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http断点续传简单实现(java)

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/* ~4"qV_M  
**SiteFileFetch.java W9NX=gE4  
*/ cw iX8e"3  
package NetFox; 45hF`b>%,  
import java.io.*; ca+5=+X7  
import java.net.*; %p%%~ewmx  
q, O$ %-70  
g}@OUG"D  
public class SiteFileFetch extends Thread { YPHS 1E?  
%|s+jeUDn|  
tcxcup%  
SiteInfoBean siteInfoBean = null; //文件信息Bean >EY3/Go>  
long[] nStartPos; //开始位置 boDt`2=  
long[] nEndPos; //结束位置 %^RN#_ro(3  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ]_N|L|]M  
long nFileLength; //文件长度 95el'K[R  
boolean bFirst = true; //是否第一次取文件 )"Ztlhs`#  
boolean bStop = false; //停止标志 /SYw;<=  
File tmpFile; //文件下载的临时信息 @)J+,tg/7  
DataOutputStream output; //输出到文件的输出流 <&C]s b  
iY21Ql%  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) J2:y6kGj>  
public SiteFileFetch(SiteInfoBean bean) throws IOException &b:1I 7Cp*  
{ /?SLdW  
siteInfoBean = bean; lg^Z*&(  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 7uzk p&+:  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); kc0E%odF.v  
if(tmpFile.exists ()) |i++0BU  
{ Ub6jxib  
bFirst = false; 0_88V  
read_nPos(); T=ev[ mS  
} x7O-Y~[2  
else JtER_(.  
{ |\pbir  
nStartPos = new long[bean.getNSplitter()]; /Rl6g9}  
nEndPos = new long[bean.getNSplitter()]; 3Z1CWzq(  
} p5G?N(l  
S]+ :{9d  
K6R.@BMN  
TYW&!sm  
} wmTb97o  
B_.%i+ZZ  
'inFKy'H  
public void run() nr<4M0tIp  
{ ]q4rlT.i  
//获得文件长度 =E.wv  
//分割文件 @;"|@!l|  
//实例FileSplitterFetch E>K!Vrh-L  
//启动FileSplitterFetch线程 V:joFRH9  
//等待子线程返回 {;2PL^i  
try{ Zu7)gf  
if(bFirst) wpN=,&!  
{ q@{Bt{$x  
nFileLength = getFileSize(); lnjXD oVb<  
if(nFileLength == -1) $&=S#_HQS  
{ vam;4vyu  
System.err.println("File Length is not known!"); n@) K #  
} $` ""  
else if(nFileLength == -2) |p,P46I  
{ kDsFR#w&`  
System.err.println("File is not access!"); \.-bZ$  
} gw!vlwC&T  
else w(L4A0K[  
{ :> 5@cvc  
for(int i=0;i<nStartPos.length;i++) DA\2rLs  
{ j:v@pzTD  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ;0Tx-8l  
} uLV#SQ=bZN  
for(int i=0;i<nEndPos.length-1;i++) `x*Pof!Io  
{ [TmIVQ!B  
nEndPos = nStartPos[i+1]; d$1@4r  
} ,5h)x"s  
nEndPos[nEndPos.length-1] = nFileLength; I`!<9OTBj  
} DW[N|-L  
} F'21jy&  
BI%$c~wS  
<J`0  
//启动子线程 $| @ (  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];  tVN  
for(int i=0;i<nStartPos.length;i++) EFM5,gB.m  
{ Y^wW2-,m  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {ttysQ-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), yd d7I&$  
nStartPos,nEndPos,i); =c\>(2D  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); gi1^3R[  
fileSplitterFetch.start(); 8<QdMkI  
} Hquc o  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),  "y}--  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); b0Ps5G\ u  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", )6Fok3u  
nEndPos = " + nFileLength); _uy44; zq  
// fileSplitterFetch[nPos.length-1].start(); V2wb%;q  
Po^?QVJ7  
ig/xv  
//等待子线程结束 )"7iJb<E  
//int count = 0; UM"- nZ>[  
//是否结束while循环 i9,ge Q7d  
boolean breakWhile = false; 1~NT.tY  
qm/22:&v5  
)vE~'W  
while(!bStop) t.i 8 2Q  
{ EM(gmWHij  
write_nPos(); tEvut=k'  
Utility.sleep(500); u04kF^  
breakWhile = true; 'c9]&B  
G[uK-U  
nAsh:6${  
for(int i=0;i<nStartPos.length;i++) <L8'!q}  
{ TNe l/   
if(!fileSplitterFetch.bDownOver) P@V0Mi),  
{ rZ}:Z'`  
breakWhile = false; kTOzSiq  
break; y51e%n$  
} NJWA3zz   
} I-]?"Q7Jz  
if(breakWhile) .ypL=~Rp  
break; ^@s1Z7  
Ot_]3:`J~  
6]WAUK%h  
//count++; z!ZtzD]cb  
//if(count>4) h+g_rvIG*  
// siteStop(); N/"{.3{W  
} 84& $^lNV  
|4;Fd9q^m  
,~N/- 5  
System.err.println("文件下载结束!"); IL#"~D?  
