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http断点续传简单实现(java)

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/* )-[ 2vhXz  
**SiteFileFetch.java i3*?fMxhu)  
*/ b2H!{a"  
package NetFox; 0;3;Rs  
import java.io.*; Y+V*$73`  
import java.net.*; <2ffcBv  
lyIstfRh15  
1p23&\\~  
public class SiteFileFetch extends Thread { Nj.(iBmr  
&m4 \"X@  
* C~  
SiteInfoBean siteInfoBean = null; //文件信息Bean 23y7l=.b/  
long[] nStartPos; //开始位置 f3V&i)w(  
long[] nEndPos; //结束位置 sxO_K^eD  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 rNqJL_!  
long nFileLength; //文件长度 nV McHN   
boolean bFirst = true; //是否第一次取文件 =q^o6{d0"  
boolean bStop = false; //停止标志 =5%jKHo+9z  
File tmpFile; //文件下载的临时信息 %7O`]ik:  
DataOutputStream output; //输出到文件的输出流 "(/|[7D)  
l?a(=  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ?qw&H /R  
public SiteFileFetch(SiteInfoBean bean) throws IOException u|WX?@\  
{ 2ADUJ  
siteInfoBean = bean; %zd1\We  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); W]_+3qvZ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); LZM[Wg#  
if(tmpFile.exists ()) Z,,Da|edH  
{ BYVp~!u  
bFirst = false; ZHICpL  
read_nPos(); xh @H@Q\  
} ?9v!UT&#  
else zScV 9,H1  
{ h^~eTi;c]Q  
nStartPos = new long[bean.getNSplitter()]; Otn,(j;u  
nEndPos = new long[bean.getNSplitter()]; k^]+I% ?Q  
} Fmt5"3B  
_xAdvr' W  
mv SNKS  
KHcf P7  
} {.H}+@0  
|vTirZP  
5D-xm$8C  
public void run() K,|Gtaa~  
{ W8yr06{]  
//获得文件长度 2[9hl@=%  
//分割文件 Trbgg  
//实例FileSplitterFetch (Y, @-V  
//启动FileSplitterFetch线程 11X-X  
//等待子线程返回 emw3cQ  
try{ /.$n>:XR  
if(bFirst) RX=C)q2c  
{ !F;W#Gc  
nFileLength = getFileSize(); }N2T/U  
if(nFileLength == -1) nrwb6wj  
{ A7+eWg{  
System.err.println("File Length is not known!"); -q(,}/Xf  
} A:p7\Kp;5}  
else if(nFileLength == -2) ;TMH.E,h:  
{ z6|P]u  
System.err.println("File is not access!"); `8xe2=Ub  
} 6rt.ec(  
else eAu3,qoM  
{ rNfua   
for(int i=0;i<nStartPos.length;i++) 3r+vpyu  
{ =o{zw+|% %  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ',kYZay  
} vj[ .`fY  
for(int i=0;i<nEndPos.length-1;i++) $62ospR^Y  
{ V`S6cmwdc\  
nEndPos = nStartPos[i+1]; GZXUB0W\@)  
} uzho>p[ae  
nEndPos[nEndPos.length-1] = nFileLength; H`),PY2  
} WSi Utf|g  
} D D"]as"#  
G:c)e ,pD  
*@cXBav/<  
//启动子线程 b&HA_G4  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; cEve70MV  
for(int i=0;i<nStartPos.length;i++) h+,zfVJu  
{ 2B=yT8  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :~ zK0v"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 9i yNR!  
nStartPos,nEndPos,i); UR1U; k  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7AV!v`  
fileSplitterFetch.start(); u{ JAC!  
