http断点续传简单实现（java)

/* x+]"  
**SiteFileFetch.java !G|@6W`  
*/  Z\sDUJ  
package NetFox; M6TD"-  
import java.io.*; 7_t'( /yu  
import java.net.*; /dHF6yW  
* y,v}-  
46;uW{EY  
public class SiteFileFetch extends Thread { Zd+bx*rD  
Hn:Crl y#  
&^nGtW%a 9  
SiteInfoBean siteInfoBean = null; //文件信息Bean ?JUeuNs9  
long[] nStartPos; //开始位置 V]^$S"Tv  
long[] nEndPos; //结束位置 G~m<;  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 gqR(.Pu  
long nFileLength; //文件长度 []T8k9g/-  
boolean bFirst = true; //是否第一次取文件 Bw.i}3UT6  
boolean bStop = false; //停止标志 -\MG}5?!  
File tmpFile; //文件下载的临时信息 $cgcX  
DataOutputStream output; //输出到文件的输出流 ^zr`;cJ+c  
4M T 7`sr  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） qP ,E
BE  
public SiteFileFetch(SiteInfoBean bean) throws IOException '%;m?t%q  
{ HOi`$vX}N  
siteInfoBean = bean; Wn6Sn{8W{  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); k7^5Bp8=  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 18Emi<&A  
if(tmpFile.exists ()) p<%d2@lp  
{ F"kAkX>3}  
bFirst = false; EX"yxZ~  
read_nPos(); QV8g#&z  
} 3' 'me  
else p4QU9DF  
{ A}w/OA97RO  
nStartPos = new long[bean.getNSplitter()]; }B^tL$k  
nEndPos = new long[bean.getNSplitter()]; _v:SP LU  
} C,zohlpC  
AFn7uW!9Gw  
y>L
Bl]  
tX[WH\(xI  
} 
bMBLXk  
eH,or,r  
u:b=\T L  
public void run() NlXimq  
{ sq]F;=[5  
//获得文件长度 }2oc#0  
//分割文件 |a@L}m  
//实例FileSplitterFetch 5R7DDJk  
//启动FileSplitterFetch线程 /Kbl%u  
//等待子线程返回 DwF hK*  
try{ P~dcW  
if(bFirst) fy$1YI>!Q  
{ t,'<gI
 
nFileLength = getFileSize(); 5-M-X#(  
if(nFileLength == -1) X?Au/  
{ .^.z2 e  
System.err.println("File Length is not known!"); 7z-[f'EIUI  
} M=Wz  
else if(nFileLength == -2) $xQL]FmS  
{ 4+i
g' |o  
System.err.println("File is not access!"); Hv, LS;W  
} v0y(58Rz.  
else n`KY9[0U=  
{ SAz   
for(int i=0;i<nStartPos.length;i++) hOeRd#AQK  
{ H.0K?N&\?>  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); =lC7gS!U  
} 'PHl$f*k  
for(int i=0;i<nEndPos.length-1;i++) E.f%H(b  
{ Wjc'*QCPl  
nEndPos = nStartPos[i+1]; _G0x3  
} ~5g~;f[4  
nEndPos[nEndPos.length-1] = nFileLength; YK\X+"lB  
} 7d vnupLh  
} Y ay?=Y{  
+v\oOBB)  
;PH~<
T  
//启动子线程 Z{R>  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; v2?ZQeHr_(  
for(int i=0;i<nStartPos.length;i++) UI#h&j5pW  
{
F\! `/4  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), y)pk6d  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 6wxs1G  
nStartPos,nEndPos,i); *2?@ |<(r  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >V~E]P%@  
fileSplitterFetch.start(); "oD[v  
} ,s(,
S  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), l,8##7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); &NWEqBz*2  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", `9 L>*  
nEndPos = " + nFileLength); $?Wb}DU7_L  
// fileSplitterFetch[nPos.length-1].start(); o@Oqm>]SS  
TNth  
vbNBLCwug  
//等待子线程结束 JO;Uus{?  
//int count = 0; Ib`XT0k  
//是否结束while循环 2?5>o!C  
boolean breakWhile = false; $k?>DP4  
jF>[?L  
#jk_5W  
while(!bStop) G#CXs:1pd+  
{ N$DkX)Z  
write_nPos(); H.c7Nle  
Utility.sleep(500); Jvi#)  
breakWhile = true; B6"0OIDY"  
n ;Ei\\p!  
;,TFr}p`
 
