http断点续传简单实现（java)

/* gc:p@<  
**SiteFileFetch.java h8= MVh(I  
*/ .y_bV=  
package NetFox; m *bKy;'8  
import java.io.*; P}WhE  
import java.net.*; hOLy*%  
}V#9tWW  
CE7pg&dJ)i  
public class SiteFileFetch extends Thread { K6yFpVl  
~v(M6dz~vk  
KY
mWfM3^  
SiteInfoBean siteInfoBean = null; //文件信息Bean Z=Y_;dS9  
long[] nStartPos; //开始位置 a0/n13c?G  
long[] nEndPos; //结束位置 y7IbE  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 I1 R\Ts@  
long nFileLength; //文件长度 yZ~eLWz  
boolean bFirst = true; //是否第一次取文件 [FV=@NI  
boolean bStop = false; //停止标志 s?;<F  
File tmpFile; //文件下载的临时信息 C|~JPcl  
DataOutputStream output; //输出到文件的输出流 ]^6y NtLK  
)av'u.]%c  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） cwWSNm|  
public SiteFileFetch(SiteInfoBean bean) throws IOException >?{iv1  
{ vz#wP  
siteInfoBean = bean; Zj+}T  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 3{I=#>;  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); EBDC'^  
if(tmpFile.exists ()) K0DXOVT\  
{ XAULD]Q  
bFirst = false; 6(q`Oj  
read_nPos(); 77&^$JpM  
} *CPB5s  
else wp]7Lx?F  
{ j zmSFKg*  
nStartPos = new long[bean.getNSplitter()]; lgjo
F_D  
nEndPos = new long[bean.getNSplitter()]; ?4,*RCaI  
} 2c>H(t h=  
&DbGyV8d"|  
[>M*_1F  
$G-N0LV  
} MNf@HG  
fdq^!MWTi  
?;r8SowZ7  
public void run() #-gGs
j;F  
{ nzE,F\k  
//获得文件长度 x(3 I?#kE  
//分割文件 H?=pWB  
//实例FileSplitterFetch 
O2'bNR  
//启动FileSplitterFetch线程 :9x084ESR)  
//等待子线程返回 8W1K3[Jj<  
try{ j_6`s!Yw  
if(bFirst) e1 
{t0f  
{ WDoKbTv  
nFileLength = getFileSize(); )S wG+k,  
if(nFileLength == -1) =ve*g&  
{ =_?pOq  
System.err.println("File Length is not known!"); FUzMc1zy|  
} .n)!ZN  
else if(nFileLength == -2) R!_8jD:$  
{ P
"V{y|2  
System.err.println("File is not access!"); fZw9zqg  
} 35%[DUkb
 
else L)R[)$2(g  
{ Xew1LPI  
for(int i=0;i<nStartPos.length;i++) sx[&4 k[  
{ A'~%
_}  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ax72ehL}  
} :!+}XT7)/  
for(int i=0;i<nEndPos.length-1;i++) D8@nkSP  
{ pT3X/ra  
nEndPos = nStartPos[i+1]; {;Y 89&*R  
} OD?
y  
nEndPos[nEndPos.length-1] = nFileLength; 7|+|\7l#  
} S/nj5Lh  
} m{bZRkt  
I9[1U  
d%#!nq{vd  
//启动子线程 `x{.z=xC  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; *]}CSZ[>  
for(int i=0;i<nStartPos.length;i++) tT@w%Sz57N  
{ [5?4c'Ev  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), E(QZ!'%K+m  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), @)W(q5)}9"  
nStartPos,nEndPos,i); yyY~ *Le  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "EcX
_>  
fileSplitterFetch.start(); E ;BPN  
} :jt;EzCLg%  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 93W  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ;ZQ-uz  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", DU5:+" u3  
nEndPos = " + nFileLength); ]6$,IKE7  
// fileSplitterFetch[nPos.length-1].start(); ia%z+:G  
HE#,(;1i  
GBH_r0  
//等待子线程结束 YG0PxZmi  
//int count = 0; fm(mO%  
//是否结束while循环
./
'~];&  
boolean breakWhile = false; di6B!YQP  
[>W"R1/  
{]wIM^$6+  
while(!bStop) \#4m@  
{ ;{<aA 5  
write_nPos(); f4]N0  
Utility.sleep(500); /y}"M  
breakWhile = true; #O2wyG)oU  
wP[xmO-%  
3lo;^KX !  
