http断点续传简单实现（java)

/* UTTC:=F+  
**SiteFileFetch.java yo*iv+l  
*/
/,Rc
a1W  
package NetFox; nFfCw%T?  
import java.io.*; }91mQ`3  
import java.net.*; H<;Fb;b  
P*PL6UQ  
f^)uK+:.  
public class SiteFileFetch extends Thread { +2zuIW.  
Xo@YTol  
tqQ0lv^J  
SiteInfoBean siteInfoBean = null; //文件信息Bean 2\w=U,;(  
long[] nStartPos; //开始位置 ~}5Ml_J$,l  
long[] nEndPos; //结束位置 30_un  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 MA+-2pMc|7  
long nFileLength; //文件长度 ^-IsK#r.k  
boolean bFirst = true; //是否第一次取文件 {}pqxouE  
boolean bStop = false; //停止标志 kppRQ Q*[  
File tmpFile; //文件下载的临时信息 +?iM$}8!U  
DataOutputStream output; //输出到文件的输出流 ~+#--BhV  
?*'$(}r3  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） uit-Q5@~  
public SiteFileFetch(SiteInfoBean bean) throws IOException UNQRtR/  
{ 4*vas]  
siteInfoBean = bean; s1vrzze  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); BZ?W>'B%$  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); zcB2[eaV  
if(tmpFile.exists ()) z`/.v&<>V  
{ #Q3PzDfj  
bFirst = false; RW7oL:$dt  
read_nPos(); %?f:"  
} $a^isd4  
else $G_Q`w=jM  
{ ,Us2UEWNv  
nStartPos = new long[bean.getNSplitter()]; >J}n@MZ  
nEndPos = new long[bean.getNSplitter()]; 5!ubY 6Ph  
} zw:C*sY  
z"K( bw6  
q{GSsDo-:V  
JYd7@Msfc  
} b;L>%;  
}E5#X R  
)_v\{N  
public void run() )@qup _M@  
{ (a}
  
//获得文件长度 P=^#%7J/l  
//分割文件 W3/ 7BW`  
//实例FileSplitterFetch 5)yOw|Bd  
//启动FileSplitterFetch线程 "PyWo  
//等待子线程返回 ,iVPcza  
try{ ]&:b<]K3  
if(bFirst) nnE_OK!}T  
{ h1XMx'}B  
nFileLength = getFileSize(); (
.1 rtj  
if(nFileLength == -1) Q)S>VDLA  
{ ,k~j6Z  
System.err.println("File Length is not known!"); umjhG6  
} y|.fR>5  
else if(nFileLength == -2) v'@b.R,  
{ `x} Dk<HF  
System.err.println("File is not access!"); _D
j<Eu_  
} 23-t$y]  
else h/Hl?O8[  
{ y?#9>S >:\  
for(int i=0;i<nStartPos.length;i++) Znta#G0  
{ A/"}Y1#qX\  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); -~][0PVL9  
} NQC3!=pQ}Y  
for(int i=0;i<nEndPos.length-1;i++) A=%k/  
{ xpTDYF
 
