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http断点续传简单实现(java)

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/* Gj`Y2X2r  
**SiteFileFetch.java k<zGrq=8J  
*/ Ks2%F&\cE  
package NetFox; %C0O?q  
import java.io.*; pm@Z[g  
import java.net.*; IA#*T`  
e uHu}  
,9wenr  
public class SiteFileFetch extends Thread { R(N(@KC  
%W',cu  
u%T$XG  
SiteInfoBean siteInfoBean = null; //文件信息Bean %yM' Z[-  
long[] nStartPos; //开始位置 N3p 7 0  
long[] nEndPos; //结束位置 {JCz^0DV  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 g*?+ ~0"`Y  
long nFileLength; //文件长度 umZ g}|C_  
boolean bFirst = true; //是否第一次取文件 *jw$d8q2  
boolean bStop = false; //停止标志 $1zeY6O  
File tmpFile; //文件下载的临时信息 kjC{Zr  
DataOutputStream output; //输出到文件的输出流 XW_xNkpL5c  
Tv,.  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 9$V_=Bo  
public SiteFileFetch(SiteInfoBean bean) throws IOException 9^#gVTGXv  
{ a {$k<@Ww  
siteInfoBean = bean; 0k 0c   
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); " IkF/  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); .L5*E(<K0  
if(tmpFile.exists ()) G4%M$LJ h  
{ m4SXH> o  
bFirst = false; I5yd )72  
read_nPos(); I= h4s(  
} 8Gl5)=2  
else ZQ'  z  
{ W$Q)aA7  
nStartPos = new long[bean.getNSplitter()]; ,9tbu!Pvq  
nEndPos = new long[bean.getNSplitter()]; :8Ts'OGwI  
} gq_7_Y/  
 vs])%l%t  
n vpPmc  
Y:!/4GF  
} a$zm/  
ciGpluQF  
N!Wq}#&l  
public void run() N' $DE  
{ v7<S F  
//获得文件长度 5*wApu{2A  
//分割文件 h9BD ^j  
//实例FileSplitterFetch a;'E}b{`F  
//启动FileSplitterFetch线程 r;on0wm&B  
//等待子线程返回 .1}rzh}8  
try{ ]AZ\5C-J  
if(bFirst) g[wP!y%V  
{ *JY`.t  
nFileLength = getFileSize(); D PS1GO*  
if(nFileLength == -1) J={OOj  
{ iPY vePQ  
System.err.println("File Length is not known!"); <m /b]|  
} yg-FJ/  
else if(nFileLength == -2)  @6YBK+"  
{ Pm#x?1rAj  
System.err.println("File is not access!"); ~r>EF!U`h  
} tk)>CK11  
else #ON#4WD?  
{ ELrZ8&5G  
for(int i=0;i<nStartPos.length;i++) /pIb@:Y1?  
{ <qq'h  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); UC+7-y,  
} le^_6| ek  
for(int i=0;i<nEndPos.length-1;i++) x<*IF,o  
{ aEEz4,x_  
nEndPos = nStartPos[i+1]; uVq5fT`B  
} k99gjL`  
nEndPos[nEndPos.length-1] = nFileLength; b1+hr(kMRM  
} -_EY$ ?4  
} )`s;~_ZZ  
>^H'ZYzw  
Cwsoz  
//启动子线程 Ck3QrfM  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; =|gJb|?w  
for(int i=0;i<nStartPos.length;i++) 3Zaq#uA  
{ ])QO%  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), jV4hxuc$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), VM!-I8t  
nStartPos,nEndPos,i); +Y5(hjE  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); BA1MGh  
fileSplitterFetch.start(); t(j_eq}J  
} ,a9D~i 9R  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), xgtJl}L  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); B%eDBu ")  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ^Cc8F3os=  
nEndPos = " + nFileLength); k_K,J 6_)  
// fileSplitterFetch[nPos.length-1].start(); e+F}9HR7  
j(Fa=pi  
Q3BLL` W~  
//等待子线程结束 9QC"Od9H  
//int count = 0; x5fgF;  
//是否结束while循环 ~tg1N^]kV  
boolean breakWhile = false; J}) $  
wuIsO;}/9  
c_ qcb7<~.  