for(int i=0;i<nStartPos.length;i++) <[phnU^ 8  
{ ?(PKeq6  
if(!fileSplitterFetch.bDownOver) pI[uUu7O  
{ >Q/Dk7#  
breakWhile = false; TV:9bn?r)  
break; qLCR] _*  
} SKtrtm  
} mR~&)QBP.  
if(breakWhile) I|OoRq  
break; l.]xB,k  
*_e3 @g  
\GBuWY3B  
//count++; n|hNM?v  
//if(count>4) O<I-
  
// siteStop(); No$3"4wk  
} FsPw1A$y  
KXrjqqXs  
Y@v>FlqI{  
System.err.println("文件下载结束！"); 6LZCgdS{  
} NRuNKl.v  
catch(Exception e){e.printStackTrace ();} I'Hf{Erw  
} TzZq(?V  
@ZJS&23E  
Zfw,7am/  
//获得文件长度 rjP/l6 ~'  
public long getFileSize() SJLis"8  
{ TvM~y\s  
int nFileLength = -1; QPx^_jA  
try{ =D(j)<9$A  
URL url = new URL(siteInfoBean.getSSiteURL()); AX INThJ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @iiT
<
 
httpConnection.setRequestProperty("User-Agent","NetFox"); pCDmXB  
h;Kx!5)y  
T|$H#n}  
int responseCode=httpConnection.getResponseCode(); <b.D&  
if(responseCode>=400) qK+5NF|  
{ `^vE9nW7  
processErrorCode(responseCode); $qiya[&G4  
return -2; //-2 represent access is error /FII07V  
} =I<R!ZSN  
OI*H,Z"  
1 zZlC#V  
String sHeader; e.>P8C<&  
3Vwh|1?  
DXo|.!P=3  
for(int i=1;;i++) 6863xOv{T  
{ ' QG?nu  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); !if   
//Utility.log(in.readLine()); wJ]d&::@h  
sHeader=httpConnection.getHeaderFieldKey(i); ]]mJ']l  
if(sHeader!=null) ZNoDFf*h  
{ \m,PA'nd/  
if(sHeader.equals("Content-Length")) bOB\--:]  
{ :h$$J lP  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); |>Vb9:q9Po  
break; 8y L Y  
} UZMd~|  
} q'DW~!>qX  
else 2HdC |$_+  
break;  Sf'CN8  
} E.TAbD&5(  
} $X6h|?3U,  
catch(IOException e){e.printStackTrace ();} %A`+WYeuX  
catch(Exception e){e.printStackTrace ();} uph(V  
TxD#9]Q`  
JI}'dU>*U:  
Utility.log(nFileLength); y0#2m6u  
%Zi} MPx  
DI>s-7  
return nFileLength; tA;}h7/Lc~  
} +whDU2 "  
,prf;|e?  
>Ry01G]_/h  
//保存下载信息（文件指针位置） k:;r2f  
private void write_nPos() 2ESo2  
{ 5+'<R8{:,  
try{ [WmM6UEVS  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ~Y;*u]^  
output.writeInt(nStartPos.length); $i&zex{\  
for(int i=0;i<nStartPos.length;i++) t_^4`dW`  
{  e
p8  
// output.writeLong(nPos); Hka2  
output.writeLong(fileSplitterFetch.nStartPos); oU8q o-J1H  
output.writeLong(fileSplitterFetch.nEndPos); d0D]Q  
} &Jj<h: *  
output.close(); :X=hQ:>P  
} d=(mw_-
?  
catch(IOException e){e.printStackTrace ();} ^[[P*NX3  
catch(Exception e){e.printStackTrace ();} K0~rN.C!0  
} _f83-':W6  
V!
Uc(  
h{Y",7]!  
//读取保存的下载信息（文件指针位置） # d  
private void read_nPos() 2G7Wi!J  
{
1Mzmg[L8  
try{ 7#XzrT]  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); -RwE%cr  
int nCount = input.readInt(); )
7F/O3Tq  
nStartPos = new long[nCount]; %J(:ADu]  
