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http断点续传简单实现(java)

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/* IKrojK8-?  
**SiteFileFetch.java %jo,Gv  
*/ ~v@.YJoZ4Z  
package NetFox; wzj :PS  
import java.io.*; :u,Ji9 u  
import java.net.*; h1~/zM/`  
7](aPm8  
:IX_|8e ^  
public class SiteFileFetch extends Thread { ^\oMsU5(  
r0Zj'F_e  
C14"lB.  
SiteInfoBean siteInfoBean = null; //文件信息Bean 3o2x&v  
long[] nStartPos; //开始位置 kmg/hNtN  
long[] nEndPos; //结束位置 \IhHbcF`d  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ;uho.)%N`F  
long nFileLength; //文件长度 wii.0~p  
boolean bFirst = true; //是否第一次取文件 YJ !jdE}  
boolean bStop = false; //停止标志 Yc:>Yzj(z  
File tmpFile; //文件下载的临时信息 Z5V_?bm$  
DataOutputStream output; //输出到文件的输出流 a"{b}UP  
OI,F,4e  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) j;<s!A#  
public SiteFileFetch(SiteInfoBean bean) throws IOException ]pWn%aGv*Y  
{ vX?C9Fr2  
siteInfoBean = bean; d" =)=hm!  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); )GfL?'Z  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); sB*!Nf^y  
if(tmpFile.exists ()) v'Pbx  
{ Nh01NY;  
bFirst = false; rMoz+{1A  
read_nPos(); 58t_j54  
} ,`8:@<e  
else E#E&z(G2  
{ ^U6VJ(58P  
nStartPos = new long[bean.getNSplitter()]; gg.lajX  
nEndPos = new long[bean.getNSplitter()]; U]&/F{3 im  
} L0R$T=~%)  
y5j ;Daq  
Gs>4/  
!<<wI'8  
} Jsa;pG=3&  
O YfRtfE  
QuBA'4ht  
public void run() b"2_EnE}1  
{ Jim5Ul  
//获得文件长度 \('WS[$2  
//分割文件 ?^ R"a##  
//实例FileSplitterFetch /&E]qc*-p  
//启动FileSplitterFetch线程 Uuktq)NU  
//等待子线程返回 I%jlM0ZUI"  
try{ ub2B!6f a  
if(bFirst) JkEITuTth  
{ sD9OV6^{?K  
nFileLength = getFileSize(); g^{a;=  
if(nFileLength == -1) )m I i.  
{ l\TL=8u2c  
System.err.println("File Length is not known!"); 6n\){dkZ~  
} 5~OKKSUmT  
else if(nFileLength == -2) Jv8VM\ *  
{ VHLt, ?G  
System.err.println("File is not access!"); yuhY )T  
} xJin %:O  
else <r)5jf  
{ Zul@aS !  
for(int i=0;i<nStartPos.length;i++) fjMmlp  
{ xP 7mP+D  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); It]GlxMX  
} JH#p;7;  
for(int i=0;i<nEndPos.length-1;i++) ^}UFtL i  
{ I0N~>SpZ5  
nEndPos = nStartPos[i+1]; iGBHlw;A  
} CropHB/t  
nEndPos[nEndPos.length-1] = nFileLength; ^[6#Kw&E  
} (ylZ[M&B:  
} iM$iZ;Tp  
+fHqGZ]  
4YXp,U  
//启动子线程 mln%Rd6u/  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 4m%Yck{R  
for(int i=0;i<nStartPos.length;i++) s6DPb_,  
{ 9fYof  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +1K= ]#a  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), !FQS9SoO9  
nStartPos,nEndPos,i); O' Mma5  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @P">4xVX{  
fileSplitterFetch.start(); M 9 N'Hk=  
} EL6<%~,V"I  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _`Dz%(c  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); \SBAk h  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", vvLzUxV  
nEndPos = " + nFileLength);  `ghNS  
// fileSplitterFetch[nPos.length-1].start(); !>WW(n07Ma  
H{uR+&<  
,nWZJ&B  
//等待子线程结束 of'H]IZ  
//int count = 0; U%KgLg#  
//是否结束while循环 [4-u{Tu  
boolean breakWhile = false; Jmu oYlf|  
g@m__   
@2eH;?uO  
while(!bStop) +D?Re%HI  
{ 6?-,@e  
write_nPos(); `a8&7 J(  
Utility.sleep(500); 9 1ec^g  
breakWhile = true; y(j vl|z[  
i x_a  
jF{)2|5  
for(int i=0;i<nStartPos.length;i++) _@Y17L.  
