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http断点续传简单实现(java)

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/* |||m5(`S  
**SiteFileFetch.java w,X)g{^T  
*/ SHs [te[  
package NetFox; Lc?"4  
import java.io.*; m_Pk$Vwx  
import java.net.*; VQ,5&-9Y3  
1TX3/]:  
)^BZ,e  
public class SiteFileFetch extends Thread { f,i2U|1pbj  
K\KQ(N8F  
kkfBVmuW  
SiteInfoBean siteInfoBean = null; //文件信息Bean k-a1^K3  
long[] nStartPos; //开始位置 C+P.7]?&  
long[] nEndPos; //结束位置 rHjDf[5+  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 C[<{>fl)  
long nFileLength; //文件长度 'zav%}b]L  
boolean bFirst = true; //是否第一次取文件 p+<qI~  
boolean bStop = false; //停止标志 p2Gd6v.t  
File tmpFile; //文件下载的临时信息 1) K<x  
DataOutputStream output; //输出到文件的输出流 x${C[gxq9F  
xI<B)6D;f  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) &OZx!G^Z  
public SiteFileFetch(SiteInfoBean bean) throws IOException :-#7j} R&  
{ <{8x-zbR+  
siteInfoBean = bean; "=n%L +6%  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); M"W#_wY;  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); BKO^ux%  
if(tmpFile.exists ()) )b (+=  
{ \BH?GMoP  
bFirst = false; W!T[ ^+  
read_nPos(); ob8}v*s  
} r>! @Z2%s  
else (1q(6!  
{ ftcLP  
nStartPos = new long[bean.getNSplitter()]; Ip`1Wv_  
nEndPos = new long[bean.getNSplitter()]; 5x|$q kI  
} b$0;fEvIJn  
Q!3-P  
ZbVn"he  
)X," NJG  
} y`8U0TE3R  
Ym"^Ds}  
]hy@5Jyh  
public void run() Du +_dr^4  
{ Z2@e~&L  
//获得文件长度 fd #QCs  
//分割文件 'hPW#*#W<  
//实例FileSplitterFetch g]JRAM  
//启动FileSplitterFetch线程 GFE3p  
//等待子线程返回 GOGS"q  
try{ Tc!n@!RA|  
if(bFirst) *~4<CP+"0  
{ ~8 UMwpl-  
nFileLength = getFileSize();  AV|:v3  
if(nFileLength == -1) {X2uFw Gi  
{ 5D=U.UdR  
System.err.println("File Length is not known!"); ]@cI_n  
} d&L  
else if(nFileLength == -2) r_+!3   
{ olr#3te  
System.err.println("File is not access!"); N.+A-[7,W  
} 5#x[rr{^*  
else 9>0OpgvC(  
{ KztQT9kY  
for(int i=0;i<nStartPos.length;i++) Sh5)36  
{ h5T~dGRlR  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 0}`.Z03fy  
} [ _ `yy  
for(int i=0;i<nEndPos.length-1;i++) !-n* ]C  
{ >);M\,1\I  
nEndPos = nStartPos[i+1]; sw}^@0ua=  
} ^i8biOSZu  
nEndPos[nEndPos.length-1] = nFileLength; rN7JJHV  
} )g?jHm-p\  
} "M+I$*]  
 \v+c.  
)(yaX  
//启动子线程 v!DK.PZbi  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; OGLA1}k4  
for(int i=0;i<nStartPos.length;i++) G5OGyQp  
{ qhG2j;  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), mJd8?d  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 4 ;)t\9cy_  
nStartPos,nEndPos,i); %"oGJp  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); G;#xcld  
fileSplitterFetch.start(); DF-PBVfpu  
} T`j {2  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 55TFBDc  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); pO fw *lD  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Het>G{  
nEndPos = " + nFileLength); 6C<GYzzo  
// fileSplitterFetch[nPos.length-1].start(); %XBTN  
K$GQc"  
a%a0/!U[  
//等待子线程结束 >dgq2ok!u  
//int count = 0; ar 7.O;e  
//是否结束while循环 _qk&W_u  
boolean breakWhile = false; \(=xc2  
v9,cL.0&  
|;(P+Q4lB  
while(!bStop) IO7gq+  
{ hT_Q_1,  
write_nPos(); k^ fW /  
Utility.sleep(500); *' es(]W  
breakWhile = true; q9VBK(,X  
G#f3 WpD  
N}[!QE  
for(int i=0;i<nStartPos.length;i++) |{-?OOKj  
{ ^x/D8 M  
if(!fileSplitterFetch.bDownOver) })kx#_o]'d  
{ 1ljcbD)T;  
breakWhile = false; )+Z.J]$O-  
break; b&QI#w  
} SYQP7oG9oQ  
} C2zKt/)A  
if(breakWhile) FYu30  
break; qf ]le]J  
I*JJvqh  
F\&^(EL  
//count++; vaHtWz!P  
//if(count>4) Uc ,..  
