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http断点续传简单实现(java)

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/* I\NiA>c  
**SiteFileFetch.java 1-_op !N  
*/ Va^AEuzF  
package NetFox; #[.vfG  
import java.io.*; 5k0r{^#M  
import java.net.*; \ (y6o}aW  
[ \I&/?On  
vmI2o'zi  
public class SiteFileFetch extends Thread { zdDn. vG  
"AN2K  
rlj @ '  
SiteInfoBean siteInfoBean = null; //文件信息Bean pdcP;.   
long[] nStartPos; //开始位置 DqgYc[UGA  
long[] nEndPos; //结束位置 UjmBLXz@T  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 uZsm=('ww  
long nFileLength; //文件长度 !PN;XZ~{  
boolean bFirst = true; //是否第一次取文件 !Vtt.j &4  
boolean bStop = false; //停止标志 /O"IA4O  
File tmpFile; //文件下载的临时信息 .C avb  
DataOutputStream output; //输出到文件的输出流 HGuY-f  
u{0'" jVJ  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) z^s40707x  
public SiteFileFetch(SiteInfoBean bean) throws IOException + y!B`'J  
{ W"9?D  
siteInfoBean = bean; \3P.GS{l  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); }}a<!L,{  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); *9"L?S(X#  
if(tmpFile.exists ()) y'(bp=Nq  
{ ~z)diF<  
bFirst = false; 0qXkWGB  
read_nPos(); x:TBZh?@$  
} s>E u[ uA  
else IY@)  
{ $y !k)"k  
nStartPos = new long[bean.getNSplitter()]; \>0F{-cR$  
nEndPos = new long[bean.getNSplitter()]; m?;aTSa  
} xNG 'UbU  
]?P9M<0PM  
h.Cr;w,2R  
L@*0wx`fU  
} kc&>l (  
@:$zReS2  
MF>1u%  
public void run() Ro+/=*ql~  
{ 5MJ`B: He+  
//获得文件长度 6x\+j  
//分割文件 f o])=KM  
//实例FileSplitterFetch E.v~<[g  
//启动FileSplitterFetch线程 csTX',c  
//等待子线程返回 7&G[mOx0  
try{ y6KI.LWR9  
if(bFirst) l[]K5?AS>-  
{ azMrY<  
nFileLength = getFileSize(); ~ei\~;n\@  
if(nFileLength == -1) ?'H);ou-p  
{ ]}Hcb)'j@  
System.err.println("File Length is not known!"); 9WQC\/w  
} aK'`yuN  
else if(nFileLength == -2) fRo_rj _  
{ z^ +CD-  
System.err.println("File is not access!"); X<s']C9c  
} C)> ])'S  
else o"@y=n/  
{ 2Mx9Kd'a r  
for(int i=0;i<nStartPos.length;i++) P>%\pCJ])  
{ :<d\//5<9  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); v#0R   
} }J t( H  
for(int i=0;i<nEndPos.length-1;i++) r@+IDW.=9  
{ c_xtwdkL9  
nEndPos = nStartPos[i+1]; iK%<0m  
} R}4o{l6  
nEndPos[nEndPos.length-1] = nFileLength; SymSAq0$F  
} X ^>o/U  
} uf,4GPo,  
S1^u/$*6  
*zX*k 7LnV  
//启动子线程 =tl[?6  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; NUBzmnA>8  
for(int i=0;i<nStartPos.length;i++) N1WP  
{ Ky`rf}cI>  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), U:>'^tkp  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), C,C%1  
nStartPos,nEndPos,i); ByeyUw  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); J=6 7As  
fileSplitterFetch.start(); J) v~  
} ''!pvxA  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), O!='U!X@P  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ZC3b9:tk  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 13Ga #  
nEndPos = " + nFileLength); O z%K*  
// fileSplitterFetch[nPos.length-1].start(); ~u1ox_v`%(  
!c:Q+:,H  
1Nx.aji  
//等待子线程结束 :7p0JGd  
//int count = 0; evPr~_  
//是否结束while循环 2}]6~i  
boolean breakWhile = false; zvL&V .>  
{ yU1db^  
)F&@ M;2p'  
while(!bStop) H[V^wyi'z  
{ wXDF7tJh  
write_nPos(); 4cL NPl<  
Utility.sleep(500); -h*Yd)  
breakWhile = true; &/R@cS6}'  
)gV+BHK  
(w]w 2&Y D  
for(int i=0;i<nStartPos.length;i++) aGNVqS%y  
{ JU:!lyd  
if(!fileSplitterFetch.bDownOver) %Rr!I:[ $  
{ 5/DTE:M<  
breakWhile = false; wRb%-s  
break; y?<[g;MuT  
} RGhl` ;  
} v83uGEq(  
if(breakWhile) Vj4 if@Z  
break; c a_N76o!  
