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http断点续传简单实现(java)

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/* "7,FXTaer  
**SiteFileFetch.java =wG+Ao  
*/ H6K`\8/SeN  
package NetFox; c0_E_~  
import java.io.*; O/Rhf[7v*  
import java.net.*; ";x+1R.d  
G_ >G'2  
e)H!uR  
public class SiteFileFetch extends Thread { "B{ECM;  
bc I']WgB-  
~6aCfbu%V  
SiteInfoBean siteInfoBean = null; //文件信息Bean D)Q)NI  
long[] nStartPos; //开始位置 -r<#rITH"  
long[] nEndPos; //结束位置 ?kTWpXx"=  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 -.IEgggf  
long nFileLength; //文件长度 e5?PkFV^a1  
boolean bFirst = true; //是否第一次取文件 1u|V`J)0  
boolean bStop = false; //停止标志 egk7O4zwP  
File tmpFile; //文件下载的临时信息 2HD]?:Fk7  
DataOutputStream output; //输出到文件的输出流 XL$* _c <)  
;sPoUn s'  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) -|S]oJy  
public SiteFileFetch(SiteInfoBean bean) throws IOException {Qv>q$Q  
{ h3* x[W  
siteInfoBean = bean; |Ic`,>XM  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); l;A,0,i  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 8RW&r  
if(tmpFile.exists ()) 5J2=`=FK  
{ /) 4GSC}Gg  
bFirst = false; B,WTHU[AV  
read_nPos(); tK(g-u0N`(  
} Y&HK1>M_  
else 5O/i3m26  
{ px;/8c-  
nStartPos = new long[bean.getNSplitter()]; k S# CEU7  
nEndPos = new long[bean.getNSplitter()]; qZv =  
} \2 y5_;O  
.@q-B+Eg  
a:, y Z  
uX/$CM  
} 8~lIe:F-  
)E#2J$TD  
/93l74.w  
public void run() 3REx45M2  
{ nlYR-.  
//获得文件长度 O,2~"~kF  
//分割文件 '*^yAlgtt  
//实例FileSplitterFetch $2^`Uca  
//启动FileSplitterFetch线程 "9EE1];NT  
//等待子线程返回 z4#(Ze@u~_  
try{ mW2,1}Jv  
if(bFirst) $''?HjB}T  
{ xT&(n/  
nFileLength = getFileSize(); `;|5  
if(nFileLength == -1) }v9\F-0>Q  
{ "xmP6=1  
System.err.println("File Length is not known!"); .d;Iht,[  
} %3q0(Xl  
else if(nFileLength == -2) i,A#&YDl  
{ u 's`*T@.  
System.err.println("File is not access!"); oI:o"T77sA  
} do*}syQ`O  
else A1)wo^,  
{ n79QJl/  
for(int i=0;i<nStartPos.length;i++) 99$ 5`R;  
{ H1GRMDNXOA  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Aa0b6?Jm  
} &cWjE x  
for(int i=0;i<nEndPos.length-1;i++) Z/x*Y#0@n  
{ b`yZ|j'ikd  
nEndPos = nStartPos[i+1]; '7wd$rl  
} |Fm6#1A@  
nEndPos[nEndPos.length-1] = nFileLength; bNFLO Q  
} YprH wL  
} Pq*s{  
dY?`f<*  
ES~^M840f  
//启动子线程 H>9CW<8  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; b|Q)[y]  
for(int i=0;i<nStartPos.length;i++) b" xmqWa  
{ du$|lxC  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Mb3}7@/[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), |qZko[W}=  
nStartPos,nEndPos,i); (b?{xf'G  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Go,N>HN  
fileSplitterFetch.start(); u2oKH{/z  
}  Qk!;M |  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), PH"hn]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ,+`61J3W  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", #;n +YM">:  
nEndPos = " + nFileLength); M"%Q&o/I  
// fileSplitterFetch[nPos.length-1].start(); ]yjl~3  
`1{N=!U(&  
%WqNiF0-  
//等待子线程结束 UAR5^  
//int count = 0; H|cNH=  
//是否结束while循环 Dnc(l(  
boolean breakWhile = false; $+.l*]  
1&fc1uYB4  
dU\%Cq-G)  
while(!bStop) l5l>d62  
{ U hIDRR  
write_nPos(); \!]Ua.e<  
Utility.sleep(500); # :T-hRu  
breakWhile = true; ,=?{("+  
cA6lge<{~  
%OgS^_tu  
for(int i=0;i<nStartPos.length;i++) eIl]oC7*  
{ As+t##gN  
if(!fileSplitterFetch.bDownOver) T~h5B(J;  
{ jxJv.  
