JSON字符串转JavaBean，net.sf.ezmorph.bean.MorphDynaBean cannot be cast to ……

在json字符串转java bean时，一般的对象，可以直接转，如：一个学生类，属性有姓名、年龄等

public class Student implements java.io.Serializable{

/**
* @Fields serialVersionUID : TODO
*/
private static final long serialVersionUID = -1943961352036134112L;
private String sname;
private Integer age;
public String getSname() {
return sname;
}
public void setSname(String sname) {
this.sname = sname;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}

}

由字符串转java bean时可以使用以下方法：

JSONObject jobj = JSONObject.fromObject(str);
Student s = (Student) JSONObject.tobean(jobj，Student.class);

是没有问题的，但是如果属性中含有复杂的类型，当其中属性有类似List , Map ,ArrayList、自定义的类型，如List<Teacher> teachers, 就不可以了。 会报错：MorphDynaBean cannot be cast to con.test……

在JSONObject.toBean的时候如果转换的类中有集合,可以先定义Map<String, Class> classMap = new HashMap<String, Class>();在classMap中put你要转换的类中的集合名,像:classMap.put("teachers", Teacher.class);然后在toBean()的时候把参数加上, 像:Student student=(Student) JSONObject.toBean(str, Student.class, classMap);

比如我定义了如下类型：

import java.util.List;
/**
*
* <P>Tiltle: AnalysisModel.java </P>
* <P>Description:模型类  </P>
* @author biyutong
* @date Jun 11, 2012 9:37:54 AM
* @version:V1.0
*/
public class AnalysisModel implements java.io.Serializable{

/**
* 固定条件
*/
private List<Condition> regularCondtionList;//
/**
* 动态条件
*/
private List<ConditionField> dynamicConFieldList;
/**
* 结果
*/
private List<ResultField> resultField;
/**
* 获取前多少条数据
*/
private Integer topnum;
/**
* 顺序还是随机
*/
private String sortFlag;
/**
* 备注
*/
private String remark;
/**
* 模型名称
*/
private String modelName;
/**
* 对应的xml文件名称
*/
private String fileName;
public List<Condition> getRegularCondtionList() {
return regularCondtionList;
}
public void setRegularCondtionList(List<Condition> regularCondtionList) {
this.regularCondtionList = regularCondtionList;
}
public List<ConditionField> getDynamicConFieldList() {
return dynamicConFieldList;
}
public void setDynamicConFieldList(List<ConditionField> dynamicConFieldList) {
this.dynamicConFieldList = dynamicConFieldList;
}
public Integer getTopnum() {
return topnum;
}
public void setTopnum(Integer topnum) {
this.topnum = topnum;
}
public String getSortFlag() {
return sortFlag;
}
public void setSortFlag(String sortFlag) {
this.sortFlag = sortFlag;
}
public String getRemark() {
return remark;
}
public void setRemark(String remark) {
this.remark = remark;
}

public String getModelName() {
return modelName;
}
public void setModelName(String modelName) {
this.modelName = modelName;
}
public List<ResultField> getResultField() {
return resultField;
}
public void setResultField(List<ResultField> resultField) {
this.resultField = resultField;
}
public String getFileName() {
return fileName;
}
public void setFileName(String fileName) {
this.fileName = fileName;
}

}

在转化的时候需要这样来写：

Map<String, Class> classMap = new HashMap<String, Class>();

classMap.put("regularCondtionList", Condition.class);

classMap.put("dynamicConFieldList", ConditionField.class);

classMap.put("resultField", ResultField.class);

AnalysisModel analysisModel=(AnalysisModel) JSONObject.toBean(str, AnalysisModel.class, classMap);

from: http://biyutong.iteye.com/blog/1566708