1. 得到某个对象的属?br />
1 public Object getProperty(Object owner, String fieldName) throws Exception {
2 Class ownerClass = owner.getClass();
3
4 Field field = ownerClass.getField(fieldName);
5
6 Object property = field.get(owner);
7
8 return property;
9 }
2 Class ownerClass = owner.getClass();
3
4 Field field = ownerClass.getField(fieldName);
5
6 Object property = field.get(owner);
7
8 return property;
9 }
Class ownerClass = owner.getClass()Q得到该对象的Class?br />
Field field = ownerClass.getField(fieldName)Q通过Class得到cd明的属性?br />
Object property = field.get(owner)Q通过对象得到该属性的实例Q如果这个属性是非公有的Q这里会报IllegalAccessException?br />
2. 得到某个cȝ静态属?br />
1 public Object getStaticProperty(String className, String fieldName)
2 throws Exception {
3 Class ownerClass = Class.forName(className);
4
5 Field field = ownerClass.getField(fieldName);
6
7 Object property = field.get(ownerClass);
8
9 return property;
10 }
2 throws Exception {
3 Class ownerClass = Class.forName(className);
4
5 Field field = ownerClass.getField(fieldName);
6
7 Object property = field.get(ownerClass);
8
9 return property;
10 }
Class ownerClass = Class.forName(className) Q首先得到这个类的Class?br />
Field field = ownerClass.getField(fieldName)Q和上面一P通过Class得到cd明的属性?br />
Object property = field.get(ownerClass) Q这里和上面有些不同Q因属性是静态的Q所以直接从cȝClass里取?br />
3. 执行某对象的Ҏ(gu)
1 public Object invokeMethod(Object owner, String methodName, Object[] args) throws Exception {
2
3 Class ownerClass = owner.getClass();
4
5 Class[] argsClass = new Class[args.length];
6
7 for (int i = 0, j = args.length; i < j; i++) {
8 argsClass[i] = args[i].getClass();
9 }
10
11 Method method = ownerClass.getMethod(methodName, argsClass);
12
13 return method.invoke(owner, args);
14 }
2
3 Class ownerClass = owner.getClass();
4
5 Class[] argsClass = new Class[args.length];
6
7 for (int i = 0, j = args.length; i < j; i++) {
8 argsClass[i] = args[i].getClass();
9 }
10
11 Method method = ownerClass.getMethod(methodName, argsClass);
12
13 return method.invoke(owner, args);
14 }
Class owner_class = owner.getClass() Q首先还是必d到这个对象的Class?br />
5?行：配置参数的Class数组Q作为寻找Method的条件?br />
Method method = ownerClass.getMethod(methodName, argsClass)Q通过Method名和参数的Class数组得到要执行的Method?br />
method.invoke(owner, args)Q执行该MethodQinvokeҎ(gu)的参数是执行q个Ҏ(gu)的对象，和参数数l。返回值是ObjectQ也既是该方法的q回倹{?br />
4. 执行某个cȝ静态方?br />
1 public Object invokeStaticMethod(String className, String methodName,
2 Object[] args) throws Exception {
3 Class ownerClass = Class.forName(className);
4
5 Class[] argsClass = new Class[args.length];
6
7 for (int i = 0, j = args.length; i < j; i++) {
8 argsClass[i] = args[i].getClass();
9 }
10
11 Method method = ownerClass.getMethod(methodName, argsClass);
12
13 return method.invoke(null, args);
14 }
2 Object[] args) throws Exception {
3 Class ownerClass = Class.forName(className);
4
5 Class[] argsClass = new Class[args.length];
6
7 for (int i = 0, j = args.length; i < j; i++) {
8 argsClass[i] = args[i].getClass();
9 }
10
11 Method method = ownerClass.getMethod(methodName, argsClass);
12
13 return method.invoke(null, args);
14 }
基本的原理和实例3相同Q不同点是最后一行，invoke的一个参数是nullQ因是静态方法，不需要借助实例q行?br />
5. 新徏实例
1
2 public Object newInstance(String className, Object[] args) throws Exception {
3 Class newoneClass = Class.forName(className);
4
5 Class[] argsClass = new Class[args.length];
6
7 for (int i = 0, j = args.length; i < j; i++) {