} wDal5GJp  
catch(Exception e){e.printStackTrace ();} }HYbS8'  
} 2lH&  
3Ei#q+7  
BLQ6A<  
//获得文件长度 P64PPbP  
public long getFileSize() >* f-Wde  
{ pP&7rRhw  
int nFileLength = -1; O:;w3u7;u  
try{ c_$=-Khk  
URL url = new URL(siteInfoBean.getSSiteURL()); ;PF<y9M  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &N^9JxN?8  
httpConnection.setRequestProperty("User-Agent","NetFox"); aFX=C >M  
UNu#(nP  
 dVtG/0  
int responseCode=httpConnection.getResponseCode(); BUDi& |,  
if(responseCode>=400) *5C7d*'  
{ g[' ^L +hd  
processErrorCode(responseCode); qZ}^;)a^  
return -2; //-2 represent access is error vxBgGl  
} C!<Ou6}!b  
H(ARw'M  
)4e.k$X^  
String sHeader; _YhES-Ff  
l`lk-nb  
= SMXDaH  
for(int i=1;;i++) cKca;SNql1  
{ G:<aB  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); #4 <SAgq  
//Utility.log(in.readLine()); *SJ_z(CZm  
sHeader=httpConnection.getHeaderFieldKey(i); :'X&bn  
if(sHeader!=null) >C>.\  
{ ? =Z?6fw  
if(sHeader.equals("Content-Length")) C`hU]  
{  ~d.Y&b  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); _aSxc)?  
break; K<3A1'_  
} X]TG<r  
} )hsgC'H{~]  
else Ko<:Z)PS  
break; w3ResQ   
} EeE7#$l  
} D0-3eV -  
catch(IOException e){e.printStackTrace ();} z#wkiCRYm  
catch(Exception e){e.printStackTrace ();} T4Uev*A  
<44G]eb  
Cv.C;H  
Utility.log(nFileLength); lfow1WRF  
*w`sM%]Rq  
Z"xvh81P  
return nFileLength; 2*& ^v  
} vm8eZG|  
 ?(1 y  
rH Lm\3  
//保存下载信息(文件指针位置) 6xx ?A>:  
private void write_nPos() 6P l<'3&  
{ MAR'y8I  
try{ Gx/Oi)&/  
output = new DataOutputStream(new FileOutputStream(tmpFile)); >y7?-*0  
output.writeInt(nStartPos.length); ~,Zc%s~|  
for(int i=0;i<nStartPos.length;i++) +Mb.:_7'  
{ dFB]~QEK  
// output.writeLong(nPos); GR_-9}jQP  
output.writeLong(fileSplitterFetch.nStartPos); `4J$Et%S  
output.writeLong(fileSplitterFetch.nEndPos); l ukB8  
} m=:9+z  
output.close(); p?OoC  
} Dw.J2>uj  
catch(IOException e){e.printStackTrace ();} k1~&x$G  
catch(Exception e){e.printStackTrace ();} e#8Q L  
} H/ HMm{4  
NH4#  
IHac:=*Q  
//读取保存的下载信息(文件指针位置) rglXs  
private void read_nPos() ~q.F<6O  
{ p8O2Z? \  
try{ (y~TL*B  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); mO7]9 p  
int nCount = input.readInt(); +~$ ]} %  
nStartPos = new long[nCount]; !wVM= z^G  
nEndPos = new long[nCount]; sY&IquK^  
for(int i=0;i<nStartPos.length;i++) j</: WRA`]  
{ Wqw1J=]  
nStartPos = input.readLong(); *i%.;Z"  
nEndPos = input.readLong(); %5n_ p^xp  
} Xl#ggub?  
