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http断点续传简单实现(java)

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/* 9m-)Xdoy  
**SiteFileFetch.java 1&/FG(*/  
*/ *-12VIG'H  
package NetFox; 5"/J^"!h  
import java.io.*; [lk'xzE  
import java.net.*; $46{<4.  
X{^}\,cVtG  
gt\MS;jMa  
public class SiteFileFetch extends Thread { 5qf BEPJ  
Q.Aw2  
xP=/N!,#  
SiteInfoBean siteInfoBean = null; //文件信息Bean )9S>Z ZF  
long[] nStartPos; //开始位置 jAh2N3)  
long[] nEndPos; //结束位置 &wU'p-V  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 fA=#Fzk2  
long nFileLength; //文件长度 hb/]8mR  
boolean bFirst = true; //是否第一次取文件 ~w</!s  
boolean bStop = false; //停止标志 a,Gxm!  
File tmpFile; //文件下载的临时信息 >3gi yeJ  
DataOutputStream output; //输出到文件的输出流 ,+;:3gRk9  
X1tXqHJF}  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) `p'Q7m2y/b  
public SiteFileFetch(SiteInfoBean bean) throws IOException u4"SH(  
{ x"4} isp<  
siteInfoBean = bean; JjXobNQf  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); kGkA:g:  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); y{9~&r  
if(tmpFile.exists ()) 0GDvwy D1  
{ nJ?^?M'F%  
bFirst = false; $ \*` }Y  
read_nPos(); \#'TNmS  
} (]*H[)F/  
else q@hp.(V  
{ O9(r{Vu7u  
nStartPos = new long[bean.getNSplitter()]; }<jb vCeK  
nEndPos = new long[bean.getNSplitter()]; Zs2-u^3&  
} 65,(4Udz!  
-xg2q V\c  
/$"[k2 N  
]v G{kAnH  
} 7{oe ->r  
S<nq8Ebmw  
T88Y qI  
public void run() $[@0^IJq=K  
{ *FR$vLGn  
//获得文件长度 `A/j1UWJ  
//分割文件 r' BAT3  
//实例FileSplitterFetch /q\_&@  
//启动FileSplitterFetch线程 RE3Z%;'  
//等待子线程返回 = \ , qP  
try{ 9^F2$+T[:  
if(bFirst) kJs^ z  
{ w'7R4  
nFileLength = getFileSize(); iF+RnWX\  
if(nFileLength == -1) V+wH?H=  
{ %ICglF R  
System.err.println("File Length is not known!"); lz | 64J  
} Q}A=jew  
else if(nFileLength == -2) mV9A{h  
{ %qsvtc`  
System.err.println("File is not access!"); @LD6:gy  
}  PWgDFL?  
else -qV{WZHp  
{ _'x8M  
for(int i=0;i<nStartPos.length;i++) TB aVW  
{ [IM%b~j(^  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 7q9gngT1LA  
} o5Rz%k#h  
for(int i=0;i<nEndPos.length-1;i++) E^ h=!RW{  
{ 5iFV;W  
nEndPos = nStartPos[i+1]; Vs 0 SXj  
} cJ}QXuuUv  
nEndPos[nEndPos.length-1] = nFileLength; %NHYW\sKX  
} QYE7p\  
} 6a}r( yP  
_94s(~g:  
%.x@gi q  
//启动子线程 17UK1Jx,  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; (hZ:X)E>  
for(int i=0;i<nStartPos.length;i++) GaNq2G  
{ F#q&(  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _ptP[SV^j  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), :pKG\A  
nStartPos,nEndPos,i); ?p8Qx\%*  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |DG@ht  
fileSplitterFetch.start(); &,W$-[  
} z)L}ECZh9  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +$beo2x6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); E)'8U  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", s^|\9%WD  
nEndPos = " + nFileLength); p%RUHN3G[  
// fileSplitterFetch[nPos.length-1].start(); R ZcH+?7  
jqoPLbxT  
saK;[&I*  
//等待子线程结束 u35q,u=I  
//int count = 0; ]O{_O&w  
//是否结束while循环 !;}2F-  
boolean breakWhile = false; w6,*9(;$Pk  
,?b78_,2  
ua& @GXvZ  
while(!bStop) Sb<\-O14"  
{ LcUlc)YH5  
write_nPos(); u(vw|nj`  
Utility.sleep(500); (wL3 +  
breakWhile = true; i!~>\r\6\  
&:vsc Ol  
T^)plWw  
for(int i=0;i<nStartPos.length;i++) (Pz8 iz  
{ l BiovT  
if(!fileSplitterFetch.bDownOver) XJFnih  
{ t"YIq/08  
breakWhile = false; ~/c5 hyTx  
break; %Dyh:h   
} mU]s7` %<>  
} [ -12]3  
if(breakWhile) 'O "kt T  
break; i_Ar<9a~  
u5E/m  
9t }xXk  
//count++; YC)hX'A\  
//if(count>4) )5i* /I\  
// siteStop(); Jk*QcEE=  
} u9}!Gq  
C"No5r'K3  
N9*UMVU  
System.err.println("文件下载结束!"); `E;)`J8b  
} W?PWJkIw  
catch(Exception e){e.printStackTrace ();} .;Z.F7{q  
} !rHx}n{rw  
[tN` :}?  
