java 多重if判断怎么优化

Question

if(id == null || id.isEmpty()){
if(type == null){
if(name==null || name.isEmpty()){
//...select..sql...
}else {
//...select..sql...
}
}else {
if(name==null || name.isEmpty()){
//...select..sql...
}else {
//...select..sql...
}
}
}else {
if(type == null){
if(name==null || name.isEmpty()){
//...select..sql...
}else {
//...select..sql...
}
}else {
if(name==null || name.isEmpty()){
//...select..sql...
}else {
//...select..sql...
}
}
}

Answer 1

把4个重复的部分提出来，这样代码是否清晰些，一定要写好注释哦
if (id == null || id.isEmpty()) {
                if (type == null) {
                    getSql(1, name);
                } else {
                    getSql(2, name);
                }
} else {
                if (type == null) {
                    getSql(3, name);
                } else {
                    getSql(4, name);
                }

}
public String getSql(int state, List name) {
switch (state) {
case 1:
if (name == null || name.isEmpty()) {
// ...select..sql...
} else {
// ...select..sql...
}
case 2:
if (name == null || name.isEmpty()) {
// ...select..sql...
} else {
// ...select..sql...
}
case 3:
if (name == null || name.isEmpty()) {
// ...select..sql...
} else {
// ...select..sql...
}
case 4:
if (name == null || name.isEmpty()) {
// ...select..sql...
} else {
// ...select..sql...
}
}
}