// siteStop(); |9.J?YP8 (  
} _I3"35a  
 Y%y  
B<Cg_C  
System.err.println("文件下载结束!"); 2'OY,Ooe  
} (E,[Ad,$  
catch(Exception e){e.printStackTrace ();} Unq~lt%2  
} }M"])B I  
'qde#[VB  
VM&Ref4  
//获得文件长度 Y}q~ Km  
public long getFileSize() W?!rqo2SP  
{ K5^zu`19  
int nFileLength = -1; LH @B\ mS  
try{ 9M1DE  
URL url = new URL(siteInfoBean.getSSiteURL()); .q:6F*,1M  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |=~mRqG  
httpConnection.setRequestProperty("User-Agent","NetFox"); Hd7Vp:KM  
v$JW7CKA  
v+trHdSBYE  
int responseCode=httpConnection.getResponseCode(); t;PG  
if(responseCode>=400) 8'qlg|{!~  
{ &w`Ho)P  
processErrorCode(responseCode); (Uu5$q(  
return -2; //-2 represent access is error eTw9 c }[  
} ieWXr4@:  
,!,M'<?"  
=oiz@Q@H  
String sHeader; y0?HZ Xq  
qe e_wx  
cH:&S=>h  
for(int i=1;;i++) i PG:w+G  
{ YSfJUB!I  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); o@[o6.B<  
//Utility.log(in.readLine()); #4"eQ*.*"  
sHeader=httpConnection.getHeaderFieldKey(i); r4X\/  
if(sHeader!=null) 5.oY$tb(  
{ :J x%K  
if(sHeader.equals("Content-Length")) & @_PY  
{ Ku uiU= (L  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); |yp^T  
break; )Spa F)N8  
} D^p)`*  
} "cjD-4 2  
else " ;T a8  
break; GNB'.tJ:0Y  
} BNb_i H  
} * uccY_  
catch(IOException e){e.printStackTrace ();} 2~ETu&R:  
catch(Exception e){e.printStackTrace ();} ]c|JxgU  
@8aV*zjB  
GiK,+M"d  
Utility.log(nFileLength); q|s:&&Wf  
$[Nf?`f(t_  
7zU~ X,  
return nFileLength; }vgM$o  
} s[/d}S@ >  
pzQc UG  
E[zq<&P@  
//保存下载信息(文件指针位置) saQo]6#  
private void write_nPos() vgg)f~  
{ ,+C?UW  
try{ w}(pc }^U  
output = new DataOutputStream(new FileOutputStream(tmpFile)); =,qY\@fq  
output.writeInt(nStartPos.length); iYw1{U  
for(int i=0;i<nStartPos.length;i++) O*]}0*CT  
{ q;f L@L@-  
// output.writeLong(nPos); 'gD./|Z0  
output.writeLong(fileSplitterFetch.nStartPos); []yIz1P=j  
output.writeLong(fileSplitterFetch.nEndPos); 28+{  
} `fJ;4$4  
output.close(); >f-RzQ k  
} ER[$TH&  
catch(IOException e){e.printStackTrace ();} $3ZQ|X[|+  
catch(Exception e){e.printStackTrace ();} ]]}iSw'  
} 'Ce?!U O  
0a@tPskV  
v6! `H  
//读取保存的下载信息(文件指针位置) -!M>;M@  
private void read_nPos() Q.V@Sawe5  
{ nG?Z* n  
try{ 8NE[L#k  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); H<g8u{ $  
int nCount = input.readInt(); =eDC{/K  
nStartPos = new long[nCount]; u$ o 19n  
nEndPos = new long[nCount]; ;yjw(OAI*  
for(int i=0;i<nStartPos.length;i++) I*a .!/$)  
{ Ytqx 0  
nStartPos = input.readLong(); Hl{ul'o  
nEndPos = input.readLong(); jJ2{g> P0P  
} xH,e$t#@@~  
input.close(); ^HT vw~]5  
} |m*l/@1  
catch(IOException e){e.printStackTrace ();} 0A8G8^T  
catch(Exception e){e.printStackTrace ();} G@T_o4t  
} a?Y>hvI  
}&s |~  
}"%mP 4]&  
private void processErrorCode(int nErrorCode) ]y$/~(OW  
{ GN5*  
System.err.println("Error Code : " + nErrorCode); %=s2>vv9  
} E6 T=lwOZ  