breakWhile = false; WyP W*  
break; CK, 6ytB  
} eNiaM6(J  
} -W,}rcj*|  
if(breakWhile) 2lL,zFAq  
break; oD}uOC}FS{  
'zh7_%  
bQ|V!mrN}  
//count++; DcSnia62f  
//if(count>4) <0S=,!  
// siteStop(); pm{|?R  
} V.wqZ {G  
m7T)m0  
tGB@$UmfU  
System.err.println("文件下载结束!"); :!zl^J;  
} dg4vc][  
catch(Exception e){e.printStackTrace ();} +l=r#JF  
} R *F l8   
Zw wqSyuGf  
@29U@T  
//获得文件长度 !bV5Sr^  
public long getFileSize() d;n."+=[x  
{ Pz$R(TV  
int nFileLength = -1; Nan[<  
try{ TIvRhbu  
URL url = new URL(siteInfoBean.getSSiteURL()); v9T_&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); H4]Ul eU  
httpConnection.setRequestProperty("User-Agent","NetFox"); soCi[j$lH  
]~Y<o  
u+{a8=  
int responseCode=httpConnection.getResponseCode(); epgPT'^  
if(responseCode>=400) ^_lzZOhG  
{ KN-avu_Ix  
processErrorCode(responseCode); 5E notp[  
return -2; //-2 represent access is error ``E/m<r:$  
} ^U]UqX`  
.KdyJ6o  
q{+_ <2U|  
String sHeader; LY+|[qka  
zRPeNdX  
c&L"N!4z  
for(int i=1;;i++) Ao/ jt<  
{ *}8t{ F@k  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); r [ K5w  
//Utility.log(in.readLine()); 8mQmi`  
sHeader=httpConnection.getHeaderFieldKey(i); N<DGw?Rl  
if(sHeader!=null) +>4;Zd!@d  
{ jMpD+Mb  
if(sHeader.equals("Content-Length")) &?h,7 D;A  
{ WVLHfkN  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ;`6^6p\p  
break; VcoOeAKL  
} U)3DQ6T99  
} RVeEkv[qp  
else ;D$)P7k6  
break; @]ao"ui@/  
} IUwm}9Q!  
} <mAhr  
catch(IOException e){e.printStackTrace ();} yBI'djL~>  
catch(Exception e){e.printStackTrace ();} MR}Agu#LG  
JY6 Q p  
Q~T$N  
Utility.log(nFileLength); )&!&AlLn  
nMJ#<'v^!2  
;amXY@RmH  
return nFileLength; )wNP( @$L  
} aE2.L;Tk?  
&-;5* lg)0  
oJfr +3I  
//保存下载信息(文件指针位置) 73){K?R  
private void write_nPos() [Jv@J\  
{ h*v8#\b$J_  
try{ L`24 ?Y{  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 6 :~v4W!k  
output.writeInt(nStartPos.length); o]opdw  
for(int i=0;i<nStartPos.length;i++) IC7M$  
{ h2D>;k  
// output.writeLong(nPos); uS^Ipxe\  
output.writeLong(fileSplitterFetch.nStartPos); /3{b%0Aa  
output.writeLong(fileSplitterFetch.nEndPos); s)pbS}L  
} hodgDrmO/  
output.close(); vuYSVI2=H  
} )-. _FOZ6  
catch(IOException e){e.printStackTrace ();} 1@-Ns  
catch(Exception e){e.printStackTrace ();} '  <=+;q  
} VTH> o>g  
pfI"36]F  
sQ\8>[]   
//读取保存的下载信息(文件指针位置) q7E~+p(>(  
private void read_nPos() gdQvp=v]  
{ c??mL4$'N  
try{ S.f5v8  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); &oX>* 6L  
int nCount = input.readInt(); O`<KwUx !  