8 argsClass[i] = args[i].getClass();
9 }
10
11 Constructor cons = newoneClass.getConstructor(argsClass);
12
13 return cons.newInstance(args);
14
15 }
2 public Object newInstance(String className, Object[] args) throws Exception {
3 Class newoneClass = Class.forName(className);
4
5 Class[] argsClass = new Class[args.length];
6
7 for (int i = 0, j = args.length; i < j; i++) {
8 argsClass[i] = args[i].getClass();
9 }
10
11 Constructor cons = newoneClass.getConstructor(argsClass);
12
13 return cons.newInstance(args);
14
15 }
q里说的Ҏ(gu)是执行带参数的构造函数来新徏实例的方法。如果不需要参敎ͼ可以直接使用newoneClass.newInstance()来实现?br />
Class newoneClass = Class.forName(className)Q第一步，得到要构造的实例的Class?br />
W?～第9行：得到参数的Class数组?br />
Constructor cons = newoneClass.getConstructor(argsClass)Q得到构造子?br />
cons.newInstance(args)Q新建实例?br />
6. 判断是否为某个类的实?br />
1 public boolean isInstance(Object obj, Class cls) {
2 return cls.isInstance(obj);
3 }
2 return cls.isInstance(obj);
3 }
7. 得到数组中的某个元素
1 public Object getByArray(Object array, int index) {
2 return Array.get(array,index);
3 }
2 return Array.get(array,index);
3 }
附完整源码：
import java.lang.reflect.Array;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
/**
* Java Reflection Cookbook
*
* @author Michael Lee
* @since 2006-8-23
* @version 0.1a
*/
public class Reflection {
/**
* 得到某个对象的公共属?br /> *
* @param owner, fieldName
* @return 该属性对?br /> * @throws Exception
*
*/
public Object getProperty(Object owner, String fieldName) throws Exception {
Class ownerClass = owner.getClass();
Field field = ownerClass.getField(fieldName);
Object property = field.get(owner);
return property;
}
/**
* 得到某类的静态公共属?br /> *
* @param className cd
* @param fieldName 属性名
* @return 该属性对?br /> * @throws Exception
*/
public Object getStaticProperty(String className, String fieldName)
throws Exception {
Class ownerClass = Class.forName(className);
Field field = ownerClass.getField(fieldName);
Object property = field.get(ownerClass);
return property;
}
/**
* 执行某对象方?br /> *
* @param owner
* 对象
* @param methodName
* Ҏ(gu)?br /> * @param args
* 参数
* @return Ҏ(gu)q回?br /> * @throws Exception
*/
public Object invokeMethod(Object owner, String methodName, Object[] args)
throws Exception {
Class ownerClass = owner.getClass();
Class[] argsClass = new Class[args.length];
for (int i = 0, j = args.length; i < j; i++) {
argsClass[i] = args[i].getClass();
}
Method method = ownerClass.getMethod(methodName, argsClass);
return method.invoke(owner, args);
}
/**
* 执行某类的静态方?br /> *
* @param className
* cd
* @param methodName
* Ҏ(gu)?br /> * @param args
* 参数数组
* @return 执行Ҏ(gu)q回的结?br /> * @throws Exception
*/
public Object invokeStaticMethod(String className, String methodName,
Object[] args) throws Exception {
Class ownerClass = Class.forName(className);
Class[] argsClass = new Class[args.length];
for (int i = 0, j = args.length; i < j; i++) {
argsClass[i] = args[i].getClass();
}
Method method = ownerClass.getMethod(methodName, argsClass);
return method.invoke(null, args);
}
/**
* 新徏实例
*
* @param className
* cd
* @param args
* 构造函数的参数
* @return 新徏的实?br /> * @throws Exception
*/
public Object newInstance(String className, Object[] args) throws Exception {
Class newoneClass = Class.forName(className);
Class[] argsClass = new Class[args.length];
for (int i = 0, j = args.length; i < j; i++) {
argsClass[i] = args[i].getClass();
}
Constructor cons = newoneClass.getConstructor(argsClass);