F}0QocD  
Rp A76ug  
//count++; E xKH%I  
//if(count>4) KoiU\r  
// siteStop(); Ql%7wrK  
} =nFT0];  
B+);y  
*x`z5_yfO  
System.err.println("文件下载结束!"); x `PIJE  
} K%qunjv  
catch(Exception e){e.printStackTrace ();} W)^:*z  
} 52m^jT Sx  
>?'q P ]  
Yc=y  Vh  
//获得文件长度 vPmP<c)cb  
public long getFileSize() "+_]N9%)  
{ % %c0UaV  
int nFileLength = -1; (&PamsV*8  
try{ , p1 (0i  
URL url = new URL(siteInfoBean.getSSiteURL()); rZu_"bcJ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >1pD'UZIy7  
httpConnection.setRequestProperty("User-Agent","NetFox"); @M#2T  
MGc=TQ.  
Sx;zvc  
int responseCode=httpConnection.getResponseCode(); {,IWjt &>  
if(responseCode>=400) "c!s\iuBU  
{ ||`w MWq  
processErrorCode(responseCode); }S*6+4  
return -2; //-2 represent access is error T 6QnCmB4  
} lx$Y-Tb^F  
IS&`O= 7  
HZ 8 j[kO  
String sHeader; C$*`c6R  
 cD0  
IL.Jx:(0  
for(int i=1;;i++) ~pzaX8!  
{ cnLC>_hY  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 32~Tf,  
//Utility.log(in.readLine()); 1Dt"Rcn"4  
sHeader=httpConnection.getHeaderFieldKey(i); -mY90]g  
if(sHeader!=null) $nn~K  
{ <g*rTqT'  
if(sHeader.equals("Content-Length")) M|n)LyL  
{ %M}zi'qQ?  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); rFx2 S  
break; dZ%b|CUb  
} q{U -kuui  
} Maa5a  
else ~;+i[Z&e  
break; *}/xy SH3  
} &51/Pm2O  
} I,YGm  
catch(IOException e){e.printStackTrace ();} "b1_vA]03  
catch(Exception e){e.printStackTrace ();} I.KYWs  
v/m`rc]e  
v~jN,f*  
Utility.log(nFileLength); ~%<PEl|  
LrPDpTd  
GC4$9q}C4Z  
return nFileLength; JYSw!!eC  
} FblGFm"P  
:[ITjkhde0  
rA1 gH6D  
//保存下载信息(文件指针位置) }rO4b>J  
private void write_nPos() MO _9Yi  
{ 7PQedZ<\  
try{ @=;6:akz`  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 2Cr+Z(f  
output.writeInt(nStartPos.length); W!X#:UM)  
for(int i=0;i<nStartPos.length;i++)  fx;5j;  
{ r#Pd@SV  
// output.writeLong(nPos); 8U;!1!+ 7)  
output.writeLong(fileSplitterFetch.nStartPos); z?  {#/  
output.writeLong(fileSplitterFetch.nEndPos); z 9D2,N.  