nStartPos = new long[nCount]; (}2~<   
nEndPos = new long[nCount]; pS7w' H  
for(int i=0;i<nStartPos.length;i++) sL$:"=  
{ \:UIc*S  
nStartPos = input.readLong(); a5 TioQ  
nEndPos = input.readLong(); ~ (jKz}'~U  
} n~V ]Z  
input.close(); b"{'T]"*j  
} :Cj OPl  
catch(IOException e){e.printStackTrace ();} &*aIEa^  
catch(Exception e){e.printStackTrace ();} ;67x0)kn  
} ]'=)2 .}  
e\:+uVzz  
Sxh]R+Xb  
private void processErrorCode(int nErrorCode) 71t* %  
{ ~o~!+`@q  
System.err.println("Error Code : " + nErrorCode); TJR:vr  
} L bmawi^  
TtTj28 k7  
lE(a%'36  
//停止文件下载 ][p>Y>:b-  
public void siteStop() $cU!m(SILQ  
{ 5l UF7:A>#  
bStop = true; !*B'?|a<\  
for(int i=0;i<nStartPos.length;i++) gq'Y!BBQy  
fileSplitterFetch.splitterStop(); /^#;d UB  
kZGRxp9  
>]vlkA(  
} -^hWM}F  
} f@|A[>"V  
//负责部分文件的抓取 Lo N< oj5  
**FileSplitterFetch.java =V-|#j  
*/ x#xFh0CA  
package NetFox; HOJs[mqB%  
naR0@Q"\h  
IS&ZqE(`e  
import java.io.*; 3@$,s~+ 3  
import java.net.*; 9CWezI+  
Zy?Hi`  
,NyY>~+  
public class FileSplitterFetch extends Thread { E^/t$M|H  
@] DVD  
|es?;s'  
String sURL; //File URL 3 09hn  
long nStartPos; //File Snippet Start Position TE7nJ gm  
long nEndPos; //File Snippet End Position SBfT20z[  
int nThreadID; //Thread's ID ?kH8Lw~{5W  
boolean bDownOver = false; //Downing is over -~v2BN/  
boolean bStop = false; //Stop identical 1q:2\d]  
FileAccessI fileAccessI = null; //File Access interface ] [+#;avU  
g+Sbl  
W_\5nF  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ;RC{<wBTx  
{ xy/`ZS2WPq  
this.sURL = sURL; QSdHm  
this.nStartPos = nStart; 8"2=U6*C  
this.nEndPos = nEnd; CUBEW~X}M  
nThreadID = id; i]YV {  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 p'*>vk  
} pz\ +U7  
mGJKvJF   
ORHp$Un~)  
public void run() i@)i$i4  
{ "/3'XOK|  
while(nStartPos < nEndPos && !bStop) [65 `$x-  
{ P2BWuh F  
`1$@|FgyC  
1PQ~jfGi  
try{ k;AD`7(=  
URL url = new URL(sURL); V3Q+s8OIF  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); c[wla<dO*  
httpConnection.setRequestProperty("User-Agent","NetFox"); Z'`g J&6n  
String sProperty = "bytes="+nStartPos+"-"; r ~jm`y  
httpConnection.setRequestProperty("RANGE",sProperty); hV8[@&Sx3  
Utility.log(sProperty); 4sF"6+%5d  
1PVtxL?1P  
p*4':TFuD;  
InputStream input = httpConnection.getInputStream(); .h@rLorm>  
//logResponseHead(httpConnection); GP!?^r:en  
n'wU;!W9  
V:In>u$QJ!  
byte[] b = new byte[1024]; Bu<M\w?7Y  
int nRead; @5=oeOg36  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) "pi=$/RD9  
{ Z0x ar]4V  
nStartPos += fileAccessI.write(b,0,nRead); bv]`!g: C  
//if(nThreadID == 1) z1PBMSG  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); X@ +{5%  
} 8Wrh]egu1  
bhTb[r  
H[s(e5 6z  
Utility.log("Thread " + nThreadID + " is over!"); y I HXg#  
bDownOver = true; fxgPhnaC>  
//nPos = fileAccessI.write (b,0,nRead); p `8 s  
} m ,* QP*  
catch(Exception e){e.printStackTrace ();} #|Y5,a ,{  
} /\ y?Y  
} tvkb~  
9_L[w\P|4  
*xx'@e|<;  
//打印回应的头信息 1tEgl\u\  
public void logResponseHead(HttpURLConnection con) +X#vVD3"  
{ >BR(Wd.  