while(!bStop) - - i&"  
{ 9ra HSzK@d  
write_nPos(); ;# R3k  
Utility.sleep(500); VBbUl|X\  
breakWhile = true; %="~\1y  
u>,lf\Fgz  
to!mz\F  
for(int i=0;i<nStartPos.length;i++) e0v9uQ%F5  
{ ;Na8 _}  
if(!fileSplitterFetch.bDownOver) nW $A^  
{ S_T{L  
breakWhile = false; &Rt+LN0qB0  
break; } g3HoFC  
} QmH/yy3.%  
} d7W%zg\T  
if(breakWhile) FX|0R#4vm  
break; FylWbQU9  
/'Qu u)~  
G}=`VYK  
//count++; CdBthOPX)  
//if(count>4) i O%Zd[  
// siteStop(); VO. -.  
}  ``(}4 a  
0)A=+zSS1  
Xzx[C_G  
System.err.println("文件下载结束!"); wUZQB1$F  
} NK+FQ^m[  
catch(Exception e){e.printStackTrace ();} '^Pq(b~  
} JdaFY+f :  
ee&nU(pK  
$xRo<,OV+  
//获得文件长度 o5N]((9  
public long getFileSize() 0M#N=%31  
{ dr| | !{\  
int nFileLength = -1; z3^RUoGU  
try{ 7XUhJN3n  
URL url = new URL(siteInfoBean.getSSiteURL()); eZ!yPdgy|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); f![xn2T  
httpConnection.setRequestProperty("User-Agent","NetFox"); y!7B,  
ZhGh {D[,  
Nl~Z,hT$*  
int responseCode=httpConnection.getResponseCode(); 9USrgY6_  
if(responseCode>=400) Rz.i/w g}  
{ " t5 +*  
processErrorCode(responseCode); W;fH&r)d@  
return -2; //-2 represent access is error qxf+#  
} ?*CRa$_I|  
sTd}cP  
5"1!p3`\D{  
String sHeader; /yx=7<  
Jq# [uX  
8_"3Yb`f  
for(int i=1;;i++) "NxOOLL  
{ J*}VV9H  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ijvNmn1k  
//Utility.log(in.readLine()); r@|R-Binz  
sHeader=httpConnection.getHeaderFieldKey(i); T1lXYhAWS  
if(sHeader!=null) ^D9 /  
{ i'M^ez)u  
if(sHeader.equals("Content-Length")) nHI(V-E2:H  
{ `[X6#` <  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); rU; g0'4e  
break; 8'3"uv  
} k!Vn4?B"k  
} &[NVP&9&U  
else S#P+B*v  
break; ^Lsc`<xC  
} ~J%R-{U9  
} a;56k  
catch(IOException e){e.printStackTrace ();} uAp -$?  
catch(Exception e){e.printStackTrace ();} x HY+q ;  
M{*kB2jr  
&@=u+)^-{  
Utility.log(nFileLength); TRSOO}  
h^['rmd  
'/Cg*o/  
return nFileLength; (d54C(")  
} k |^vCZ<(x  
,`D/sNP ,q  
B`LD7]ew  
//保存下载信息(文件指针位置) >-VWm A  
private void write_nPos() CI IY|DI`l  
{ Lqg] Fd  
try{ kVWGDI$~  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 63.( j P1;  
output.writeInt(nStartPos.length); gB>(xY>LrA  
for(int i=0;i<nStartPos.length;i++) 3b<: :t  
{ O-i4_YdVt  
// output.writeLong(nPos); vB Sm=M  
output.writeLong(fileSplitterFetch.nStartPos); _i-\mR_~  
output.writeLong(fileSplitterFetch.nEndPos); k& OC&  
} $RpF xi  
output.close(); \^yXc*C  
} D=2~37CzQ1  
catch(IOException e){e.printStackTrace ();} <H<!ht%q3  
catch(Exception e){e.printStackTrace ();} \.5F](:  
} .H ,pO#{;  
ex.+'m<g  
&8Zeq3~  
//读取保存的下载信息(文件指针位置) 3b#L17D3_  
private void read_nPos() j0AwL7  
{ 7`Qde!+C  
try{ >+L7k^[,0  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); |Es0[cU  
int nCount = input.readInt(); Ny[Q T*nV  
