[英]Generate a dynamic query in java using string builder
我正在尝试在Java中生成动态查询,我需要生成相同的表Cos_Class_Allocation
和相同的列class_name = ? AND CLASS_ALLOCATION = ?
class_name = ? AND CLASS_ALLOCATION = ?
。 如何注意到我声明了alloc但没有调用alloc的循环中的代码,是否有更好的方法编写循环,以及如何从第一个foreach循环中删除最后一个逗号,最后删除最后一个“来自第二个foreach循环。
我的查询应如下所示:
SELECT * FROM TRAFFIC_PROFILE
WHERE COS_MODEL = 'cos4' AND DIRECTION = 'Egress'
AND (PE_INGRESS_FLAG = 'Y' OR PE_EGRESS_FLAG = 'Y')
and TRAFFIC_PROFILE_ID IN (
select distinct (C1.Traffic_PROFILE_ID) from Cos_Class_Allocation C1,
Cos_Class_Allocation C2, Cos_Class_Allocation C3,
Cos_Class_Allocation C4, Cos_Class_Allocation C5, Cos_Class_Allocation C6
where c1.class_name = ? AND c1.CLASS_ALLOCATION = ?
and c2.class_name = ? AND c2.CLASS_ALLOCATION = ?
and c3.class_name = ? AND c3.CLASS_ALLOCATION = ?
and c4.class_name = ? AND c4.CLASS_ALLOCATION = ?
and c5.class_name = ? AND c5.CLASS_ALLOCATION = ?
and c6.class_name = ? AND c6.CLASS_ALLOCATION = ?
and C1.TRAFFIC_PROFILE_ID = c2.TRAFFIC_PROFILE_ID
and C1.TRAFFIC_PROFILE_ID = c3.TRAFFIC_PROFILE_ID
and C1.TRAFFIC_PROFILE_ID = c4.TRAFFIC_PROFILE_ID
and C1.TRAFFIC_PROFILE_ID = c5.TRAFFIC_PROFILE_ID
and C1.TRAFFIC_PROFILE_ID = c6.TRAFFIC_PROFILE_ID ) ;
码:
private String buildTrafficProfileByCosClassAllocationQuery(TrafficProfileExtension.CosModel cosModel, Direction direction, List<ClassOfServiceAllocation> cosAllocation, RouterType routerType){
StringBuilder builder = new StringBuilder();
builder.append(queryByDirectionRouterTypeAndCosClassAllocation);
builder.append(buildRouterQuery(routerType));
builder.append("and TRAFFIC_PROFILE_ID IN ( select distinct (C1.Traffic_PROFILE_ID) from ");
// builder.append(buildCosModelQuery(cosModel));
int i = 1;
for(ClassOfServiceAllocation alloc : cosAllocation){
builder.append(" Cos_Class_Allocation c" + i++ +"," );
}
builder.append(" where " );
int n = 1;
int a =1;
for(ClassOfServiceAllocation alloc : cosAllocation){
builder.append("c" + n++ + ".class_name = ? AND c" + a++ + ".CLASS_ALLOCATION = ? AND ");
}
int tp = 2;
for(ClassOfServiceAllocation alloc : cosAllocation){
builder.append("and C1.TRAFFIC_PROFILE_ID = c" + tp++ + ".TRAFFIC_PROFILE_ID " );
}
return builder.toString();
}
这是下面的输出:(我在最后一个表comma
之后有一个额外的AND
和额外的)
SELECT * FROM TRAFFIC_PROFILE
WHERE COS_MODEL = ? AND DIRECTION = ?
AND (PE_INGRESS_FLAG = 'Y' OR PE_EGRESS_FLAG = 'Y')
and TRAFFIC_PROFILE_ID IN (
select distinct (C1.Traffic_PROFILE_ID)
from Cos_Class_Allocation c1, Cos_Class_Allocation c2,
Cos_Class_Allocation c3, Cos_Class_Allocation c4,
Cos_Class_Allocation c5, Cos_Class_Allocation c6,
where c1.class_name = ? AND c1.CLASS_ALLOCATION = ?
AND c2.class_name = ? AND c2.CLASS_ALLOCATION = ?
AND c3.class_name = ? AND c3.CLASS_ALLOCATION = ?
AND c4.class_name = ? AND c4.CLASS_ALLOCATION = ?
AND c5.class_name = ? AND c5.CLASS_ALLOCATION = ?
AND c6.class_name = ? AND c6.CLASS_ALLOCATION = ?
AND and C1.TRAFFIC_PROFILE_ID = c2.TRAFFIC_PROFILE_ID
and C1.TRAFFIC_PROFILE_ID = c3.TRAFFIC_PROFILE_ID
and C1.TRAFFIC_PROFILE_ID = c4.TRAFFIC_PROFILE_ID
and C1.TRAFFIC_PROFILE_ID = c5.TRAFFIC_PROFILE_ID
and C1.TRAFFIC_PROFILE_ID = c6.TRAFFIC_PROFILE_ID
我能够通过使用for循环而不是foreach循环来生成动态查询。
private String buildTrafficProfileByCosClassAllocationQuery(TrafficProfileExtension.CosModel cosModel, Direction direction, List<ClassOfServiceAllocation> cosAllocation, RouterType routerType){
StringBuilder builder = new StringBuilder();
builder.append(queryByDirectionRouterTypeAndCosClassAllocation);
builder.append(buildRouterQuery(routerType));
builder.append("and TRAFFIC_PROFILE_ID IN ( select distinct (C1.Traffic_PROFILE_ID) from ");
// builder.append(buildCosModelQuery(cosModel));
for (int i = 1; i <= cosAllocation.size(); i++) {
if (i > 1) builder.append(",");
builder.append(" Cos_Class_Allocation c").append(i);
}
for (int i = 1; i <= cosAllocation.size(); i++) {
builder.append(i == 1 ? " where " : " and ");
builder.append("c").append(i).append(".class_name = ? AND c").append(i).append(".CLASS_ALLOCATION = ?");
if (i > 1) {
builder.append(" and C1.TRAFFIC_PROFILE_ID = c").append(i).append(".TRAFFIC_PROFILE_ID");
}
}
builder.append(" )");
return builder.toString();
}
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