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http断点续传简单实现(java)

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/* cgg6E O(  
**SiteFileFetch.java ?[ xgt )  
*/ Hr|f(9xA  
package NetFox; <^5!]8*O  
import java.io.*; 2{-29bq  
import java.net.*; &9L4 t%As  
/( Wq  
zBF~:Uc`B  
public class SiteFileFetch extends Thread { mci> MEb  
uUH4vUa  
IiU> VLa  
SiteInfoBean siteInfoBean = null; //文件信息Bean XB)D".\  
long[] nStartPos; //开始位置 $|N6I  
long[] nEndPos; //结束位置 M.W X&;>  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 T ozx0??)  
long nFileLength; //文件长度 3U[O :  
boolean bFirst = true; //是否第一次取文件 U"PcNQy  
boolean bStop = false; //停止标志 (2g a: }K  
File tmpFile; //文件下载的临时信息 )4yP(6|lx  
DataOutputStream output; //输出到文件的输出流 8dGsV5"*  
BI1M(d#1L"  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) NJUKH1lIhR  
public SiteFileFetch(SiteInfoBean bean) throws IOException GWA"!~Hu  
{ ^q:-ZgM>  
siteInfoBean = bean; b}[S+G-9W  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Y6` xb`  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 1EyN |m|  
if(tmpFile.exists ()) k# [!; <  
{ <LHhs <M'  
bFirst = false; S,#1^S  
read_nPos(); OW7  
}  YKyno?m  
else {w@qFE'b  
{ o`bch? ]  
nStartPos = new long[bean.getNSplitter()]; xye-Z\-t  
nEndPos = new long[bean.getNSplitter()]; g6GkA.!X$  
} '!HTE` Aj  
po| Ux`u  
`2lS@  
n6/Ous  
} (Ou%0 KW  
GAz -yCJp  
lA^1}  
public void run() b9b Ivjm_  
{ [&)]-2w2  
//获得文件长度 OUX7 *_  
//分割文件 uYh!04u  
//实例FileSplitterFetch 02;jeZ#z  
//启动FileSplitterFetch线程 akj<*,  
//等待子线程返回 a=z] tTs4  
try{ M(%H  
if(bFirst) >B BV/C'9  
{ kK6O ZhLH  
nFileLength = getFileSize(); g`XngRb|j  
if(nFileLength == -1) W }N UU  
{ ~tDYo)hH8  
System.err.println("File Length is not known!"); aJu&h2 G  
} 7sot?gF  
else if(nFileLength == -2) t R^f]+Up  
{ WtT;y|W  
System.err.println("File is not access!"); 8=8 hbdy;  
} &7L7|{18  
else @X==[gQ  
{ Q:}]-lJg  
for(int i=0;i<nStartPos.length;i++) MpV<E0CmE  
{ /bo}I-<2  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ~ao:9 ynY  
} YQBLbtn6(  
for(int i=0;i<nEndPos.length-1;i++) >3 o4 U2  
{ 6(n0{A  
nEndPos = nStartPos[i+1]; djd/QAfSC  
} )U/jD  
nEndPos[nEndPos.length-1] = nFileLength; VYk:c`E  
} fvu{(Tb  
} ]Q^)9uE\D  
!/FRL<mp  
\J'}CX*aQ  
//启动子线程 M0V<Ay\%O  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; TW|K.t@5#H  
for(int i=0;i<nStartPos.length;i++) VkQ@c;C  
{ kAftW '  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $8tk|uh  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), D"7}&Ry:  
nStartPos,nEndPos,i); 55Ss%$k@  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); qZ1'uln=C-  
fileSplitterFetch.start(); )6"}M;v  
} K-RmB4WI  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),  RD$:.   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); %OQdUH4x  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 2W AeSUX  
nEndPos = " + nFileLength); .-gJS-.c  
// fileSplitterFetch[nPos.length-1].start(); D,#UJPyg  
#{i*9'  
waMF~#PJlt  
//等待子线程结束 WAu>p3   
//int count = 0; NxP(&M(  
//是否结束while循环 Kz HYh  
boolean breakWhile = false; lC<;Q*Y  
a4Q@sn;]  
}(EH5jZ'  
while(!bStop) !fOPYgAGKn  
{ epy2}TI  
write_nPos(); zsL@0]e&  
Utility.sleep(500); 9+ 'i(q z  
breakWhile = true; rXx#<7`  
-TUJ"ep]QJ  
6VW *8~~Xy  
for(int i=0;i<nStartPos.length;i++) ZW4f "  
{ XKp&GE@Y  
if(!fileSplitterFetch.bDownOver) 8^7Oc,:~  
{ I)rnF  
breakWhile = false; qng ~,m  
break; a5*r1,  
} ImXYI7PL  
} \&"C  
if(breakWhile) \xYVnjG,  
break; 4Aj~mA  
d NACE*g;q  
lF}[ YL  
//count++; >pq~ &)^u  
//if(count>4) @16GF!.  
