3(8  
{ "8"aYD_  
e.printStackTrace (); K?Sy ?Kz  
} dyk(/# *7W  
} .)SR3?   
f!#+cM  
//日志 +w-J;GLSy  
public static void log(String sMsg) }*C*!?pcd  
{ 3I(;c ,S  
System.err.println(sMsg); K:^0*5Y-k  
} `2hg?(ul  
oEX^U4/=  
91]sO%3  
public static void log(int sMsg) k<5g  
{ >ZW|wpO  
System.err.println(sMsg); Y2;2Exp^  
} T];dFv-GT  
} uuxVVgWp{  
qXhdU/ =  
P8Wv&5A  
/* 6oKdw|(Q#  
**TestMethod.java 'u E;8.,  
*/ .T)wG;+  
package NetFox; TkJ[N4'0  
#f< v%  
aHVzBcCPh  
public class TestMethod { #y[U2s Se  
YM};85K  
PfZS"yk  
public TestMethod() b\"w/'XX  
{ ///xx/weblogic60b2_win.exe D$7#&2y  
try{ 78Du  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); J/O{x  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); +<j7^AEG  
SiteFileFetch fileFetch = new SiteFileFetch(bean); UoPY:(?;i  
fileFetch.start(); s*s~yH6  
} Q@7d:v  
catch(Exception e){e.printStackTrace ();} z~ywFk}KGd  
R|v'+bv  
H]pI$t3~  
} yIrJaS-  
Zk`yd8C  
'E+"N'M|  
public static void main(String[] args) 6pSi-FH  
{ N0.|Mb"?t  
new TestMethod(); E5$]0#jB  
} ?3p7MjvZ  
} ;AE-=/<  
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