for(int i=1;;i++) )M,Of Xa  
{ ypbe!Y<i]  
String header=con.getHeaderFieldKey(i); ''q@>  
if(header!=null) wxR,OR  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); s>B5l2Q4  
Utility.log(header+" : "+con.getHeaderField(header)); $:=A'd2  
else Ed0QQyC@9  
break; <;9 I@VYK  
} A_XY'z1  
} N|8P)  
6*PYFf`  
^!<U_;+  
public void splitterStop() j#X.KM   
{ 6_J$UBT  
bStop = true; y~Bh  
} h%o%fH&F!  
8qk?E6  
Pj#<K%Bz  
} 5QW=&zI`=  
\a5U8shc  
k52/w)Ro,$  
/* ^`*9QjY  
**FileAccess.java 3VsW@SG7N  
*//文件访问(定位,写) <LmIK  
package NetFox; 3p3 9`"~  
import java.io.*; @E;=*9ek{u  
1{r3#MVL  
Hc!  mB  
public class FileAccessI implements Serializable{ na#CpS;pc  
]p _L)  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 |*oZ _gI  
RandomAccessFile oSavedFile; N^#ZJoR  
long nPos; I3=%h  
kY&k-K\  
=@m &s^R  
public FileAccessI() throws IOException {%<OD8>p  
{ pf%=h |  
this("",0); H(R1o~  
} '[U8}z3  
dq7x3v^"ZG  
#Vl 0.l3  
public FileAccessI(String sName,long nPos) throws IOException EqyeJq .  
{ z{[xze-f  
oSavedFile = new RandomAccessFile(sName,"rw"); z8jk[5z  
this.nPos = nPos; 4zASMu  
oSavedFile.seek(nPos); 8I-u2Y$Sr  
} u}>#Eb  
o 4`hY/<t  
B268e  
public synchronized int write(byte[] b,int nStart,int nLen) vqnw#U4`  
{ us ;YV<)d  
int n = -1; m#8m] Y  
try{ CAWA3fcQp  
oSavedFile.write(b,nStart,nLen); 6BY-^"W5`  
n = nLen; O?NeSx 1  
} O#x*iI%  
catch(IOException e) %u`8minCt  
{ !$DIc  
e.printStackTrace (); k ]W[`  
} 3,>0a  
g3Ec"_>P  
:@kGAI  
return n; XOxr?NPQ^  
} 4oK?-|=?  
I'\kFjc  
g+DzscIT  
} LG-y]4a}  
kv8Fko  
bsuus R9W  
/* x N=i]~  
**SiteInfoBean.java [r3!\HI7x  
*/ P#pn*L*"T  
package NetFox; ,^?^ dB  
7x#Ckep:I  
-c(F1l  
public class SiteInfoBean { ^=C{.{n  
0F@"b{&0  
if}-_E<F  
private String sSiteURL; //Site's URL ;+0t;B!V  
private String sFilePath; //Saved File's Path aki _RG>U'  
private String sFileName; //Saved File's Name jL(qf~c_  
private int nSplitter; //Count of Splited Downloading File >GQEqXs  
H:!7:  
0*%Z's\M"  
public SiteInfoBean() zEs>b(5u  
{//nSplitter的缺省值为5 nNrPHNfqD  
//default value of nSplitter is 5 TS/.`.gT  
this("","","",5); A{UULVp  
} z."a.>fPaO  
Fkvl%n  
m6n?bEl6I  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Em?d*z  
{ &Ts-a$Z7?S  
sSiteURL= sURL; aD=a,  
sFilePath = sPath; _Xnqb+  
sFileName = sName; 3mYiQ2  
this.nSplitter = nSpiltter; yMyE s8  
*_R]*o!W'  
n,=VQ Ou  
} WtViW=j'  
kHXL8k#T  
hZh9uI7.  