.\4l'THn,0  
//获得文件长度 *.dKR  
public long getFileSize() S-P{/;c@  
{ R9E6uz.j  
int nFileLength = -1; R\ q):,  
try{ F G _,  
URL url = new URL(siteInfoBean.getSSiteURL()); d"l}Ny)C  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); g 2#F_  
httpConnection.setRequestProperty("User-Agent","NetFox"); 4g'}h`kh  
dk4D+*R  
~._ko  
int responseCode=httpConnection.getResponseCode(); 7uA\&/ ,  
if(responseCode>=400) N4+g("  
{ KE#$+,?  
processErrorCode(responseCode); TRCI\  
return -2; //-2 represent access is error cS 4T\{B;  
} kpWzMd &RK  
2b~ HHVruX  
"_oLe;?$c  
String sHeader; U[Nosh)hu\  
m/" J s  
PuU*vs3  
for(int i=1;;i++) ip674'bq7R  
{ \@:j  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); }2mI*"%)\u  
//Utility.log(in.readLine()); L3g9b53\  
sHeader=httpConnection.getHeaderFieldKey(i); ,-!2 5G  
if(sHeader!=null) 1zR/HT  
{ ^K/G5  
if(sHeader.equals("Content-Length")) AW62~*  
{ ~Q_F~0y  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); <\Vi,,  
break; z2ds8-z  
} 0ovZ&l  
} CY5w$E  
else -2z,cj&E{  
break; @,GjeF]!  
} z=[l.Af_  
} ^}tL nF  
catch(IOException e){e.printStackTrace ();} 4^`PiRGt  
catch(Exception e){e.printStackTrace ();} "W3W:vl!  
9Dy)nm^  
jB`7T^bU  
Utility.log(nFileLength); t+jIHo  
([1=>Jw"  
<TL])@da  
return nFileLength; kO jEY  
} {GAsFnZk  
eC.w?(RB  
C1n? ?Y[  
//保存下载信息(文件指针位置) J/L)3y   
private void write_nPos() n}42'9p  
{ 6(,ItMbI  
try{ P`z7@9*j  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 9A(n _Rs7?  
