英文:
Java Generic method for accept any class and return data?
问题
在Spring Batch代码中，在编写batchUpdate时，我已经添加了异常处理，以防有任何记录失败，我正在使用下面的逻辑处理，这个逻辑运行良好。但是我在项目中有大约70个写入器，我想为下面的代码创建一个通用方法，并在运行时传递Employee、Department、Student、Stock等类，并获取详细信息。
我该如何做？
私有List
List
if (e.getCause() instanceof BatchUpdateException) {
BatchUpdateException be = (BatchUpdateException) e.getCause();
int[] batchRes = be.getUpdateCounts();
if (batchRes != null && batchRes.length > 0) {
for (int index = 0; index < batchRes.length; index++) {
if (batchRes[index] == Statement.EXECUTE_FAILED) {
data.add(items.get(index));
map.put(index, e.getMessage());
}
}
}
}
return data;
}
英文:
In Spring Batch code, while writing batchUpdate I have added exception handling, in case of any records failed I am handling with the below logic which works fine. But I've around 70 writer in my project and I wanted to make a generic method for the below code and at run time pass the Employee, Department, Student, Stock etc class and get the details back.
How can I do that ?
private List<Employee> getFailedRecords(Exception e, List<? extends Employee> items, Map<Integer, String> map){
List<Employee> data = new ArrayList<>();
if (e.getCause() instanceof BatchUpdateException) {
BatchUpdateException be = (BatchUpdateException) e.getCause();
int[] batchRes = be.getUpdateCounts();
if (batchRes != null && batchRes.length > 0) {
for (int index = 0; index < batchRes.length; index++) {
if (batchRes[index] == Statement.EXECUTE_FAILED) {
data.add(items.get(index));
map.put(index, e.getMessage());
}
}
}
}
return data;
}
答案1
得分: 1
你可以简单地将这个方法变成通用的：
private <T> List<T> getFailedRecords(Exception e, List<? extends T> items,
Map<Integer, String> map) {
List<T> data = new ArrayList<>();
if (e.getCause() instanceof BatchUpdateException) {
BatchUpdateException be = (BatchUpdateException) e.getCause();
int[] batchRes = be.getUpdateCounts();
if (batchRes != null && batchRes.length > 0) {
for (int index = 0; index < batchRes.length; index++) {
if (batchRes[index] == Statement.EXECUTE_FAILED) {
data.add(items.get(index));
map.put(index, e.getMessage());
}
}
}
}
return data;
}
除非有必要使用有界通配符（例如，当您需要传递Employee/Student等子类的列表时），您应该可以省略它，并将第二个参数类型化为List<T>。
英文:
You can simply make the method generic:
private <T> List<T> getFailedRecords(Exception e, List<? extends T> items,
Map<Integer, String> map) {
List<T> data = new ArrayList<>();
if (e.getCause() instanceof BatchUpdateException) {
BatchUpdateException be = (BatchUpdateException) e.getCause();
int[] batchRes = be.getUpdateCounts();
if (batchRes != null && batchRes.length > 0) {
for (int index = 0; index < batchRes.length; index++) {
if (batchRes[index] == Statement.EXECUTE_FAILED) {
data.add(items.get(index));
map.put(index, e.getMessage());
}
}
}
}
return data;
}
Unless the bounded wildcard is necessary (such as when you need to pass a list of subclasses of Employee/Student, etc.), you should be able to dispense with it, and type the second parameter as List<T>.
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