} (XW#,=rYk  
output.close(); Fn[~5/  
} qb"!  
catch(IOException e){e.printStackTrace ();} QlXy9-oJ"  
catch(Exception e){e.printStackTrace ();} Rp@u.C <  
} htF&VeIte  
(vI7qD_  
 R(zsn;  
//读取保存的下载信息(文件指针位置) wz, \zh  
private void read_nPos() \]9;c6(  
{ #5H@/o8!s=  
try{ KDXo9FzF  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Iewq?s\Fo  
int nCount = input.readInt(); wZC'BLD  
nStartPos = new long[nCount]; ~f@<]  
nEndPos = new long[nCount]; &>s(f-\8  
for(int i=0;i<nStartPos.length;i++) +$UfP(XmH  
{ iF%q 6R  
nStartPos = input.readLong(); SHGO;  
nEndPos = input.readLong(); Fx@ {]  
} B}MJ?uvA  
input.close(); sRMzU  
} `Ch6"= t  
catch(IOException e){e.printStackTrace ();} P\M+Z A ;  
catch(Exception e){e.printStackTrace ();} 8odVdivh  
} HhpP}9P;  
$(NfHIX  
~Fx[YPO,  
private void processErrorCode(int nErrorCode) q6ikJ8E8b  
{ "~[Rwh?  
System.err.println("Error Code : " + nErrorCode); - a=yi d  
} t]` 2f3UO  
q@\_q!  
.Yf h*  
//停止文件下载 .U1dcL6  
public void siteStop() fC-^[Af)  
{ p;5WLAF  
bStop = true; b9Y pUm7#  
for(int i=0;i<nStartPos.length;i++) D3K`b4YV  
fileSplitterFetch.splitterStop(); 6 %=BYDF  
JxvwquI  
tS9m8(Hr%Q  
} 1y@-  
} H,I}R  
//负责部分文件的抓取 :D,YR(])  
**FileSplitterFetch.java -?]ltn9!  
*/ lvN{R{7 >  
package NetFox; W+eN%w5  
;+jp,( 7  
oF>GWst TR  
import java.io.*; E??%)q  
import java.net.*; C=]3NB>Jc  
FjydEV  
#<~f~{x  
public class FileSplitterFetch extends Thread { F9<OKcXH  
Cn55%:  
[x)e6p)  
String sURL; //File URL yjr@v!o  
long nStartPos; //File Snippet Start Position m3WV<Cbz  
long nEndPos; //File Snippet End Position w\mF2h  
int nThreadID; //Thread's ID N<{ `n;  
boolean bDownOver = false; //Downing is over BmM,vllO  
boolean bStop = false; //Stop identical esHiWHAC  
FileAccessI fileAccessI = null; //File Access interface xL BG}C  
|")x1' M  
`u}x:f !  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException  #.><A8J  
{ $W?XxgkB?  
this.sURL = sURL; nx4aGS"F:  
this.nStartPos = nStart; \fhT#/0N  
this.nEndPos = nEnd; S?{5DxilO  
nThreadID = id; ,YY#ed&l  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 '-vy Q^  
} 4 * OU  
Gw./qu-W  
HDEG/k/~m  
public void run() Z~uKT n  
{ br;G5^j3?  
while(nStartPos < nEndPos && !bStop) 42u\Y_^ID  
{ md`ToU  
aYgJTep>r  
G4}q*&:k  
try{ wgyO%  
URL url = new URL(sURL); hG@ys5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `[KhG)Y7t  
httpConnection.setRequestProperty("User-Agent","NetFox"); LnDj   
String sProperty = "bytes="+nStartPos+"-"; QdTe!f|  
httpConnection.setRequestProperty("RANGE",sProperty); AH`15k_i  
Utility.log(sProperty); 1+jYpYEQW  
rTm{-b)r  
["F,|e{y$  
InputStream input = httpConnection.getInputStream(); 9yh@_~rZ  
//logResponseHead(httpConnection); zFn&~lFB  
.ndQ(B  
LC{hoq\  
byte[] b = new byte[1024]; T]W -g  
int nRead; 8x" d/D  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) f*],j  
{ (HI%C@e9  
nStartPos += fileAccessI.write(b,0,nRead); gp HwiFc  
//if(nThreadID == 1) 9qDGxW '1  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Dkb&/k:)  
} 2FzS_\":I  
RV` j>1  
{H V,2-z  
Utility.log("Thread " + nThreadID + " is over!"); RuZ;hnE&  