nEndPos = new long[nCount]; e6*8K@LHB  
for(int i=0;i<nStartPos.length;i++) G{}VPcrbC  
{ FPz9N@M%Q  
nStartPos = input.readLong(); MtdG
>TzUn  
nEndPos = input.readLong(); 79gT+~z  
} afVT~Sf{  
input.close(); u9e@a9c  
} Ud?Q%)X  
catch(IOException e){e.printStackTrace ();} 01]f2.5  
catch(Exception e){e.printStackTrace ();} 6P3*Z  
} |Cv!,]9:r  
.v K-LHs  
VA%J\T|G2\  
private void processErrorCode(int nErrorCode) h p1Bi  
{ 5m@V#2^P  
System.err.println("Error Code : " + nErrorCode); $Sq:q0  
} P.cyO3l  
e~OpofJNb  
x2xRBkRg=  
//停止文件下载 F9PxSk_\9  
public void siteStop() i-1op> Y  
{ "oyo#-5z  
bStop = true; 9hl_|r~%*  
for(int i=0;i<nStartPos.length;i++) \bXa&Lq  
fileSplitterFetch.splitterStop(); e\rp)[>'  
hrk r'3lv  
)%TmAaj9d  
} U{mYTN*:j$  
} }MySaL>  
//负责部分文件的抓取 ~%oR[B7=|  
**FileSplitterFetch.java WJi]t93  
*/ X$ D6Ey  
package NetFox; *~`(RV  
F|8&  
 " bG2:  
import java.io.*; R2NZ{"h  
import java.net.*; (Ldi|jL  
_c07}aQ ],  
Z+SRXKQ  
public class FileSplitterFetch extends Thread { %T[]zJ(  
4H/OBR  
XW/o<[91  
String sURL; //File URL \V:^h[ad  
long nStartPos; //File Snippet Start Position #yen8SskB  
long nEndPos; //File Snippet End Position ]e3Ax(i)  
int nThreadID; //Thread's ID NK+o1  
boolean bDownOver = false; //Downing is over 6!o1XQr=Z  
boolean bStop = false; //Stop identical xw%0>K[  
FileAccessI fileAccessI = null; //File Access interface ]9-\~Mwh  
M|-)GvR$J  
}Jw,>}  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException pAEx#ck  
{ *hrd5na  
this.sURL = sURL; =Qq+4F)MD  
this.nStartPos = nStart; '-6~tWC~7  
this.nEndPos = nEnd; E`q_bn  
nThreadID = id; $]1=\I  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 <3iMRe  
} zDp2g)  
POW>~Tof1  
GILfbNcd  
public void run() dx]>(e@(t{  
{ ;<5q]/IHK  
while(nStartPos < nEndPos && !bStop) lr?;*f^3  
{ ivPg9J1S  
?"FbsMk.d  
l%ZhA=TKQ  
try{ zT/\Cj68  
URL url = new URL(sURL); l2d{ 73h  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); d _ e WcI  
httpConnection.setRequestProperty("User-Agent","NetFox"); DlT{`  
String sProperty = "bytes="+nStartPos+"-"; ?upM>69{  
httpConnection.setRequestProperty("RANGE",sProperty); >p/`;Kq@  
Utility.log(sProperty); GfG|&VNlz  
,[Fb[#Qqb  
S'14hk<  
InputStream input = httpConnection.getInputStream(); m*;ERK  
//logResponseHead(httpConnection); ]k(]qZ  
p'fYULYE  
HDKbF/  
byte[] b = new byte[1024]; r>\bW)e  
int nRead; BHw, 4#F1;  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ]9XDS[<2`  
{ _
U0f=m  
nStartPos += fileAccessI.write(b,0,nRead); eFAnFJ][L  
//if(nThreadID == 1) 6RM/GM  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); p7Cs.2>M>S  
} nm+s{  
mTh]PPo
 