} T1M4@j  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8.{5c6G  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); NLoJmOi;L7  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", rm+|xvZ4  
nEndPos = " + nFileLength); BGLJ>zkq  
// fileSplitterFetch[nPos.length-1].start(); `cy_@Z5A  
+7^%fX;3pW  
P9G c)$6{p  
//等待子线程结束 a&.8*|w3  
//int count = 0; 3 5B0L.R  
//是否结束while循环 5z5#_*)O  
boolean breakWhile = false; 2o6KVQ  
^Ml)g=Fq  
;5PXPpJ  
while(!bStop) tP"C >#LO  
{ zK k;&y|{  
write_nPos(); Iy8Ehwejd  
Utility.sleep(500); \uQ(-ji  
breakWhile = true; 2e/ JFhA  
DFVaZN?~  
^7Z)/c`"  
for(int i=0;i<nStartPos.length;i++) jU@qQ@|  
{ J6n@|L!yO  
if(!fileSplitterFetch.bDownOver) (](:0H  
{ ,m8l /wG  
breakWhile = false; \gDf&I  
break; jC@$D*"J  
} ou6yi; l%  
} @4sv(HyDY  
if(breakWhile) (05/}PhB`  
break; 2%. A{!  
oa}-=hG  
A=I]1r  
//count++; }_@*,  
//if(count>4) 9=ns.r  
// siteStop(); Xb?P'nD  
} ?`u Y*+u  
Eu l,1yR  
(6^v`SZ  
System.err.println("文件下载结束!"); Al5E  
} rs]%`"&=  
catch(Exception e){e.printStackTrace ();} yS@c2I602  
} q$(aMO&J  
k9~NIvnB`  
!L2R0Y:a  
//获得文件长度 L1VUfEG-  
public long getFileSize() l"f.eo0@7  
{ d2Z5HFtY  
int nFileLength = -1; Y]Vt&*{JV  
try{ u+&BR1)C  
URL url = new URL(siteInfoBean.getSSiteURL()); 7!]$XGz[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0 x4Xs  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]p\7s  
)U`6` &F  
\5_+6  
int responseCode=httpConnection.getResponseCode(); 3 i Id>  
if(responseCode>=400) (]w_}E]N  
{ Dwj!B;AZ_  
processErrorCode(responseCode); "|{ NRIE  
return -2; //-2 represent access is error (Dlh;Ic r9  
} $.a<b^.Xi  
o:.={)rX  
~4"adOv  
String sHeader; P%8 Gaa=  
sG=D(n1  
?w#V<3=  
for(int i=1;;i++) ^vn8s~#  
{ aqQ YU5l4~  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 6y)TXp  
//Utility.log(in.readLine()); 47|Lk]+O  
sHeader=httpConnection.getHeaderFieldKey(i); n;@PaE^8=  
if(sHeader!=null) W-qec  
{ "T=Z/@Vy  
if(sHeader.equals("Content-Length"))  "_eHK#)  
{ MRR5j;4GK  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); $]2srRA^A  
break; Q>8F&p?R  
} "9'~6b  
} GbUw:I  
else DJVH}w}9_P  
break; x{6KsYEY  
} ,)TtI~6Q  
} qsOA(+ZP  
catch(IOException e){e.printStackTrace ();} JR8 b[Oj.S  
catch(Exception e){e.printStackTrace ();} wN>k&J  
k |k  
[CL.Xil=  
Utility.log(nFileLength); EiQX* v  
9utiev~3  
4nK\gXz19  
return nFileLength; {;4Y5kj  
} j]U sb_7  
29("gB  
9^6E> S{=  
//保存下载信息(文件指针位置) b#`XmB  
private void write_nPos() VkTdpeBV  
{ 7I;xRo|  
try{ NRN3*YGo  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 9>yLSM,!rS  
output.writeInt(nStartPos.length); M<s16  
for(int i=0;i<nStartPos.length;i++) 4[m})X2(  
{ /j/,@,lw7z  
// output.writeLong(nPos); )9I>y2WU~  
output.writeLong(fileSplitterFetch.nStartPos); Aslh}'$}-  
output.writeLong(fileSplitterFetch.nEndPos); #5)0~4%l  
} KJn@2x6LP  
output.close(); Ir&rTGFN  
} }(k#,&Fv`  
catch(IOException e){e.printStackTrace ();} TUHm.!+a  
catch(Exception e){e.printStackTrace ();} B~+3<#B  
} +Z> Y//  
,cZhkXd  
l/1u>'  
//读取保存的下载信息(文件指针位置) GKT2x '(e  