for(int i=0;i<nStartPos.length;i++) aWyUu/g<A`  
{ 96(R'^kNX  
if(!fileSplitterFetch.bDownOver) j|:dYt`WM  
{ s|Z:}W?{  
breakWhile = false; ?Bo?JMV  
break; >Bc>IO  
} !Y (apVQ  
} PJzc=XPU  
if(breakWhile) \|CPR6I  
break; f}^I=pS&  
I*EJHBsQ5  
 %BUEX  
//count++; Pm4e8b  
//if(count>4) k`Nyi)AGe  
// siteStop(); *HR+a#o  
} )2xE z  
]eE 1n2  
4SgF,ac3r  
System.err.println("文件下载结束！"); /Rj#sxtdw  
} v
?L  
catch(Exception e){e.printStackTrace ();} m6^ 5S  
} Q]@c&*_|  
i[\w%(83Fi  
7p
aUpQit  
//获得文件长度 +b^]Pz5  
public long getFileSize() Ly;I,)w  
{ ?v:ZU~i  
int nFileLength = -1; @5xu>gKn  
try{ GF8 -_X  
URL url = new URL(siteInfoBean.getSSiteURL()); yGxv?%%2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); F@Q^?WV  
httpConnection.setRequestProperty("User-Agent","NetFox"); v5_7r%Hiw  
}Dn^d}?s||  
#uSK#>H_!  
int responseCode=httpConnection.getResponseCode(); 8'A72*dhX  
if(responseCode>=400) ldGojnS  
{ #EDEYEW7  
processErrorCode(responseCode); %%%S"$t  
return -2; //-2 represent access is error 5Fmav5  
} qz!Ph5(  
3GF2eS$$P  
`9Yn0B.  
String sHeader; P ZxFZvE  
qi(*ty  
"X04mQn15  
for(int i=1;;i++) T dk ,&8  
{ 5+- I5HX|~  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); [ %}u=}@  
//Utility.log(in.readLine()); [84F09HU  
sHeader=httpConnection.getHeaderFieldKey(i); w\Mnu}<e$  
if(sHeader!=null) */z??fI27  
{ )55\4<ty  
if(sHeader.equals("Content-Length")) e4`uVq5  
{ >xqM5#m`E$  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); !lTda<;]  
break; ?<U
{{C  
} ";x+1R.d  
} t9^A(Vh"-  
else %g3,qI  
break; h5"Ov,K3[  
} Wh( |+rJ?Z  
} t\4[``t  
catch(IOException e){e.printStackTrace ();} LOvHkk@+  
catch(Exception e){e.printStackTrace ();} [8XLK4e  
[q*%U4qGO  
]]0,|My7  
Utility.log(nFileLength); X[](Kj^`<  
t*G/]  
-c%dvck^,  
return nFileLength; C3'rtY.  
} (;_FIUz0  

aG+j9Q_  
9H0Hu]zM  
//保存下载信息（文件指针位置） HYK!}&  
private void write_nPos() ;eL9{eF  
{ UPiW73Nu  
try{ =1p8i  
output = new DataOutputStream(new FileOutputStream(tmpFile)); \HZ9S=  
output.writeInt(nStartPos.length); 0aI;\D*Ts  
for(int i=0;i<nStartPos.length;i++) +7V{ABfGl  
{ crcA\lJf  
// output.writeLong(nPos); ^|!I+  
output.writeLong(fileSplitterFetch.nStartPos); Bux [6O%  
output.writeLong(fileSplitterFetch.nEndPos); ccFn.($p?,  
} w Y  
output.close(); SOZPZUUEJ  
} S8d8%R~1=h  
catch(IOException e){e.printStackTrace ();} !7bw5H  
catch(Exception e){e.printStackTrace ();} iRV~Il#~!  