nStartPos = new long[nCount]; (viWY  
nEndPos = new long[nCount]; =ntft SH  
for(int i=0;i<nStartPos.length;i++) KCE=|*6::|  
{ 5n:nZ_D  
nStartPos = input.readLong(); !zU/Hq{wcK  
nEndPos = input.readLong(); N A8 sN  
} 0%/,>IR>r  
input.close(); VXiui'/(  
} wqcDAO (  
catch(IOException e){e.printStackTrace ();} 6Ux[,]G K  
catch(Exception e){e.printStackTrace ();} '[%jjUU  
} ?qy*s3 j'M  
[@ILc*2O  
3]N q@t  
private void processErrorCode(int nErrorCode) wXz\NGW  
{ Qy/uB$q{A  
System.err.println("Error Code : " + nErrorCode); *E.LP1xP  
}  +.=1^+a  
;;M"hI3@  
]7*kWc2  
//停止文件下载 ;3mL^  
public void siteStop() >8%M*-=p  
{ Ha?G=X  
bStop = true; lHcA j{6  
for(int i=0;i<nStartPos.length;i++) <&`:&7  
fileSplitterFetch.splitterStop(); WX LK89ev\  
xg?auje  
}*h47t}  
} k j-=xhJ{=  
} Mw+v"l&mU  
//负责部分文件的抓取 ,'=hjIel  
**FileSplitterFetch.java 7q!?1 -?8R  
*/ 0fA=_=A,  
package NetFox; B& "RS  
fSbS(a  
'(tj[&aL  
import java.io.*; @`6}`k  
import java.net.*; .wP/ai>}  
 e#1.T  
hzq5![/sV  
public class FileSplitterFetch extends Thread { >:A<"wZ  
as(;]  
zOL;"/R  
String sURL; //File URL ;uK";we  
long nStartPos; //File Snippet Start Position *<7l!#  
long nEndPos; //File Snippet End Position s"q=2i  
int nThreadID; //Thread's ID d @m\f  
boolean bDownOver = false; //Downing is over bf1)M>g,O  
boolean bStop = false; //Stop identical a#$N%=j  
FileAccessI fileAccessI = null; //File Access interface qIz}$%!A  
^,`M0g\$  
S#mK Pi+3  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException f\ 'T_  
{ C!5I?z&  
this.sURL = sURL; &~'S)Nun  
this.nStartPos = nStart; [z2eCH  
this.nEndPos = nEnd; Xo\S9,s{  
nThreadID = id; eSn$k:\W  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 h D.)M  
} *,0+RASvq  
nZxSMN0]  
+mLD/gK`  
public void run() 7k'gt/#up  
{ &sdx`,  
while(nStartPos < nEndPos && !bStop) 6Kp}_^|z  
{ }3J=DCtS  
J+|/-{g  
modC6d%  
try{ Z%OW5]q  
URL url = new URL(sURL); 0p `")/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (-(QDRxK  
httpConnection.setRequestProperty("User-Agent","NetFox"); T)~!mifX  
String sProperty = "bytes="+nStartPos+"-"; -=a[J;'q  
httpConnection.setRequestProperty("RANGE",sProperty); \E77SO,$  
Utility.log(sProperty); 5B?i(2&#  
Im+ 7<3Z  
Yz\ N&0"  
InputStream input = httpConnection.getInputStream(); X8Fzs!L`  
//logResponseHead(httpConnection); BPewc9RxV  
P$OUi!"  
v%nP*i9  
byte[] b = new byte[1024]; $''UlWK  
int nRead; ?A&%Cwj  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) G|*G9nQ  
{ 7&foEJ3q  
nStartPos += fileAccessI.write(b,0,nRead); ~)?|J  
//if(nThreadID == 1) R5ZIC4p  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); N 2Ssf$  
} >Nh`rkR2[  
*VDVC0R  
)NIv  "Q  
Utility.log("Thread " + nThreadID + " is over!"); `XgFga)  
bDownOver = true; B`1kGEx .  
