标签：rop time roc 转换 runtime ext utils src prope
工作中经常会遇到将行数据转换成Java（POJO）对象的场景，其中关于字段校验和类型转换的处理繁琐而冗余，对于有代码洁癖的人着实不能忍。这里分享下自己封装的工具代码，也许能够帮助你更简单地完成此类任务。
先将以下五个文件加入你豪华午餐（项目??）中
FieldItem：
/** * * @author lichmama * */ public class FieldItem { public int getIndex() { return index; } public void setIndex(int index) { this.index = index; } public String getName() { return name; } public void setName(String name) { this.name = name; } public Object getValue() { return value; } public void setValue(Object value) { this.value = value; } public FieldProcessor getProcessor() { return processor; } public void setProcessor(FieldProcessor processor) { this.processor = processor; } public void setValidator(FieldValidator validator) { this.validator = validator; } public FieldValidator getValidator() { return validator; } public boolean validate() { return validator.validate(this); } public Object process() throws Exception { return processor.process(this); } private int index; private String name; private Object value; private FieldValidator validator = new FieldValidator() { @Override public boolean validate(FieldItem field) { return true; } }; private FieldProcessor processor = new FieldProcessor() { @Override public Object process(FieldItem field) { return field.getValue(); } }; public FieldItem() { } public FieldItem(int index, String name) { this.index = index; this.name = name; } public FieldItem(int index, String name, FieldValidator validator) { this.index = index; this.name = name; this.validator = validator; } public FieldItem(int index, String name, FieldProcessor processor) { this.index = index; this.name = name; this.processor = processor; } public FieldItem(int index, String name, FieldValidator validator, FieldProcessor processor) { this.index = index; this.name = name; this.validator = validator; this.processor = processor; } }
FieldProcessor：
/** * 扩展接口：可针对字段做个性化处理 * * @author lichmama * */ public interface FieldProcessor { Object process(FieldItem field) throws Exception; }
FieldValidator：
/** * 校验接口：可针对字段做个性化校验 * * @author lichmama * */ public interface FieldValidator { boolean validate(FieldItem field); }
ConvertException：
/** * 转换异常 * * @author lichmama * */ public class ConvertException extends RuntimeException { public ConvertException(String msg) { super(msg); } public ConvertException(Throwable throwable) { super(throwable); } public ConvertException(String msg, Throwable throwable) { super(msg, throwable); } }
RowConverter：
/** * 行转换器：用于将行数据转换成bean * * @author lichmama * */ public class RowConverter { private Map<String, FieldItem> fieldMap = new HashMap<String, FieldItem>(); public RowConverter() {} public RowConverter(String[] fieldNames) { for (int i = 0; i < fieldNames.length; i++) { String name = fieldNames[i]; FieldItem field = new FieldItem(); field.setIndex(i); field.setName(name); fieldMap.put(name, field); } } public void setField(FieldItem field) { if (field == null) { throw new ConvertException("field is null"); } String name = field.getName(); if (!fieldMap.containsKey(name)) { throw new ConvertException("the field \"" + name + "\" not found"); } fieldMap.put(name, field); } public void setFieldValidator(String name, FieldValidator validator) { if (!fieldMap.containsKey(name)) { throw new ConvertException("the field \"" + name + "\" not found"); } fieldMap.get(name).setValidator(validator); } public void setFieldProcessor(String name, FieldProcessor processor) { if (!fieldMap.containsKey(name)) { throw new ConvertException("the field \"" + name + "\" not found"); } fieldMap.get(name).setProcessor(processor); } public <T> T convert(Object[] row, Class<T> beanClass) throws Exception { Map<String, Object> properties = new HashMap<String, Object>(); Iterator<FieldItem> iter = fieldMap.values().iterator(); while (iter.hasNext()) { FieldItem field = iter.next(); Object value = row[field.getIndex()]; field.setValue(value); if (!field.validate()) { throw new ConvertException("the field \"" + field.getName() + "\" validate failed"); } Object processedValue = field.process(); properties.put(field.getName(), processedValue); } T bean = beanClass.newInstance(); // powered by commons-beanutils BeanUtils.populate(bean, properties); return bean; } }
下面我们就可以愉快的写代码了：
目标类User：
public class User implements Serializable { private int id; private String name; private String gender; private int age; private String birthday; // 省略getter、setter @Override public String toString() { return "User [id=" + id + ", name=" + name + ", gender=" + gender + ", age=" + age + ", birthday=" + birthday + "]"; } }
测试类Test：
public class Test { public static void main(String[] args) throws Exception { String[] fieldNames = { "id", "name", "gender", "age", "birthday" }; Object[] row = { 1, "lichmama", "man", 17, new Date() }; RowConverter converter = new RowConverter(fieldNames); testValidator(row, converter); testProcessor(row, converter); } /** * 字段个性化校验 * * @param row * @param converter * @throws Exception */ public static void testValidator(Object[] row, RowConverter converter) throws Exception { converter.setFieldValidator("age", (FieldItem field) -> { int age = (int) field.getValue(); return age >= 18; // 未成年禁止入内?? }); User user = converter.convert(row, User.class); } /** * 字段个性化处理 * * @param row * @param converter * @throws Exception */ public static void testProcessor(Object[] row, RowConverter converter) throws Exception { converter.setFieldProcessor("birthday", (FieldItem field) -> { return new SimpleDateFormat("yyyy-MM-dd").format(field.getValue()); // 将日期转换成格式化字符串 }); User user = converter.convert(row, User.class); } }
看上去是不是好多了??
标签：rop time roc 转换 runtime ext utils src prope
原文地址：https://www.cnblogs.com/lichmama/p/11148518.html