{ LbnF8tj}h  
if(!fileSplitterFetch.bDownOver) fK{Z{)D  
{ ^AT#A<{1(  
breakWhile = false; nIl<2H]F`  
break; m@yx6[E#  
} {sUc2vR  
} Bm;@}Ly=G  
if(breakWhile) ):V)Hrq?x  
break; P9]95.j  
XeXK~  
!/Wv\qm  
//count++; CYNpbv  
//if(count>4) ?xt${?KP  
// siteStop(); _mDvRFq  
} R/&C}6G n  
}S9uh-j6l  
h=_h,?_  
System.err.println("文件下载结束!"); _2eL3xXha.  
} !< ^`Sx/+  
catch(Exception e){e.printStackTrace ();} PU%WpI.w  
} CM+wkU ?,  
BgwZZ<B  
pXe]hnY  
//获得文件长度 *4 Kc "M  
public long getFileSize() QezDm^<  
{ !e0/1 j=  
int nFileLength = -1; L/:u  
try{ 7P D D  
URL url = new URL(siteInfoBean.getSSiteURL()); ^j'vM\^`ml  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ntF#x.1Pm  
httpConnection.setRequestProperty("User-Agent","NetFox"); 0.!Q 4bhD  
5O"wPsl  
q?oJ=]m"  
int responseCode=httpConnection.getResponseCode(); 7 P]Sc   
if(responseCode>=400) +e) RT<  
{ dYhLk2  
processErrorCode(responseCode); mWU*}-M  
return -2; //-2 represent access is error 0Y\7A  
} =Y5*J#  
.w)T2(  
1;9  %L@  
String sHeader; CYC6:g|)  
Ox f,2r  
h_h6@/1l  
for(int i=1;;i++) 0"M0tA#  
{ e7gWz~  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); b"z9Dpv  
//Utility.log(in.readLine()); %suXp,j  
sHeader=httpConnection.getHeaderFieldKey(i); .g6(07TyV  
if(sHeader!=null) Ps{}SZn  
{ N+NS\Y5  
if(sHeader.equals("Content-Length")) %i`YJ  
{ kx3]A"]>'  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); f%Bmx{Ttq  
break; Hy1f,D  
} ACxjY2  
} \6v*c;ZF  
else PRF^<%mkI  
break; ~ TALpd  
} "G!V?~;  
} :#p!&Fi  
catch(IOException e){e.printStackTrace ();} tL@m5M%:N2  
catch(Exception e){e.printStackTrace ();} N @sVA%L.  
-%)8=  
$kk!NAW  
Utility.log(nFileLength); W>]=0u4  
`'<&<P  
(6\ H~  
return nFileLength; |/AY!Y3  
} }[I|oV5*+&  
M kadl<  
& pS5_x  
//保存下载信息(文件指针位置) {!vz 6QDS  
private void write_nPos() w`OHNwXh#I  
{ oGi{d5  
try{ cX/ ["AM  
output = new DataOutputStream(new FileOutputStream(tmpFile)); kP}91kja  
output.writeInt(nStartPos.length); [8.w2\<?  