input.close(); E{`fF8]K  
} 45c$nuZ  
catch(IOException e){e.printStackTrace ();} *] ) `z8Ox  
catch(Exception e){e.printStackTrace ();} ]h+j)J}[A  
} R 'zWYQ  
FcU SE  
uw_Y\F-$  
private void processErrorCode(int nErrorCode) R&k<AZ  
{ 8OU\V5i[,q  
System.err.println("Error Code : " + nErrorCode); 8Fu(Ft^9  
} "<1{9  
YjKxb9  
}&J q}j  
//停止文件下载 :crW9+  
public void siteStop() 0'C1YvF  
{ dR,fXQm  
bStop = true; 29.h91  
for(int i=0;i<nStartPos.length;i++) ?k{?GtSs  
fileSplitterFetch.splitterStop(); q>+k@>bk @  
JPw.8|V)y  
]{@-HTt  
} ( Erc3Ac8  
} K w ]=  
//负责部分文件的抓取 3F2w-+L  
**FileSplitterFetch.java pl?`8@dI  
*/ ?CPahU  
package NetFox; bROLOf4S  
9W2Vo [(  
5U$0F$BBp  
import java.io.*; '\iCP1>+S  
import java.net.*; )3EY;  
w<(pl%  
rg!r[1c  
public class FileSplitterFetch extends Thread { rjYJs*#  
0x@ mZ  
OQJ6e:BGt  
String sURL; //File URL q@8*Xa>  
long nStartPos; //File Snippet Start Position jQB9j  
long nEndPos; //File Snippet End Position Tyx_/pJT  
int nThreadID; //Thread's ID /82b S|  
boolean bDownOver = false; //Downing is over s.C_Zf~3  
boolean bStop = false; //Stop identical &V/Mmm T  
FileAccessI fileAccessI = null; //File Access interface b8 likP"T  
M .mfw#*  
t'ql[  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException eeB{c.#  
{ uK Hxe~  
this.sURL = sURL; _w +Qy.  
this.nStartPos = nStart; cVF "!.  
this.nEndPos = nEnd; 3 Za}b|  
nThreadID = id; AoxA+.O  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 U>N1Od4vTO  
} m9rp8r*e  
T_4/C2  
,k3FRes3  
public void run() ISvpQ 3{)s  
{ S<Xf>-8w  
while(nStartPos < nEndPos && !bStop) 4^:=xL  
{ "4{r6[dn  
g}c~:p  
aPL+=58r  
try{ vEJbA  
URL url = new URL(sURL); Q*Pq{]0K  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); H/M@t\$Dc  
httpConnection.setRequestProperty("User-Agent","NetFox"); cbTm'}R(G  
String sProperty = "bytes="+nStartPos+"-"; PdWx|y{%  
httpConnection.setRequestProperty("RANGE",sProperty); 5=ryDrx  
Utility.log(sProperty); 6=Otq=WH  
_oeS Uzq.  
gg2( 5FPP  
InputStream input = httpConnection.getInputStream(); `;egv*!P  
//logResponseHead(httpConnection); 3^yK!-Wp(  
Nj/ x. X  
jmZI7?<z  
byte[] b = new byte[1024]; utV_W&  
int nRead; TM%%O :3  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) + {'.7#  
{ uwGc@xOgg,  
nStartPos += fileAccessI.write(b,0,nRead); zdam^o  
//if(nThreadID == 1) Zj'9rXhrM1  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); m)v &v6  
} 'm$L Ij?@  
DN6Mo<H  
p4Z(^+Aa  
Utility.log("Thread " + nThreadID + " is over!"); l.M0`Cn-%  
bDownOver = true; Iu=(qU  
//nPos = fileAccessI.write (b,0,nRead); f3y=Wxk[  
} sRb9`u =)  
catch(Exception e){e.printStackTrace ();} }Zp,+U*"  
} |2A:eI8 ^  
} SOIN']L|V[  
do'GlU oMC  
'LDQgC*%  
//打印回应的头信息 \s\?l(ooq"  
public void logResponseHead(HttpURLConnection con) wUJcmM;  
{ P]C<U aW'!  