} 6K`c/)  
mmXm\]r>4  
R6-n IY,  
//读取保存的下载信息（文件指针位置） ^Xb7[+I6  
private void read_nPos() 4Y> Yi*n  
{ I<td1Y1q  
try{ wXMDh$  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));  p?D2)(  
int nCount = input.readInt(); ?>c=}I#Ui-  
nStartPos = new long[nCount]; *^\HU=&  
nEndPos = new long[nCount]; TjMe?p  
for(int i=0;i<nStartPos.length;i++) $?G"GQ!.  
{ fWc|gq  
nStartPos = input.readLong(); "@A![iP  
nEndPos = input.readLong();
kum#^^4G|  
} cJo\#cr  
input.close(); ^9OUzTF  
} 7;@ST`cC  
catch(IOException e){e.printStackTrace ();} T<3BT  
catch(Exception e){e.printStackTrace ();} NcOPL\  
} >(w2GD?  
1OLqL
 
).` S/F  
private void processErrorCode(int nErrorCode) zya5Jb:Sg  
{ A1)wo^,  
System.err.println("Error Code : " + nErrorCode); PWRy7d  
} >d"3<S ;b  
G+xt5n.%  
<~TP#uAz  
//停止文件下载 'i;|c  
public void siteStop() XC 7?VE  
{
l0&EZN0V2  
bStop = true; '7wd$rl  
for(int i=0;i<nStartPos.length;i++)
T_b^ Tc`  
fileSplitterFetch.splitterStop(); a?|vQ*W  
G22NQ~w8  
fO'Wj`&a  
} 2%*MW"Q  
} 6S6f\gAM  
//负责部分文件的抓取 Q9}dHIe1E  
**FileSplitterFetch.java Ol"3a|  
*/ Uv YF[@  
package NetFox; W$U0[^1  
1O].v&{  
/bj <Ft\  
import java.io.*; 43?^7_l-  
import java.net.*; h)~=Dm  
Pe C7  
EbeI{-'aF  
public class FileSplitterFetch extends Thread { 'r(1N
j  
`V)Z)uN{0  
zR!o{8  
String sURL; //File URL ^c~)/F/cF  
long nStartPos; //File Snippet Start Position m}>F<;hQ  
long nEndPos; //File Snippet End Position vR0];{  
int nThreadID; //Thread's ID H|cNH=  
boolean bDownOver = false; //Downing is over Dnc(l(  
boolean bStop = false; //Stop identical tm7u^9]  
FileAccessI fileAccessI = null; //File Access interface Ii7QJ:^  
eh,~^x5  
VG/3xR&y  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException n wI!O  
{ -{^}"N  
this.sURL = sURL; Ax!+P\\2~  
this.nStartPos = nStart; Y#!h9F  
this.nEndPos = nEnd; cA6lge<{~  
nThreadID = id; %OgS^_tu  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 eIl]oC7*  
} As+t#
#gN  
qfcYE=  
n$xQ[4eH)  
public void run() .z13 =yv  
{ eY{+~|KZ  
while(nStartPos < nEndPos && !bStop) e#/E~r&  
{ jA#/Z  
(C]o,7cYS  
(E]!Z vE  
try{ EyY.KxCB  
URL url = new URL(sURL); ie-vqLc  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); yV)la@c  
httpConnection.setRequestProperty("User-Agent","NetFox"); sB69R:U;  
String sProperty = "bytes="+nStartPos+"-"; !mXxAo  
httpConnection.setRequestProperty("RANGE",sProperty); ?eV4SH  
Utility.log(sProperty); KR7@[
  
?f/n0U4w  
3> /K0N|$  
InputStream input = httpConnection.getInputStream(); ktDC/8
  
//logResponseHead(httpConnection); /c):}PJ^#7  
Z,iHy3`  
jY_T/233d  
byte[] b = new byte[1024]; wcDRH)AW.  