nEndPos = nStartPos[i+1]; 6z3T?`}Y  
} RxZm/:yuJ.  
nEndPos[nEndPos.length-1] = nFileLength; Taf n:Nw}  
} >`89N'lZBm  
} MCeu0e^)  
@8nLQh^  
BF36V\  
//启动子线程 HK0::6n{  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 's[BK/  
for(int i=0;i<nStartPos.length;i++) W7L+8LU;  
{ 4TUtY:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~o@\ n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), H#L#2M%  
nStartPos,nEndPos,i); IyS"  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); -|}%~0)/bH  
fileSplitterFetch.start(); 0/\PZX+  
}
yW\XNX  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {/d4PI7)tK  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); {7?9jEj  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", &$qF4B*  
nEndPos = " + nFileLength); \Mb(6~nC  
// fileSplitterFetch[nPos.length-1].start(); hCM8/Vvx6  
o\ngR\>  
py{eX`(MS  
//等待子线程结束 dL_QX,X-]  
//int count = 0; [?chK^8  
//是否结束while循环 =4tO0  
boolean breakWhile = false; c^=R8y-N  
E
Z"bW  
{'h_'Y`bOQ  
while(!bStop) ;1W6"3t-Y  
{ W]]q=c%2  
write_nPos(); g5#CN:%f  
Utility.sleep(500); $n= O  
breakWhile = true; 84
=-Lw  
QsF
4Dl   
dhHEE|vrz  
for(int i=0;i<nStartPos.length;i++) M8';%=@  
{ G#H9g PY  
if(!fileSplitterFetch.bDownOver) !4R>O6k  
{ 74K)aA  
breakWhile = false; X JY5@I.  
break; 3;*z3;#}  
} &%^K,Q"  
} 6eQsoKK  
if(breakWhile) \M5P+Wk'  
break; Lt1U+o[ot  
=<{h^-j;a  
#{!O,`qD  
//count++; -(*nSD9  
//if(count>4) vwKw?Z0%J  
// siteStop(); [O2h-`  
} +YTx  
&Y1`?1;nw  
uBmxh%]C~  
System.err.println("文件下载结束！"); bV@7mmz:X+  
} I:#Ok+   
catch(Exception e){e.printStackTrace ();} :pwa{P  
} 3bH~';<  
 tPA:_  
p8=|5.  
//获得文件长度 Qyz>ZPu}sz  
public long getFileSize() u4YM^* S.  
{ &Yp+k}XU  
int nFileLength = -1; q7,^E`5EgU  
try{ <_9!   
URL url = new URL(siteInfoBean.getSSiteURL()); s~^*+kq  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6xHi\L  
httpConnection.setRequestProperty("User-Agent","NetFox"); :zlpfm2  
Ah-8"`E  
j 1(T )T  
int responseCode=httpConnection.getResponseCode(); _gKu8$o=-  
if(responseCode>=400) $A`xhh[  
{ !.EcP=S  
processErrorCode(responseCode); )1f+ld%R  
return -2; //-2 represent access is error o(qEkR:4kd  
} c3] C:t+  
3 >|uF  
-Q$b7*"z(  
String sHeader;
KAed!z9  
'M8aW!~  
Wr5Q5s)c  
for(int i=1;;i++) EJLQ&oH[  
{ vU!8`x)  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Z:@6Lv?CN  
//Utility.log(in.readLine()); _gW{gLYyJ  
sHeader=httpConnection.getHeaderFieldKey(i); )lh8 k{  
if(sHeader!=null) tMFsA`ng  
{ h4(JUio  
if(sHeader.equals("Content-Length")) DLi?'K3t  
{ XJSa]P^B1  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); R}r~p?(M  
break; "jR]MZ  
} HzvlF0f  
} d&jjWlHgEN  
else ` W4dx&  
break; rjUBLY1(  
} CWi8Fv  
} 0(gq;H5x'  
catch(IOException e){e.printStackTrace ();} QU/fT_ORw  
catch(Exception e){e.printStackTrace ();} E-fr}R}  
QHzgy?  
2n|CD|V$ux  
Utility.log(nFileLength); DyfsTx  
Mra35  
QU T"z'  
return nFileLength; O*G1 QX  
} l~J*' m2  