for(int i=1;;i++) G' 1'/  
{ x]j W<A  
String header=con.getHeaderFieldKey(i); UJ2U1H54h  
if(header!=null) xyXa .  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 4^<?Wq~  
Utility.log(header+" : "+con.getHeaderField(header)); n+M<\  
else 6ik$B   
break; '~ 47)fN  
} .T`%tJ-Em  
} <1TAw.  
<F'\lA9  
J<lW<:!3]  
public void splitterStop() JW&gJASGC  
{ gjlx~.0d  
bStop = true; !5!<C,U  
} {{!-Gr  
Q+{n-? :  
 Nz-&MS  
} |DwZ{(R"W  
0> \sQ,T  
eyxW 0}[  
/* #O&8A  
**FileAccess.java Pg{J{gn  
*//文件访问(定位,写) m]&SNz=  
package NetFox; t6t!t*jO  
import java.io.*; 7d\QB (~  
#\ErY3k6&  
l U]nd[x  
public class FileAccessI implements Serializable{ 7t3!) a|lI  
+ZX{>:vo   
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 # f\rt   
RandomAccessFile oSavedFile; 8zb /xP>  
long nPos; n=q 76W\  
0n'_{\yz  
cZ3v=ke^  
public FileAccessI() throws IOException _yT Ed"$  
{ '5tCz9}Y  
this("",0); ?V=CB,^  
} h2QmQ>y"  
4^d?D!j  
0*v2y*2V  
public FileAccessI(String sName,long nPos) throws IOException XK vi=0B  
{ cz$2R  
oSavedFile = new RandomAccessFile(sName,"rw"); /mZE/>&~ ,  
this.nPos = nPos; Zwx%7l;C  
oSavedFile.seek(nPos); !5N.B|N t  
} 5lum$5  
|':{lH6+1  
Y4YJJYvD  
public synchronized int write(byte[] b,int nStart,int nLen) .RL=xb|[  
{ {4PwLCy  
int n = -1; 9tnD=A<PS  
try{ z(~_AN M4,  
oSavedFile.write(b,nStart,nLen); u1.BN>G  
n = nLen; ~>XxGjxe  
} eJX#@`K  
catch(IOException e) ji= "DYtL  
{ R@2X3s:  
e.printStackTrace (); A=>u 1h69  
} D m9sL!  
X wtqi@zlE  
h yIV.W/  
return n; [-x7_=E#  
} k;W XB|k  
`H+ lPM66  
4&iCht =  
} Z30A{6}  
"wc<B4"  
")25 qZae  
/* S|}L&A  
**SiteInfoBean.java  AOx[  
*/ " Yy n/  
package NetFox; t`QENXA}  
Xnh8e  
##ANrG l  
public class SiteInfoBean { i@'dH3-kO  
P93@;{c(  
6H|S;K+  
private String sSiteURL; //Site's URL z?//rXuO  
private String sFilePath; //Saved File's Path UCWBYC+  
private String sFileName; //Saved File's Name Ir]\|t  
private int nSplitter; //Count of Splited Downloading File zW nR6*\  
?h2}#wg  
`y0FY&y=  
public SiteInfoBean() zBH2@d3W  
{//nSplitter的缺省值为5 WEpoBP CL  
//default value of nSplitter is 5 bPMhfK2 %  
this("","","",5); wyG;8I  
} yDS4h(^  
nRY5xRvK  
:hA#m[  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) E\$W_Lmr  
{ Q@HV- (A  
sSiteURL= sURL; Y\tui+?J  
sFilePath = sPath; !&\INl-Z  
sFileName = sName; tnIX:6  
this.nSplitter = nSpiltter; D`AsRd  
.e5Mnd%$M  
j|Q-*]V  
} C7?/%7{  
et+0FF ,  
P|> ~_$W  
public String getSSiteURL() ?fS9J  
{ PaN"sf  
return sSiteURL; N uI9iU  
} QCJM&  
oXS}IL og'  
H[|~/0?K  
public void setSSiteURL(String value) d!{r  v  
{ q'11^V!0  
sSiteURL = value; B1Oq!k  
} |'2d_vR  
BORA(,  
LHmZxi?  