// siteStop(); p9v:T1 ?  
} 7=-Yxt  
d$!Q6ux;  
g=Xf&}&=x  
System.err.println("文件下载结束!"); ?sN{U\  
} DDE-$)lf>  
catch(Exception e){e.printStackTrace ();} %>+uEjbT  
} X[BP0:`t  
kR=sr/{  
!%>RHh[  
//获得文件长度 {_9O4 + &  
public long getFileSize() =?5)M_6)  
{ BgQEd@cN  
int nFileLength = -1; k:0j;\Sx  
try{ ;1k& }v&  
URL url = new URL(siteInfoBean.getSSiteURL()); E&U_1D9=L<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Z?)g'n  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7;jD>wp 9D  
"O34 E?ql.  
6bm7^e(  
int responseCode=httpConnection.getResponseCode(); ,#Z%0NLe  
if(responseCode>=400) ;;0'BdsL`  
{ |UTajEL  
processErrorCode(responseCode); {npm9w<;  
return -2; //-2 represent access is error :=Olp;+_  
} 2` o @L  
B+W7zv  
v[dU UR f  
String sHeader; xf,[F8 2y  
]?^V xB7L  
adLL7  
for(int i=1;;i++) z33UER"  
{ nCQtn%j't  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); =%<=Bn  
//Utility.log(in.readLine()); hGtz[u#p  
sHeader=httpConnection.getHeaderFieldKey(i); l5 9a3=q  
if(sHeader!=null) Pn,I^Ej.  
{ M(X _I`\E  
if(sHeader.equals("Content-Length")) wQ33Gc  
{ )qy?x7   
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); bP18w0>,  
break; 2KLMFI.F  
} ibkB>n{(  
} @KQ>DBWQM  
else EI_-5TtRD  
break; >wW{ $  
} mnm ZO}   
} ] Lv3XMa  
catch(IOException e){e.printStackTrace ();} wJC[[_"3 I  
catch(Exception e){e.printStackTrace ();} L FWp}#%  
lV\iYX2#  
1K Vit{  
Utility.log(nFileLength); JduO^Fit  
2Q6;SF"Z  
gUklP(T=u  
return nFileLength; K(;qd Ir  
} ,rMf;/[  
sVHF\{<  
P< OH{l  
//保存下载信息(文件指针位置) ,,Qg"C  
private void write_nPos() s= %3`3Fo  
{ #^}H)>jWy  
try{ oU\]#e^  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Rqe. =+Qs  
output.writeInt(nStartPos.length); nxZz{&  
for(int i=0;i<nStartPos.length;i++) C19N0=  
{ Pe<VPf9+  
// output.writeLong(nPos); 8~Kq "wrbu  
output.writeLong(fileSplitterFetch.nStartPos); e,%|sAs[  
output.writeLong(fileSplitterFetch.nEndPos); DNGyEC  
} O#)1 zD}  
output.close(); AjK5x@\  
} KA2>[x2  
catch(IOException e){e.printStackTrace ();} 8pnD6Lp>  
catch(Exception e){e.printStackTrace ();} 5,Fq:j)MxW  
} Skr (C5T  
r#zcl)rbU  
OxHcoNrz  
//读取保存的下载信息(文件指针位置) ;\K]~  
private void read_nPos() $;^|]/-  
{ $Cz2b/O  
try{ s#^0[ Rt  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Ul8HWk[6Iw  
int nCount = input.readInt(); m.lR]!Y=w  
nStartPos = new long[nCount]; ;W- A2g  
nEndPos = new long[nCount]; 2 7)If E  
for(int i=0;i<nStartPos.length;i++) gmVN(K}SR5  
{ \Oq2{S x\  
nStartPos = input.readLong(); }O\IF}X  
nEndPos = input.readLong(); i:s=  
} M-@RgWvF  
input.close(); JwI99I'  
} 2Qe&FeT  
catch(IOException e){e.printStackTrace ();} o;@~uU  