//nPos = fileAccessI.write (b,0,nRead); ?-,6<K1  
} j^nu|  
catch(Exception e){e.printStackTrace ();} \c% g M1  
} 9@'4P  
} hl]S'yr  
!}t-j3bCs  
V%51k{  
//打印回应的头信息 r]T0+oQ>  
public void logResponseHead(HttpURLConnection con) T,OS0;7O  
{ ]]PE#DDg  
for(int i=1;;i++) \z:<DsQ&  
{ CN\=9Rvs  
String header=con.getHeaderFieldKey(i); yb?|Eww_o  
if(header!=null) l'uOORI  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); $8g42LR'  
Utility.log(header+" : "+con.getHeaderField(header)); p9iu:MucD<  
else V;;#/$oU:4  
break; N}mh}  
} w & P&7  
} ]\dHU.i  
t^U^Tr  
AY88h$a  
public void splitterStop() R6P\T\~E  
{ BIj   
bStop = true; c\K<sM{  
} $>r5>6  
:)4*^a/lC  
U&W"Ea=R/  
} $3\,h; y  
YlKFw|=  
Y.-S=Y   
/* T5e^J"   
**FileAccess.java q.T:0|  
*//文件访问(定位,写) H,K`6HH  
package NetFox; ?1w"IjUS  
import java.io.*; a g;dc  
FN\GE\H  
;;Tq$#vd  
public class FileAccessI implements Serializable{ -?fR|[\[U  
t!qwxX*$T  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 IaasHo\  
RandomAccessFile oSavedFile; 5g0_WpO  
long nPos; S{:Cu}o  
7 :U8 f:  
t$I|E  
public FileAccessI() throws IOException l"\uf(0K  
{ U=m=1FYaG  
this("",0); m&/=&S  
} ~kb{K;  
PeNF+5s/K  
_ECB^s_  
public FileAccessI(String sName,long nPos) throws IOException S>t>6&A  
{ OZOb1D  
oSavedFile = new RandomAccessFile(sName,"rw"); [r9d<Zi}{  
this.nPos = nPos; nzuF]vo  
oSavedFile.seek(nPos); xS+rHC  
} eY}V9*.v  
wS$46M<  
u"FjwF?  
public synchronized int write(byte[] b,int nStart,int nLen) "b%FmM  
{ 0( //D;j  
int n = -1; WeVi] n  
try{ : Ss3ck*=  
oSavedFile.write(b,nStart,nLen); n)RM+g  
n = nLen; 3U;1D2"AE  
} kUbnVF5'  
catch(IOException e) CDCC1BG"  
{ 2f..sNz  
e.printStackTrace (); RxG^  
} z<<Tk.65  
Gru ALx7  
u-.L^!k  
return n; '[f Zt#  
} ~L'nz quF  
f#OQ (WTJE  
ZqK]jT6V/X  
} % rcFT_  
T4GW1NP  
N`1r;%5  
/* lRND  
**SiteInfoBean.java r/PKrw sC  
*/ *rf$>8~$n  
package NetFox; aR)?a;}H  
M[s\E4l:t  
zH=hI Vc  
public class SiteInfoBean { Dl A Z"C  
p+<}Y DMb  
K\^&+7&zVg  
private String sSiteURL; //Site's URL t.U{Bu P  
private String sFilePath; //Saved File's Path Pz`hX$  
private String sFileName; //Saved File's Name \]8i}E1  
private int nSplitter; //Count of Splited Downloading File /^ 4"Qv\@/  
j@v-|  
D9o*8h2$  
public SiteInfoBean() Ub)M*Cq0(o  
{//nSplitter的缺省值为5 aQ|hi F}  
//default value of nSplitter is 5 8*Zvr&B,G  
this("","","",5); 4bI*jEc\[  
} M&[b.t*  
F$yeF^\g  
[Vp\$;\nT  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Le&;g4%  
{ , N 344y  
sSiteURL= sURL; J"&y |; G  
sFilePath = sPath; oEIqA  
sFileName = sName; Y iZx{5  
this.nSplitter = nSpiltter; v<&v]!nF  
sykFSPy`'  
sN]Z #7  
} [z+x"9l0!  