int nRead; u^029sH6j  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) q&:=<+2"  
{ y\{%\$  
nStartPos += fileAccessI.write(b,0,nRead); !'L
W_@  
//if(nThreadID == 1) Ecs,$\  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %4HRW;IU  
} 3]?#he  
h<~7"ONhV  
|>z3E z  
Utility.log("Thread " + nThreadID + " is over!"); (rg;IXAq%  
bDownOver = true; 7 I>G{  
//nPos = fileAccessI.write (b,0,nRead); A=Ss6-Je  
} F
v<`AU  
catch(Exception e){e.printStackTrace ();} ~)(\6^&=|  
} ``E/m<r:$  
} <id}<H  
2k<;R':  
^wS5>lf7p  
//打印回应的头信息 |^@dFOz  
public void logResponseHead(HttpURLConnection con) d|4}obCt  
{ `=7j$#6U  
for(int i=1;;i++)
0T46sm r  
{ [LRLJ_~g5  
String header=con.getHeaderFieldKey(i); c_elShK8#  
if(header!=null)
N<DGw?Rl  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); t]Xw{)T  
Utility.log(header+" : "+con.getHeaderField(header)); t'ZWc\  
else VsA'de!V4[  
break; Uo2GK3nT  
} |<O9Sb_  
} <jed!x  
MMj9{ou  
D.mHIsX6\  
public void splitterStop() 3N_"rNKD  
{ <\;#jF%V  
bStop = true; S%`0'lzzj  
} `:axzCrCfR  
p ]d]QMu  
MR}Agu#LG  
} t#2(j1  
Q
~T$N  
k?'B*L_Mzv  
/* :^(>YAyHj^  
**FileAccess.java -{ZWo:,r~q  
*//文件访问(定位，写) w}=5ElB  
package NetFox; A,4fEmWM  
import java.io.*; 50={%R  
oJfr +3I  
7nuU^wc  
public class FileAccessI implements Serializable{ YIjTL!bA"  
&%-73nYw  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ? YG)I;(  
RandomAccessFile oSavedFile; RU\/j%^  
long nPos; 4]E3cAJ  
%Z1N;g0  
ow]053:i  
public FileAccessI() throws IOException `*shF9.\C  
{ !@v7Zu43,  
this("",0); X*\J_  
} K1T4cUo  
1@-Ns  
ctGL-kp  
public FileAccessI(String sName,long nPos) throws IOException 9th,VnD0  
{ q*9!,!e  
oSavedFile = new RandomAccessFile(sName,"rw"); is-7 j7;  
this.nPos = nPos; tdu$pC6  
oSavedFile.seek(nPos); ){b@}13cF  
} OtNd,U.dE  
P ! _rEV  
d}4Y(   
public synchronized int write(byte[] b,int nStart,int nLen) >j QWn@  
{ v'3J.?N  
int n = -1; ^RI?ybDd  
try{ $\U4hHOo  
oSavedFile.write(b,nStart,nLen); $A-J,_:T<  
n = nLen; ^=-y%kp"  
} 5yz(>EVH  
catch(IOException e) Qr{E[6  
{ #NryLE!/  
e.printStackTrace (); U3dwI:cG  
} *vwbgJG! *  
q1KZ5G)6GJ  
s|y "WDyx5  
return n; BNs@n"k  
} jIyB  
TJR:vr  
@W"KVPd  
}  cHk)i  
@/ohg0  
LF& z  
/* 1 P!Yxeh  
**SiteInfoBean.java y#z  
*/ !'9Feoez  
package NetFox; S;286[oq@  
HK0!P*  
4?q
<e*W  
public class SiteInfoBean { [rV>57`YD  
!`Hd-&}bYz  
2KYw}j|5  
private String sSiteURL; //Site's URL ud'-;W  
private String sFilePath; //Saved File's Path TI,&!E?;  
private String sFileName; //Saved File's Name M:[ %[+6  
private int nSplitter; //Count of Splited Downloading File /n{omx  
kr9*,E9cv  
GkTiDm?  