return cons.newInstance(args);
}
/**
* 是不是某个类的实?br /> * @param obj 实例
* @param cls c?br /> * @return 如果 obj 是此cȝ实例Q则q回 true
*/
public boolean isInstance(Object obj, Class cls) {
return cls.isInstance(obj);
}
/**
* 得到数组中的某个元素
* @param array 数组
* @param index 索引
* @return q回指定数组对象中烦引组件的?br /> */
public Object getByArray(Object array, int index) {
return Array.get(array,index);
}
}
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
/**
* Java Reflection Cookbook
*
* @author Michael Lee
* @since 2006-8-23
* @version 0.1a
*/
public class Reflection {
/**
* 得到某个对象的公共属?br /> *
* @param owner, fieldName
* @return 该属性对?br /> * @throws Exception
*
*/
public Object getProperty(Object owner, String fieldName) throws Exception {
Class ownerClass = owner.getClass();
Field field = ownerClass.getField(fieldName);
Object property = field.get(owner);
return property;
}
/**
* 得到某类的静态公共属?br /> *
* @param className cd
* @param fieldName 属性名
* @return 该属性对?br /> * @throws Exception
*/
public Object getStaticProperty(String className, String fieldName)
throws Exception {
Class ownerClass = Class.forName(className);
Field field = ownerClass.getField(fieldName);
Object property = field.get(ownerClass);
return property;
}
/**
* 执行某对象方?br /> *
* @param owner
* 对象
* @param methodName
* Ҏ(gu)?br /> * @param args
* 参数
* @return Ҏ(gu)q回?br /> * @throws Exception
*/
public Object invokeMethod(Object owner, String methodName, Object[] args)
throws Exception {
Class ownerClass = owner.getClass();
Class[] argsClass = new Class[args.length];
for (int i = 0, j = args.length; i < j; i++) {
argsClass[i] = args[i].getClass();
}
Method method = ownerClass.getMethod(methodName, argsClass);
return method.invoke(owner, args);
}
/**
* 执行某类的静态方?br /> *
* @param className
* cd
* @param methodName
* Ҏ(gu)?br /> * @param args
* 参数数组
* @return 执行Ҏ(gu)q回的结?br /> * @throws Exception
*/
public Object invokeStaticMethod(String className, String methodName,
Object[] args) throws Exception {
Class ownerClass = Class.forName(className);
Class[] argsClass = new Class[args.length];
for (int i = 0, j = args.length; i < j; i++) {
argsClass[i] = args[i].getClass();
}
Method method = ownerClass.getMethod(methodName, argsClass);
return method.invoke(null, args);
}
/**
* 新徏实例
*
* @param className
* cd
* @param args
* 构造函数的参数
* @return 新徏的实?br /> * @throws Exception
*/
public Object newInstance(String className, Object[] args) throws Exception {
Class newoneClass = Class.forName(className);
Class[] argsClass = new Class[args.length];
for (int i = 0, j = args.length; i < j; i++) {
argsClass[i] = args[i].getClass();
}
Constructor cons = newoneClass.getConstructor(argsClass);
return cons.newInstance(args);
}
/**
* 是不是某个类的实?br /> * @param obj 实例
* @param cls c?br /> * @return 如果 obj 是此cȝ实例Q则q回 true
*/
public boolean isInstance(Object obj, Class cls) {
return cls.isInstance(obj);
}
/**
* 得到数组中的某个元素
* @param array 数组
* @param index 索引
* @return q回指定数组对象中烦引组件的?br /> */
public Object getByArray(Object array, int index) {
return Array.get(array,index);
}
}
]]>
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFCellStyle;
import org.apache.poi.hssf.util.HSSFColor;
import org.apache.poi.hssf.util.Region;
import org.apache.poi.hssf.usermodel.HSSFFont;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
HSSFCellStylecM表一U单元格样式。可以通过q些cL讄单元格的Ҏ(gu)样式、背景颜艌Ӏ字体、水q_垂直方式的对齐?br />?
