one ： When an exception may be encountered in the code, you need to use the try{ }catch{Exception e} To handle , Otherwise, the program will crash
try{
int i = 1/0;
}catch(Exception e){
........
}
two ： Don't for Nested inside loop try catch clause
for (int i = 0; i < array.length; i++) {
try {
.......
} catch (IOException e) {
.......
} catch (Exception e) {
.......
}
}
Change to ：
try {
for (int i = 0; i < array.length; i++) {
.......
}
} catch (IOException e) {
.......
} catch (Exception e) {
.......
}
three ： Minimize try catch Nesting of clauses , Will affect performance
try {
try {
.......
} catch (IOException e) {
.......
}
} catch (Exception e) {
.......
}
Change to
try {
.......
}catch (IOException e) {
.......
} catch (Exception e) {
.......
}
four ： Same try Multiple in Clause catch Hour , Exception handling principle
When a try Block contains numerous statements , Many different exceptions may be thrown , Only through multiple catch Block to catch different exceptions . If there is an inheritance relationship between two exceptions , You should catch subclass exceptions before your parent exceptions , Or put the minimum range exception first
, Wide range put in the back , Because according to catch Block matching from top to bottom , When it matches a catch Block time , He went straight into this catch In the block , There's more in the back catch Block words , It does nothing , Jump straight over , Ignore all . If any finally Enter finally Go ahead inside .Exception The root class of this exception must just be in the last catch inside , If placed in the front or middle , Any exceptions will be associated with Exception Matched , It will be reported that it has been captured ... Unexpected error . Simultaneous coordination log4j It will be very helpful for the future maintenance of the program .
try {
.......
}catch (IOException e) {
.......
} catch (Exception e) {
.......
}
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