output.writeInt(nStartPos.length); n}+wd9J*!2  
for(int i=0;i<nStartPos.length;i++) l<s :%%CX  
{ ]}_p3W "Y9  
// output.writeLong(nPos); JXlTN[O  
output.writeLong(fileSplitterFetch.nStartPos); j-j'phK  
output.writeLong(fileSplitterFetch.nEndPos); *>G ^!e.u  
} |G>q:]+AV  
output.close(); 4$ ..r4@  
} mf+K{y,L  
catch(IOException e){e.printStackTrace ();} tP&{ J^G  
catch(Exception e){e.printStackTrace ();} md.*  
} )~1.<((<  
"$# $f  
Ml'bZLwq  
//读取保存的下载信息(文件指针位置) ?Ozk^#H[  
private void read_nPos() jM{qRfOrg  
{ [^h/(a`  
try{ @ysJt  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 3S;>ki4(0  
int nCount = input.readInt(); 2=i+L z^  
nStartPos = new long[nCount]; ,oC= {^l{  
nEndPos = new long[nCount]; niXHK$@5  
for(int i=0;i<nStartPos.length;i++) ?aP1  
{ Rc$=+K#  
nStartPos = input.readLong(); ' 2;Ny23  
nEndPos = input.readLong(); Ej-=y2j{g  
} ,)0/Ec  
input.close(); ?,.HA@T%  
}  ]H@v  
catch(IOException e){e.printStackTrace ();} BnY\FQ)K  
catch(Exception e){e.printStackTrace ();} AaJ,=eQ  
} N:m@D][/sW  
A}az m>  
BiVd ka  
private void processErrorCode(int nErrorCode) z:0-aDe M  
{ 2<`gs(oxXe  
System.err.println("Error Code : " + nErrorCode); iKP\/LR<n  
} "~ .8eKRQ  
g?k#wj1uH  
S-H-tFy\\  
//停止文件下载 4WBo ZJ  
public void siteStop() Om&{4a\  
{ d;@E~~o?B]  
bStop = true; NgDZ4&L  
for(int i=0;i<nStartPos.length;i++) j TB<E=WC  
fileSplitterFetch.splitterStop(); e<: 4czh8  
,"v)vTt  
9-X{x95]  
} 6KBzlj0T+  
} 1{;[q3a  
//负责部分文件的抓取 p@!@^1j=  
**FileSplitterFetch.java >*<6 zQf  
*/ f4A4  
package NetFox; KoxGxHz^Y3  
UH1S_:6  
q9g[+*9]$  
import java.io.*; RGx]DP$5G  
import java.net.*; }uV?  
L*SSv wSL  
2Be?5+  
public class FileSplitterFetch extends Thread { YokZar2a0  
GDNh?R  
Bsih<`KF^  
String sURL; //File URL T9U2j-lA?  
long nStartPos; //File Snippet Start Position ]iE.fQ?;J  
long nEndPos; //File Snippet End Position lN][xnP  
int nThreadID; //Thread's ID _taHf %\4  
boolean bDownOver = false; //Downing is over ib""Fv7{  
boolean bStop = false; //Stop identical &?5{z\;1"  
FileAccessI fileAccessI = null; //File Access interface f2SU5e2  
u]>>B>KOJ7  
mv9E{m  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException b[&,%Sm+6  
{ ,:dEEL+>c  
this.sURL = sURL; ^! v}  
this.nStartPos = nStart; iz%A0Z+`bg  
this.nEndPos = nEnd; Te U7W?M^  
nThreadID = id; w$U/;C  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 4, *^QK  
} 7S~9E2N  
=p&'_a^$  
_:fO)gs|1  
public void run() #.<F5  
{ mC[U)` ey  
while(nStartPos < nEndPos && !bStop) 9Sj:nn^/u  
{ w?$u!X  
z kX-"}$8  
]ZryY EB  
try{ ]zwqGA  
URL url = new URL(sURL); rO?x/{;ai  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "<jEI /  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~b6<uRnM.  