;
]fs'LH  
Utility.log("Thread " + nThreadID + " is over!"); {)"vN(mX  
bDownOver = true; FqifriLN  
//nPos = fileAccessI.write (b,0,nRead); AEuG v}#  
} [V!tVDs&'o  
catch(Exception e){e.printStackTrace ();} nie%eC&U  
} $|@ r!/W  
} f-d1
KNY  
B:
QHwzd
 
i&k7-<  
//打印回应的头信息 W l16`9  
public void logResponseHead(HttpURLConnection con)  9akH  
{ 3[&Cg  
for(int i=1;;i++) 8] ikygt"  
{ E e]-qN*8  
String header=con.getHeaderFieldKey(i); <| &Np
d'  
if(header!=null) +>9Q/E  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Ha#>G<;n  
Utility.log(header+" : "+con.getHeaderField(header)); Wvqhl 'J  
else mqJ_W[y7  
break; vI]N^j2%  
} 1U\z5$V  
} &[SC|=U'M  
MW{8VH6+  
njw|JnDv  
public void splitterStop() akT6^cP^  
{ c|1&lYal;  
bStop = true; 5-G@L?~Vw  
} d7i]FV  
JLi|Td"1%  
CP{cAzHO  
} d| {r5[&  
frQ{iUx  
Rh |nP&6  
/* $kKjgQS(  
**FileAccess.java C $JmzrE  
*//文件访问(定位，写) xvy.=(  
package NetFox; EZj9wd"u  
import java.io.*; *:NQ&y*uj  
"vslZ`RU  
j+(I"h3  
public class FileAccessI implements Serializable{ PuO&wI]:  
&M'*6A  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 IMfqiH)  
RandomAccessFile oSavedFile; ^VACf|0  
long nPos; X|8c>_}  
&w~
d_</  
42{:G8  
public FileAccessI() throws IOException h*Pc=/p  
{ @]#1(9P  
this("",0); d:{O\   
} yOg+iFTr  

69 o7EA  
EyLuO-5  
public FileAccessI(String sName,long nPos) throws IOException PzR[KUK  
{ ->{KVPHe{  
oSavedFile = new RandomAccessFile(sName,"rw"); e*n@j  
this.nPos = nPos; ;Q&5,< N)j  
oSavedFile.seek(nPos); %!L9)(}"  
} 0C*7K?/  
fg{n(
TE"8  
+t:0SRSt  
public synchronized int write(byte[] b,int nStart,int nLen) _]*>*XfF(  
{ (%:c#;#  
int n = -1; tdaL/rRe  
try{ Q1l'7N  
oSavedFile.write(b,nStart,nLen); c7E11 \%&Z  
n = nLen; HX{`VahE  
} ;
]jNk'oa  
catch(IOException e) 2,P^n4~A?w  
{ ;xs"j-r/  
e.printStackTrace (); zZC9\V}R  
} 63~ E#Dt4  
"v4B5:bmqW  
9 5RBO4w%w  
return n; )@'}\_a3[]  
} 5lT*hF  
0k(a VkZ I  
K:Q<CQ2  
} '!a'ZjYyi  
RlDn0s  
-8rjgB~."/  
/* ApXy=?fc  
**SiteInfoBean.java R n*L  
*/ 78H'ax9m  
package NetFox; }<y7bqA  
+|>k
CtZH%  
Oh\<VvZuN  
public class SiteInfoBean { .Twk {p  
 xLZG:^(I  
`P;s8~  
private String sSiteURL; //Site's URL 3K/MvNI>  
private String sFilePath; //Saved File's Path k/gZ,  
private String sFileName; //Saved File's Name L4|`;WP  
private int nSplitter; //Count of Splited Downloading File c#tjp(-  
#3 pb(fbw  
2Jmz(cH%  
public SiteInfoBean() [o5Hl^  
{//nSplitter的缺省值为5 h_IDO%  
//default value of nSplitter is 5 X=8{$:  
this("","","",5); TSWM |#u':  
} 7y@Pa&^8  
4J([6<  
tlp@?(u  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) n%s]30Xs  
{ :s6o"VkW  
sSiteURL= sURL; x&T[*i  
sFilePath = sPath; Ev(>z-{F  
sFileName = sName; jc f #6   
this.nSplitter = nSpiltter; 2nIw7>.}f  

