写了一段代码，主要是解决ResultSet 对象往bean中赋值的问... - 黑马程序员技术交流社区

public class BeanInformation {
private String fieldName; //属性名称
private String methodName; //方法名称
private Class type; //属性类型
public String getFieldName() {
return fieldName;
}
public void setFieldName(String fieldName) {
this.fieldName = fieldName;
}
public String getMethodName() {
return methodName;
}
public void setMethodName(String methodName) {
this.methodName = methodName;
}
public Class getType() {
return type;
}
public void setType(Class type) {
this.type = type;
}
}
下面是解析bean属性的代码，和对bean的赋值
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class VOTools {
private Class className; //bean的字节码
private ResultSet rs; //ResultSet结果集
//VOTools的第一种构造函数
public VOTools(ResultSet rs,String className){
try {
this.className = Class.forName(className);
this.rs = rs;
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}
//VOTools的第二种构造函数
public VOTools(ResultSet rs,Class className){
this.className = className;
this.rs = rs;
}
//返回List，list中存放的是已被赋值好的bean
public List getBeanList () throws SecurityException,NoSuchMethodException,IllegalArgumentException,InvocationTargetException{
return getBeanList(this.rs,this.className);
}
//获取单个bean
public Object getBean() throws Exception{
Object obj = null;
List<Object> list = getBeanList(this.rs,this.className);
if(list!=null && list.size()==1){
obj = list.get(0);
}
return obj;
}
//获取bean中的属性信息
private Map<String,BeanInformation> getBeanInformationToMap(Class className){
//创建Map key为属性名 value为该属性的属性解析对象
Map<String,BeanInformation> beanInformationToMap = new HashMap<String, BeanInformation>();
Class beanClass = null;
try {
beanClass = className;
//获取传入的bean的所有属性
Field[] beanField = beanClass.getDeclaredFields();
//循环遍历
for(int i=0;i<beanField.length;i++){
//创建bean解析对象
BeanInformation bean = new BeanInformation();
//获取属性名，并大写存入BeanInformation里
bean.setFieldName(beanField.getName().toUpperCase());
//获取方法set方法名
bean.setMethodName("set"+beanField.getName().substring(0, 1).toUpperCase().concat(beanField.getName().substring(1)));
//获取属性类型
bean.setType(beanField.getType());
//将BeanInformation存入map
beanInformationToMap.put(bean.getFieldName(), bean);
}
} catch (Exception e) {
e.printStackTrace();
}
return beanInformationToMap;
}
//遍历ResultSet结果集，并赋值
private List getBeanList(ResultSet result,Class beanName)throws SecurityException,NoSuchMethodException,IllegalArgumentException,InvocationTargetException{
Map<String,BeanInformation> beanInformationMap = getBeanInformationToMap(beanName);
List list = new ArrayList();
ResultSetMetaData resm;
try {
//获取结果集信息
resm = result.getMetaData();
while(result.next()){
Class classz = beanName;
//反射实例化对象
Object obj = classz.newInstance();
//循环结果集的列
for(int i=0;i<resm.getColumnCount();i++){
//获取结果集每列的名称
String key = resm.getColumnName(i+1).toUpperCase();
//如果这个名称在之前解析的bean中能匹配上就对其进行赋值
if(beanInformationMap.get(key) != null){
//获取方法名
String methodName = beanInformationMap.get(key).getMethodName();
//获取属性类型
Class type = beanInformationMap.get(key).getType();
//类型匹配
if(type.equals(String.class)){
//反射赋值
classz.getMethod(methodName,type).invoke(obj, new Object[]{result.getString(key)});
}else if(type.equals(int.class) || type.equals(Integer.class)){
classz.getMethod(methodName,type).invoke(obj, new Object[]{result.getInt(key)});
}else if(type.equals(double.class) || type.equals(Double.class)){
classz.getMethod(methodName,type).invoke(obj, new Object[]{result.getDouble(key)});
}else if(type.equals(char.class) || type.equals(Character.class)){
classz.getMethod(methodName,type).invoke(obj, new Object[]{result.getCharacterStream(key)});
}
}
//String value = result.getString(key);
}
list.add(obj);
}
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}finally{
try {
this.rs.close();
} catch (SQLException e) {
rs = null;
e.printStackTrace();
}
}
return list;
}
}

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