String sProperty = "bytes="+nStartPos+"-"; a@_Cx  
httpConnection.setRequestProperty("RANGE",sProperty); Mn }Z9S[  
Utility.log(sProperty); yzM+28}L<I  
gt t$O  
)T};Q:  
InputStream input = httpConnection.getInputStream(); eDM0417O(  
//logResponseHead(httpConnection); >%p m "+h{  
>*t>U8  
kj3o1Y  
byte[] b = new byte[1024]; )`+@j.75  
int nRead; /4B4IT  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) I\uB"Z{9  
{ 6 XOu~+7  
nStartPos += fileAccessI.write(b,0,nRead); g=YiR/O1QN  
//if(nThreadID == 1) +S5_J&~  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); YT(1 "{:  
} P7k$^n  
C}P \kDM  
=@jMx^A"  
Utility.log("Thread " + nThreadID + " is over!"); F)5B[.ce  
bDownOver = true; ,pa&he  
//nPos = fileAccessI.write (b,0,nRead); QH' [ (  
} JJHvj=9'o  
catch(Exception e){e.printStackTrace ();} $H:h(ia:  
} ! 7*_Z=  
} .kKwdqO+zB  
yDyeP{  
hHl-;%#  
//打印回应的头信息 dbUZGn~  
public void logResponseHead(HttpURLConnection con) 6u, 0y$3  
{ ^'I5]cRa  
for(int i=1;;i++) !4,xQ ^   
{ ic]tUOC:  
String header=con.getHeaderFieldKey(i); (F '  
if(header!=null) T!xy^n]}  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Ce'2lo  
Utility.log(header+" : "+con.getHeaderField(header)); 8!%"/*P$  
else j _9<=Vu  
break; P~ pbx  
} [O+^eE6h  
} yqb <<4I  
zcWxyLifl0  
7RFkHME  
public void splitterStop() Qp{-!*  
{ Ww tQ>'R"  
bStop = true; YB3=ij!K  
} >;r05,mc  
$z,DcO.vz  
cA SHgm  
} <$6'Mzf  
{5IG3'  
u&_U CJCf  
/* EM w(%}8w  
**FileAccess.java 'CO[s.03  
*//文件访问(定位,写) LqsJHG  
package NetFox; sfPN\^k2  
import java.io.*; Jb.u^3R@  
1`_)%Y[ZJ  
4bzn^  
public class FileAccessI implements Serializable{ Bg0cC  
vl~   
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Hf{%N'4  
RandomAccessFile oSavedFile; 4^ 6L])y  
long nPos; }/r%~cZ  
sLqvDH?V  
B]F7t4Y!  
public FileAccessI() throws IOException *9(1:N;#  
{ X3O$Sd(D  
this("",0); W*`6ero  
} ld?.o/  
`#8R+c=$  
rg/vxTl  
public FileAccessI(String sName,long nPos) throws IOException ~RAH -]  
{ H^:|`T|,  
oSavedFile = new RandomAccessFile(sName,"rw"); 8vW`E_n  
this.nPos = nPos; 2B dr#qr  
oSavedFile.seek(nPos); $-fY8V3[  
} r$Qh`[<  
BQ0\+  
_N';`wjDY  
public synchronized int write(byte[] b,int nStart,int nLen) -Ep6 .v  
{ }c5`~ LLK  
int n = -1; :]Qx T8B  
try{ q#3X*!)  
oSavedFile.write(b,nStart,nLen); g^UWf<xp  
n = nLen; h18y?e7MU  
} T["(YFCByg  
catch(IOException e) fEv36xb2S  
{ D~&e.y/gHN  
e.printStackTrace (); _u2  
} JhIK$Ti  
*S_Iza #&x  
0*@S-Lj^c  
return n; Lo9?,^S  
} M[_I16s  
 )6+W6:  
3y,?>-  
} mP[u[|]  
@{lnfOESl  
$7d"9s\$"  
/* 6E]rxps}"  
**SiteInfoBean.java %WN2 xCSf  
*/ #?6RoFgMe  
package NetFox; 0+pJv0u  
h cXqg  
c iX2G  
public class SiteInfoBean { .y+U7 "?s*  
]]3D` F}  
+KNr1rG  
private String sSiteURL; //Site's URL \]%U?`A  
private String sFilePath; //Saved File's Path ?9TogW>W  
private String sFileName; //Saved File's Name OhEL9"\<  
private int nSplitter; //Count of Splited Downloading File 0{F.DDiNT  
>.\E'e5^C  
UI;{3Bn  
public SiteInfoBean() S &u94hlC  
{//nSplitter的缺省值为5 m@~x*+Iz  
//default value of nSplitter is 5 g"Bv!9*H  
this("","","",5); n]Y _C^  
} 1[^d8!U  
yk2j&}M  
q3`t0eLZ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) e_V(G  
{ y{JkY\g  
sSiteURL= sURL; ;zDc0qpw  
sFilePath = sPath; Xk'.t|  
sFileName = sName; {IWb:p#I]  
this.nSplitter = nSpiltter; K>y+3HN[6  
.~J^`/o  
{wI0 =U  
} Lt_]3g o  
's<}@-]  
S}X:LHr*  
public String getSSiteURL() BL67sva;  
{ fF%r$`2  
return sSiteURL; 'oG'`ED"  
} O5 SX"A  
1~ Nz6  
:%{7Q$Xv<  
public void setSSiteURL(String value) 1zRO== b  
{ 7~'@m(9e  
sSiteURL = value; 9[M u   
} u2QJDLMJv  
xh0!H| R  
K4BMa]/U  
public String getSFilePath() bX,Z<BvbF  
{ 5 *_#"  
return sFilePath; ']Z8C)tK  
} \#slZ;&s  
rQJoaP+\q  
lxZXz JkqZ  
public void setSFilePath(String value) J$0*K+m  
{ w]_a0{Uh  
sFilePath = value; @ 55Y2  
} O);V{1P  
bGZy0.  