for(int i=0;i<nStartPos.length;i++) &\o !-EIK8  
{ awa$o  
// output.writeLong(nPos); >P\/\xL=  
output.writeLong(fileSplitterFetch.nStartPos); ZN?UkFnE  
output.writeLong(fileSplitterFetch.nEndPos); ;}gS8I|  
} tvG/oe .1'  
output.close(); FqK2[]8  
} ZX!u\O|w  
catch(IOException e){e.printStackTrace ();} />9?/&N6"  
catch(Exception e){e.printStackTrace ();} (Dx]!FFz  
} y|@=j~}Zq  
k"2xyzt*  
*QpKeI  
//读取保存的下载信息(文件指针位置) I|?Z.!I|  
private void read_nPos() 675x/0}GO  
{ Fu cLcq2Z  
try{ hkL[hD  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 8TnByKZz  
int nCount = input.readInt(); ~V4&l3o  
nStartPos = new long[nCount]; y(RK|r  
nEndPos = new long[nCount]; Ka\%kB>*`  
for(int i=0;i<nStartPos.length;i++) SggS8$a`  
{ fX2PteA0qX  
nStartPos = input.readLong(); S?_ ;$Cn  
nEndPos = input.readLong(); 3QrYH @7zx  
} pJE317 p'  
input.close(); U ]6 Hml;l  
} yegTKoY  
catch(IOException e){e.printStackTrace ();} B[0XzV]Z  
catch(Exception e){e.printStackTrace ();} %%w]-`^h,  
} 3q.O^`y FU  
xFY;aK  
v+|N7  
private void processErrorCode(int nErrorCode) nUvxO `2  
{ b%<i&YY#  
System.err.println("Error Code : " + nErrorCode); ( U |[C*  
} UC34AKm  
Py8<db%  
|0mVK`  
//停止文件下载 3J{`]v5`  
public void siteStop() BZE~k?*  
{ /IC7q?avQN  
bStop = true; l&4TfzkY  
for(int i=0;i<nStartPos.length;i++) rE bC_<  
fileSplitterFetch.splitterStop(); @M-+-6+  
2|)3Ly9  
~a5p_xP  
} [EJ[Gg0m  
} Kj_hCSvf3e  
//负责部分文件的抓取 _azg 0.)  
**FileSplitterFetch.java l*]*.?m/5  
*/ e/m ,PE  
package NetFox; DT@6Q.  
\@4_l?M  
5"5D(  
import java.io.*; 8uX1('+T*  
import java.net.*; B;?"R  
 (Ia}]q  
iG*/m><-  
public class FileSplitterFetch extends Thread { r c7"sIkV  
qlSc[nEk  
DH_Mll>  
String sURL; //File URL @l^=&53T  
long nStartPos; //File Snippet Start Position u5 EHzoq  
long nEndPos; //File Snippet End Position 2Ek6YNx  
int nThreadID; //Thread's ID 2hRaYX,g  
boolean bDownOver = false; //Downing is over EIwTx:{F  
boolean bStop = false; //Stop identical V>j6Juh  
FileAccessI fileAccessI = null; //File Access interface lV-7bZ  
)dJaF#6j  
RvYH(!pQ  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException  # a 'h,  
{ 9psX"*s  
this.sURL = sURL; '@u/] ra:  
this.nStartPos = nStart; 9(Vq@.;Z`j  
this.nEndPos = nEnd; /}Y>_8 7  
nThreadID = id; [BHf>  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Mrp'wF D  
} 8Z!+1b  
k|,pj^  
2@o_7w98  
public void run() FG-w7a2mn  
{ Nf>1`eP  
while(nStartPos < nEndPos && !bStop) 02} &h  
{ +n]U3b  
]S[zD|U%  
#{GUu ',?&  
try{ n< [np;\  
URL url = new URL(sURL); %,GY&hTw  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); SU9#Y|I  
httpConnection.setRequestProperty("User-Agent","NetFox"); Pn5@7~  
String sProperty = "bytes="+nStartPos+"-"; lC +p2OG^[  
httpConnection.setRequestProperty("RANGE",sProperty); tgDmHxB]0  
Utility.log(sProperty); 9/RbfV[)  
SM5i3EcFYP  
UcDJ%vI  
InputStream input = httpConnection.getInputStream(); [K[tL|EK  
//logResponseHead(httpConnection); _`L,}=um'  
4em7PmT  
vfJ}t#%UH  
byte[] b = new byte[1024];  pFGK-J  
int nRead; k'wF+>  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) LQ?J r>4  
{ 3KfZI&g  
nStartPos += fileAccessI.write(b,0,nRead); _$By c(.c  
//if(nThreadID == 1) Wy,DA^\ef  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); rB}UFS)  
} V{fYMgv  
BUv;BzyV  
3Qe:d_  
Utility.log("Thread " + nThreadID + " is over!"); >/EmC3?b!  