bDownOver = true; ='0!B]<G  
//nPos = fileAccessI.write (b,0,nRead); m'tk#C  
} ?nW#qy!R  
catch(Exception e){e.printStackTrace ();} d mz3O(]$  
} YZl%JX  
} ,7P^]V1  
!P$xh  
\2pFFVT  
//打印回应的头信息 A232"p_  
public void logResponseHead(HttpURLConnection con) E5 oD|'=WA  
{ Y2-bU 7mo  
for(int i=1;;i++) >n~p1:$  
{ HIm, "iYk  
String header=con.getHeaderFieldKey(i); 1RbYPX  
if(header!=null) $0}bi:7  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); BA-nxR  
Utility.log(header+" : "+con.getHeaderField(header)); qJU)d  
else )|R9mW=k9P  
break; =-LX)|x}  
} gi'agB^  
} ^4pKsO3ul  
W_\L_)^X  
3|Sy'J0'K  
public void splitterStop() Ki/5xK=s  
{ cl{W]4*$  
bStop = true; V1)P=?%(US  
} i8_x1=A  
*\KvcRMGUa  
SRN9(LN  
} qLi9ym, ]  
jHlOP,kc  
!9xANSb  
/* /}`/i(k  
**FileAccess.java |.O!zRm  
*//文件访问(定位,写) `l2<  
package NetFox; d[e:}1  
import java.io.*; z-G7Y#  
IXvz&4VD  
&17,]#3  
public class FileAccessI implements Serializable{ ef}E.Bl  
|sqo+E  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 @gSFvb bc  
RandomAccessFile oSavedFile; 8@yc}~8 *  
long nPos; U@J/  
iW1ih Q X  
N~; khS]  
public FileAccessI() throws IOException {L4>2rF  
{ o1X/<.0+  
this("",0); x*&&?nV Iz  
} 6!%d-Z7)  
x)VIA]  
m>+,^`0  
public FileAccessI(String sName,long nPos) throws IOException i\Pr3 7 "  
{ 9MB\z"b?A  
oSavedFile = new RandomAccessFile(sName,"rw"); ?[ S >&Vq  
this.nPos = nPos; frmqBCVJ:  
oSavedFile.seek(nPos); W]D`f8r9  
} 52MCUl  
>[XOMKgQ](  
-[=AlqL  
public synchronized int write(byte[] b,int nStart,int nLen) a\&(Ua  
{ 1R2o6`_  
int n = -1; #OD@q;  
try{ o7Cnyy#:  
oSavedFile.write(b,nStart,nLen); ~*mOt 7G  
n = nLen; k>:/D  
} p&OJa$N$[  
catch(IOException e) (I7&8$Zl  
{ JMirz~%ib  
e.printStackTrace (); 1akD]Z  
} Q.9Ph ~  
)iEa2uJ  
68p\WheCal  
return n; 5mna7 BCEb  
} h\=p=M  
JA?,0S  
Siz!/O!'  
} ZSF=  
m~Y'$3w  
HzD>-f  
/* t,=@hs hN  
**SiteInfoBean.java FVsu8z u  
*/ >9o,S3  
package NetFox; +}c|O+6g  
e8d5(e  
6(N.T+;]  
public class SiteInfoBean { +  ZR(  
A*7Io4e!  
lFp!XZ!  
private String sSiteURL; //Site's URL M^j<J0(O  
private String sFilePath; //Saved File's Path O+G~Qp0b>  
private String sFileName; //Saved File's Name e9~cBG|  
private int nSplitter; //Count of Splited Downloading File Y!++C MzU  
0|+>A?E}E  
|8&-66pX  
public SiteInfoBean() j+_S$T8w  
{//nSplitter的缺省值为5 I@3Q=14k%  
//default value of nSplitter is 5 o &BPG@n  
this("","","",5); 8- dRdQu]  
} *Rz{44LP&  
TK; \_yN  
k~0#'I9  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) abM84EU  
{ :D"@6PC]  
sSiteURL= sURL; La`h$=#`  
sFilePath = sPath; 3C277nx  
sFileName = sName; 5a=nF9/  
this.nSplitter = nSpiltter; a`7%A H)  
uew0R;+oa  
Y3-]+y%l  
} >?S\~Y  
= y?#^  
'n~fR]h}  
public String getSSiteURL() %lXbCE:[  
{ 3H1Pp*PH  
return sSiteURL; (l Lu?NpIi  
} ,/~[S  
N g58/}zO  
?K0U3V$s  
public void setSSiteURL(String value) -Bj.hx*  
{ 6H0W`S0a  
sSiteURL = value; 3f_i1|>)'  
} ]x1p!TSU  
>Cvjs  
a IQOs  
public String getSFilePath()  G]b8]3^  
{ i#k-)N _$  
return sFilePath; -<6v:Z  
} iu +3,]7Fm  
:JR<SFjm  
F@9Y\. ,  
public void setSFilePath(String value) d5Qd'  
{ -)X{n?i  
sFilePath = value; s,w YlVYf!  