public String getSFilePath() .8|X   
{ SY8C4vb'h  
return sFilePath; B\n[.(].r  
} F5#YOck&,  
H:\k}*w  
"h ^Z  
public void setSFilePath(String value) aN=B]{!  
{ Er[A X.3  
sFilePath = value; J-4:H gx  
} 'W#D(l9nI  
1nOCQ\$l  
bN88ua}k{  
public String getSFileName() |Ds=)S" K  
{ A(N4N  
return sFileName; 1&$ nVQ  
} XZwK6F)L  
c"xK`%e  
\(T /O~b2  
public void setSFileName(String value) ,=N.FS  
{ k+4#!.HX^  
sFileName = value; Cls%M5MH  
} 07$o;W@  
'3H_wd  
[8*)8jP3  
public int getNSplitter() Xx(T">]vJ  
{ 3BLqCZ  
return nSplitter; M@ZI\  
} KG5>]_GH  
]s748+  
]9,; K;1<  
public void setNSplitter(int nCount) FGQzoS  
{ v9UD%@tZ  
nSplitter = nCount; #o2[hibq  
} Q5_o/wk  
} o`RKXfCq  
o? $.fhD   
6`-jPR  
/* JMM W  
**Utility.java [fIg{Q  
*/ c0fo7|  
package NetFox; I2^8pTLh  
<^uBoKB/f  
sT' 5%4  
public class Utility { ]0\MmAJRn  
O| hpXkV  
+'w3 =2Bo  
public Utility() r"R#@V\'1b  
{ cFWc<55aX6  
FsryEHz  
188*XCtjQ9  
} 5PnDN\  
k;L6R!V  
//线程睡眠 :,I:usW"  
public static void sleep(int nSecond) E+JqWR5  
{ V2G6Kw9gt  
try{ ]$_NyAoBb  
Thread.sleep(nSecond); kSh( u  
} ?F;8Pa/  
catch(Exception e) ! v0LBe4  
{ /FJu)H..U  
e.printStackTrace (); })?GzblI&  
} = 9]~ yt  
} B93+BwN>95  
vZoaT|3 G]  
//日志 eGHaY4|  
public static void log(String sMsg) Ub!(H^zu  
{ O1mKe%'|  
System.err.println(sMsg); ,4oo=&  
} ?K\axf>F  
ZQ0F$J)2~  
:08,JL{  
public static void log(int sMsg) ?S$P9^ii'  
{ xF44M]i  
System.err.println(sMsg); 8ITdSg  
} '6Q =#:mc\  
} C73 kJa  
?1eK#Z.  
Ue~CwFOc  
/* >oe]$r  
**TestMethod.java ^a1^\X.~  
*/ :[!j?)%>  
package NetFox; abLnI =W`  
uU25iDn  
Z/;aT -N  
public class TestMethod { I(0~n,=j  
iW /}#  
9p2&) kb6  
public TestMethod() cjIh}:| '  
{ ///xx/weblogic60b2_win.exe {,~3.5u   
try{ 6f*CvW  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); & 9 ?\b7  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 7x4PaX(  
SiteFileFetch fileFetch = new SiteFileFetch(bean); qeZ? 7#Gf  
fileFetch.start(); KMjhZap%  
} <HVt V9R  
catch(Exception e){e.printStackTrace ();} "!%l/_p?  
YV anW  
Gk /fBs  
} :A'y+MnK<  
)/?$3h;  
b`O'1r\Y;  
public static void main(String[] args) ={wcfhUl+  
{ R[x_j  
new TestMethod(); }d}Ke_Q0  
} 5S--'=fu+  
} ?oHpFlj  
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