>EIrw$V$  
x'i0KF   
public String getSSiteURL() #LWg"i  
{ wPH+n-&e  
return sSiteURL; <25ccE9^c  
} &7Kb]Ti  
g1V)$s 7  
<V S2]13  
public void setSSiteURL(String value) !Uy>eji}  
{ e1 ^l.>2d6  
sSiteURL = value; |yv]Y/ =  
} c&e0OV\m  
^Y 7U1I  
,8VXA +'_  
public String getSFilePath() yVYkuO  
{ xJc.pvVPw  
return sFilePath; [YE?OQ7#  
} FL&dv  
TQ-KkH}y  
LyP`{_"CM  
public void setSFilePath(String value) a}yR p  
{ VDn:SGj5  
sFilePath = value; )7AM3%z1?  
} Efr3x{ j  
4Py3I9  
UkfA}b^@v  
public String getSFileName() b1)\Zi  
{ v, 0<9!'v  
return sFileName; 7d9Z/J@>  
} /7vE>mSY  
0WXVc  
**HrWM%?8o  
public void setSFileName(String value) E9R]sXf8  
{ L*^ V5^-  
sFileName = value; .vaJ Avg  
} 5!h<b3u>]  
NWnWk  
C P&o%Uc*  
public int getNSplitter() )_Iz>)  
{ {aIZFe}B  
return nSplitter; dEET}s\  
} R@$+t:}  
k =|K|  
r=\P!`{5  
public void setNSplitter(int nCount) `oXg<tivU  
{ t= *Jg/$  
nSplitter = nCount; ;qb Dbg  
} y/\ZAtnLo  
} ;sQ2 0 B'  
f1\7vEE,  
_yJ|`g]U3  
/* Ql8^]gbp+  
**Utility.java %omu  
*/ y#e ?iE@  
package NetFox; !ew6 n I  
,!H\^Vfl  
#[(gIOrNn8  
public class Utility { D-D #`  
I4:rie\hjC  
?FDJqJM  
public Utility() 8})|^%@n  
{ f}blB?e  
6VFirLd  
=h7[E./U1  
} |?yE^$a  
xD^wTtT  
//线程睡眠 pJ6Jx(  
public static void sleep(int nSecond) Rdj8 *f  
{ )r#,ML  
try{ hpas'H>J  
Thread.sleep(nSecond); O!,Ca1N  
} l.uN$B  
catch(Exception e) Z*Zc]hD  
{ Bs@:rhDi  
e.printStackTrace (); 8W@dtZ,d  
} p9Z ].5Pd"  
} 9BO|1{  
,3k@L\$.x  
//日志 0}D-KvjyP  
public static void log(String sMsg) 4uPH  
{ Q-3r}jJe  
System.err.println(sMsg); ajGcKyj8i  
} IqXBz.p  
Fr2kbQTg;  
W7$s5G,  
public static void log(int sMsg) y,V6h*x2  
{ -EVs@:3]j  
System.err.println(sMsg); VZTmzIk.Y  
} X'xUwT|_+  
} n_1jHJo  
@wMQC\Z  
@Jm.HST#S8  
/* {x9j_/R  
**TestMethod.java Xout:dn  
*/ r:73uRk  
package NetFox; 3Qk/ Ll  
nPcxknl(pd  
a^(2q{*  
public class TestMethod { ^glX1 )  
{N "*olx  
7MoR9,(  
public TestMethod() z>7=k`x`:  
{ ///xx/weblogic60b2_win.exe 6-tiRk~  
try{ %uj[`  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ~z&0qQ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); WX ,p`>n  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ;eP_;N5+J  
fileFetch.start(); p1klLX  
} ^]i" H|(x  
catch(Exception e){e.printStackTrace ();} @K7ebYr?  
<o ~t$TH  
&{BBxv)y  
} ?THa5%8f  
> n1h^AW  
We\KDU\n  
public static void main(String[] args) #jOOsfH|k  
{ dV)Y,Yx0${  
new TestMethod(); \|blRm;  
} WFRsSp2  
} ~m!#FTc*  
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