catch(Exception e){e.printStackTrace ();} L3b0e_8>R  
} <|r|s  
 }u8(7  
Ta\F~$M  
private void processErrorCode(int nErrorCode) J _rrc;F  
{ R+HX'W  
System.err.println("Error Code : " + nErrorCode); }H ~-oYMu  
} KElEGW  
{Z2nc)|7C  
CcQc!`YC  
//停止文件下载 F\eQV<  
public void siteStop() 5aaM;45C  
{ +jhzE%  
bStop = true; Ar<5UnT  
for(int i=0;i<nStartPos.length;i++) L6h<B :l  
fileSplitterFetch.splitterStop(); g+B7~Z5,  
_y4O2n[e  
F0!Z1S0g  
} ei-\t qY_  
} (_ G>dP_  
//负责部分文件的抓取 |OeWM  
**FileSplitterFetch.java [q|W*[B:@  
*/ ,sitOy}ks  
package NetFox; o< @![P  
rd7p$e=i  
ao)';[%9s  
import java.io.*; 35l%iaj]G5  
import java.net.*; BL&AZv/T  
]W;6gmV  
`df!-\#  
public class FileSplitterFetch extends Thread { O50_qu33ju  
~u&gU1}  
7"!`<5o^  
String sURL; //File URL 7<su8*?  
long nStartPos; //File Snippet Start Position SnG(/1C8  
long nEndPos; //File Snippet End Position +&S 7l%-  
int nThreadID; //Thread's ID @ujwN([I  
boolean bDownOver = false; //Downing is over K 4GuOl  
boolean bStop = false; //Stop identical o8X_uKEI  
FileAccessI fileAccessI = null; //File Access interface _0+X32HjJ  
GST#b6S  
/0}Z>i K  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException x=cucZ  
{ i D9 */  
this.sURL = sURL; U~D~C~\2;  
this.nStartPos = nStart; 0B(s+#s  
this.nEndPos = nEnd; <&m50pq  
nThreadID = id; jfG of*  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 {wC*61@1  
} G4'Ia$  
pa46,q&M  
x`g,>>&C  
public void run() $z[S0Cm  
{ Z3JUYEAS  
while(nStartPos < nEndPos && !bStop) JuSS(dJw  
{ v#x`c_  
<8}FsRr;J  
eN<L)a:J_  
try{ + ,Krq 3P  
URL url = new URL(sURL); l/={aF7+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); D^4nT,&8  
httpConnection.setRequestProperty("User-Agent","NetFox"); WO.u{vW]'  
String sProperty = "bytes="+nStartPos+"-"; VgVDTWs7  
httpConnection.setRequestProperty("RANGE",sProperty); Qa,=  
Utility.log(sProperty); TVcA%]y{;  
E !ndXz 59  
7?yS>(VmT  
InputStream input = httpConnection.getInputStream(); 9)7$UQY  
//logResponseHead(httpConnection); AJ%E.+@=r  
YVc cO~!8  
!~|-CF0z=  
byte[] b = new byte[1024]; TR3U<:  
int nRead; a U\|ZCH\]  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) & jqylX  
{ PcC@}3  
nStartPos += fileAccessI.write(b,0,nRead); ?JZ$M  
//if(nThreadID == 1) >eA@s}_8  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); e@vtJaSu  
} ]mMJ6n  
9:p-F+  
Aax;0qGbH  
Utility.log("Thread " + nThreadID + " is over!"); l~"T>=jq3  
bDownOver = true; KAnV%j  
//nPos = fileAccessI.write (b,0,nRead); jh/,G5RM9  
} BP9#}{kE  
catch(Exception e){e.printStackTrace ();} YH\9Je%jx  
} ~yJ2@2I  
} qt}M&=}8Q  
(=^KP7  
&Pb:P?I  
//打印回应的头信息 bg Ux&3  
public void logResponseHead(HttpURLConnection con) $.vm n,:.  