X`&E,;bIb  
public String getSFileName() Y%3j >_\;  
{ \;}dS SB1  
return sFileName; PyYe>a;.  
} -UO$$)Q  
v!2`hq O  
^IpS 3y  
public void setSFileName(String value) 7DD ot_qb  
{ 4"{q|~&=:$  
sFileName = value; Ab`Gb  
} gIeo7>u  
_wIAr  
3XIxuQwf  
public int getNSplitter() /=%4gWtr  
{ ||qW'kNWM  
return nSplitter; }U9e#>e x  
} IcB>Hg5  
V%))%?3x_  
52oR^ |  
public void setNSplitter(int nCount) E)Dik`Ccl  
{ @Z)&3ss  
nSplitter = nCount; ^-DK<jZ^  
} "xWC49   
} =Oy,SX  
fYwumx`J  
p?Y1^/   
/* t^q/'9Ai&J  
**Utility.java *{uu_O  
*/ /SyiJCx0  
package NetFox; h<?Vzl  
1UOFTI2S|  
 A/9 wr  
public class Utility { {2!.3<#  
'SC`->F4D  
xMe[/7)4  
public Utility()  '{),gV.  
{ 1_A< nt?'R  
nF=h|rN  
iKu5K0x{>I  
} E]bjI$j  
rKO[;]_*  
//线程睡眠 xSw ^v6!2  
public static void sleep(int nSecond) DwoO([&I  
{ $N~8 ^6  
try{ ;#AV~Y- s  
Thread.sleep(nSecond); <MoWS9s!yb  
} lE4.O  
catch(Exception e) By" =]|Q  
{ Kpg]b"9.R  
e.printStackTrace (); v=!]t=P)t  
} vFQ'sd]C  
} Nx~8]h1(  
>xT8[  
//日志 <J\z6+,4E  
public static void log(String sMsg) `w2hJP  
{ nT:ZSJWM  
System.err.println(sMsg); WUKYwA/t  
} $cnIsyKWY  
geua8;  
@`)A )  
public static void log(int sMsg) 4\>Cnc{  
{ ]"^U  
System.err.println(sMsg); c{z QX0  
} 7&E3d P  
} +[ !K  
OT+LQ TE  
Dr&2q X!  
/* tv5G']vO\  
**TestMethod.java h>9GfF3  
*/ }!x\qpA  
package NetFox; h49|x&03  
Bi9 S1 p  
Ab/gY$l  
public class TestMethod { 6|L<? X  
NZ7g}+GTG  
xM'bb5  
public TestMethod() CtfI&rb[  
{ ///xx/weblogic60b2_win.exe P-.>vi^+  
try{ o[X 'We;  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); HTA Jn_  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 2Gd.B/L6  
SiteFileFetch fileFetch = new SiteFileFetch(bean); `{#0C-  
fileFetch.start(); )l~:P uvh  
} _SY4Q s`d  
catch(Exception e){e.printStackTrace ();} A}W) La\  
=Q>'?w>  
},lHa!<^  
} D6fry\  
Bvb.N$G  
7.`Fe g.  
public static void main(String[] args) B&3oo   
{ @z[,w`  
new TestMethod(); cks53/Z  
} 5[suwaJQ  
} ssj(-\5  
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