B !rb*"[  
"^ dMCS@  
//停止文件下载 ]z=dRq  
public void siteStop() N6S@e\*  
{ T0b/txS  
bStop = true; d]sg9`  
for(int i=0;i<nStartPos.length;i++) tF<&R& =  
fileSplitterFetch.splitterStop(); YT)1_>*\  
Zm6jF  
&H}Xk!q5b^  
} Y(T$k9%}+  
} rF{,]U9`  
//负责部分文件的抓取 [L|vBr  
**FileSplitterFetch.java Zk|PQfi+  
*/ )`gxaT>&l  
package NetFox; H3iYE~^#  
KMl3`+i  
]S@DVXH  
import java.io.*; t)O]0) s  
import java.net.*; fmLDufx  
}~0}B[Rf  
X%;4G^%ZI  
public class FileSplitterFetch extends Thread { dEX67rUj;  
am| 81)|a  
{`> pigo  
String sURL; //File URL /%{CJ0Y  
long nStartPos; //File Snippet Start Position SF ^$p$mC  
long nEndPos; //File Snippet End Position (58r9WhS  
int nThreadID; //Thread's ID +OSSgY$  
boolean bDownOver = false; //Downing is over j!0-3YKv  
boolean bStop = false; //Stop identical 5;XU6Rz!  
FileAccessI fileAccessI = null; //File Access interface mr]~(]B?r  
*8u<?~9F  
a%an={  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 5~#oQ&  
{ !# xi^I  
this.sURL = sURL; u,`V%J?vW  
this.nStartPos = nStart; a |]}uFr  
this.nEndPos = nEnd; D&],.N  
nThreadID = id; c% ?@3d  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 P/k#([:2  
} G \$x.  
3YUF\L]yyw  
mWLiXKnb  
public void run() 4JH^R^O<n  
{ U:PtRSdn!b  
while(nStartPos < nEndPos && !bStop) _tQM<~Y]u\  
{ l Yj$ 3  
onv0gb/J  
2@N-#x '  
try{ X@A8~ kj1  
URL url = new URL(sURL); 0juP"v$C>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); V9>$M=  
httpConnection.setRequestProperty("User-Agent","NetFox"); VjeF3pmBa  
String sProperty = "bytes="+nStartPos+"-"; T7Ju7_q}  
httpConnection.setRequestProperty("RANGE",sProperty); ~eiD(04^r*  
Utility.log(sProperty); "b)EH/ s  
Kz]\o"K  
8ddBQfCY  
InputStream input = httpConnection.getInputStream(); qR%as0;  
//logResponseHead(httpConnection); H5jk#^FD  
LW!4KA]  
p<FqK/  
byte[] b = new byte[1024]; {t]8#[lo  
int nRead; @j(2tJ,w  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) G6\`Iy68/v  
{ S]&aDg1y}  
nStartPos += fileAccessI.write(b,0,nRead); !rZZ/M"i  
//if(nThreadID == 1) /(%!txSNEt  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); B_3N:K Y 9  
} UzV78^:,iD  
h`p=~u +  
QUz4 Kt  
Utility.log("Thread " + nThreadID + " is over!"); <e@4;Z(h04  
bDownOver = true; lpbcpB  
//nPos = fileAccessI.write (b,0,nRead); 4#B 56f8  
} \34:]NM  
catch(Exception e){e.printStackTrace ();} (7??5gjh  
} -V'Y^Df  
} |#(y?! A^  
w,<n5dMv  
7eFFKl  
//打印回应的头信息 ^=gN >xP  
public void logResponseHead(HttpURLConnection con) _+Pz~_+kS  
{ Juk'eH2^s  
for(int i=1;;i++) 5n e&6  
{ | `?J2WGe  
String header=con.getHeaderFieldKey(i); fK^;?4  
if(header!=null) @$~;vS  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ~svea>Fmr  
Utility.log(header+" : "+con.getHeaderField(header)); ?ihRt+eR~  
else S++jwP  
break; d^5x@E_Td  
} nM!_C-yX  
} $?;)uoAg  
+h1X-K:I  
yy`XtJBWWs  
public void splitterStop() n<A<Xj08T9  
{ >5 2%^ ?  