1.9}_4!  
t#pS{.I  
} <=0 u2~E  
X;c'[q  
k
<{{*  
public String getSSiteURL() RnI&8  
{ Q &K  
return sSiteURL; FXN/Yq  
} ,1CIBFY  
|3[Wa^U5  
bPt!
yI:  
public void setSSiteURL(String value) }YNR"X9*)/  
{ !~D}/Q;#}\  
sSiteURL = value; \\dMy9M-  
} 2=`o
_<P'"  

'>0fWBs  
$!yW_HTx  
public String getSFilePath() emPM4iG?!  
{ m6CI{Sa](l  
return sFilePath; aV|hCN~  
} {Um)15K  
tL)t"  i  
c>RFdc:U  
public void setSFilePath(String value) v,{yU\)  
{ ft
KTnK.  
sFilePath = value; /qGf 1MHD  
} g8xQ|px  
D9 |n)f  
i?g5_HI  
public String getSFileName() z'\_jaj^  
{ `a/%W4  
return sFileName; lXiKY@R#  
} Xudg2t)+K  
z>Hgkp8D"  

$?<Z!*x  
public void setSFileName(String value) _5# y06Q  
{ 48qV>Gwf  
sFileName = value; F,dx2ZPIs?  
} 5$&%re!{Z  
=L:4i\4  
sOJQ,"sB  
public int getNSplitter() 4?7W+/~<&  
{ /bi[e9R
 
return nSplitter; X+S9{X#Cm  
}
EzV96+  
v` 7RCg`  
fb8g7H|  
public void setNSplitter(int nCount) 7=WT69,&  
{ 5Z\#0":e  
nSplitter = nCount; 

#Xb+`'  
} %$Z7x\_  
} 7-T{a<g  
6qaQ[XTxf  
Jjv=u  
/* DRgTe&+  
**Utility.java &LVn6zAba  
*/ "zRoU$X  
package NetFox; k |%B?\m  
^[XYFQTL  
;z:UN}  
public class Utility { Vq;A>  
;)e2@'Agl  
o=?C&f{  
public Utility() #KXa&C  
{ Mt5PaTjj  
kO{s^_qR^c  
~-
m"  
} [P7N{l=I  
%V{7DA&C  
//线程睡眠 4^Q:  
public static void sleep(int nSecond) )5U[o0td  
{ D]~MC  
try{ W.0L:3<"  
Thread.sleep(nSecond); H& Ca
`B  
} FE!lok  
catch(Exception e)  S"$m]  
{ EEZ
w_ 1  
e.printStackTrace (); /&{$ pM|?  
} x,S P'fcP  
} z`FCs,?K  
/BV03B  
//日志 Adgc% .#  
public static void log(String sMsg) z;wELz1L{  
{ 5N*Ux4M  
System.err.println(sMsg); sx51X^d  
} 7C2&NyWJ  
X>. NFB  
jSuL5|Gui  
public static void log(int sMsg) Ch%m  
{ ' dx1x6  
System.err.println(sMsg); !G}+E2fDA  
} 9>rPe1iv  
} FH%GIi  
@%
lBrM  
9Q-*@6G  
/* 'fNKlPMv4D  
**TestMethod.java ,
qrQ"r9  
*/ {$^DMANDx  
package NetFox; v\"S Gc  
[mr9(m[F  
dVo.Czyd  
public class TestMethod { _fP&&}  
dG71*)<)t  
t 6^l`6:p  
public TestMethod() MqA`yvQm  
{ ///xx/weblogic60b2_win.exe Tl|:9_:t  
try{ h"[+)q%L  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %-AE]-/HI  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ;kJA'|GX  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 5pRV3K{H  
fileFetch.start(); 3#45m+D  
} eBO@7F$  
catch(Exception e){e.printStackTrace ();} \yGsr Bl  
@M8|(N%  
Z0
>DNmH*  
} 2{.QjYw^  
^p/O
b'!  
b4""|P?L  
public static void main(String[] args) zn@N'R/  
{ ,mL !(US  
new TestMethod(); d@3
}U6,  
}
$eBX  
} K!mOr  
点击下载更多相关资料