public SiteInfoBean() NRIG1v>  
{//nSplitter的缺省值为5 9\mLW"  
//default value of nSplitter is 5 l:,'j@%  
this("","","",5); |8l<$J  
} <(fRn`)PT  
|es?;s'  
eoG$.M"  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ZJzt~ H  
{ qGB{7-ru  
sSiteURL= sURL; &;[Io  
sFilePath = sPath; xRzFlay8  
sFileName = sName; Q/(K$6]j  
this.nSplitter = nSpiltter; `tA" }1;ka  
1VG4S){}\9  
i%#+\F.&  
} q$Zh@  
}J:U=HJ  
7e|s wJ>4  
public String getSSiteURL() t!W(_8j  
{ 4~Vx3gEV:  
return sSiteURL; ^6MU 0Q2  
} /_AnP  
lhAX;s&9  
8pIP  
public void setSSiteURL(String value) S >X:ZYYC  
{ v1+3}5b'uF  
sSiteURL = value; 1{ ~#H<K  
} hKLCJ#
T  
(:TjoXXiY  
tl,.fjZn  
public String getSFilePath() Wz49
i9e+d  
{ )_syZ1j  
return sFilePath; v&Yi  
} eTI%^d|  
\E72L5nJW  
*'.|9W  
public void setSFilePath(String value) MDhRR*CBh  
{ u~7hWiY<2  
sFilePath = value; _~IR6dKE  
} A&.WH?p  
Fq~yL!#!  
8_BV:o9kL  
public String getSFileName()  Ch&a/S}  
{ [YF>:ydk  
return sFileName;
+Mo9kC  
} [842&5Pd?  
c}Ft^Il  
m4hX 'F  
public void setSFileName(String value) A!s`[2 Z  
{ #^lL5=  
sFileName = value; !;&p"E|b#  
} @Owb?(6?  
'y;EhOwj,  
=x%dNf$e{W  
public int getNSplitter() j"
ThEx0  
{ PWaw]*dFmy  
return nSplitter; <Swt);  
} }iXDa?6%  
3
KRd  
~("5yG  
public void setNSplitter(int nCount) KyVQh8  
{ @TLS<~  
nSplitter = nCount; a]JYDq`,3  
} W]"zctE  
} J`peX0Stl  
A>vBQN  
^W`<gR  
/* zvYq@Mhr  
**Utility.java rXmn7;B}g  
*/ PlU*X8  
package NetFox; +6sy-<ZL:  
*rM^;4Zt  
p#ol*m5wE  
public class Utility { ?Nup1!D  
&vo--V1|  
9A/\h3HrJ  
public Utility() oz,np@f)J  
{ l7XUXbYp&=  
?x$
"+,  
3B1XZm  
} 8;d:-C
p  
X\]L=>]C  
//线程睡眠 WQ~;;.v#  
public static void sleep(int nSecond) %7"q"A r[  
{ nG,A@/N  
try{ :Ux?,  
Thread.sleep(nSecond); "W=AB&  
} q-  
catch(Exception e) "9m2/D`=  
{ ebm])~ZL  
e.printStackTrace (); H35S#+KX  
} LIS)(
X<]?  
} I!^;8Pg  
txJr;  
//日志 8qY79)vD4E  
public static void log(String sMsg) DwaBdN[!7  
{ OP~Hdo
cB  
System.err.println(sMsg); bt"W(m&f  
} $:cE ^8K  
^"VJd[Hn  
aDq5C-MzG  
public static void log(int sMsg) &qMPq->  
{ bP8Sj16q  
System.err.println(sMsg); 52SaKA[  
} 1/RsptN"v  
} @>d*H75  
'= _/1F*q  
QP@%(]fG  
/* rx $mk  
**TestMethod.java 3 *d"B tg  
*/ `{eyvW[Ks  
package NetFox; 2>|dF~"  
]=.\-K  

g$7{-OpB  
public class TestMethod { ;,$NAejgd  
$$D}I*^Dt  
@PN#p"KaT  
public TestMethod() IC#>X5  
{ ///xx/weblogic60b2_win.exe d_AK`wR  
try{ FqkDKTS\&  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); wA
X1l*`  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); l]@&D#3ZM  
SiteFileFetch fileFetch = new SiteFileFetch(bean); p`mS[bxv!  
fileFetch.start(); r>dwDBE  
} IYqBQnX}oM  
catch(Exception e){e.printStackTrace ();} Tu@8}C  
* 1T&  
mYxuA0/k  
} oE<`VY|  
tna .52*/  
9!f/aI  
public static void main(String[] args) ~1cnE:x;V  
{ `D>S;[~S7  
new TestMethod(); 1)9sf0LyU  
} y]2qd35u_A  
} Q<z_/j9  
点击下载更多相关资料