bDownOver = true; _h7+.U=  
//nPos = fileAccessI.write (b,0,nRead); dZRz'd  
} f 5_n2  
catch(Exception e){e.printStackTrace ();} L._I"g5 H9  
} Nm#VA.~  
} $g _h9L  
A L}c-#GG  
Xd66"k\b+  
//打印回应的头信息 e%j+,)Ry  
public void logResponseHead(HttpURLConnection con) .5 dZaI)  
{ H<NYm#a"  
for(int i=1;;i++) 3}h&/KN{  
{ ;^rZ"2U l  
String header=con.getHeaderFieldKey(i); BV!Kiw  
if(header!=null) sL\|y38'  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); }VFSF/\^  
Utility.log(header+" : "+con.getHeaderField(header)); ^ g4)aaBZ  
else Y^6=_^  
break; DG:=E/@  
} VS}Vl  
} gf3/kll9  
u{3KV6MS  
:ZzG5[o3  
public void splitterStop() ar^`r!ABEh  
{ 9Q.j <  
bStop = true; lhjPS!A~  
} I 9u=RI s  
#|e <l1F  
}>OE"#si  
} J`x9 XWYw  
R -h7c!ko  
aSK$#Xeu  
/* my} P\r.  
**FileAccess.java -[7.VP   
*//文件访问(定位,写) "Km`B1f`  
package NetFox; 1u` Z?S(  
import java.io.*; 2xnOWW   
UG!&n@R  
9rid98~d  
public class FileAccessI implements Serializable{ qMUqd}=P  
|/(5GX,X  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 h]=chz  
RandomAccessFile oSavedFile; P#0 _  
long nPos; {otvJ |'N  
MUo?ajbqOd  
}.hBmhnZmI  
public FileAccessI() throws IOException O@$hG8:  
{ K:Ap|F  
this("",0); 2cDC6rul  
} _9-Ajv  
"d#s|_n,d)  
'0=U+Egp  
public FileAccessI(String sName,long nPos) throws IOException cK258mY  
{ $K iMu  
oSavedFile = new RandomAccessFile(sName,"rw"); ?y '.sQ  
this.nPos = nPos; 6JL 7ut  
oSavedFile.seek(nPos); dqe_&C@*O  
} =?2y <B  
pQ/:*cd+M  
L"Gi~:z  
public synchronized int write(byte[] b,int nStart,int nLen) F;ZLoG*U  
{ fg9sZ%67]\  
int n = -1; V4"AFArI  
try{ lAGxE-B^a"  
oSavedFile.write(b,nStart,nLen); :vr,@1c  
n = nLen; #[si.rv->  
} \?g%>D:O;  
catch(IOException e) u1"e+4f  
{ L=p.@VSZ  
e.printStackTrace (); l&rDa=m.J  
} nqH^%/7)A@  
u7;A`  
?1{`~)"  
return n; I*ej_cFQ^  
} %,^7J;  
|B n=$T]  
^4[\-L8Lpq  
} }}2 kA  
aw 7f$Fqk  
j@ "`!uPz  
/* ^DH*@M  
**SiteInfoBean.java x B?:G  
*/ B -KOf  
package NetFox; ky#6M? \  
K c<z;  
w0IB8GdF  
public class SiteInfoBean { `%Ghtm*  
^Pf&C0xXv  
gv,T<A?Z2  
private String sSiteURL; //Site's URL E,|n'  
private String sFilePath; //Saved File's Path \XN5))  
private String sFileName; //Saved File's Name 5u;Rr 1D  
private int nSplitter; //Count of Splited Downloading File 7P/?wv9+n*  
x|@1 wQ" 6  
I&TTr7  
public SiteInfoBean() Gur8.A;Y  
{//nSplitter的缺省值为5 z(g%ue\  
//default value of nSplitter is 5 :DtZ8$I`]C  
this("","","",5); / h}PEu3y  
} Mx O W)$f  
.'t (-eT,  
FOOQ'o[}  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) IL~]m?'V(  
{ )XLj[6j0  
sSiteURL= sURL; 2d-TU_JqX  
sFilePath = sPath; 9W{,=.%MX$  
sFileName = sName; 6 gj]y^}  
this.nSplitter = nSpiltter; {0is wq'J  
j0g5<M  
:3f-9aRC!  