Hx %$X  
?TpUf  
//保存下载信息（文件指针位置） #Fs|f3-@  
private void write_nPos() &[_ZXVva~  
{ YT=eVg53  
try{ & Kmy}q  
output = new DataOutputStream(new FileOutputStream(tmpFile)); yNa;\UF  
output.writeInt(nStartPos.length); ffE#^|  
for(int i=0;i<nStartPos.length;i++) Au.:OeJm  
{ I@\+l6&#;  
// output.writeLong(nPos); 5G(E&>~  
output.writeLong(fileSplitterFetch.nStartPos); k_aW  
output.writeLong(fileSplitterFetch.nEndPos); DM),|Nq"  
} c?K~/bx.  
output.close(); Ei5wel6!  
} i#W*'  
catch(IOException e){e.printStackTrace ();} s;Y<BD  
catch(Exception e){e.printStackTrace ();} ^.goO]  
} Izo!rC  
Zx{96G+1  
bik*ZC?E  
//读取保存的下载信息（文件指针位置） >(3\kiYS  
private void read_nPos() T8XY fcc*h  
{ U O<:.6"  
try{ |P~;C6sf  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 2f{T6=SK  
int nCount = input.readInt(); >7b)y  
nStartPos = new long[nCount]; s0C:m  
nEndPos = new long[nCount]; *1A&'T2  
for(int i=0;i<nStartPos.length;i++) a#0;==#  
{ 3f
r^ T  
nStartPos = input.readLong(); OgCy4_a[f  
nEndPos = input.readLong(); wLJ]&puwm  
} tous#(&pK  
input.close(); oyx^a9  
} E m{aM  
catch(IOException e){e.printStackTrace ();} XOy2lJ/  
catch(Exception e){e.printStackTrace ();} w%a8XnW]1  
} ~/-eyxLTm  
-rSIBc:$8  
#0"~G][#  
private void processErrorCode(int nErrorCode) +(?>-3_z  
{ U \oy8FZ  
System.err.println("Error Code : " + nErrorCode); kV&9`c+  
} !HK^AwNY  
u[oUCTY  
h#qN+qt}  
//停止文件下载 +dW|^I{H}  
public void siteStop() "y;bsZBd"  
{ UMMB0(0D  
bStop = true; `bG7"o`  
for(int i=0;i<nStartPos.length;i++) @
-:]P8  
fileSplitterFetch.splitterStop(); E D"!n-Hq  
{1-V]h.<J  
iwF9[wAft  
} iL]'y\?lv  
} }#`:Qb \U  
//负责部分文件的抓取 <l,o&p,>|c  
**FileSplitterFetch.java
lr@#^  
*/ 8g~EL{'  
package NetFox; q]% T:A=  
T:iP="?{  
_.V?A*  
import java.io.*; Sq2P-y!w  
import java.net.*; NHQF^2\\  
M+P$/Wk  
X~9j$3lUBR  
public class FileSplitterFetch extends Thread { HU;#XU1  
{~Tg7<\L  
, YW|n:X  
String sURL; //File URL 4QHS{tj  
long nStartPos; //File Snippet Start Position s!+ pL|  
long nEndPos; //File Snippet End Position ?]O7Ao  
int nThreadID; //Thread's ID e}yX_Z'P<  
boolean bDownOver = false; //Downing is over Vw
{*P2v)  
boolean bStop = false; //Stop identical g);^NAA  
FileAccessI fileAccessI = null; //File Access interface hJ;$A*Y  
EbY,N:LK  
'gMfN  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ]wVk+%
e  
{
,)FdRRj  
this.sURL = sURL; aA'TD:&p1  
this.nStartPos = nStart; s5&@Cxzl  
this.nEndPos = nEnd; #*%q'gyHT  
nThreadID = id; tY|8s]{2  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ~x:DXEV,  
} G}d-(X
 
m#!=3P7T  
YB(Gk;]  
public void run() |N/G'>TS  
{ BUZ _)  
while(nStartPos < nEndPos && !bStop) H^%lDz  
{ Z.PBu|Kx  
*fMpZ+;[m  
IM@tN L  
try{ ?~e
3&ux  
URL url = new URL(sURL); cre;P5^E  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); J3RB]O_  
httpConnection.setRequestProperty("User-Agent","NetFox"); <O<LYN+(  
String sProperty = "bytes="+nStartPos+"-"; (!L5-8O  
httpConnection.setRequestProperty("RANGE",sProperty); 4u;9
J*r4  
Utility.log(sProperty); */qtzt  
4,Ic}CvM  
(N-RIk73/O  
InputStream input = httpConnection.getInputStream(); =uHnRY  
//logResponseHead(httpConnection); !^oV
 #  
kOwMs<1J  
g=L]S-e  
byte[] b = new byte[1024]; 1c4/}3*  
int nRead; DOS0;^f  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) dUrElXbXd  
{ ||7x;2e  
nStartPos += fileAccessI.write(b,0,nRead); LW6ZAETyL  
//if(nThreadID == 1) VosZJv=  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); f|7\DeY9U  
} Uu s.  
B!]2Se2G  
!|hoYU>@2L  
Utility.log("Thread " + nThreadID + " is over!"); LkruL_E>  
bDownOver = true; &)wiKh"$  
//nPos = fileAccessI.write (b,0,nRead); }Db[ 4
 