{ 3q73L<f  
for(int i=1;;i++) *|S6iSn9R!  
{ {R ),7U8  
String header=con.getHeaderFieldKey(i); o*)Sg6Yk  
if(header!=null) yn mjIQ  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); -  ]wT  
Utility.log(header+" : "+con.getHeaderField(header));  p?f\/  
else bVzi^R"  
break; }O*`I(  
} @?<[//1  
} T)gulP  
KFbB}oId  
3'.@aMA@  
public void splitterStop() bVUIeX'  
{ *:yG)J 3F  
bStop = true; k^Qf |  
} N#l2wT  
?)1Y|W'Rv  
ol"|?*3q  
} kY$EK]s  
I Id4w~|  
XY| y1L 3[  
/* 44} 5o  
**FileAccess.java f7a4E+}  
*//文件访问(定位,写) &1Ndi<Y^  
package NetFox; _94 W@dW  
import java.io.*; ??"_o3  
YHEn{z7  
U|3!ixk>>w  
public class FileAccessI implements Serializable{ Nhs!_-_I  
dLp1l2h!0  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 tfU*U>j  
RandomAccessFile oSavedFile; o=YOn&@%  
long nPos; M?lh1Yu"  
}R}+8  
U=bx30brh%  
public FileAccessI() throws IOException >S I'Q7k  
{ M,fL(b;2  
this("",0); n.+'9Fj  
} wS}c \!@<,  
LH4A!a]  
:$"{-n  
public FileAccessI(String sName,long nPos) throws IOException W q<t+E[  
{ lndz  
oSavedFile = new RandomAccessFile(sName,"rw"); &q>8D'  
this.nPos = nPos; e\C-a4[C8P  
oSavedFile.seek(nPos); dQ8RrD=$&  
} U:TkO=/>:  
{T-\BTh&Q  
Qx4)'n  
public synchronized int write(byte[] b,int nStart,int nLen) zz*PAYl.  
{ [8 Pt$5]^  
int n = -1; :dt[ #  
try{ _<c"/B  
oSavedFile.write(b,nStart,nLen); ARu_S B  
n = nLen; s-IE}I?;  
} ts~VO`  
catch(IOException e) {\(G^B*\  
{ C*2%Ix18+N  
e.printStackTrace (); fi HE`]0  
} 2?~nA2+vm  
!}!KT(% %  
:C_/K(Rkl  
return n; (C. $w  
} 1(Is 7  
m~&  
<'4Wne.z!  
} D;!sH?J@+  
`Xos]L'w  
dq '2y  
/* c6[m'cy  
**SiteInfoBean.java >B{qPrmI  
*/ ]pvHsiI:  
package NetFox; MZz9R*_VS  
Rmw=~NP5  
]Uwp\2Bc  
public class SiteInfoBean { "IU}>y>J  
lBfthLBa  
\na$Sb+  
private String sSiteURL; //Site's URL uJ2ZHrJ  
private String sFilePath; //Saved File's Path H7'42J@  
private String sFileName; //Saved File's Name QDn_`c  
private int nSplitter; //Count of Splited Downloading File r4mh:T4i  
Sl8+A+  
~ =u8H  
public SiteInfoBean() 4;L|Ua  
{//nSplitter的缺省值为5 Z+ k) N  
//default value of nSplitter is 5 hA ){>B<;  
this("","","",5); o:#jvi84F  
} eF%M2:&c;  
''9]`B,:a0  
0HWSdf|w  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) a Y)vi$;]  
{ %d+Fq=<  
sSiteURL= sURL; ^dpM2$J  
sFilePath = sPath; w<B S  
sFileName = sName; 'aEK{#en  
this.nSplitter = nSpiltter; TIJH} Ri  
$}(Z]z}O;  
:Hq%y/  
} ^P9mJ:  
V<9L-7X 8  
p-"C^=l  
public String getSSiteURL() Qp<*o r@  
{ "9xJ},:-  
return sSiteURL; ?>+uO0*S  
} ={xRNNUj_  
) r.Wge  
m^oG9&";  
public void setSSiteURL(String value) LhAN( [  
{ 1vq2`lWpx  
sSiteURL = value; 9C \}bT  
} vT#R>0@mi  
q%G[tXw  
B5 /8LEWw  
public String getSFilePath() "1gIR^S%9  
{ Y!j/,FU  
return sFilePath; ^!B]V>L-  
} diNSF-wi,,  
gN}$$vS  
p|gVIsg[-e  
public void setSFilePath(String value) C1{Q 4(K%  
{ "S#$:92  
sFilePath = value; [,U l  
} K-]) RIM  
<p<6!tdO  
#om Gj&  
public String getSFileName() M%:\ry4:  
{ yreH/$Ou 8  
return sFileName; 0 @#Jz#?  