} F(Lb8\to\M  
R%>jJ[4\[  
_1I K$gb[  
public String getSSiteURL() h&)fu{   
{ :PgF  
return sSiteURL; z-n>9  
} uQH%.A  
=WIE>*3[  
/8f>':zUb  
public void setSSiteURL(String value) }5Yj  
{ ,"~WkLI~\t  
sSiteURL = value; 'S =sj}X  
} `_|aeoK_  
:1:3Svb<Y  
%dEB/[  
public String getSFilePath() hT?6sWa  
{ 10mK}HT>4B  
return sFilePath; ov8 ByJc  
} dVa!.q_3  
F"!agc2!  
+wipfL~&S  
public void setSFilePath(String value) FC6xFg^  
{ e|yX QTlvL  
sFilePath = value; }*NF&PD5RU  
} BWWq4mdb{  
fV 3r|Bp  
`)T&~2n  
public String getSFileName() 1@xP(XS  
{ )B6# A0  
return sFileName; 2gt+l?O<PS  
} hi!`9k  
c7\VTYT  
+=7:4LFOL  
public void setSFileName(String value) cph~4wCS[U  
{ tR1FO%nC  
sFileName = value; WSRy%#  
} C}q>YRubZ  
ld.7`)  
r4u z} jl{  
public int getNSplitter() r$ =qQ7^#  
{ b^x07lO  
return nSplitter; # Q}_e7t  
} Z0-ytODI I  
Ql8bt77eI-  
L;S}s, 2x  
public void setNSplitter(int nCount) ?Nf 5w  
{ b HE7yv [  
nSplitter = nCount; Z, T#,  
} KVN"XqE4  
} Q8q@Y R#  
4/'N|c.  
sHdp  
/* EiWd+v,QJQ  
**Utility.java Lu=O+{*8  
*/ z\TLsx  
package NetFox; &$=!dA  
_7"5wB?|+  
'H|~u&?  
public class Utility { NLyXBV[hV  
e4\dpvL  
ZSB?Y 1wG  
public Utility() Y.sz|u 1  
{ w2dcH4&  
j+kC-U;  
Q9c)k{QZ  
} bMm3F%FFq&  
.TpsJXF  
//线程睡眠 %d2!\x%bG  
public static void sleep(int nSecond) })Yv9],6  
{ QA?oJ_}y  
try{ *jITOR!uF`  
Thread.sleep(nSecond); D#Kuo$  
} n?xTkkr0  
catch(Exception e) 8 lT{1ro  
{ tg\|?  
e.printStackTrace (); )8,|-o=  
} )OP){/   
} Kz?#C  
@Jn!0Y1_3  
//日志 =qu(~]2(  
public static void log(String sMsg) $B (kZ  
{ {tiKH=&J  
System.err.println(sMsg); -_N)E ))G  
} k N7Bd}  
WsGths+[  
|~0UM$OB^3  
public static void log(int sMsg) 9902+pW  
{ eiVC"0-c}  
System.err.println(sMsg); <vV_%uo M  
} Ib=x~za@n  
} ]?+{aS-]?k  
9+=gke  
p@ NaD=9  
/* ?)D^~/ A  
**TestMethod.java L gk   
*/ 4rg2y]  
package NetFox; yx38g ca  
SmwQET<H  
p>w]rE:}  
public class TestMethod { V)ig)(CT  
GL$De,V  
saf&dd  
public TestMethod() q*7<)VwI  
{ ///xx/weblogic60b2_win.exe ^x>Qf(b  
try{ )kXhtjOl|  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); tBbOY}.VD  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); rwLAW"0Qz  
SiteFileFetch fileFetch = new SiteFileFetch(bean); \y`+B*\i  
fileFetch.start(); :Qt  
} ElhRF{R  
catch(Exception e){e.printStackTrace ();} {76c%<`WaP  
dO> VwP  
GzXUU@p  
} #G" xNl  
~}EMk3  
GPz(j'jU  
public static void main(String[] args) P262Q&.}d  
{ tGvG  
new TestMethod(); _|[UI.a  
} 58\&/lYW  
} &s Pq<lo  
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