HSSFWorkbook workbook = new HSSFWorkbook(); //建立一个工作薄
HSSFCellStyle titleStyle=workbook.createCellStyle(); //在工作薄的基上徏立一个样?br /> titleStyle.setBorderBottom(HSSFCellStyle.BORDER_DOUBLE); //讄Ҏ(gu)样式
titleStyle.setBorderLeft((short)1); //左边?br /> titleStyle.setBorderRight((short)1); //双?br /> titleStyle.setBorderTop(HSSFCellStyle.BORDER_DOUBLE); //边?br /> titleStyle.setFillForegroundColor(HSSFColor.LIGHT_ORANGE.index); //填充的背景颜?br /> titleStyle.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND); //填充图案
假设什么定义了一个样式，惛_填充W一个单元格的时候填充红Q第二格单元格填充蓝艌Ӏ?br />如果:
HSSFCellStyle cellStyle = workbook.createCellStyle(); //创徏一个样?/font>
cellStyle.setFillForegroundColor(HSSFColor.RED.index); //讄颜色为红?br /> cellStyle.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);
HSSFCell cell1 = row.createCell((short)1); //l单元格cell1填充U色
cell1.setCellStyle(cellStyle);
? cellStyle.setFillForegroundColor(HSSFColor.BLUE.index); //讄颜色?br />
HSSFCell cell2 = row.createCell((short)2); //l单元格cell2填充蓝色
cell2.setCellStyle(cellStyle);
q个时候会出现的现象是单元格cell1和cell2都变成了蓝色。遇到这U情况，要预先定义两U不同的单元格样式?/font>
当一个EXCEL文g同时需要很多大同小异的单元格样式时Q这样一一定义很麻烦。POI HSSF提供了一个HSSFCellUtilc（在org.apache.poi. hssf.usermodel.contrib包）Q里面有几个Ҏ(gu)可以l过HSSFCellStyle直接讑֮单元格的样式Q但q几个方法会抛出NestableException?nbsp; 常，要处理这个异常，需要引用Apache的几个Common包：
commons-beanutils.jar
commons-beanutils-bean-collections.jar
commons-beanutils-core.jar
commons-lang.jar
commons-logging-api.jar
以下是其他各U情늚处理Q?br />1、中文处理：
要在通过POI生成的EXCEL中正常显CZ文，需要ؓ单元D|编码：
cell.setEncoding(HSSFCell.ENCODING_UTF_16);
cell.setCellValue("部门");
2、合q单元格Q?br />HSSFSheet.addMergedRegion(new Region())Ҏ(gu)可以合ƈ单元|Region()中的一个构造函数含有四个参敎ͼ分别代表起始行、v始列、结?nbsp; 行、结束列Q?br /> sheet.addMergedRegion(new Region(initRow, (short)(initCol-2), initRow + lists.size() - 1, (short)(initCol-2)));
3、公式的处理Q?br />HSSFCell.setCellFormula()Ҏ(gu)用来在EXCEL单元g写入公式?br /> cell = row.createCell((short)(dataFlag));
cell.setCellType(HSSFCell.CELL_TYPE_FORMULA);
cell.setCellFormula("SUM(" + getColLetter(initCol) + (listFlag+1) +":" + getColLetter(dataFlag-1) + (listFlag+1) + ")");
cell.setCellStyle(nameStyle);
4、链接的处理Q?br />在POI中往单元g写链接，是用HYPERLINK函数搞定的?br />HYPERLINK函数包含两个参数Q第一个参数是指向的URL地址Q第二个参数是显C字丌Ӏ?br /> cell = row.createCell((short)(dataFlag));
cell.setCellType(HSSFCell.CELL_TYPE_FORMULA);
cell.setCellFormula("HYPERLINK(\"http://www.xxxxx.com/xxx.jsp?id=1\",\"homepage\")");
cell.setCellStyle(linkStyle);
Z佉K接效果更好，我们可以l链接所在单元格定义一U样式，佉K接显CZؓ有下划线的蓝色字Ԍ
HSSFCellStyle linkStyle = workbook.createCellStyle();
linkStyle.setBorderBottom((short)1);
linkStyle.setBorderLeft((short)1);
linkStyle.setBorderRight((short)1);
linkStyle.setBorderTop((short)1);
linkStyle.setFillForegroundColor(HSSFColor.SKY_BLUE.index);
linkStyle.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);
HSSFFont font = workbook.createFont();
font.setFontName(HSSFFont.FONT_ARIAL);
font.setUnderline((byte)1);
font.setColor(HSSFColor.BLUE.index);
linkStyle.setFont(font);
]]>
]]>