private void read_nPos() _&V%idz!0  
{ &.XlXihnt  
try{ POvxZU  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 8=QOp[w   
int nCount = input.readInt(); c%y(Z5  
nStartPos = new long[nCount]; vT/e&8w  
nEndPos = new long[nCount]; P 4Vi~zMX  
for(int i=0;i<nStartPos.length;i++) <7'`N\a  
{ !"1}zeve  
nStartPos = input.readLong(); Y-!~x0-H  
nEndPos = input.readLong(); KYE)#<V}@  
} 1 aWzd[i  
input.close(); rPhx^ QKH2  
} PD #9Z=Hj  
catch(IOException e){e.printStackTrace ();} EQe!&;   
catch(Exception e){e.printStackTrace ();} "NEg]LB5  
} 8T6LD  
!d nCrR  
g)0>J  
private void processErrorCode(int nErrorCode) YnM&t ;TX  
{ w-iu/|}  
System.err.println("Error Code : " + nErrorCode); X$*MxMNs  
} Pq\ `0/4_  
L\0;)eJ#M  
 N>ncv  
//停止文件下载 w>#{Nl7gz  
public void siteStop() ot\  FZ  
{ ;f;A"  
bStop = true; q4u,pm,@  
for(int i=0;i<nStartPos.length;i++) m=Mb'<  
fileSplitterFetch.splitterStop(); (V&5EO8)  
a8 X}r.  
e"}JHXs  
} ba5,?FVI~  
} o\/&05rp]  
//负责部分文件的抓取 /{1sU}k-  
**FileSplitterFetch.java y yPQ^{zD  
*/ "PgVvm#w'  
package NetFox; &10l80vj  
M3XG s|gw  
?^Gi;d5  
import java.io.*; ?'_Ty`vT  
import java.net.*; Cws;6i*=@  
s!k7Wwj  
G5WQTMzf&  
public class FileSplitterFetch extends Thread { d]A.=NAc  
PP*6nW8  
u<L<o 2  
String sURL; //File URL Sg%h}]~   
long nStartPos; //File Snippet Start Position wnioIpRkh  
long nEndPos; //File Snippet End Position CdBpz/  
int nThreadID; //Thread's ID aE|'%72g  
boolean bDownOver = false; //Downing is over 0Q7teXRM  
boolean bStop = false; //Stop identical ( p(/  
FileAccessI fileAccessI = null; //File Access interface yMG(FAyu  
8F>u6Y[P  
(Q5rOrA"  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException R*[X. H  
{ 9Lus,l\  
this.sURL = sURL; :g%hT$,]3b  
this.nStartPos = nStart; N5PW]  
this.nEndPos = nEnd; -L-#-dK'  
nThreadID = id; Ky0}phGRu  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 2xLEB&  
} ^VC /tJ  
# &,W x  
}Q2v~eD  
public void run() 7xF)\um  
{ ]?< wUd  
while(nStartPos < nEndPos && !bStop) U g:  
{ *S xDwN  
awXK9}.  
FR9w0{o  
try{ HNJR&U t  
URL url = new URL(sURL); RWg'W,v=!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /^]/ iTg  
httpConnection.setRequestProperty("User-Agent","NetFox"); Z";&1cK  
String sProperty = "bytes="+nStartPos+"-"; ` 0$i^,}  
httpConnection.setRequestProperty("RANGE",sProperty); zqHG2:MN"  
Utility.log(sProperty); OV G|WC  
0g 2?  
Iuyq!R4:7  
InputStream input = httpConnection.getInputStream(); }/w]+f*  
//logResponseHead(httpConnection); m?< ^b_a}  
~8 B]  
{+~ JTrp  
byte[] b = new byte[1024]; '[Sm w'n6-  
int nRead; |}7!'f\M  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) MzFFWk  
{ DsB30  
nStartPos += fileAccessI.write(b,0,nRead); Ucx"\/"  
//if(nThreadID == 1) z!M #   
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); I4|LD/b  
} xH\!j  
eJ*u]GH U  
ZveNe~D7C  
Utility.log("Thread " + nThreadID + " is over!"); `q9n`h1  
bDownOver = true; eMV{rFmT  
//nPos = fileAccessI.write (b,0,nRead); k vpkWD;  
} e# U@n j6  
catch(Exception e){e.printStackTrace ();} ;A G&QdTMh  
} tj? %{L  
} r|63T%q!  