} 3g'S\G@  
catch(Exception e){e.printStackTrace ();} s8"8y
`u  
} {P%9  
} u7%D6W~m0  
IY'=DePd  
zG }?  
//打印回应的头信息 f"G-  
public void logResponseHead(HttpURLConnection con) CvSIV7zYo  
{ ?Ea;J0V  
for(int i=1;;i++) jl.p'$Fbn  
{ ^FmU_Q0  
String header=con.getHeaderFieldKey(i); >eQr<-8  
if(header!=null) ^|~mlY@w  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); H<hVTc{K  
Utility.log(header+" : "+con.getHeaderField(header)); !3n)|~r;K  
else $4kH3
+WJ  
break; 8I20*#  
} 'VyM{:8  
} Bs+(L [Z  
ok^d@zI  
=uk0@hy9b  
public void splitterStop() NL=|z=q  
{ )~
4II.`%^  
bStop = true; Mv544>:  
} EC2+`HJ"  
GcIDG`RX  
\6n!3FLl  
} ZX!r1*c 6  
$n^MD_1!  
h!~3Dw>,N  
/* o+`6LKg;  
**FileAccess.java l&4,v  
*//文件访问(定位，写) <U5wB]]  
package NetFox; s^0/"j|7  
import java.io.*; 4'j sDcs  
F^"_TV0va  
Hgeg@RP Q  
public class FileAccessI implements Serializable{ ORGD  
>z;[2n'  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 AqKz$  
RandomAccessFile oSavedFile; w\54j)rb  
long nPos; P./V6i<:  
S=R7`a<.5  
+;$oJJ  
public FileAccessI() throws IOException ](tx<3h  
{ {2/LRPT  
this("",0); <DKS
+R  
} 5$DHn]  
q"O.Cbk  
/>¬$>  
public FileAccessI(String sName,long nPos) throws IOException B]m@:|Q  
{ 4c oJRqf=  
oSavedFile = new RandomAccessFile(sName,"rw"); U~h'*nV&  
this.nPos = nPos; xq-17HK
s  
oSavedFile.seek(nPos); 7^wc)E^H
 
} :tIC~GG]_)  
IDkWGh  
*n]7  
public synchronized int write(byte[] b,int nStart,int nLen) \k;`}3uO  
{ s]mo$ _na  
int n = -1; R>DaOH2K*  
try{ `U+l?S^$  
oSavedFile.write(b,nStart,nLen); [A}rbD K  
n = nLen; Q-ni|  
} kKD`rfyG\  
catch(IOException e) #-pc}Y|<  
{ 7g R@$(1Z  
e.printStackTrace (); hjaT^(Y  
} .s#;s'>g  
1h
6^>()^  
6x"Q  
return n; aQI^^$9g  
} `D9]*c !mO  
:4~g;2oag  
^TMJ8`e  
}  `:
P  
[SJ6@q  
3qY K_M^[  
/* 5H=ko8fZ=  
**SiteInfoBean.java ~/mwx8~  
*/ >zDF2Y[  
package NetFox; DI!V^M[~u  
G
pm{m:$L  
qo<&J f  
public class SiteInfoBean { Q{k At%  
8G5Da|\  
zBO(`=|  
private String sSiteURL; //Site's URL [((;+B  
private String sFilePath; //Saved File's Path D:Q 21Ch  
private String sFileName; //Saved File's Name Ib
cZ@'RSw  
private int nSplitter; //Count of Splited Downloading File >^Se'SE]  
Hm+ODv9  
D")_;NLE1  
public SiteInfoBean() Lh.`C7]
  
{//nSplitter的缺省值为5 hp{OL<2M  
//default value of nSplitter is 5  8q1wHZ  
this("","","",5); Wrrcx(  
} :4^\3~i1X  
P2nft2/eu?  
2e$w?W0^  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) P"<U6zM\sP  
{ )DYI .  
sSiteURL= sURL; "t^URp3  
sFilePath = sPath; hJzxbr <  
sFileName = sName; <hwy*uBrD  
this.nSplitter = nSpiltter; a0Ik`8^`  
FgLrb#  
_fZZ_0\Q  
} Oy 2+b1{  
j5 g# 
M  
+ >cBVx6  
public String getSSiteURL() bzdb|I6Z  
{ 0i8LWX_M  
return sSiteURL; ^ wY[3"{  
} <>m }}^  