bStop = true; py%:,hi  
} 8rLhOA  
6R#igLm  
[z'jL'\4  
} AU8sU?=  
8/"C0I (G  
qtz~Y~h|>  
/* /.t1Ow  
**FileAccess.java kJCeQK:W  
*//文件访问(定位,写) {=MRJg!U  
package NetFox; b4(,ls  
import java.io.*; fBBtS S  
g6OPYUPg  
{m_y<  
public class FileAccessI implements Serializable{ :8A@4vMS)?  
{WTy/$ Qk  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 xg'xuz$U  
RandomAccessFile oSavedFile; 79+i4(H  
long nPos; DjvPeX  
59X XmVg  
 1%";|  
public FileAccessI() throws IOException )E^Pn|H  
{ wVF qkJ  
this("",0); LMLrH.  
} R}D[ z7  
D8WKy  
p& Kfy~  
public FileAccessI(String sName,long nPos) throws IOException |z0% q2(  
{ cG1iO:  
oSavedFile = new RandomAccessFile(sName,"rw"); ^W~8)Rbf  
this.nPos = nPos; VU+=b+B~m  
oSavedFile.seek(nPos); w8`B}Dr23  
} jcRe),  
:OA;vp~$x  
G(bl)p^  
public synchronized int write(byte[] b,int nStart,int nLen) xZVZYvC,t  
{ $dsLU5]1o  
int n = -1; /RWD\u<l  
try{ 4rpry@1  
oSavedFile.write(b,nStart,nLen); Fv:x>qZr@  
n = nLen; mA^3?y j  
} D/wJF[_  
catch(IOException e) VKSn \HT~  
{ E *782>  
e.printStackTrace (); G\~?.s|^  
} zd{sw}  
_.I58r  
dt/-0~U  
return n; "@t bm[  
} /bLL!nD=^  
BQB<+o'  
LyG`q3@  
} U6YHq2<  
S#Tu/2<}  
8T Tj<T!N  
/* e2L>"/  
**SiteInfoBean.java `$3ktQ$  
*/ ST,+]p3L(  
package NetFox; .0MY$0s  
pdjRakN  
Y&bO[(>1  
public class SiteInfoBean { .9UrWBW\I  
_v++NyZXx  
tqjjn5!  
private String sSiteURL; //Site's URL 01NP  
private String sFilePath; //Saved File's Path >4os%T  
private String sFileName; //Saved File's Name ,V{Bpr  
private int nSplitter; //Count of Splited Downloading File '-3K`[  
imB/P M  
alBnN<UM  
public SiteInfoBean() 3Zwhv+CP[  
{//nSplitter的缺省值为5 _9?v?mL5;  
//default value of nSplitter is 5 5f2=`C0_  
this("","","",5);  \+:`nz3m  
} $f>(TW  
:SY,;..3e  
^)h&s*  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) +{#Z^y6&  
{ KEf1GU6s  
sSiteURL= sURL; ;j+*}|!  