HA J[Y3d<  
)3 I~6ar  
//打印回应的头信息 O#<F"e;$  
public void logResponseHead(HttpURLConnection con) A`--*$8\  
{ +CVB[r#hu  
for(int i=1;;i++) Dm@h'*  
{ Z0/$XS9|h;  
String header=con.getHeaderFieldKey(i); |KR8=-!7  
if(header!=null) lak,lDt]  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ~.tl7wKkR/  
Utility.log(header+" : "+con.getHeaderField(header)); \.aKxj5  
else 4tEAi4H|`@  
break; NXk~o!D  
} eZ oAy[  
} fikDpR  
4]HW!J  
LOgFi%!6:  
public void splitterStop() d5>EvK U  
{ t~H0Qeb[v=  
bStop = true; '3w%K+eJY  
} YV8PybThc  
#bJp)&LO  
.=)[S5.BVq  
} ~,_@|,)  
BbM/Rd1tAm  
1V wcJd  
/*  _!_^B  
**FileAccess.java 'yosDT2{#  
*//文件访问(定位,写) Hd\. ,2a"  
package NetFox; f}~=C2R1<!  
import java.io.*; Q #X'.](1  
p+pu_T;~  
A^E 6)A=  
public class FileAccessI implements Serializable{ r#A*{4wz  
S0Ur{!9\#^  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 !{4'=+  
RandomAccessFile oSavedFile; )7{r8a  
long nPos; pw&k0?K#  
L PS,\+  
g[R4/]K^$  
public FileAccessI() throws IOException it-]-=mqb  
{ 2FW"uYA;6  
this("",0); 2z.~K&+x  
} )QW hzY  
a)4%sX*I  
.EPv4[2%F8  
public FileAccessI(String sName,long nPos) throws IOException Qqi?DW1)-  
{ Z4X, D`s  
oSavedFile = new RandomAccessFile(sName,"rw"); l1#.r g  
this.nPos = nPos; qqJghV$Oj  
oSavedFile.seek(nPos); M}j[{wW3  
} JljCI@  
2">de/jS  
^D]J68)#a  
public synchronized int write(byte[] b,int nStart,int nLen) t 9t '9  
{ #1C]ZV] B  
int n = -1; eIEL';N6  
try{ ?S'aA !/;  
oSavedFile.write(b,nStart,nLen); >S-JAPuO  
n = nLen; v`c;1?=,q  
} eh%{BXW[p  
catch(IOException e) @`#x:p:  
{ hj&~Dn(  
e.printStackTrace (); z` YC3_d  
} 5*f54g"'  
mlCBstt{  
L }3eZ-  
return n; d``wx}#Uk  
} tot~\S  
QFnpp\K  
qe'ssX;  
} )7]yzc  
SuB8mPn  
gTgoS:M"_O  
/* +I-BqA9  
**SiteInfoBean.java kh{3s:RQfC  
*/ C=|8C70[%N  
package NetFox; {=\Fc`74  
B;F ~6i  
ahIDKvJ4  
public class SiteInfoBean { ij|>hQC5i  
w[D]\>QHa  
p!~1~q6  
private String sSiteURL; //Site's URL ZDAW>H<  
private String sFilePath; //Saved File's Path ).IyjHY  
private String sFileName; //Saved File's Name vBJxhK-  
private int nSplitter; //Count of Splited Downloading File dC8}Ttc}  
*`|xa@1v`  
,[T/O\k  
public SiteInfoBean()  \m~p;B  
{//nSplitter的缺省值为5 *sZH3:  
//default value of nSplitter is 5 6-uLK'E  
this("","","",5); -)B_o#2=2  
} gwsIzYV  
PqL. ^  
Qclq^|O0  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Y8^ WuN$  
{ j#2E Q  
sSiteURL= sURL; u]7wd3(  
sFilePath = sPath; dWQB1Y*N  
sFileName = sName; !V(r p80  
this.nSplitter = nSpiltter; s*_fRf:  
dHTx^1  
;2\6U;  
} W8$0y2  
122s 7A  
JBLUX,  
public String getSSiteURL() <&3aP}  
{ ez!W0  
return sSiteURL; ^H7xFd|>  
} -|^)8  
GA$fueiQNs  
a;^lOU|L{  
public void setSSiteURL(String value) g`Cv[Pq?at  
{ $/|) ,n  
sSiteURL = value; HzKY2F(,  
} "oNl!<ep  
UKZ )Boo  
z6l'v~\  
public String getSFilePath() 8PH4v\tJEK  
{ mNacLkh[  
return sFilePath; In?#?:Q@&  
} pqb`g@  
|,5|ZpgL  
oQ,<Yx%E3  
public void setSFilePath(String value) v*qbzW`  
{ -aVC`  
sFilePath = value; ZZZ9C#hK^9  
} b=xn(HE8|  
 .gmS1ju  
0+$gR~^^  
public String getSFileName() s2NBYDi$?  