!QDQ_  
# O4gg  
public void setSSiteURL(String value)  JHf  
{ )5|I_PXB  
sSiteURL = value; ='TE,et@d  
} 6sa"O89  
~G27;Npy  
8foJI^3  
public String getSFilePath() YC_1Ks  
{ l2;CQ7  
return sFilePath; E~LTb) !  
} 9b?SHzAa  
nenU)*o  
~EK'&Y"1  
public void setSFilePath(String value) O5H9Y}i]  
{ hDV20&hq  
sFilePath = value; :>itXD!  
} *6 _tQ9G  
tK k#LWB  
?BhMjsy.  
public String getSFileName() P>9aI/d9  
{ h^j?01*Et  
return sFileName; 1^i Pji/  
} M>M`baM1  
erVO|<%=R  
EC|
'
l  
public void setSFileName(String value) Jv.UQ  
{ #z1H8CFL"  
sFileName = value; w,R[C\#J  
} P;pl,~  
2< hAa9y  
3BpZX`l*p  
public int getNSplitter() D~
o$GW%  
{ N41R  
return nSplitter; <L&m4O#|  
} .(Qx{r$  
,RN:^5 p  
"QvmqI>  
public void setNSplitter(int nCount) QMEcQV
>  
{ (|wz7AY2  
nSplitter = nCount; R0oKbs{  
} :{(w3<i  
} $<ld3[l i  
 r[?1  
h[Gg}N!  
/* WoxwEi1~0  
**Utility.java *'"^NSJ  
*/ |AC1\)2tT  
package NetFox; '_b.\_s-d  
4[r/}/iGo  
fr!Pj(Q1  
public class Utility { Py{<bd  
(MHAJ]Rx  
d6i6hcQE  
public Utility() cWajrLw  
{ 1,5E`J  
h=_mNG>R)  
R-^96fFBy  
} 1He{v#  
l|5fE1K9U  
//线程睡眠 ;\MW$/[JCy  
public static void sleep(int nSecond) [%&ZPJT%i  
{ % >;#9"O4  
try{ XR!us/U`a  
Thread.sleep(nSecond); n<B<93f
/  
} /pp1~r.s?>  
catch(Exception e) j1 =`|  
{ cwV]!=RtO  
e.printStackTrace (); 5[n(7;+gw  
} id?h>g  
} <LRey%{q  
WMMO5_Mz  
//日志 X>?b#Eva  
public static void log(String sMsg)
n&A'C\  
{ ^T~gEv  
System.err.println(sMsg); CIVnCy z  
} -l}IZY  
[=%TnT+^9  
_20#2i&  
public static void log(int sMsg) i_][PTH  
{ w{k)XY40sW  
System.err.println(sMsg); dJ?XPo"Cm=  
} z6py"J@  
} /.M+fr S  
<W]g2>9o9  
yPw'] "  
/* 2
YuN~-  
**TestMethod.java X0*QV- RN  
*/ nADX0KI  
package NetFox; <5=JE*s$NS  
<)*2LBF@]  
*-s,. F+c  
public class TestMethod { OiDhJ  
^s.V;R  
mZIoaF>t  
public TestMethod() n&MG7`]N  
{ ///xx/weblogic60b2_win.exe e?bYjJq  
try{ 76.{0c  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5);
h d~$WV0#  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); wv^rS^~  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8P: Rg%0)  
fileFetch.start(); jPnM>=  
} }3R13  
catch(Exception e){e.printStackTrace ();}
XYoIFv?'  
:fk2]{KTL  
 '8j$';&`  
} HG'{J^t  
y0~Ia:y  
5X.e*;  
public static void main(String[] args) r6'UUu  
{ (Toq^+`c  
new TestMethod(); e"r)R8  
} `]Bxn)b(  
} {A|TowBN  
点击下载更多相关资料