public String getSSiteURL() Wm_4avXtO  
{ ;FBUwR}  
return sSiteURL; K3m]%m2\  
} uIcn{RZ_z  
350_CN,  
)_mr! z(S  
public void setSSiteURL(String value) U"q/rcA  
{ Atflf2K  
sSiteURL = value; 8CnRi  
} 8#(Q_  
@kk4]:,w  
)jkXS TZ  
public String getSFilePath()  yyv8gH  
{ ,oaw0Vw  
return sFilePath; +|bmT  
} 0TN;86Mo  
gN24M3{C  
6:q"l\n>  
public void setSFilePath(String value) xZ|Y ?R5m  
{ vJ\pR~?  
sFilePath = value; e?_@aa9~@{  
} r`AuvwHPs[  
*NkA8PC  
RY c!~Wh~Y  
public String getSFileName() BYs-V:  
{ @fs`=lL/  
return sFileName; [[>wB[w  
} ta`N8vnf  
Y2d;E.DH8  
w;k):; $  
public void setSFileName(String value) xEf'Bmebk  
{ tj Gd )  
sFileName = value; }-~X4u#   
} Cl ^\OZN\=  
FDVcow*]n  
H2 $GIY  
public int getNSplitter() w" SoeU  
{ R  zf  
return nSplitter; _Qh z3'I1  
} Kw8u`$Ad7  
kGd<5vCs  
:4MB]v[K  
public void setNSplitter(int nCount) F)s{PCl  
{ AtF3%Z v2  
nSplitter = nCount; deM7fN4lTi  
} Mk=mT3=#  
} TjHwjRa  
JJ{9U(`_y6  
H^.IY_I`U*  
/* C?i >.t  
**Utility.java Pu"R,a  
*/ X{we/'>  
package NetFox; U Z|HJ8_  
U$ F{nZ1  
:WSDf VX  
public class Utility { L0&RvI#  
Y`o+XimX  
/9zE^YcT  
public Utility() ep=qf/vd<  
{ C4hx@abA  
J|X 6j&-  
TQ`Rk;0R  
} X=Ys<TM,  
vfl5Mx4  
//线程睡眠 -T&.kYqnb$  
public static void sleep(int nSecond) jS+AGE?5e  
{ >m# e:[N  
try{ K]j0_~3s  
Thread.sleep(nSecond); nPs7c %  
} "=6v&G]U4  
catch(Exception e) -s|}Rh?Y  
{ x7vctjM|  
e.printStackTrace (); BWrv%7  
} Ov UI@,Ef  
} I j$lDJS  
$uap8nN  
//日志 &BtK($  
public static void log(String sMsg) o$[z],RO  
{ +=]!P#  
System.err.println(sMsg); 5w\fSY  
} YKbaf(K )9  
fm(e3]  
KAsS [  
public static void log(int sMsg) {@<J_ A  
{ = <j"M85.  
System.err.println(sMsg); 0vVV%,v  
} 6<N5_1  
} m$9w"8R  
M.nvB)  
h.!}3\Y  
/* DhX#E&  
**TestMethod.java % , N<  
*/ 52. >+GC  
package NetFox; }?&k a$rI  
3Wwj p  
CH fVQ|!\  
public class TestMethod { 7T"XPV|W6  
MwfOy@|N  
avy"r$v_&  
public TestMethod() Yp0/Ab(v  
{ ///xx/weblogic60b2_win.exe xl"HotsX-x  
try{ ? tfT8$  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); >(y<0   
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); RJy=pNztm  
SiteFileFetch fileFetch = new SiteFileFetch(bean); +4\U)Z/\  
fileFetch.start(); O:{U^K:*  
} l~D N1z6`  
catch(Exception e){e.printStackTrace ();} K_ lVISBQ  
A<\JQ  
TRZRYm"  
} L{E^?iX  
0<PR+Iv*i  
lpRR&  
public static void main(String[] args) O$kq`'9  
{ w nTV|^Q  
new TestMethod(); [xh*"wT#g  
} zE)~0v4  
} , * ]d~Y  
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