} oPs asa  
=EVB?k ,  
aO$0[-A  
public void setSFileName(String value) EJ {vJZO  
{ pImq< Z  
sFileName = value; U`) " ;WN  
} <q'?[aKvR  
 zr ez*  
Srw`vql{(  
public int getNSplitter() "d-vs t5  
{ 5dv|NLl  
return nSplitter; 1;m?:|6K{  
} AM?ZhM  
lFuW8G,-f@  
k @fxs]Y_L  
public void setNSplitter(int nCount) )r"R  
{ Z<|x6%  
nSplitter = nCount; B[mZQ&Gz`a  
} @8\0@[]  
} v3[ZPc;;  
Ew]&~:$Ki  
LntRLB'  
/* +mG"m hF  
**Utility.java T=w0T-[f  
*/ j 7);N  
package NetFox; [|$C2Dhw=  
GF@` ~im  
ug}u>vQ>  
public class Utility { IHW s<U  
[6K[P3UZx  
4NRj>y  
public Utility() E @r &K  
{ Lwtp,.)pR  
I5j|\ /Ht  
R{H8@JLD  
} "uZ^zV`"  
]hlQU%&  
//线程睡眠 xTG5VBv  
public static void sleep(int nSecond) S9*68l  
{ 0 {d)f1  
try{ fvta<  
Thread.sleep(nSecond); ?pQ0* O0  
} zBca$Vp  
catch(Exception e) l^tRy_T:-  
{ k0FAI0~(  
e.printStackTrace (); 0f_`;{  
} Q-iBK*-w  
} - ]/=WAOK  
`}ZtK574  
//日志 ?Z!R  
public static void log(String sMsg) "KCG']DF  
{ 3it*l-i\  
System.err.println(sMsg); kg(}%Ih  
} asQ^33g z  
modem6#x'  
cAx$W6S  
public static void log(int sMsg) ,ZYPffu<*  
{ }]1C=~lC  
System.err.println(sMsg); `)8S Ix  
} |BtFT  
} jc32s}/H  
LGtw4'yr  
)`<&~>qp  
/* `p)U6J  
**TestMethod.java  b utBS  
*/ -oZw+ge}  
package NetFox; T#e|{ZCbq  
N3Q .4? z9  
Z>/ *q2  
public class TestMethod { CZ^ ,bad  
]"O* &  
u!HbS*jqq  
public TestMethod() Ke[`zui@?  
{ ///xx/weblogic60b2_win.exe h0x'QiCc  
try{ Jz0AYiCq  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); _/ 5  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); $WRRCB/A6  
SiteFileFetch fileFetch = new SiteFileFetch(bean); %b h: c5  
fileFetch.start(); <Pf4[q&wM  
} L*rCUv`  
catch(Exception e){e.printStackTrace ();} [Tvdchl OC  
ES(qu]CjI  
6h) &h1Yd  
} K4RQ{fWpm  
00>knCe6  
klc$n07  
public static void main(String[] args) L[5U(`q[  
{ benqm ~{\  
new TestMethod(); b!/-9{  
} %ol1WG9  
} Y~r)WV!G  
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