32_use BeanUtils toolkit to operate JavaBean and beanutilsjavabean

Source: Internet
Author: User

32_use BeanUtils toolkit to operate JavaBean and beanutilsjavabean


Some open-source warriors are not satisfied with the IntroSpector In the JavaBean API to operate beans because they require a lot of attribute setting values and obtaining values,

Write out the common BeanUtils tool to further simplify java bean operations and provide free download on the apache website.


Beanutils Toolkit

  • Demonstrate how to add a jar package with eclipse. First, introduce the beanutils package, and then introduce the logging package after an error occurs.
1 commons-beanutils-1.9.2-bin.zip http://u2l.info/3VN80n
2 commons-beanutils-1.9.2-src.zip http://u2l.info/3o99D3
3 commons-logging-1.1.3-bin.zip http://u2l.info/2D1d0m
4 commons-logging-1.1.3-src.zip http://u2l.info/nKLKp


Java. lang. NoClassDefFoundError: org/apache/commons/logging/LogFactory the jar package for logging is missing

This log package is used by many frameworks.

  • Based on the preceding example, use the BeanUtils class to get the previously set attribute and then set it to a new value.
    • The result returned by the get attribute is a string, and the set attribute can accept any type of objects. A string is usually used.

This is very suitable for the set object of the string passed by the browser.

  • Use the PropertyUtils class to first get the previously set attribute and then set it as a new value.
    • The result returned by the get attribute is the original type of the property, and the set attribute only accepts the original type of the property.

java bean

package com.itcast.day1;import java.util.Date;public class ReflectPoint {    private Date birthday=new Date();        private int x;    public int y;    public ReflectPoint(int x, int y) {        super();        this.x = x;        this.y = y;    }    @Override    public int hashCode() {        final int prime = 31;        int result = 1;        result = prime * result + x;        result = prime * result + y;        return result;    }    @Override    public boolean equals(Object obj) {        if (this == obj)            return true;        if (obj == null)            return false;        if (getClass() != obj.getClass())            return false;        ReflectPoint other = (ReflectPoint) obj;        if (x != other.x)            return false;        if (y != other.y)            return false;        return true;    }    public int getX() {        return x;    }    public void setX(int x) {        this.x = x;    }    public int getY() {        return y;    }    public void setY(int y) {        this.y = y;    }    public Date getBirthday() {        return birthday;    }    public void setBirthday(Date birthday) {        this.birthday = birthday;    }    @Override    public String toString() {        return "ReflectPoint [birthday=" + birthday + ", x=" + x + ", y=" + y                + "]";    }    }


Test class:

Package com. itcast. day2; import java. beans. beanInfo; import java. beans. introspectionException; import java. beans. introspector; import java. beans. propertyDescriptor; import java. lang. reflect. invocationTargetException; import java. lang. reflect. method; import java. util. hashMap; import java. util. map; import org. apache. commons. beanutils. beanUtils; import org. apache. commons. beanutils. propertyUtils; import com. itcast. day1.ReflectPoint; public class IntroSpectorTest {public static void main (String [] args) throws Exception {ReflectPoint rf1 = new ReflectPoint (3, 4); Object value = 6; System. out. println (BeanUtils. getProperty (rf1, "x "). getClass (). getName (); // x is an int, but the value set by beanutils is java. lang. string System. out. println (rf1.getX (); BeanUtils. setProperty (rf1, "x", 1); // BeanUtils of the original type.SetProperty(Rf1, "x", "2"); // supports the String type setting value System. out. println (rf1.getX (); BeanUtils. setProperty (rf1, "birthday. time "," 111 "); // supports attribute cascade operation System. out. println (BeanUtils.GetProperty(Rf1, "birthday. time"). getClass (). getName (); // java. lang. String 111 Map mm = BeanUtils.Describe(Rf1); // convert javabean to map System. out. println (rf1); // ReflectPoint [birthday = Thu Jan 01 08:00:00 GMT + 08:00 1970, x = 2, y = 4] Map map = new HashMap (); map. put ("x", 1); map. put ("y", 1); BeanUtils.Populate(Rf1, map); // converts a map to a javabean System. out. println (rf1); // ReflectPoint [birthday = Thu Jan 01 08:00:00 GMT + 08:00 1970, x = 1, y = 1] // PropertyUtils. setProperty (rf1, "x", "9"); // An error occurred while running! Because PropertyUtils only supports the original type, this is not as powerful as BeanUtils! PropertyUtils. setProperty (rf1, "x", 9); System. out. println (rf1.getX (); // 9 }}

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