{ c ?EvrtND  
return sFileName; 7(X z%v   
} GM'yOJo  
YI;iG[T,&  
G"E_4YkJ  
public void setSFileName(String value) >;hAw!|#  
{ i>,AnkI&  
sFileName = value; ~gW^9nWYU  
} d)bsyZ;U  
7L6L{~8 W  
A"&<$5Q  
public int getNSplitter() CxjB9#  
{ Xpn\TD<_I  
return nSplitter; [2Zy~`*y{  
} 0QW=2rs  
wiZ  
!rr,(!Ip?O  
public void setNSplitter(int nCount) hL6;n*S=  
{ ~gff{Nzk  
nSplitter = nCount; o h\$u5  
} %+Ze$c}X  
} Tn1V+)  
}.E^_`  
,0,FzxX0!  
/* abT,"a\h  
**Utility.java =WW5H\?  
*/ $.,B2}'  
package NetFox; >@Ht*h{~  
qf\W,SM  
?.%dQ0  
public class Utility { SU4i'o  
]#^v754X^T  
tx>7?e8E  
public Utility() E5)0YYjHZ  
{ 9l &q}  
6V]m0{:E  
:,aY|2si  
} Sk>=C0f:  
!|xB>d q?  
//线程睡眠 t~j 6wsx;  
public static void sleep(int nSecond) \q1tT!]  
{ <MkvlLu((o  
try{ ~Ay)kv;  
Thread.sleep(nSecond); HrvyI)4{  
} WIf.;B)L  
catch(Exception e) [ UI>SN  
{ <6Gs0\JB  
e.printStackTrace (); >h;]rMD!|  
} :tU^  
} 4k@n5JNa  
> d p/  
//日志 >bze0`}Z  
public static void log(String sMsg) 0t^FM<7G  
{ dGBjV #bNT  
System.err.println(sMsg); e~zgH\`  
} rY45.,qWs  
mLZ1u\ 7W  
G@`F{l  
public static void log(int sMsg) 4/`;(*]Fv  
{ Z>g>OPu  
System.err.println(sMsg); rx2'].  
} CL1*pL  
} |*NZ^6`@  
)/>BgXwH  
O;<wD h)Yt  
/* M['O`^  
**TestMethod.java 77O$^fG2  
*/ 3PU_STSix  
package NetFox; /"?DOsJ.  
W<pr Y  
8(\}\4G_  
public class TestMethod { cZ:jht  
(b f IS  
gPMfn:a-8  
public TestMethod() bp:`m>4<  
{ ///xx/weblogic60b2_win.exe Mww^  
try{ \(j*K6#  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); .yZLC%}  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); dE_Xd :>  
SiteFileFetch fileFetch = new SiteFileFetch(bean); l EFd^@t  
fileFetch.start(); H575W"53  
} 0<\|D^m=&h  
catch(Exception e){e.printStackTrace ();} R#4l"  
1$vGQ  
OA3J(4!"W  
} 6(`N!]e*L  
<N=k&\  
YJ6~P   
public static void main(String[] args) T[|#DMg$F  
{ !2Nk  
new TestMethod(); )DXt_leLg  
} <3B^5p\/  
} /"gRyv  
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