jasperreports实现通用数据源-优快云博客

本文介绍了一种名为CommonQueryResultDataSource的Java类实现，该类作为通用的数据源，用于为JasperReports报告提供数据。它接收查询结果列表及字段名数组作为输入，并通过迭代器逐一返回每条记录的字段值。

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package com.icetree.datasource;

import java.util.Iterator;
import java.util.List;

import net.sf.jasperreports.engine.JRDataSource;
import net.sf.jasperreports.engine.JRException;
import net.sf.jasperreports.engine.JRField;

public class CommonQueryResultDataSource implements JRDataSource {

private String[] fields;

private Iterator iterator;

private Object currentValue;

public CommonQueryResultDataSource(List list, String[] fields) {
this.fields = fields;
this.iterator = list.iterator();
}

public Object getFieldValue(JRField field) throws JRException {
Object value = null;
String fieldName = field.getName();
int index = getFieldIndex(fieldName);
if (index > -1) {
Object[] values = (Object[]) currentValue;
value = values[index];
}
return value;
}

public boolean next() throws JRException {
currentValue = iterator.hasNext() ? iterator.next() : null;
return (currentValue != null);
}

private int getFieldIndex(String field) {
int index = -1;
for (int i = 0; i < fields.length; i++) {
if (fields[i].equals(field)) {
index = i;
break;
}
}
return index;
}

}