} [KMS<4t'  
w}d}hI  
f7Zf}1|  
public String getSFileName() WJAYM2 6\  
{ :.DI_XN`  
return sFileName; QskUdzQ=  
} L%f;J/  
t~ -J %$  
0rcjorWI  
public void setSFileName(String value) mk\i}U>`  
{ A';n6ne%i  
sFileName = value; wk@yTTnb  
} d Qai4e>[  
Yc d3QRB  
Y xJ`-6  
public int getNSplitter() v`SY6;<2  
{ %]#VdS|N  
return nSplitter; l&3ki!  
} z>|)ieL  
Y#`Lcg+r,  
YN^T$,*  
public void setNSplitter(int nCount) :c=v}  
{ -AC`q/bCD  
nSplitter = nCount; 6|^0_6_  
} SW#BZ3L  
} T/5"}P`  
lBmm(<~Z  
Ft) lp>3gv  
/* U@?6*,b(.  
**Utility.java YDFCGA  
*/ 69/?7r  
package NetFox; `L\)ahM  
.LObOR 5J7  
72,"Cj  
public class Utility { x'qWM/  
13a(FG  
q^*6C[G B  
public Utility() ej52AK7  
{ wbi3lH:;  
9U^$.Lb  
Us-A+)r*!  
} ] H&c'  
kaQ2A  
//线程睡眠 P'tMu6+)  
public static void sleep(int nSecond) ^i'y6J  
{ LeHiT>aX!  
try{ /.$L"u  
Thread.sleep(nSecond); :6lwO%=F  
} M4?8xuC  
catch(Exception e) %!y89x=E  
{ =IHje;s  
e.printStackTrace (); q8sb n  
} w!`Umll2  
} hS:jBp,  
XlkGjjW#/J  
//日志 ArzDI{1  
public static void log(String sMsg) 2\0Oji\6  
{ [se^.[0,  
System.err.println(sMsg); c!Dc8=nE0m  
} z(H?VfJo  
|pW\Ec#(  
6Cc7ejt|u  
public static void log(int sMsg) JE!("]&  
{ -(IC~   
System.err.println(sMsg); V=}1[^  
} |0 !I5|<k  
} i-lKdpv  
I:$"E% >=  
IU!Ht>  
/* 4:1)~z  
**TestMethod.java ]V<-J   
*/ wsnK3tM7-  
package NetFox; mqFq_UX/ T  
|J3NR`-R  
AhxGj+  
public class TestMethod { n?E}b$6  
k^An97J  
uZ(? >  
public TestMethod() `.^ |]|u  
{ ///xx/weblogic60b2_win.exe P5?<_x0v4b  
try{ `ZGcgO<c\  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 8eyl,W=dn  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ({[,$dEa;  
SiteFileFetch fileFetch = new SiteFileFetch(bean); wss?|XCI  
fileFetch.start(); ]b}B2F'n  
} YV([2  
catch(Exception e){e.printStackTrace ();} $1 @,Qor  
*H2]H @QHN  
N 8t=@~]  
} (E!!pz  
kso*}uh0  
S>f&6ZDNY(  
public static void main(String[] args) ]J@/p:S>  
{ 36$[   
new TestMethod(); Vb)zZ^va+  
} `|Fp^gM  
} 'HaD~pa  
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