sFilePath = sPath; xc7Rrh]}  
sFileName = sName; '}-QZ$|*  
this.nSplitter = nSpiltter; 9WV8ZP  
PH'n`D #  
*e:2iM)8~  
} 4 []!Km  
A=70UL  
dJlK'zK  
public String getSSiteURL() pimI)1 !$'  
{ MPF({Pnx7  
return sSiteURL; x6^FpNgQ  
} 9#kk5)J  
O'QnfpQ*9  
,fo7. h4{  
public void setSSiteURL(String value) PF+Or  
{ 9D;ono3  
sSiteURL = value; [w)KNl  
} Qh* }v!3Jo  
YdUcO.V  
Mky^X,r  
public String getSFilePath() - b`  
{ J/PK #<  
return sFilePath;  '{cFr  
} 6rO^ p  
`G=+qti  
ft0tRv(s:  
public void setSFilePath(String value) 12Fnv/[n'K  
{ 7uO tdH+  
sFilePath = value; 6z'0fi|EN  
} 77j"zr7v  
?v'CuWS  
_,I~1"  
public String getSFileName() LvU/,.$  
{ 3Q2NiYg3  
return sFileName; 5glEV`.je  
} ch0cFF^]  
`S4G+j>u6  
3K/]{ dkD  
public void setSFileName(String value) vG=Pi'4XXo  
{ =\\rk,F  
sFileName = value; fgHsg@33N  
} "hZ `^ "0b  
9NZq k  
$_e{Zv[  
public int getNSplitter() rA @|nL{  
{ jR*iA3LDo  
return nSplitter; }r"E\~E  
} Ok}e|b[D  
P]L%$!g  
$#wi2Ve=6b  
public void setNSplitter(int nCount) O"_QDl<ya  
{ Lmw)Ts>  
nSplitter = nCount; A{\DzUV9,  
} ::3[H$  
} 4#I=n~8a  
{}=5uU2Tu  
^9YS dFH/  
/* <,H/7Ba  
**Utility.java !#E-p?O.  
*/ >xH?`I7;f  
package NetFox; y5VohVa`  
oeI[x  
{7v|\6@e3  
public class Utility { |C,]-mJG  
jP<6Q|5F  
TPY&O{ q  
public Utility() u{dkUG1ia  
{ u/N_62sk5  
dN){w _  
CurU6x1  
} M R,A{X  
YeB C6`7y  
//线程睡眠 {yi!vw  
public static void sleep(int nSecond) #kJ8 qN  
{ O.aAa5^uh  
try{ ,V&E"D{u  
Thread.sleep(nSecond); x/0x&la  
} z_8Bl2tl  
catch(Exception e) =CL,+  
{ psS^  
e.printStackTrace (); $-E<{   
} TQvjU!>  
} LOgB_$9_3  
UA#=K+2  
//日志 `eGp.[ffT  
public static void log(String sMsg) jASK!3pY  
{ `G>|g^6%i  
System.err.println(sMsg); ~u?rjkSFoh  
} v v   
'OMl9}M  
SO~pe$c-  
public static void log(int sMsg) Yt r*"-  
{ MJK PpQ(,  
System.err.println(sMsg); .&K?@T4l  
} XD[9wd5w8  
} lHu/pSu@k  
9(bbV5}  
GW9,%}l^;  
/* 9AD0|,g  
**TestMethod.java 4dh> B>Q  
*/ b}N \h<\G  
package NetFox; f_:>36{1^!  
d 5h x%M  
A~L Ti  
public class TestMethod { 6\)u\m`7-l  
LD,T$"  
u R!'v  
public TestMethod() ux[13]yY  
{ ///xx/weblogic60b2_win.exe 'qeUI}[  
try{ YT@H^=  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); va.Ve# N  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); )P.,h&h/  
SiteFileFetch fileFetch = new SiteFileFetch(bean); [c99m:*+  
fileFetch.start(); sr:hR Q27  
} rj<-sfs  
catch(Exception e){e.printStackTrace ();} >waA\C}  
_G)x\K]N  
-1R7 8(1  
} ork{a.1-_w  
>Q)S-4iR  
g G|4+' t  
public static void main(String[] args) 4&~*;an7  
{ YIYuqtnSJ  
new TestMethod(); >EgMtZ88.<  
} W7IAW7w8U  
} rE\&FVx  
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